Downstream o2 sensor reading 0 volts. 24v, drops when the revs are increased.

There will be fluctuations or toggles that occurs several times a second. 0. It's constantly reporting 0. Mar 31, 2021 · After driving on the highway, my downstream O2 sensor voltage was a steady 0. Downstream o2 fluctuates slowly, from about 0. 3 Turn Ignition Off. Apr 19, 2022 · When I check under O2 sensor data in the app I can choose "O2 Sensor1 Wide Range Current" or "O2 Sensor1 Wide Range Equivalence Ratio (Lambda)". 45 volts or higher. If it is now at about a half a volt then replace the o2 sensor. 47 of about 0. Ever after the motor was replaced I was told the car smoked for a good hour before the coolant cleared out of the system. Jun 23, 2021 · Again, determine which bank is which first or you’ll waste a lot of time and effort. 9 volts signals a Feb 1, 2013 · If the downstream O2 sensor activity mirrors the upstream O2 sensor, the converter is dead and needs to be replaced. MODE 06 CATALYST CHECKS Mar 28, 2020 · About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Jan 1, 2020 · The cat absorbs any excess O2, HC and CO and then processes that into H2O and CO2. 900. Figuring one of the new sensors was bad, I swapped the leads around just to be sure however #2 still showed as bad. Aug 24, 2016 · 2011+ Engine Related Questions - O2 Sensor Voltage Question - I have been suspecting a Catalytic Converter issue slowly developing over the last 10,000 miles. To verify the wiring, I plugged the B1S2 harness into the B2S2 o2 sensor and it worked plugged into the other side of the car. 9 volts for a healthy sensor, 0 volts for a lean air-to-fuel ratio, and 1 volt or higher for a rich mixture. When their is a lean condition, the voltage drops, when there is a rich condition, the voltage increases. General consensus seems to favor the OEM front sensor over the aftermarket brands. 8 Volts. If its slow or steady the sensor is faulty, this only goes for primary sensors (sensor 1). The downstream o2 sensor reads lean 0. 0. 9V, but they often don't get even close to that, even when the sensor voltage actually is switching over that range. Dan Ferrell (author) on September 07, 2019: You can visually inspect the sensor out of the car. As the mixture becomes rich, the voltage will Jul 26, 2023 · Project is correct. 800V My reading for Bank 1 sensor 1 (Wide Range O2) Equivalence Ratio is 1 and not changing. 20 to 0. The oxygen (O2) sensor functions as a small voltage generator. An idling engine with good fuel trim and a working catalytic converter and rear oxygen sensor will give you a steady voltage feedback of . I have a 1990, and the previous owner told me that , he was getting 0 volts from the 02 Bank 1 upstream. When it goes to . In essence, the upstream reading should have spikes. Usually you get a sense of their performance by watching live data graph. If there is no change this confirms that the sensor is not reading correctly. Jul 7, 2022 · Advertisement Although theoretically the O2 sensor should cycle between 0. 7 ish. 6-0. For example, on a cold start Bank1, watching sensor voltage with INPA, it starts out at ~0. That is why it isn't moving. 01 and 0. 850 fluctuations every couple of seconds from the low end to the high end and everything in between. Nov 3, 2023 · A downstream O2 sensor, also known as the Bank 1 Sensor 2, unlike the upstream O2 sensor, the primary purpose of the downstream O2 sensor is to monitor the effectiveness of the catalytic converter in reducing harmful emissions. 3 Jan 16, 2024 · Common O2 sensor voltage readings include 0. Sometimes the sensor with show 0. What are the Upstream and Downstream O2 Sensor Readings? An important thing you must know about both the sensors is their readings. If during the next ignition start the voltage is STILL below . 7 volts. voltage drop to 0V is not normal, it shouldn't say 0. 8 Downstream:0. Sep 25, 2023 · The upstream O2 sensor is found before the catalytic converter, while the downstream O2 sensor is located after the catalytic converter. There are no CEL/MILs . It is my understanding that the upstream (red) o2 sensor should vary (it does) but the downstream should stay constant (it does not). Changed downstream o2 If you are using a scan tool to watch or monitor the oxygen sensor voltage, the Dec 6, 2017 · The downstream sensor has the same voltage as the other sensor before I start the truck, but once I start the truck the sensor loses most of its voltage within a minute or so. 4V however #1 varies continuously between 0. Can anyone explain is these readings are correct. When the air/fuel mixture is balanced or at the equilibrium point of about 14. I have my old manifold/Cat from when it got a crack in it a few years ago. 9V when heated while immediately going back to 0V as I removed the flame. After I idled the engine for a few minutes to warm it up, the multimeter shows a steady voltage of 0. The downstream O2 ranges between 0. O2 sensors play a crucial role in monitoring the oxygen levels in the exhaust gases and provide voltage readings to the engine control unit (ECU). 3V. Jun 6, 2024 · Correct me if I'm wrong, but from what I gather, the higher the voltage on an O2 sensor, the richer the engine is running. Apr 11, 2020 · Just carried out scan on the O2 sensors. 02-0. 3 V O2 voltage wide range Bank 2 Sensor 1 3. All O2 sensors are vented to the atmosphere which contains Approximately 21% oxygen. May 16, 2013 · The book says the O2 sensors should be reading 200-800mV. 1 - 0. 1 once the vehicle enters closed loop. 45V and Oct 9, 2020 · I think the white will be the neg of the sensor and the blue will be the sig line. -Voltage readings were taken after car was running (idle) for about 20 minutes. 62 V O2 voltage Bank 2 Sensor 2 0. Instead the changes in voltage will be pretty smooth. 0 to a lambda of 1. 9 volts; however, erratic or inconsistent voltage readings can signal an array of potential issues that may compromise the vehicle’s fuel efficiency and emissions output. Feb 13, 2020 · Our PCM constantly (and very rapidly) adjusts injector pulse width longer (+ fuel trim) to richen fuel mixture - and reads O2 voltage. tke0398 The rear (o2b1s2)02 sensor need to be (A) fully warmed and (B) engine ran at 2000 rpm to be properly checked. 2006 Super Black Xterra S, Original Owner. No codes yet but with the upstream O2 sensor reading that high, I'm assuming that it's only a matter of time before a code shows up. On the other hand, when idling before the drive, it was a steady 0. Exhaust Leaks: Leaks in the exhaust system can cause air to enter the system, leading to high voltage readings from the O2 sensor. 9 volts like the upstream sensor. 9 on the scanner, I thought it was supposed to be 0. 30 F Feb 21, 2024 · The voltage readings from your O2 sensor should fluctuate rapidly between 0. O2 voltage Bank 1 Sensor 2 0. 5 to 13. An easier 'observation' is if the voltage output tends to follow the front sensor action, the CAT is degraded. Should the downstream O2 sensor fluctuate? Your upstream sensor shouldRead More → Apr 19, 2012 · (Assuming same heater for the upstream O2 sensor) Possible DTCs P0135 - Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 1) or P0141 - Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2) * Heater current is less than 0. 24 Jan 10, 2023 · The voltage produced by the upstream O2 sensor or front o2 sensor varies from 0. 700-. If you have proper voltage there then you can move on to other things. 1V and 0. 25V to . If you can't do this easily, try just raising fuel pressure as a temporary test. 12%, HC: 64 ppm, RPM: 0. 5V reference. Jun 16, 2018 · What would cause downstream o2 sensor voltage to be low, other than o2 sensor itself is bad? I understand that if the upstream o2 sensor voltage is high or low, it could possibly mean that the o2 sensor itself is good and the combustion got a problem. A standard oxygen sensor measures neither oxygen nor fuel content in exhaust gasses. 7 and 2. Suggestions? The PID I'm reading is O2S11(V). 4V. And check the downstream sensor voltage (02B1S2(V) 0. 44V. 1 and 0. Get the voltage component testing O2 specs to confirm too! May 30, 2006 · Once the converter lights off, the downstream O2 sensor will settle down and “flat-line” at a steady voltage reading usually around 0. Jun 13, 2012 · IF the downstream heated O2 sensor falls below . Watching them with my scanner, they seam to mimic each other. 1 V at idle and when driving the car it read 0. The downstream one was erratic and jumping all over the place, but had voltage going to it at least. The voltage then drops to 0 or under 0. Oct 16, 2020 · The downstream oxygen sensors are there to monitor the catalytic converters and for making Long Term Fuel Trim corrections. Jun 5, 2017 · Joined: Nov 4, 2014 Member: #141714 Messages: 2,392 Gender: Male First Name: Joe Columbus Grove, Ohio Vehicle: 2003 Tacoma, V6, 5 speed, 4x4. i. 0 volt. The upstream O2 sensor helps identify the vehicle’s fuel trim, which helps the engine computer calculate the ideal air-fuel ratio. It looks like your cats are bad, the post cat sensors are all over the place and they should be mostly steady when in closed loop. 6V) and stays there forever (it should be oscilating rapidly between less than 0. May 4, 2017 · When the mixture is lean, the sensor's output voltage will drop down to about 0. Allow the engine to idle. Use O2 socket and ratchet to tighten into place. Apr 16, 2021 · Does anyone know what the voltage readings should be between the upstream and downstream O2 sensors. If the heater is working and you have a solid ground and it doesn't send a signal to the PCM, I'd say you have a faulty O2 sensor. 83. This is the one to determine fueling. Apr 14, 2015 · • An O2 sensor with a high voltage reading does not necessarily mean that the mixture is rich or high in fuel content. Jan 1, 2023 · There are several factors that can affect the accuracy of an O2 sensor test. Check and compare both sides. From your reading I'd say the sensor is fine. 15%, HC: 71 ppm, λ: 0. An accurate diagnosis is contingent on Next Generation Controllers (NGC) provides a bias voltage of 2. It never changed. if you cut the o2 sensor from the plug, and connect the white wire to the neg of the AAA battery, and the blue to the Pos end of the battery. O2 sensor 1/1 is the upstream sensor on Bank 1 (different for a Ford than for a Chevy or a Dodge), and O2 sensor 1/2 is the downstream sensor on Bank 1. 90 volts indicates low oxygen levels. Nov 28, 2023 · For downstream sensors, common DTCs include “P0140 – O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)” and “P0141 – O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)”. After the engine (and I assume the exhaust system as well) had warmed up fully, the B2S2 came back up to like 646 mV. 5 V (low voltage) to more than 0. 21 volts for more then 2 minutes a "pending" code P0137 will set. this sensor usually trips P0420 code if it works bad (could be also a bad cat converter too if sensor is OK). 32V All sensors measure about 10-ohms cold, and about 16. it will be 1. May 30, 2006 · Once the converter lights off, the downstream O2 sensor will settle down and “flat-line” at a steady voltage reading usually around 0. On V6 and V8 applications with dual cat exhausts, you'll have upstream O2 sensor readings for each side of the engine and downstream O2 sensor readings for each converter. Start engine. There is also an obvious smell of unburned exhaust. That's interesting. First I tested the O2 sensor using a multimeter and a butane torch. About 3 months ago I got a P0157 code which is low voltage for Bank 2 Sensor 2, cleared it and it didn't come back until a week ago. 9 volts oscillating quickly back and forth roughly once every second. 9 volts or more when heated shows 0. High rpm about 0. Aug 23, 2018 · High O2 sensor voltage indicates very rich mixture or a wiring problem. 2. At idle that voltage should read 0. The downstream O2 will stay fairly steady and float between 350 to 650mV. WHY; the Cat is not cleaning the exhaust down to a stable level of Oxygen content below a limit set in program. Apr 28, 2008 · Once the sensor is hot, a zirconia-type O2 sensor will generate a voltage signal that can range from a few tenths of a volt up to almost a full volt. It’s worth noting that the voltage output and frequency can vary depending on the specific vehicle’s make, model, and engine configuration. 500v is considered stoichmetric (the proper amount of fuel). 0 Coilovers in the front and Fox 2. 2 to . 6X5 = 3 volts? Elsewhere I have read that the normalized voltage reading should vary between 0 and 1. For this test you will need a Jun 3, 2012 · As simple as that. When there is little unburned oxygen in the exhaust, the sensor usually generates 0. A/f sensor reading 2. . The O2 sensor is an O2 concentration sensitive variable voltage generator. 995 to 1. A properly functioning oxygen sensor will show a rapidly fluctuating output voltage between approximately 0. 750 but when the throttle is snapped or even slightly increase the o2 instantly drops to below . 1 to 0. Dec 17, 2013 · The last wire, #4, is a signal feed wire, 0-1 volts, from the O2 sensor to the PCM (ECU) sensor. 9-1. So, if your mileage is great - 100K+ - you might take a hard look at the front O2 sensor. The downstream tests fine at 5. Dec 5, 2017 · The 3. We also throw P0420 (Catalyst below threshold) occasionally. 07mA reading on the Feb 29, 2016 · Hmm. … But, the rear or after-cat O2 sensor is still the same old fashioned O2 sensor. 00 volts, in reality it cycles between 0. Aug 28, 2016 · Now O2 sensor Sensor 2 is a sin wave from 0. 5v. It will read very rich almost all the time in around the 0. 24v even when driving the car for 30 minutes. After some time (2mins, still no moving car) the downstream and upstream oscillates the exact same way. 0 volts. Check to see if the O2 sensor responds correctly to rich and lean fuel conditions. 2v is a normal "stoichiometric" reading. 90 volts. 275 constantly. In this step, you should take note of how quickly the O2 sensor voltage fluctuates from less than 0. Always thought the downstream should kinda level out after closed loop but it definitely does not. Secondary sensors (sensor 2) on the other hand should have a constant reading, they just monitor the catalytic converter. Is it normal for the downstream O2 sensor voltage to be so high after driving? Does this mean I have a bad catalytic converter, or is there another explanation? Oct 2, 2020 · The pre-cat O2 sensors will periodically simultaneously go from reading a normal lambda of around 1. I was up to the challenge and replaced all 4 of them with Denso models. You test the voltage both ways. 8 volts or slightly greater. My air-fuel sensor is reading around 3. A reading closer to 0. If the voltage readings remain steady or do not fluctuate enough, it could indicate a faulty sensor. 100 to 0. "O2 Sensor1 voltage" and "O2 Sensor1 Wide Range Voltage" are both grayed out and show as "No data received". 7 to 1, the sensor will read around 0. 9 V according to the discharge emission. 6 volts and straight line at idle and near 0 volts and Jul 13, 2020 · The upstream o2 sensors (B1S1 and B2S1) change voltage rapidly as they sense the changing fuel mixture, cheap scanners often do not have a fast enough refresh rate to see this fluctuation so you'll just get a dead reading. 4 and 0. From this understanding and looking at the downstream sensors on both banks, I'm inclined to think my engine is running rich on idle (about 0. I'd take the reading as close to the sensor as possible to rule out wire breakage. The downstream o2 sensor (B1S2) stays at a fairly constant voltage since it is just reading exhaust post catalytic Feb 19, 2018 · Make sure the upstream O2 sensor voltage (this parameter from your original list 02B1S1(V) 0. An o2 sensor (not Wideband o2) cannot accurately measure HOW rich or HOW lean the exhaust is. 02 Sensor. Comes on and off every 10-15 drives. Actual sensor voltage output range is about 1 V. It is an oscillating sine wave, an O2 sensor. These readings, with the swings up and down from . This indicates a serious lean condition [per the viewpoint of the pcm] . Jan 6, 2023 · Low upstream O2 sensor voltage: Lack of power, Vehicle running rough, Exhaust odor, asymptomatic sometimes : P0131: High upstream O2 sensor voltage: Vehicle running rough, Lower fuel economy: P0132: Downstream O2 sensor circuit malfunction: Decrease in MPG, Increased tailpipe emissions, asymptomatic sometimes: P0136: Low downstream O2 sensor May 29, 2013 · The upstream O2 sensor was replaced right after the rebuild by the guys who did it, and the downstream O2 sensor is also fairly new. Quality Of The O2 Sensor: Not all O2 sensors are created equal. 0v. In the idle, rear voltage (downstream) is a flat line whereas the front voltage (upstream) oscillates slowly. Sensor 2, being behind the catalytic converter, should give steadier readings. I have a P0432 for inefficient catalyst downstream. Jul 4, 2014 · The front bank exhaust manifold with the cat built into it has been replaced (rpms are back as well, see above), I took it out for a drive and noticed that whether at idle or cruising at 60 mph, both down stream 02’s are reading rich around . 45V, as they typically have a 0. This is a GENERIC code for ALL OBDII systems. 785) is fairly steady around 0. I was looking at what I believe to be the rear sensor and it was basically rock steady at 740-760mV. Mar 13, 2012 · downstream sensor output is alternating voltage from near 0V up to 1V based on readings where generally below 0. That would be in milliamps. 5 volts. 25A (at 0. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. The downstream shows readings between 0. Post cat sensor (O2S12(V)) is supposed to stay steady according to everything I've read about o2 sensors so far, but it doesn't do that. LTFT was at 1. Unless, there is a relay involved. Downstream sensors drob from 0. 100v at idle and at decel (when fuel cuts off). In WJs, the PCM using the downstream signal tries to correct the lean mixture condition indication. If the downstream O2 sensor detects a high level of oxygen in the exhaust gases, it can indicate that the catalytic converter is not working properly and needs to be replaced. The most important sensors are usually the Sensor 1 and Sensor 2. 2 to 0. How The O2 Sensor Works: The O2 sensor can be considered a small battery that has an operating range of 0 to 1 volt when fully warmed up to 600°F. 0 volts for a couple seconds then will suddenly jump back up into normal range. 8 volts. Apr 10, 2012 · Yes they operate between a wider range and do not fluctuate like traditional oxygen sensors therefore are wayyyyy more accurate as they give actual a/f readings versus constantly changing readings like an O2 sensor. 99 indicating a wildly lean air/fuel ratio. Feb 21, 2024 · Wiring Issues: If the wiring to the O2 sensor is damaged or corroded, it can cause high voltage readings. 04 volts after they became Jul 13, 2020 · The downstream O2 at idle won't give reliable readings. 5 V to sensor. This exhaust stream then passes by the downstream O2 and out the tailpipe. The A/F heater circuit is 4 ohms, specs say around 2 ohms. 05V (yes, 0. Only a factory mode scanner (something higher end) will be able to read direct voltage, or using an oscilloscope. 1 volt indicates a lean mixture while a voltage reading of 0. After warming the car up to op temp, the front O2 sensor reads 0. Other than a fuel leak I have no idea why the gas mileage is bad, and no idea why it's running so lean without the computer adjusting the fuel trims to compensate. May 13, 2019 · Downstream O2 sensor voltage drops durring acceleration Normal? 2. the fault stayed with #2 regardless of which sensor was plugged in. If it moves replace the sensor. then turn the key on and read the o2 sensor voltage of the B1S2 sensor. Oct 1, 2022 · I just bought a 2002 4wd Ltd Sequoia, and the seller told me that he hadn't had it inspected/registered in a while due to needing new O2 sensors installed. To verify the o2 sensor works, I switched the two downstream sensors. tape them in place. What Can Trigger The P0138 Code? The sensor voltage being too May 21, 2023 · Several factors can influence the O2 sensor voltage range and its fluctuations, including: Engine Load and Throttle Position: During wide-open throttle (WOT) conditions, the ECU may allow the fuel mixture to run slightly rich, resulting in a higher O2 sensor voltage, typically around 800 millivolts (0. 42 V Another question I have is the Catalyst temperature Bank 1 Sensor 1 1436. I don't hear any exhaust leaks from what I can tell. I put my scan tool on it and at idle [if it stays running] the upstream o2 sensors are returning values of 0. Mar 31, 2016 · You guys have the o2 sensor backwards. Look for signs of trouble like gray, black, white or red The less air in the exhaust gas (after passing the cats), the higher the downstream O2 sensor’s output voltage. Displayed is the desired sensor output with the voltage bias filtered out. 26V Downstream Rear: 0. 98 volts in theory. 3 second after heater is turned ON) * When the heater operates, heater current exceeds 2A P0130 2012 2500 6. Jul 12, 2019 · But the downstream O2 sensor is not moving. May 5, 2017 · It osculates its current usually between -. 9ish because it is running rich. When it comes to analyzing O2 sensor voltage readings, it’s essential to understand the different voltage patterns that can indicate the performance of the engine. . It is also known as the "broadband lambda sensor" or "lambda probe. In my "professional" experience, when the downstream sensors go above 0. Within a few seconds, it starts switching between ~0. Sep 18, 2023 · Monitor Voltage — Using a multimeter or scan tool, monitor the voltage output of O2 Sensor Bank 1, Sensor 2. May 31, 2023 · Look at your PID list and you will see another voltage feedback from the O2 sensor that will be under one bolt with the engine running. Dec 4, 2023 · A properly functioning O2 sensor should display a voltage that oscillates between approximately 0. 1V and ~0. 685-. Now, my Oct 3, 2020 · I have a P0420 code and am trying to determine if my downstream O2 sensor is working properly. Sensors are new, but you can swap the precat sensors to see if the code moves to the other bank. These readings can help diagnose fuel system problems and emission issues. Just do something to get more fuel into the engine and see if the O2 sensor starts to respond or not. Jan 5, 2022 · Upstream Front: ≈ 0. It might also be called 'front O2 sensor'. It will stay relatively steady as long as the mixture does not change rapidly. Check for harness making contact with exhaust components. Bought a code reader and watched the live data on the O2 sensors. The ECM uses this signal as one of its main inputs to regulate the air-fuel mixture and emissions. My downstream O2 sensor is reading a constant 0. Jan 21, 2023 · The downstream O2 ranges between 0. Do I have a wideband sensor perhaps? FOr example, on the new sensor, I got a real time reading of 14. I replaced the upstream O2 sensor but this did not fix the issue--it is still a flat line reading. Now the O2 sensor (B1S2) may be giving a lower reading. 45v when the catalytic converter is functioning properly. Depending on how much oxygen is in the exhaust, it does this. 9 V fluctuating, while the rear O2 sensor reads 0. 12v is 12v, and it isn't going to get there another way. Nov 30, 2004 · Any ideas? FWIW, I didn't think to check the AFR readings with the old sensor. 8 volts on your meter. Also they are used for cat mon, heating and oxygen storage capacity. 5-ohms hot. 2 litre 06 Chevrolet/220,000 miles, has had a P0420 code come and go twice in the last few weeks. An average signal close to 0. 45 volts. Dec 30, 2013 · This is a tricky call, because the front O2 sensor has a lot to do with the smooth running of the engine. That is why it is not oscillating between 0 and 1 V. Try richening your injector compensation and see if you can get the O2 sensor to move. The readings are Upstream: 0. 8 volts) with an air-fuel ratio of approximately 12. A steady voltage reading could mean that the sensor is stuck in one position, while a lack of fluctuation could mean that the sensor is not receiving Aug 8, 2015 · with that said the front O2 sensor is the main sensor the engine uses, the rear more or less serves as a secondary check. 47 volts with oscillations above and below 0. May 4, 2014 · From what someone has told me the upstream o2 sensor is a "wideband" sensor and the 2 volt reading is normal. Just got a P0420 trouble code on my 2014 Chevy Cruze. Is the O2 voltage above 1. May 5, 2018 · O2 B1S2 is reading 0. Sep 10, 2014 · A low reading could indicate a vacuum leak or possibly a leaking EGR valve. 00 volts and 1. Often at the same time the Bank 1 post-cat O2 sensor reads at 0. Downstream is Sensor 2, located after the catalytic converter. 035 or so volts but nothing compared to the same sensor on bank 1 which is . EDIT: This o2 sensor also gives a current output measurement, that goes slightly above and below 0. If, after supplying a ground to the unplugged PCM side of the o2 sensor connector, the voltage reading doesn't change then check the harness for short to ground. 9 volts. Is this normal? No codes shown on my Ultragauge. 6 - 0. Engine also runs rough with accelerator pushed from idle. 991:1 AFR, with a 0. New data. 9 volts, with a frequency of around 1-2 Hz (Hertz). The problem didn't move with the sensor. The upstream O2 sensor needs to be replaced. 2 V O2 voltage wide range Bank 1 Sensor 1 3. 56% also. Nov 21, 2014 · When the bulb of the O2 sensor is exposed to hot exhaust, the difference in oxygen levels across the bulb creates a low voltage somewhere between 0. Then the voltage for bank 2 sensors seems to flip flop; upstream flips from high to low, and the downstream goes from low to high. If it's reading 0, then there is no burnt fumes in the pipe. Trying to diagnose the issue going using O2 sensor readings is difficult. DocGonzo74, did you ever resolve the O2 sensor voltage reading? Thanks, Dave Jan 13, 2024 · Analyzing O2 Sensor Voltage Readings. 1v or below and sit there. It should fluctuate between approximately 0. 10 volts and 0. Mar 9, 2011 · A conventional O2 sensor will produce either a rich reading (0. 845v range give or take a little but then if you just let it sit it will drop down to 0. Can upstream O2 sensor stuck at 0 volts cause rough engine performance? Fuel mixture incorrect, etc. Aug 31, 2021 · Any O2 sensor that will generate 0. 9. 026 Volts. The rear O2 sensor is not nearly so critical. On idle or while cruising at a constant speed, this should be around 0. This should change the voltage reading to one extreme or the other for the sensor. When it's not, it sets the P0420 code for Catalyst Efficiency below Threshold. 5v stable. 18 F Bank 2 Sensor 1 1436. This will calibrate your evaluation skills and save you money in the Aug 11, 2015 · Step 6 – Replace O2 sensor. It will read an accurate mixture, usually, but not necessarily, a voltage of 0. 550V at the least but usually ~80% of the highest pre cat O2 reading, when cruising down the highway. If the signal from the downstream O2 sensor continues to mirror that from the upstream oxygen sensor(s), it means converter efficiency has dropped off and the converter isn’t cleaning up the Jun 1, 2011 · The upstream sensor signal indicates a lean mixture. The timing of the rough idle exactly coincided with Voltage on 02 Bank 2 Sensor 2 dropping to 0. 8 volts) or a lean reading (0. 80V and stay above that voltage the PCM will set a corresponding DTC for catalyst efficiency. 1 and 1. Feb 25, 2017 · O2 sensor was last replaced 5 years/~78,000 miles ago, Trying to eliminate weak O2 sensor as the cause for a 20% drop in fuel mileage. Nov 26, 2018 · The pre-O2 sensor different than the post-O2, or at at least the ECU is looking for different readings to make sure the cat is doing it's job. Because the catalytic converter already processed the exhaust gas, the oxygen level is stable. 1-0. Disconnect the O2S connector. Dec 5, 2023 · When faced with the diagnostic dilemma of a O2 sensor voltage high reading, one of the initial steps in troubleshooting is to inspect the oxygen sensor’s wiring and connectors for signs of damage or corrosion, which could lead to improper voltage signals being sent to the engine’s control unit. My Right O2 sensor reads 0. 0’s in the rear, Total Chaos UCA’s, Al-lpro expo leafs, K&N cold air intake, TRD headers,Magnaflow catback exhaust,URD short throw shifter, switched out my 60/40 bench seat for some Tacoma Limited seats Oct 7, 2023 · How To Know If The Downstream Oxygen Sensor Is Bad. If you are reading 0 volts there is a short to ground somewhere. 2 volts) when the fuel mixture changes. Feb 2, 2011 · Sorry but that is incorrect. The performance of the O2 sensors can be measured using a scan tool, a DVOM or a ­labscope. Aug 12, 2021 · If you’re dealing with an O2 sensor situation and you believe the sensor might need replacing, you can watch the sensor on the scan tool data screen with the throttle at about 1200 rpm and you should see about three switches from rich to lean per second, with the voltage range being at least from 0. Sensor Lifespan The lifespan of an O2 sensor can vary depending on various factors, such as driving conditions, fuel quality, and maintenance practices. yours almost flat lines on RICH side (above 0. trying to determine if O2 sensor is weak, but not weak enough to trip a fault code. Jun 24, 2019 · Disconnect the O2 sensor harness connector. I thought it was normal for the downstream 02 sensor to oscillate between 0. These include: Age And Condition Of The O2 Sensor: As the O2 sensor ages, it can become less accurate and may need to be replaced. When the cat fails, the post-O2 sensor readings will mimic the pre-O2, setting the code. But my downstream sensor reads all over the place from 0. 45V. 1 volts. If the sensor’s reading is stalled in position, or switches abnormally high or low, your sensor has failed. What I have noticed is a bit puzzling. I still have the same problem. Mar 28, 2018 · What I see is that the commanded EGR went to 0% for about a minute, then three things happened simultaneously as the check engine light turned on: The voltage for 02 Bank 2 Sensor 2 went to 0 AND the rough idle started. 2 volts? All Yes ® Go To 3 No ® Replace the Oxygen Sensor. May 5, 2014 · Dug a little deeper and discovered that Pre-cat O2 sensor #2 has a constant voltage output of 0. 5 V (high voltage). 1 volts the upstream O2 is indicating presence of Oxygen in exhaust - SO, PCM reverses the process and shortens each injector pulse width (-fuel trim) until it sees the O2 voltage go High again. Perhaps why I have P0030 Code - left one seems bad. From what I’ve researched, downstream o2 sensors can still vary between 0 and 1 volts but will not oscillate rapidly. Jan 16, 2023 · Upstream O2 sensor fluctuates up and down between 2. There is a slight possibility of a minor exhaust leak 12 Idle: CO 0. 8 to 0. Jul 14, 2020 · After I fixed that issue by myself the O2 reading were similar to the other O2 sensor (Bank 1) but I would still get the P0430 code. 4 ohms plus or minus and the upstream is barely registering and once it read . The freeze frame data shows that the B1S2 oxygen sensor reads 0 volts. Dec 22, 2023 · One standard reading from an O2 sensor is a voltage signal that oscillates between approximately 0. 1 volts or less within one second of flame removal and pass the two-minute heat test is good regardless of age. e. Dec 11, 2007 · The sensor's voltage reading should also be fairly steady (not changing up or down), and average 0. Dec 22, 2002 · I was reading the Chiltons' Manual and I 'm having the same problem, except I have a a 4 wire bosch 02 Sensor. While the engine is still running, test the downstream oxygen sensor with a multimeter and note the voltage reading. 25 volts is normal. Using a high-quality O2sensor can help ensure accurate test results. The downstream O2 sensors are traditional style and should still operate between . Perform Powertrain Verification Test VER-5A. 9v? The upstream sits a max 1. Jul 12, 2017 · Typically, with a warmed up engine at idle that is running properly, both the pre-cat and post-cat sensor signals would be steady, with the post cat sensors indicating something in the range of 0. Both upstream o2 sensors stay around 3-4v consistently, with virtually identical readings at any given time. 8V Upstream Rear: ≈ 0. 8V Downstream Front: 0. B1S1 O2 sensor reads 1. 45 volts or so. 4 at idle and it doesn’t really get to crazy but the downstream O2 sensor just seems funny to me. I did a longer drive and it appears the rear o2 sensor is posting a reading, but it is very erratic. 700 to 0. Jul 6, 2023 · So, here are the details about Normal O2 Sensor Voltage At Idle. 7 V. If the upstream O2 sensor voltages appear normal (cycling) and the downstream voltage is tracking the Dec 20, 2015 · Well I drove it a bunch today and sure enough same thing. 4V are lean and above 0. 5 volts or higher. It appears I didn't record the o2 sensors long enough. Downstream O2 voltage averages about 0. A comparison between new and old O2 sensor. I'm testing the O2 sensors with my digital multimeter. 2 and 0. 9 volts when the vehicle is running at a steady state. Sep 27, 2014 · Classic p0420 code. I just replaced this sensor a month ago. The air fuel sensor operates in the 0-5v range, rarely going above 3. The reading for what I believe to be the front sensor was all over the place - near 0 to near 800mV and constantly changing so fast I couldn't really read the numbers. It generates a voltage between 0. Looks good to me. It should stay above 0. 10 volts indicates high oxygen levels, whereas 0. Any wideband sensor like this will always operate within . Feb 5, 2020 · O2 sensor 1 pinned at 0 volts. 08 and +. Replacement is reverse of removal: Position O2 sensor, thread into hole, and tighten by hand until you cannot tighten it further. 800V. 6 -. Therefore, a normal working downstream O2 sensor stays around 0. May 25, 2001 · If the O2 sensor is reading 0, then there is no power being made. So I wonder why the 2x1 sensor fluctuates as high as 1. My Left O2 Sensor reads 0. When the O2 sensor goes bad, it causes improper air-to-fuel mixture in the combustion chambers which can cause the engine to shake, these vibrations can be felt in the cabin of the vehicle when driving. 21V for more then 2 minutes, the CEL will set P0137 "low voltage B1S2". 6 volts, does that mean the actual voltage is 0. It is also commonly referred to as a post-cat O2 sensor or rear O2 sensor. 45 volts to 0. 3v Can a bad cat make the second O2 sensor read a larger voltage? A quick way to check for this is to monitor the voltage of the sensor with a scan tool and either introduce a vacuum leak or an extra fuel source to the vehicle. Step 3: Test the downstream oxygen sensor. is that the right one for the Pre-cat o2? I'm reading that as Oxygen Sensor Bank 1 Sensor 1 Voltage. O2 sensor 2 seems ok. Mar 30, 2021 · To test the upstream O2 sensor on a 2011 Toyota Corolla, I backprobed it with a multimeter. 5 V. I've measured the O2 voltages. Jun 10, 2010 · Rear 02 sensors are used for trim and fuel adaptations in close loop, fueling. A good downstream O2 sensor should read around 0. 0 volts, but a multimeter test shows hearting and voltage is working with revs, power from car is . 10 – 0. May 9, 2014 · So if Bank 2, sensor 1 is showing 0. 8V, which is high. Feb 6, 2022 · I'm having an issue with my downstream bank 2 sensor and figured this might be the best place to ask as I have the URD equal length headers and their o2 sim. It is not the actual output reading. Do some research on this and you will find video tutorials. 200V to 0. The downstream o2 is picking up that the cat isn't functioning properly. If you poke aroung the GNType site there is an excel spreadsheet that has all the information, and original values, for all the calibration data. 6V are rich (or something similar, it varies a bit between models). 5 V), it indicates that there would be a rich exhaust code set. 18 F Bank 1 Sensor 2 1253. Voltage levels with the engine running will fluctuate around 2. Secondly, by using a voltmeter with the scale set to 1 volt, the voltage will fluctuate between 200 and 800 millivolts or . , therefore it begins to react and mimic the front sensor to the same exhaust gas passing it. 015. 1-1. And even saw it read as high as 3. 9V, so it looks like something is wrong. Monitior the 02 sensor voltage on the DRB. After coolant has reached 87/88°C, at idle (~700 rpm), O2 sensor voltage is 700-800 millivolts. 1-. No codes yet but with the upstream O2 sensor reading that high for at least over a week, I’m assuming that it’s only a matter of time before a code shows up. Mar 28, 2017 · 1. As this happens, the upstream O2 switches and outputs a varying voltage between 100 and 900mV. Sep 8, 2023 · The typical voltage output range for a properly functioning downstream O2 sensor is between 0. You will have NO CEL at this time. HOWEVER, the downstream, although new, did endure a lot of coolant when the motor blew. (Front = by radiator) (Rear = by windshield) Thanks! Dec 26, 2020 · In doing a live data run looking at my upstream O2 sensor readings for the P0442 thread, I noticed when my engine was warming up, the Bank 2 Sensor 2 reading was stuck down low like 165 mV, while B1S2 was sitting up around 750 mV. With Hose off at EGR 0. Check the wiring for any signs of damage or wear and replace as necessary. Fox 2. 9 volts as the engine runs. 4 days ago · The standard operating condition of an O2 sensor will range from 0. I thought that should be sitting around 0. 595) is cycling between about 0. There are 2 read outs, one will be 5 volts and the other is either 0 or 1, I don't remember. For the downstream sensor, I only have "O2 Sensor2 voltage" available. Featured Video: How to Remove/Replace O2 Sensor Apr 29, 2020 · The 02s1b1/2 is an air fuel sensor, not an o2 sensor. Its voltage depends on the amount of oxygen in the exhaust stream. Long Term Fuel Trims at around 10-15% 3. If the signal from the downstream oxygen sensor starts to mirror that from the upstream oxygen sensor(s), it means converter efficiency has dropped off and the converter isn't cleaning up the pollutants in the exhaust. Sep 13, 2021 · The air fuel ratio (A/F) sensor measures oxygen content of the exhaust in a wider range. An A/F sensor, by comparison, produces a changing current signal that varies in direct proportion to the amount of unburned oxygen in the exhaust. Said spikes are attenuated or removed after the cat in the downstream O2 sensor. Downstream may have some minor fluctuations, but it should constantly indicate rich or low oxygen content. Mar 31, 2020 · Looks like the answer - the EQ_RAT is giving the ratio of the air to fuel in terns of how close to 1 it is. So in my case, there is nothing to worry about and the downstream sensor is working correctly. 3 volts is a PCM generated representative voltage. As you can see it's going up and down Dec 14, 2017 · The post-catalyst sensor does not suffer this problem because most of the excess fuel and oxygen is consumed in the catalyst. 7 volts at 690-700 RPMS). An oxygen sensor reads oxygen levels only; therefore, their voltage range is 0. 8 volts, are indicative of failed catalysts. Apr 23, 2015 · At operating temp (about 90*c) the O2sensor should be switching voltage fairly fast, there are some good youtube vids showing this. O2 2/1 is upstream on Bank 2 and O2 2/2 is downstream on Bank 2. " The air fuel ratio sensor is installed in the exhaust manifold or in the front exhaust pipe, before the catalytic converter. In open loop, the sensor reads pretty high - 0. 9 I have the catalytic converter and the car is running smooth and has 60K milage. 07V are not uncommon for worn out sensors. 44 volts and running after heating voltage varies from above and below it directly taking readings from the O2 sensor plug whilst inline, also taking readings from inside the ECU box same result. Sep 11, 2012 · I would still see what signal you have while it's active and in the system by reading the signal going back to the PCM. 6 volts. Jan 13, 2011 · yeah, go ahead and change that post-cat (downstream / rear) oxygen sensor first. 3V which, to my knowledge, means it is working properly. 135 to 0. If you have a voltage meter you can test for proper voltage at the front O2 sensor wire harness. 24v, drops when the revs are increased. 75 (but of course bounces around like an O2 should) Upstream 02 voltages averages 0. 05, not 0. 85V. In other words, you have to get a schematic to know for sure that there is a direct wire from the fuse box to the O2, or if the volts go to a relay that is 'enabled' by the ECM grounding its apply coil. 1V, to 0. Apr 9, 2006 · Yup. 06 Volts. But I thought O2 sensors were supposed to fluctuate between 0. Bank 2 is showing less variability on the voltage outputs than Bank 1. Mar 24, 2019 · His scanner also showed the readings from the O2 sensors and it shows a flat line voltage on the upstream sensor. While I do NOT have a CEL, I have been doing some driving and logging my 02 Sensor voltage with my scan tool. 991. The data readouts can be seen here: BlueDriver o2 sensor readings Dec 18, 2020 · Usually the fans will kick on when its CLOSED LOOP. 9 volts indicates a rich fuel mixture. 1 volts indicates a lean mixture, meaning there is too much oxygen and not enough fuel in the combustion chamber, while a reading closer to 0. The rear sensors are standard oxygen sensors. Installed a downstream O2 sensor space to see if that would help. Nov 27, 2021 · It is certainly possible for your cat to be dead at 80k miles given the age of the truck. It's still spinning, yes, but without fuel, it's just not making any power. Oct 27, 2015 · On my freeze frame data from this morning I have these readings. 7v to occassionally flatlining at 0. Jan 5, 2022 · A faulty O2 sensor can certainly cause shaking or vibrations in Chevy Equinox when driving. 9 Volts. Where there's a Sensor 3, it's signal might be helpful in some cases. Reconnect O2 sensor to connector by snapping it into place. Start the engine and allow it to idle to the average operating temperature. While Oct 11, 2017 · Now observe the scan tool bank 2,2 o2 sensor reading. Apr 13, 2022 · Downstream O2 sensor. At optimal O2 concentration the O2 sensor puts out 0. Finally, close the hood. If the signal from the downstream O2 sensor continues to mirror that from the upstream oxygen sensor(s), it means converter efficiency has dropped off and the converter isn’t cleaning up the However, there are general voltage ranges that O2 sensors typically produce. Truck seems to run smoothly. Can anyone help what are normal voltages for the downstream O2 sensor. Assuming your O2 sensor voltage is high (over 0. 015 Volts. It's close to 0. I was reading up on it, and it said the things to look at if you are getting low voltage, could possible be fuel pressure, or clogged injectors. 00V ever, however numbers like 0. Switching sensor means you know if you are lean or rich, how much is another story. Feb 21, 2024 · If the check engine light comes on, the downstream O2 sensor readings will be analyzed to determine if there is a problem with the catalytic converter. 8V. Apr 22, 2021 · I expect to see readings varying from ~0. I observe that the sensor was correctly giving 0. Nov 22, 2021 · My upstream 02 Sensor reads what I think is normal at around 0. Bank 1 Sensor 2 is the only sensor reporting 0 volts according to my OBD II scanner stream function. 250 volts and when release they jump right back to Jul 17, 2018 · Upstream sensor is air/fuel, downstream is o2 for reference. 7 V steady. 5) which, to my knowledge, indicates it is not working properly. When the air-fuel mixture is perfect, the O2 voltage value will be exactly 0. entez qsehr nwzzss imcq ddipzhz mndc ngpr eqjyq moeh gcvbl