O2 Sensor Voltage Fluctuation

Our Universal, Direct-fit, CARB, High Performance and Diesel converter lines cover over 100,000 applications, including OBDII coverage for all 50 states and are certified in 58 countries around the world. NOTE: Unlike the front O2 sensor (O2S11), whose voltage varies constantly/rapidly between. You can then read the O2 sensor volts. If it is more than 30k miles old, it should be replaced, regardless. C5 Repair tips 5 All of the option codes are in the glove box. O2 TRUE for time > 90 sec and mod. Bank 2 sensor is working because it is fluctuating. The voltage and gauge fluctuate wildly. I havent had time to mess with it but Ill report my findings tomorrow. The amplitude of the O2 sensor voltage after TWC can be at the most half as large as the amplitude of the O2 sensor voltage before TWC (Note: If, for example, no monolith would be installed in the TWC, the O2 sensor signals before and after the TWC would be identical). 35v, is this supposed to be. The ECM uses the HO2S voltage to determine the air to fuel ratio. That was because an oxygen sensor can't produce and send the rapidly toggling voltage signal the engine computer is expecting until the sensor is really hot (above 600 F). The rear heated oxygen sensor (HO2S) normally sees a fluctuating voltage between 0 & 1 volt, for this DTC you'll likely see the voltage "stuck" at 0V. This may be related to a couple of different possibilities such as a faulty throttle position sensor or potentially a faulty instrument voltage regulator. That's why they're also called "wideband" O2 sensors. The computer pins are 29 (LH O2 with a red/black wire) and 27 (RH O2 with a gray/lt blue wire). 5 volts or stays fixed at a particular voltage, replace the oxygen sensor. If you suspect it is, install a sensor bung at a better location, use a taller O2 sensor bung or use an Innovate Motorsports HBX-1 to move the sensor probe out of the direct exhaust stream. By Nils Powell January 2001. Unless you replace your cat with a stock density one, I have no confidence that you won't get your CEL again. So if Bank 2, sensor 1 is showing 0. The PCM uses the O2 sensor voltage to determine the air to fuel ratio. Voltage should fluctuate between 0. com SO001e-7 / 23. Thus bank 1 would be at the front and #1 O2 would be the precat sensor. I am getting ready to do some custom programing with a new cam from Hesco and a Unichip. Bank 2 Sensor 1 O2 Sensor X-Type Lambda Sensor Jaguar X-Type petrol (all years) Part Number C2S51801 Jaguar XK From A30645 - A48700. I am data logging with MMCD via laptop. This may be related to a couple of different possibilities such as a faulty throttle position sensor or potentially a faulty instrument voltage regulator. However, when the MAF sensor malfunctions some faults will actually be symptoms of the root. If the exhaust smells fine and the O2 sensor is sending reasonable values, go to step 2. You have to warm up the car and monitor the voltage of the sensor. Anyway, logging while under operating temp. 90 volts (while still fluctuating rapidly). • If the post sensor shows excessive fluctuations (which echo the scope pattern of the pre sensor), this indicates that the catalytic converter is not functioning correctly and cannot consume the O2 (fault set). -Open or short in heated oxygen sensor circuit -Heated oxygen sensor -Engine Control Unit Regarding code P0132: The O2 sensors operating range should be 0. Is the correct downstream O2 sensor for a 2004 I6 Chevy trailblazer part number 21044 from rockauto?. An O2 sensor voltage that increases toward 1,000 mV indicates a rich fuel. 0 and my ODBII showed one of the O2 sensors (#1) voltage fluctuating wildly. under normal conditions it fluctuates up and down between about 0. I asked him about the supply voltage to the sensor and it turns out he didn't test that. I tried to adjust the AFM screw to raise the voltage to. i just replaced it last night. My low fuel trim keeps pegging lean no matter how I set my MAFT and my mid and high go rich. 6 and found I could not get a stable reading. Output voltage signal range of a properly functioning oxygen sensor is up to ~950mV. Eastern Catalytic manufactures catalytic converters, manifold converters and converter components for aftermarket and OEMs. The oxygen sensor used is not cross sensitive to helium so will measure correctly in the presence of a helium atmosphere. These fluctuations cause the oxygen ions inside the O2 sensor to reposition from one platinum layer to the other infinitely. Can anybody check a 4-wire Oxygen Sensor? Here's how to check a 4-wire oxygen sensor: This is the second part of testing your oxygen sensor. " The values for them don't make any sense. The post-catalyst oxygen sensors have an insulating foil shield. For pre-catalytic converter oxygen sensors used for fuel control: Less oxygen than optimal in the exhaust results in a signal voltage over 450 mV. Cheers Simon. If you don't have one of these, there is a service at www. It is constructed from high quality stainless steel, porous polytetrafluoroethylene, fluorine rubber, aluminum oxide, high-grade platinum and ceramics. It will still cycle, but not as quickly as it should. Browse more videos. P0136 O2 SENSOR CIRCUIT P0141 O2 HEATER SENSOR CIRCUIT Can anyone tell me where to start with these. Can anybody check a 4-wire Oxygen Sensor? Here's how to check a 4-wire oxygen sensor: This is the second part of testing your oxygen sensor. Standing facing the Flywheel end of the engine, Bank 2 is located on the left hand side of the engine, there are two sensors one upstream, on the engine side of the catalytic converter, and one down stream on the exhaust side of the catalytic converter. For information on converting your VTEC Honda to run on a distributorless ignition, check our handy guide here. Sounds like your O2 sensor might be on it's way out, but without looking at your fuel trims, I can't tell for sure. If you pull up the data stream, and you see no fluctuation and no lean to rich switching and take a minute to inspect the exhaust for damage parts. 65v and my exhaust smells like crap telling me it is rich. O2 sensor systems I found that the upstream left (1/1= Bank 1, Sensor 1) O2 Sensor voltage fluctuated quite a bit while the upstream right (2/1=Bank 2, Sensor 1) Sensor was quite stable. with intact catalyst voltage at 2 oxygen sensor should be about 0. The rear heated oxygen sensor (HO2S) produces a voltage between 0V and 1V. NOTE: Unlike the front O2 sensor (O2S11), whose voltage varies constantly/rapidly between. 1 to 1 volt fairly rapidly when it is working properly. Reading on other forums about O2 sensors- the ECM occillates from lean to rich causing the output from the O2 sensor to constantly fluctuate. When an O2 sensor heater fails, it usually sets off the MIL or check engine light. 29v With no O2 sensor connected !. 706 Theres no fluctuation it stays at those two #s throughout the whole datalog. When cold, the sensor is 'biased' by the ECM to about 450 millivolts. If your oxygen sensor has failed, the code checker will generate a diagnostic trouble code that specifically indicates your oxygen sensor is bad. It does say that you can do a voltage test. Toyota Enhanced Add-on Supported Parameters The Toyota Enhanced Add-on provides access to the following parameters. How can I test my oxygen sensor? You can test the O2 sensor on a vehicle by first identifying the signal wire on the sensor. (my orignal bosch finally went bad after 14years:)) bench testing shows that i have continuity through all four wires. The oxygen sensor on the Toyota 22RE engine can be easily tested to determine if it is faulty before you remove it and replace a perfectly good sensor. The lag time in the sensor makes it useless for correctly reading a surging engine. It will change from. The other end of this electrode extends out of the exhaust and is actually exposed to ambient air on the outside of the exhaust pipe. The sensor bodies are small (4. 600 deg F). The surging oxygen ions cause changes in voltage as they move between platinum layers. This paper presents a microfabricated 2 times 3 array oxygen sensor integrated with heaters and temperature sensors for measuring cellular respiration level in a solution containing cells. Voltage output from the sensor varies from 0. The O2 sensor generates a voltage signal that is proportional to the amount of unburned oxygen in the exhaust. Inside the bulb are two platinum electrodes. The voltage should fluctuate appropriately with applied throttle. The sensor is threaded into an M18 boss welded to the exhaust pipe. If the post cat O2 sensor's voltage fluctuates too rapidly (like the pre-cat O2 sensors are supposed to), that triggers the P0420. I have a question regarding the operation of O2 sensor 1 (upstream) and O2 sensor 2 (downstream). A MAP sensor that reads 1 or 2 volts at idle may read 4. Mine are new Bosch from Pelican parts. The only thing is that if your O2 sensor is an AF sensor, it will not work since it's not an O2 sensor per se. So, in poking about under the Jeep to listen for a tiny exhaust leak and to examine my O2 sensors, I find that there's a slightly abraded and kinked area on one of the white wires leading from my downstream sensor. This time, it did not cycle back to the 13. 8 volts, looking approximately like a sine wave. " The values for them don't make any sense. 401 V secondary O2 heating stable TRUE and secondary O2 sensor voltage < 0. Re: poor mpgs, oxygen sensor voltage fluctuation Well, when I did the smog check a few weeks ago, they checked my filler cap and that was fine. Testing the O2 sensor wiring harness. The pre cat sensor is an A/F sensor so normal range fluctuates a few tenths around 3. an o2 sensor is a piezoelectric sensor that will generate it's own voltage from 0-1volt, with the exception of some older jeep units tht will probably never ever be around anymore anyway so i will not cover them. 5 volts since driving voltage ranges from 0. Slow fluctuation indicates a polluted Oxygen sensor and negative values indicate a. First of all, an O2 sensor is a device typically located in the Y-pipe of the exhaust system of a vehicle, this round device takes an Fuel/Air mixture reading of the exhaust fumes by determining the ammount of Oxygen present. Sounds like your O2 sensor might be on it's way out, but without looking at your fuel trims, I can't tell for sure. Often you can narrow down diagnosis using the set trouble code. o2 sensors are supposed to pulse between 0-1 volt to maintain a stoich a/f ratio. Anyways, I vag it and one code comes up: B2 S1 o2 sensor intermittent Doing live graphs, i pick all 4 o2 to see what are they doing. But both AFS and STFT were bouncing around every second. An OBDII code checker identifies defects in the exhaust system of the car. O2 sensor systems I found that the upstream left (1/1= Bank 1, Sensor 1) O2 Sensor voltage fluctuated quite a bit while the upstream right (2/1=Bank 2, Sensor 1) Sensor was quite stable. Shorted oxygen sensor Skip to the bold type if you don't want to read the long introduction. The voltage and gauge fluctuate wildly. The rear one keeps giving me errors though: P0140 and P1114 No Activity from post-cat oxygen sensor after replacement. Also, covered is a procedure for testing the AFM and correcting problems related to erratic operation. This effectively moves the sensor slightly out of the exhaust stream so that it shows less fluctuation, exactly what the computer is looking for. If it and the catalytic converter are both operating properly, it should fluctuate very little compared to the upstream sensor. Stock o2 sensor is a narrowband sensor. 1V and 1V and it flips every cycle. The PCM uses the O2 sensor voltage to determine the air to fuel ratio. A special tester (Bosch KDJE 7453) is recommended, but a high quality analog volt meter can be used instead. The O2 sensor used in most vehicles is a voltage generating sensor. Re: poor mpgs, oxygen sensor voltage fluctuation Well, when I did the smog check a few weeks ago, they checked my filler cap and that was fine. Obviously, replacing the sensor was not the proper fix. The time taken for the voltage to change from 0. The voltage regulator is built into the alternator. The O2 sensor heating element could also be defective, and this can cause a cold O2 sensor at idle with no fluctuation in output voltage. I have really appreciated the wealth of knowledge that everyone has here, and their. You seem to be quite switched on with the tuning of these machines, which table affects part throtte acceleration, i. The voltage on the signal wire is generated by the sensor and is due to a chemical reaction between the tip of the sensor and oxygen molecules in the exhaust stream. But the two relays appear to be next to each other on the far right under the dash. Current and voltage data loggers are used when you want to monitor and record voltage and amperage levels. 0 volts, so having a quality volt meter is important. But rather, it is sensing an oxygen differential between what is inside the pipe as to what is outside the pipe. This time this is how the O2 sensor is wired. Ok Well I think the O2 sensor fits a 17mm wrench, but it doesn't seem as tight as it should be. with intact catalyst voltage at 2 oxygen sensor should be about 0. P0158 The PCM has determined that the input voltage from oxygen sensor 2 in bank 2 is too high for current operating conditions. Ford Mustang Forum > Ford Mustang Model Specific Forums > 5. Have done a ton of other things to resolve to no avail. So I wonder why the 2x1 sensor fluctuates as high as 1. I have seen random misfire codes and o2 sensor faults set. When I check the mixture at idle using a multimeter and the O2 sensor disconnected, it receives a steady voltage of. The heated oxygen sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the operating temperature during extended idle periods. What rpm was the engine at? Bank 1 appears that it is doing something and the cat on that side is working. Have noticed some poor performance after changing pcv. The O2 sensor acts as a small battery as it has the ability to produce a low voltage signal (between 0. I just installed this sensor a few days ago. As more fuel enters the combustion chamber a rich mixture is burnt and a hi number of oxygen partical are left to flow past the O2 sensor. 45 volts or higher. It is projected the sensor bodies will cost $5-$10 in production. Once the sensor is located, remove its electrical connector, then remove the sensor using the special attachment socket. In case it is not within range, there is either an engine problem (loose hose) or the o2 sensor is bad. You can then read the O2 sensor volts. The only way to simulate those voltages with any accuracy, would be to use the front A/F sensor as an input to logic module that's mimicking the rear O2 sensor. • Oxygen Pressure Range: 0-300mbar ppO2. This sensor. 6X5 = 3 volts? Elsewhere I have read that the normalized voltage reading should vary between 0 and 1. If the exhaust smells fine and the O2 sensor is sending reasonable values, go to step 2. 2L OHV I-4 While running rich by adding propane to the intake it the sensor shows a stable (?). Re: Carb cleaner to clean an O2 sensor A drop of one PSI can cause a host of problems. It is projected the sensor bodies will cost $5-$10 in production. 6 and found I could not get a stable reading. As a result of regular usage, products like oil and coolants settle inside the oxygen sensors over time. Let me tell you why. A properly functioning oxygen sensor will show a rapidly fluctuating output voltage between approximately 0. with throttle steady 2000 rpm and engine fully warm the voltage should be in the range of 60-85mv steady reading with very few fluctuations. 5 volts or stays fixed at a particular voltage, replace the oxygen sensor. I heard a guy on the radio today mention to get Bosch O2 sensors. The rear heated oxygen sensor (HO2S) normally sees a fluctuating voltage between 0 & 1 volt, for this DTC you'll likely see the voltage "stuck" at 1V. You can still however check the voltage to confirm the current air fuel ratio as well as force the sensor rich and lean to test it. The internal circuitry used in a wideband oxygen sensor produces a digital pulse width modulated signal that makes it quite different from a conventional oxygen sensor that produces an analog signal ranging from 0. The first oxygen sensor developed by Bosch was installed in a Volvo 240/260 series vehicle 25 years ago. What rpm was the engine at? Bank 1 appears that it is doing something and the cat on that side is working. The fact that it is reading a value is good but it is reading to high. What do these O2 sensor readings mean? I've been trying to get this thing to idle more comfortably and fixed some issues, but haven't made much progress. If the signal tends to show high voltage with little fluctuation, excessive unburnt fuel is reaching the sensor. It cycled the whole way home from work today. Fuel System Service O2 sensor voltage fluctuates rapidly from 0. Did the wire swap thing to a ford four wire sensor. A bad or failing O2 sensor can also cause you to fail your emissions test. This oxygen sensor is not sensitive to NOx. SENSORE Electronic GmbH Aufeldgasse 37-39, A 3400 Klosterneuburg Tel. The A/F Sensor is designed so that at the stoichiometric set point of 14. The o2 sensor's voltage should fluctuate within the 100mV - 900mV (0. As the catalytic converter warms up, the downstream oxygen sensor (bottom) changes from a switching to a constant-voltage signal. A bad sensor will be flat-lined and show no response to snapping the throttle. The O2 sensor used in most vehicles is a voltage generating sensor. 8v and under. Unfortunately, this is a pretty common code that stands for oxygen sensor voltage low. 45 volts or higher. 5 volts less than 5 times in ten seconds), the sensor may be faulty. Throttle Position (TP) Sensor circuit below minimum voltage: 123: O,C: Throttle Position (TP) Sensor circuit above maximum voltage: 124: O,C: Throttle Position (TP) Sensor voltage higher than expected: 125: C: Throttle Position fTP) Sensor voltage lower than expected: 126: C: BP Sensor higher or lower than expected: 129: O,R,C. 0V (referred to as the lean to rich response time) should be about 300 milliseconds. An HO2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture. so, with no sensor connected, you have a small antenna that will show voltage via induction(i think). Good logging software shows this relationship well when graphed. This tool is capable of looking at the voltage from the sensor and plotting it on a graph so that you have a graphic representation of what the voltage is doing. Answer C is correct. This could indicate the O2 sensor switch point has shifted meaning the sensor is aging and may be on its last legs. If voltage fluctuates through direct reading, and continuity is good, computer is bad. However, by taking the oxygen sensor off, you are able to visually inspect the sensor, which can often provide a good indication that there is a problem, and testing the sensor is also a little easier. 35v all times. Control range and reductions in exhaust under three scenarios. A generic guide to early Bosch injection systems like the L-Jet also make reference to CO levels to test the O2 sensor. Let me tell you why. 8v and under. The rear one keeps giving me errors though: P0140 and P1114 No Activity from post-cat oxygen sensor after replacement. The ECM uses the HO2S voltage to determine the air to fuel ratio. Learn what does P0135 Honda O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1 means, location and how to repair? Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. 45 volts as a lean exhaust. and the sensor gives the proper voltage when tested. Stating around model year 1999, a new type of converter came on the market, called "Low Oxygen Storage Converter" or LOC. This kind of deterioration can be caused by a variety of substances that find their way into the exhaust such as lead, silicone, sulfur, oil ash and even some fuel additives. 1V respectively flat line, after hot, driving on the freeway at steady 55mph. If it looks Ok then measure it at D7 and if it's the same you shouldn't need to do any rewiring. I understand that the voltage on the pre-cat O2 sensor must cross 0. For pre-catalytic converter oxygen sensors used for fuel control: Less oxygen than optimal in the exhaust results in a signal voltage over 450 mV. First of all, an O2 sensor is a device typically located in the Y-pipe of the exhaust system of a vehicle, this round device takes an Fuel/Air mixture reading of the exhaust fumes by determining the ammount of Oxygen present. To contact them, click here. This time, it did not cycle back to the 13. , control unit?. 5479 V dew-point end of Sec. Do a quick snap throttle and should see the change in the A/F sensor and in the after cat O2 sensor. One is "02 sensor 1 wide-range voltage" and "02 volts Bank 1 sensor 2. On many V6 and V8 engines, there are two such sensors (one for each bank of cylinders). I have an 84 Carrera 3. My bank 2 O2 sensor was reading near dead, so I checked my wiring and found that I had put it's power wire in the sensor 2 pin. Find better mechanics, someone who understands voltage drop tests and also amp tests. under normal conditions it fluctuates up and down between about 0. The reason I suspect an air leak is the low voltage signal from the O2 indicated by the P0136 in addition to the fact that I have measured the output (0 - 0. if the rear o2 sensor is "seeing" similar fluctuations as the front o2 sensor, the engine computer trips the P0442 code because it thinks the cat is not working. On early OBD II systems, the post-cat O2 sensor should show little or no voltage fluctuations on a scope waveform, since all the mixture fluctuations are being absorbed by the catalytic converter. - I've got a 2010 Chrysler T&C 4. Open or short in heated oxygen (ho2) sensor circuit (dtc p0137 or p0138). Running a scan on the OBD 2 monitors and looking over the live data log of certain emission components, I found that oxygen sensor #1 had a voltage fluctuation much more than that of the 2nd (downstream) sensor, and it had more inconsistent reading. The oxygen sensor generates voltage by a difference in oxygen content. Hi all, new here,look forwards to views and help, return the favour may be one day. 2V up until 0. The monitor (26) has a regulator (64) that changes the fluctuating voltage associated with a vehicle electrical system into a stable voltage source. I get only about 30 mV on both the 260E and 300E. The computer pins are 29 (LH O2 with a red/black wire) and 27 (RH O2 with a gray/lt blue wire). Typically, O2 sensors just die and report a voltage of 0. oxygen sensor. If a catalyst has good conversion properties, the oxygen fluctuations are smoothed by the oxygen storage capacity of the catalyst. But before the O2 sensor can produce a voltage output signal, it must be hot (approx. I have taken the induction piping apart and visually checked and cleaned the airflow sensors etc but don’t have the specs for voltage/resistance for testing these. The theory is that the converter should be capable of storing extra oxygen that comes in when the mixture is lean (low upstream HO²S voltage) and releasing it when the mixture is rich (high upstream HO²S voltage). Given that it only happens when transitioning into open loop, I'd suspect that one or more O2 sensors is bad, and that the MAP vacuum fluctuating is not the root cause, but rather the result of a bad O2 sensor disrupting smooth engine operation and producing erratic vacuum by way of the engine. I hooked up the O2 sensor and I have a constant. The oxygen sensor on the Toyota 22RE engine can be easily tested to determine if it is faulty before you remove it and replace a perfectly good sensor. This depends on how bad the car is running. 90 volts (while still fluctuating rapidly). 2 up and runnin and a day or to later it put som codes out like:21(problem with oxygen sensor signal circuit. Toyota Enhanced Add-on Supported Parameters The Toyota Enhanced Add-on provides access to the following parameters. Voltage from the O2 sensors should go up with engine revs if they're working correctly. This effectively moves the sensor slightly out of the exhaust stream so that it shows less fluctuation, exactly what the computer is looking for. This tests the ability of the sensor to detect a rich mixture condition. The voltage across these terminals should be between 0 and 0. If the signal tends to show high voltage with little fluctuation, excessive un-burnt fuel is reaching the sensor. 011 Oxygen Sensor Signal Analysis - Duration: 27:52. Did the wire swap thing to a ford four wire sensor. The PCM uses the O2 sensor voltage to determine the air to fuel ratio. Principle of operation of a zirconium oxygen sensor The zirconium oxide oxygen sensor generates an output voltage signal from 40mV¸100mV to 0. When the rpms are increased the voltage fluctuates slightly and then settles to. Once sufficient HO2S voltage fluctuation is observed by the ECM, closed loop is entered. Find better mechanics, someone who understands voltage drop tests and also amp tests. When the TWC detoriate and oxygen storage capacity drops will the rear oxygen sensor switching frequency increase. It cycled the whole way home from work today. 9 volt at idle. In your car, a functioning O2 sensor ensures that your engine is running at top performance. To counteract this, a pressure compensation sensor is used to compensate for changes in atmospheric pressure. It is necessary to clean the sensor to ensure that performance is not negatively affected. 35v, is this supposed to be. But both AFS and STFT were bouncing around every second. You will not see it switch as rapidly as you would a narrow-band oxygen sensor (4-5 times a second). As a result the O2 sensor voltage fluctuates between. The reason I suspect an air leak is the low voltage signal from the O2 indicated by the P0136 in addition to the fact that I have measured the output (0 - 0. It will do nothing except ruin your car's ability to compensate for rich/lean conditions. Installed a new Bosch O2 sensor and cleared the code. The rear heated oxygen sensor (HO2S) normally sees a fluctuating voltage between 0 & 1 volt, for this DTC you'll likely see the voltage "stuck" at 1V. The P0161 code means that the O2 sensor heater circuit is shorted or open. When the air/fuel mixture is lean and there is more oxygen in. Oxygen Sensor readings fluctuating significantly - is this ok? I'm trying to diagnose a check engine light with no codes, and I am looking at the oxygen sensor now. O2 Sensor Bank 1. First time on this forum. I understand that the voltage on the pre-cat O2 sensor must cross 0. Best Answer: When the air/fuel mixture is rich and there is little O2 in the exhaust, the difference in oxygen levels across the sensing element generates a voltage through the sensor's platinum electrodes: typically 0. com The onboard diagnostic (OBD) code P0136 is defined as an Oxygen Sensor Circuit Low Voltage in Bank 1, Sensor 2. When Monitored: With the engine running, vehicle speed above 96 kph (60 mph), throttle open for a minimum of 120 seconds, ECT greater than 70° C (158° F), catalytic converter temperature greater than 600° C (1112° F), and downstream oxygen sensor in a rich state. 90 volts (while still fluctuating rapidly). The rear O2 sensor voltage fluctuates from around a peak of nearly 1 volt at WOT, to nearly 0 on decel. It isnt the sensor, so its either a faulty o2 wire (which is shielded so not likely) or some ecu internal issue. Simply put, the oxygen sensor is not sensing oxygen in the exhaust. you're seeing "stray" voltage happening. I whipped out my Innova 3100i that I keep at home and pulled a code P0131. The rear O2 showing zero voltage. If the signal tends to show high voltage with little fluctuation, excessive unburnt fuel is reaching the sensor. I think that a “stuck” high voltage reading from an O2 sensor means that the sensor is OK and over fuelling is due to another cause. I could stand there with my DVOM hooked up till I'm blue in the face and probably never catch it. The O2 sensor s sensing ability comes about by producing a small voltage proportionate to the exhaust oxygen content. What Does an Oxygen Sensor Do in a Car? All cars that were manufactured post-1980 feature an oxygen sensor. The oxygen sensor can be found in the exhaust manifold and possibly also in each catalytic converter of your automobile. I didn't really mean to turn this into another O2 diagnosis thread. Even some fuel additives may be able to foul an O2 sensor, damaging its platinum coating and causing it to return consistently low voltage signals, and anti-seize compounds will do likewise, especially those which contain silicone. Mine tend to produce 850 milivolts at cruise and 15 milivolts on long decel. You can monitor sensor voltage and operation at the UEGO sensor electrical connector, as you would with a narrow-band oxygen sensor. 0 Mustang Forums (1979 – 1995) > 5. An O2 sensor voltage above 0. 6 and it fluctuates often. Bank 2 Sensor 1 O2 Sensor X-Type Lambda Sensor Jaguar X-Type petrol (all years) Part Number C2S51801 Jaguar XK From A30645 - A48700. Over time, an oxygen sensor may become caked with byproducts of combustion, such as sulfur, lead, fuel additives, oil ash, etc. 5 volts, or. So first thing I would do is check the sensor voltage at the sensor. This voltage will be fluctuating up and down, but should be averaging about 0. Component location of 4-pin harness connector of oxygen sensor Page 24-5. 0 V (referred to as the lean to rich response time) should be about 300 milliseconds. 7 ohms (which I believe to be a sufficient match). The upstream O2 sensor shows somewhat steady about. Then all of the sudden I would drop to. o2 sensors are supposed to pulse between 0-1 volt to maintain a stoich a/f ratio. Has anyone removed the sensors? Know what size they are? The auto parts stores only have a 7/8" - 22mm oxygen sensor socket and that's definitely too big. Locate the oxygen sensor signal wire The easy way to do this is to look it up in your Haynes, Clymer or Chilton manual for your car. Filterless optical oxygen sensor based on a CMOS buried double junction photodiode Article in Sensors and Actuators B Chemical 176(Pt B):729-735 · January 2013 with 28 Reads How we measure 'reads'. HOW THE O2 SENSOR WORKS The O2 sensor used in most vehicles is a voltage generating sensor. By the way it has the 5. It is constructed from high quality stainless steel, porous polytetrafluoroethylene, fluorine rubber, aluminum oxide, high-grade platinum and ceramics. 9 Volts, the rear O2 sensor's voltage should fluctuate less and stay around. It talks about how fluctuating voltage (my limited understanding) can cause the engine light rather than a faulty o2 sensor. This is a next in turn example that it would be wrong to say instantly that the device is faulty. Measure the voltage coming out of the O2 sensor at operating temp around 2000rpm. So we need a fast heater during engine start up, and a detection system to determine when the wide band oxygen sensor output voltage is valid. Complementary Modification: To get the oxygen sensor socket onto the hex of the socket you have to compress the foil a small amount, just enough to squeeze the socket over it. If after you do this there is not any fluctuation in the voltage then that is a good indication that the o2 sensor is bad. 7:1 there is absolutely no current flow and the resulting voltage signal put out by the circuit is 3.