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. 90 volts indicating proper a/f ratio. Your oxygen sensor, sometimes called an O2 sensor or air-fuel ratio sensor, measures the oxygen level in your exhaust gases. This test result tells you that the O2 sensor is seeing a constant rich air/fuel mixture. - Fuel level above 12%. We have all heard them make scratchy noises as you turn them up or down. AFR looks okay. Alfa 156 2. 45 volts (that is, if the oxygen sensor resistance is low), the ECM judges that the air/fuel ratio is rich. (If you encounter this problem, refer to the section below, How to Unstuck a Stuck Oxygen Sensor. Now i no longer have code p0134, but p1298 is still present, p0172 Fuel system too rich came on, and i am reading 0 volts from the Primary. 0 Ohms resistance to the middle lead of the voltage regulator). If you dont have acess to a OBD-II scanner to check your "check engine light" most of your local auto parts will scan your system for FREE. If this comparison shows little or no Oxygen in the exhaust manifold, a voltage is generated. 875 volts, but this would be off (a little above) the geometric center. This is neither rich nor lean. So I then replaced Bank 1 sensor 2. If you were to log uego R,V, S, you could see what is basically happening here. Output signal - between 0 and 1 volt or between 0 and 5 volts (depending on make and number of wires) Function: The Oxygen Sensor (also known as Lambda Sensor) is located in the exhaust manifold and measures the amount of unburned oxygen in your engine's exhaust. It is capable of varying from about 0. Modular V8 (4. I thought I would share the results for those of you are interested. 2) disconnect the sensor lead from the fire-wall connector. The O2 sensor monitors the amount of unburned oxygen in the exhaust and produces a voltage signal that varies from about 0. Bank 1 is the bank containing the cylinder number 1. Is it also the case that the voltage on the post-cat sensor must cross 0. A fully warm O2 sensor *will not spend any time at 0. The next thing that you need to do is figure out (IF) the o2 sensor output voltage is a real indication of the engine fueling (like dripping fuel injector, fouled lower spark plug, plug in the air intake, excessively high fuel pressure, etc), or if the o2 sensor output is due to other influences (like failed o2 sensor, ignition noise into the. Both upstream o2 sensors stay around 3-4v consistently, with virtually identical readings at any given time. 83 volts is the same percentage below 1. 1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. The measuring range of the multimeter is set to 1 V or 2 V. If the voltage is high (approx. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. We have all heard them make scratchy noises as you turn them up or down. is this a sign of old sensors that need replacing?. Repair as necessary. Fuel trim make no sense for a downstream O2 Sensor. You can measure zirconia sensor voltage directly, but not titania sensors because their voltage is calculated from resistance and current values. A fully warm O2 sensor *will not spend any time at 0. If your trouble code is P0132 for too high of a voltage signal, this means that your Taurus engine is running rich. 0 with a P2270 trouble code. As an oxygen sensor ages, the voltage changes get smaller and slower - the voltage change lags behind the change in exhaust gas oxygen. This article describes how to test an O2 Sensor while it is still on the vehicle. If the voltage is low (approx. The resistance is low with low O2 concentrations (rich mixtures) and high with high O2 concentrations (lean mixtures). As we discussed in previous oxygen sensor diagnosis articles the voltage that’s monitored by the PCM (Powertrain Control Module) should fluctuate rapidly. 6 V or (min) always above 0. 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. 015) at idle when the car is started, warmed up, and has entered a closed loop. The sensor basically looks at idle or closed throttle (IDL) and throttle angle opening (VTA). So, if the O2 heater power feed were to short over to the O2 signal lead, the PCM PID will display a constant 1. 8 volts) or a lean reading (0. But the downstream O2 sensor is not moving. This means that the voltage output from the sensor is either too low, or high (I have no idea if "sensor stuck rich" on a gasoline car w/ O2 sensor is too low or high an output voltage). Please note that there are Check Engine / Service Engine / CEL fault codes which are stored in the Engine Control Unit (ECU). Bank 1, sensor 2. At idle 700rpm both B1S1 and B2S1 seem to oscillate between 0. Oh, "O2 sensor stuck rich" is just the termonology used (from gas engines). Oxygen sensor input voltage maintained below normal operating range. The zirconium dioxide oxygen sensor does NOT measure oxygen concentration %, but rather it measures partial pressure of oxygen in a gas or mixture of gases. To verify the o2 sensor works, I switched the two downstream sensors. 2 seconds with 0. If the result shows that the Ox voltage is greater than 0. I understand that the voltage on the pre-cat O2 sensor must cross 0. Typically, the oxygen sensor produces a voltage between 0. If the O2 sensor is a traditional zirconia type sensor, the voltage output drops to about 0. My O2 question is when I start the car from a warm state the scanner is saying there is no voltage (0. The mid point is about 0. Bank 1 is the bank containing the cylinder number 1. /B1-S2 not OK. (If you encounter this problem, refer to the section below, How to Unstuck a Stuck Oxygen Sensor. The coolant temperature is showing normal readings but the front o2 sensor still shows 1. 2 seconds with 0. It should have, as the voltage is only 0. With KOEO (Key on engine off) disconnect the o2 sensor and look for signs of corrosion or water intrustion. 450 volts) and lack of it will send the voltage signal high (over 0. 3 If the O2 sensor (O2S11) is working correctly, it will constantly switch between a Lean and Rich Condition several times every couple of seconds. I was running my scanner to check the volts for each sensor to make sure everything was kosher, but it doesn't seem to be. It never changed. 2 volts) when the fuel mixture changes. A wideband O2 sensor produces a current signal that varies not only in amplitude but direction. It measures the current draw, rather than voltage change of the sensor, so if your were to measure the voltage on the A1A+ or A1A- pins of the sensor, they would remain constant. The PCM sends a bias voltage of approximately 450 mV to the oxygen sensor. The only things that causes this is a shorted sensor or the yellow wire to the sensor is shorted to a. The zirconium oxide oxygen sensor generates an output voltage signal from 40mV¸100mV to 0. An oxygen sensor interprets an increase in oxygen as a fuel lean condition and emits a signal close to 200mV (0. Refer to detailed repair procedures available in DealerCONNECT> TechCONNECT> Service Info Section 14 - Fuel System> Fuel. 8v and back around once per second. It should have, as the voltage is only 0. This is neither rich nor lean. If the oxygen sensors indicate a rich condition, Adaptation values will be below 0. If there is no response in the voltage, replace the oxygen sensor. A digital voltmeter should jump around a bit near 450 mV. This article describes how to test an O2 Sensor while it is still on the vehicle. Long Term Fuel Trims at around 10-15% 3. Vehicle Owners: If you are seeking an automotive repair professional to service your vehicle, visit the iATN Repair Shop Finder. 9 like the upstream sensors, itll sit very low at. My question is what should the post cat sensors voltages be?. Keeping the Chevrolet Oxygen Sensor in Good Condition. Can an oxygen sensor be bypassed instead of having to replace it on an '89 Honda If your getting around 12 volts or 0 volts, you got the wrong wire. 00 volts, in reality it cycles between 0. Replace the O2 sensor. What are the normal ranges of the sensor's output voltage? The most common MAP sensor generates an output voltage between 0 and 5 volts, depending on the pressure being measured. changed my primary o2 sensor for a Denso one, the recommended one. An oxygen sensor interprets an increase in oxygen as a fuel lean condition and emits a signal close to 200mV (0. oxygen sensor on most foreign and domestic vehicles. Once the fuel ratio is outside these limits, the accuracy of measurement rapidly changes. 9 volts when the fuel mixture is rich and there is little unburned oxygen in the. O2 Sensor wiring quick tests (Ford with no bias voltage) Print How to determine if an oxygen sensor signal wire is open or shorted to ground on a system that doesn't use a bias voltage. When the fuel mixture is rich (less oxygen in the exhaust), the sensor's output jumps up to a high of about 0. balanced (about 14. It lead to too rich fuel. The test results showed. For example HO2S11 would be the oxygen sensor on bank 1 and first in line (pre catalytic converter) and HO2S12 would be on bank 1, but second in line (the monitor) An oxygen sensor creates a voltage between 0 and 1 volt by means of a chemical reaction between the sensor element and the oxygen in the exhaust passing across that element. 95 volts instead of an expected 0. 06V) O2 sensor 2 bank 1 (0. P0152= O2 sensor 2/1 circuit high. If this code is correct, the bank 1 sensor 1 sensor should be stuck at around 0. Revving the engine should cause the sensor's voltage to change (react). Oxygen Sensor - Low Voltage? I ran numerous Diagnostics tests with the OBD-II readers and replaced many oxygen sensors (Bosch and Delphi) with my 2000 Chevrolet Silverado. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. 45 volts as a lean exhaust. Another difference is that A/F sensors don't produce a voltage signal that suddenly changes on either side of Lambda when the air/fuel goes rich or lean. Decided that it must be a connection problem and yes sir it was - the red slider lockdown piece was busted. You will see changing numbers ranging from near 0 volt to near 1 Volt. A good O2 sensor should produce an oscillating waveform at idle that makes voltage transitions from near minimum (0. (Click to enlarge) Back to top. If the sensor doesn't respond accordingly or takes time to respond, the sensor isn't working properly. the code is a p0141(bank 1 sensor 2 i believe). 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. A perfectly balanced (stoichiometric) fuel mixture of 14. Your upstream Taurus oxygen sensor can read as low as 0. O2 sensors with a different full-scale voltage shall be normalized to this range or, if a wide range sensor, may use the wide range parameters instead. To find out how to find the right O2 sensor and how to locate different banks, I recommend you to check our article: Bank 1, Bank 2 O2 sensor location. The voltage reading should now be about 0. 5V from the PCM on the command side of the circuit, which the diagnostic tech interpreted as the sensor heater being off. converter, short trip. When the air/fuel ratio is stoichiometric (between. The mid point is about 0. 45 through the O2 sensor wire. 2 volts) when the fuel mixture changes. The conditions that set the code P0131 refer to consistently low voltages or sensors that remain fixed at 0 V. oxygen sensor on most foreign and domestic vehicles. Now the P0720 code is a majority of the time a bad vehicle speed sensor. The O2 sensor voltage readings did not change, so our diagnostic tech requested voltage readings on the command (ground) side of the B2S2 wiring. I let the car idle for roughly five minutes with no changes in O2 sensor voltage. Dallas1215 I have a 2003 Ford Escape 3. Its voltage depends on the amount of oxygen in the exhaust stream. But in the process, the thin metal shielding guarding the sensor glowed cherry red. 787 volts, the oxygen sensor is driving lean to rich and creating a vacuum leak lowering the voltage to 0. 7:1 AFR voltage switch. In probably 15 seconds, the sensor gets hot enough to produce a little voltage of it's own and the diagnostic bias disappears. I disagreed. That makes it quite different from a conventional oxygen sensor that produces a voltage signal that bounces back and forth between 0. So now I am thinking maybe it is my Bank 1 Thermocouple sensor that has failed, which is why Bank 1 postcat o2 is stuck in Open Loop not being activated due to the car perceiving the cat is not up to temp and and giving me the Bank 1 o2 sensor stuck on lean CEL. Check connection to O2 sensor for corrosion as well as wire degradation. The data readouts can be seen here: BlueDriver o2 sensor readings. 7:1, gives a reading of around 0. If dropped, the sensor must be discarded and another sensor installed. - P2271 O2 Sensor 1/2 signal stuck rich - P2273 O2 Sensor 2/2 signal stuck rich When monitored and set conditions P2271, P2273 code - Ambient temperature above -7°C (19. To test, using a voltmeter with the ignition on/engine off, voltage at terminal B should be 4 - 5 volts. The perfect output voltage of the sensor should be 0. When the mixture is lean, the sensor output voltage will drop down to about 0. Air pollution problems have led to higher standards for cars to reduce emissions. This code stands for oxygen sensor bank one catalyst response slow. 11 v; sensor 2, 0. If the multimeter reading shows 0 volts however, then replace the oxygen sensor. Voltage output from the sensor varies from 0. NO POWER Testing the O2 sensors 87-93 5. When in this state, the UEGO gauge will output 2. 2 seconds with 0. 2001 F150, 4. An oxygen sensor interprets an increase in oxygen as a fuel lean condition and emits a signal close to 200mV (0. The voltage reading should now be about 0. The AFRS puts out a DC voltage of about 0. Continuous. Oxygen sensor voltage codes are an example of this, low or high voltage could be caused by a slow or no response sensor or even a weak heater. 4L Lowest Price you need, all on one website. To find out how to find the right O2 sensor and how to locate different banks, I recommend you to check our article: Bank 1, Bank 2 O2 sensor location. What are the things to consider in buying an oxygen sensor?. This is neither rich nor lean. Now try log a sensor trace for both banks Sensor 1's. 2 vvolts to ,9 volts, it will not ever be steady if the o2 sensor is good, a good sensor will switch rapidly when the engine is running, if its slow to switch, then the o2 sensor. COMPONENT DESCRIPTION. What I was trying to see was if the o2 sensor was stuck at a low voltage and not switching. Data stream for second sensor is positive and appears normal. The O-2 sensor produces a voltage once exhaust gasses heat the tip of the O-2 sensor more than 600 Degrees F. The vehicle had come from another shop, which had already replaced the oxygen sensor. Check the sensor type as Allan suggests, but based on what I see, the o2 sensor/wiring is bad. 000075, with essentially no fluctuation. 2001 F150, 4. With engine off, sensor 1 reads -0. 5 volts and 3. The voltage is greater than 600 millivolts. It still idles really rough and then dies after about 30 seconds. Another difference is that A/F sensors don't produce a voltage signal that suddenly changes on either side of Lambda when the air/fuel goes rich or lean. A digital voltmeter should jump around a bit near 450 mV. So, if the O2 heater power feed were to short over to the O2 signal lead, the PCM PID will display a constant 1. 9 volts or above) and won't respond then shut off engine. 015) at idle when the car is started, warmed up, and has entered a closed loop. The O2 sensor is mounted in the exhaust manifold to monitor unburned. Anyone seen this CEL: P2275 O2 Sensor Signal Stuck Rich 02-17-2012 11:24 AM #1 Recently put on a different sensor spacer type and after 100 miles threw the 420 again, plus P2275 which is a new one on me. Another difference is that A/F sensors don’t produce a voltage signal that suddenly changes on either side of Lambda when the air/fuel goes rich or lean. 4 volt and a rich mixture producing in. This article describes how to test an O2 Sensor while it is still on the vehicle. I have 5 volts at map sensor on power wire but with key on only have 3. O2 SENSOR TEST 1: Inducing a Rich Condition to see if Oxygen Sensor is BAD or not. The voltage reading should now be about 0. 7: 1 ratio as the PCM can make it. They are the circuits I mentioned above that ADD a voltage to the O2 sensor output to lean out the mixture. Typically, the oxygen sensor produces a voltage between 0. If you have a scope the voltage should oscillate between about 0. This process repeats for as long as the engine is running. Neither of the latter are what you would want if using the antifouling spacer. If this code is correct, the bank 1 sensor 1 sensor should be stuck at around 0. P013C-O2 SENSOR 2/2 SLOW RESPONSE - RICH TO LEAN. 9 volts, with a value of about 0. Well I drove it a bunch today and sure enough same thing. If the average voltage reading is running low (less than 0. This oxygen sensor socket removes the 7/8 in. The O2 sensor monitors the amount of unburned oxygen in the exhaust and produces a voltage signal that varies from about 0. In this rich condition, the oxygen sensor will produce a high voltage of greater than. CEL is still illuminated. 7 volts return. O2 thing supplies voltage--so find out what voltage=good, make up some kind of reducer/regulator that reduces 12 to that small number. The voltage should fluctuate constantly between 0. 8 volts) or a lean reading (0. The PCM needs to know if the vehicle is at sea level or at a higher altitude, because the air density changes with altitude. A reading of 0 volts describes a LEAN condition, while a reading of 1 volt descrigbes a RICH condition. 6 triton, 4x4. 0 is a lean reading, while 1. Only p0420 code. 8 at a frequency of about 0. Rang out harness wiring and found no opens. Removing Rusted Stuck Oxygen Sensors the Easy Way! - Duration: 13:15. Check out all the relays, sensors and switches available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. The O2 data should rapidly oscillate from 0. The problem didn't move with the sensor. Anyway, I will try and replace a new air fuel ratio sensor and see if p0420 goes away. If it's voltage is stuck low (less than 0. 0 Volt fluctuating voltage range. When the air and fuel mixture is rich (too much fuel), the oxygen sensor signal increases and vice versa. A fully warm O2 sensor *will not spend any time at 0. what could it be? Dash lights stay on. 2 second delay between deflections. Tech Tip: Test for O2 sensors in front of catalytic converter (S1B1 and S1B2 on your scantool). The O2 sensor is mounted in the exhaust manifold to monitor unburned. 8 volts range for the duration of the 30 minute drive. 6V are rich (or something similar, it varies a bit between models). This process repeats for as long as the engine is running. At idle 700rpm both B1S1 and B2S1 seem to oscillate between 0. 7K to replace the catalytic converter. 9 volts when the fuel mixture is rich and there is little unburned oxygen in the exhaust. 06V) O2 sensor 2 bank 1 (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. 00 volts, in reality it cycles between 0. I have a 1g Talon TSi AWD and just got it running and hooked up the data logger and noticed that the o2 sensor just stays at 0 volts and all the fuel trims(L/M/H) are all 100% at idle and driving. The O2 sensor monitors the amount of unburned oxygen in the exhaust and produces a voltage signal that varies from about 0. 45 volts representing a midpoint at which the air/fuel mixture is as close to the ideal 14. Did you know that more than 60% of smog or emissions test failures are the result of a bad oxygen sensor? If your car has a bad or defective oxygen sensor, it would be difficult to pass the emissions test, whether the check engine light is illuminated or not. It detects the amount of oxygen in the exhaust gas compared to the outside air. 7 while B2S2 hovers around 0. 0L,I had a CEL light for a P0430, Catalyst System Efficiency Below Threshold (Bank 2), and my RPM's would not go above 2500 unless I floored it. 99v and doesnt change at all. When the throttle is closed rapidly, the O2 sensors' voltage will show lean (voltage at or near 0. I have PV with TT and the bike started to have the cylinders shutting down. 5% when Engine speed is > 800 RPM 40 test failures within a 100 test sample. It is weird but I’ve never thought to look at or think about a KOEO O2 sensor voltage. If the result shows that the Ox voltage is greater than 0. Try another power source for your SM-AFR. Check voltage of CKT 412 at O2 sensor harness connector using a digital voltmeter. Now the P0720 code is a majority of the time a bad vehicle speed sensor. Because of its importance for your engine and exhaust system, keeping your Subaru Impreza oxygen sensor in top condition should be a priority. - P2271 O2 Sensor 1/2 signal stuck rich - P2273 O2 Sensor 2/2 signal stuck rich When monitored and set conditions P2271, P2273 code - Ambient temperature above -7°C (19. At idle 700rpm both B1S1 and B2S1 seem to oscillate between 0. On the low end, 0. The O2 sensor is mounted in the exhaust manifold to monitor unburned. For example HO2S11 would be the oxygen sensor on bank 1 and first in line (pre catalytic converter) and HO2S12 would be on bank 1, but second in line (the monitor) An oxygen sensor creates a voltage between 0 and 1 volt by means of a chemical reaction between the sensor element and the oxygen in the exhaust passing across that element. The MSA XCell O2 sensor is designed to have a very long shelf-life. A wideband O2 sensor produces a current signal that varies not only in amplitude but direction. It measures the amount of unburned oxygen in the exhaust and sends a voltage signal to an engine computer to help it fine-tune the fuel mixture. The O2 voltage will be exactly 450. Although theoretically the O2 sensor should cycle between 0. 7:1, gives a reading of around 0. 01, 1997 year. 0 Volt or 0 up to 5 Volt fluctuating voltage range. What is an Oxygen Sensor? Functioning like a monitor, your oxygen sensor works like this: the O2 sensor tip is located inside of your exhaust pipe, the oxygen sensor detects the percentage of oxygen in the exhaust. 4L Lowest Price you need, all on one website. 999 volts) that the computer uses to calculate AFR. Learn what does P2195 Oxygen Sensor Signal Biased/Stuck Lean - Bank 1 Sensor 1 means, location and how to repair? oxygen sensor generates output voltage between 0. It said voltage should be 3 volts indeed. sensor starts the second the sensor is manufactured. Alfa 156 2. When the mixture is lean, the sensor output voltage will drop down to about 0. Disconnect the sensor output and the ECU will probably drive the mixture in accordance with a factory default parameter. I still have the same problem. Unplug the O2 sensor connector and measure resistance on the sensor side of the connector that the blue with black and black with yellow wire go to. Upstream Oxygen Sensor for Chevrolet Cruze Sonic Trax Volt Buick Encore Cadillac ELR 1. As we discussed in previous oxygen sensor diagnosis articles the voltage that's monitored by the PCM (Powertrain Control Module) should fluctuate rapidly. A good O2 sensor should show a lot of switching activity with readings bouncing back and forth from 0. The output of the sensor is usually between 0 and 1. Output voltage of heated oxygen sensor remains at 0. I put my scan tool on it and at idle [if it stays running] the upstream o2 sensors are returning values of 0. 5 is the middle of the road. 0) because the fuel injectors are being shut off by the ECU. 0l TPS Voltage WAY TOO HIGH!!! Please help! On your SN95-model 5. An oxygen sensor will typically generate up to about 0. If the oxygen sensors indicate a rich condition, Adaptation values will be below 0. Once the fuel ratio is outside these limits, the accuracy of measurement rapidly changes. Calibration is simple and only requires a single-point air calibration, and its large electrolyte reservoir decreases downtime due to maintenance. Unlike other meters which use a bar graph format with a 0. i had p0134 primary a/f sensor no activity, and p1298 ELD High voltage. If there is no obviously crossed or shorted wires, it is possible there is a rub-thru somewhere, or the PCM itself could have been damaged and actually shorting the sensor circuit. p0131 o2 sensor 1/1 circuit low p0135 o2 sensor 1/1 heater performance p0137 o2 sensor 1/2 circuit low p0138 o2 sensor 1/2 circuit high p013a o2 sensor 1/2 slow response – rich to lean p013b o2 sensor 1/2 slow response – lean to rich p0141 o2 sensor 1/2 heater performance p0148 fuel delivery error. so the voltage from the O2 #1 Volts parameter matches the voltage input at the EMS from the O2 sensor. For Nissan to go back to an O2 sensor for pre cat would be like going back to vacuum tubes. If the o2 sensor reading remains high (0. Hopefully not ohms - as resistance measurements would probably the O2 sensor. C4 Corvette Sensor Coolant Temperature P/N 25036708 : 185 Ohms @ 210F, 3400 Ohms @ 68F, 7,500 Ohms @ 39 F. 2 volts to above 0. If the voltage is low (approx. It is as if the circuit between the sensor and computer is not complete. 1 v) to near maximum (0. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. 2 second delay between deflections. If the A/F sensor voltage output is less than 2. When the air/fuel mixture is at the stoichiometric ratio (14. Having one new sensor and one old one on the same bank can cause problems. The sensor is supposed to give readings between +0. If the sensor detects too much fuel or gases, the ECU reduces the flow of fuel into the engine, and if the sensor detects too little fuel, the ECU increases the amount of fuel entering the engine. 445 v with ignition on and initial start of vehicle. 1-5 volts with the engine off( ignition on) is with a Titania sensor, because the ECU is putting it out as a referece voltage. Although theoretically the O2 sensor should cycle between 0. - P2271 O2 Sensor 1/2 signal stuck rich - P2273 O2 Sensor 2/2 signal stuck rich When monitored and set conditions P2271, P2273 code - Ambient temperature above -7°C (19. Hey guys, My truck is a 1996 Nissan Truck IMAGE. 1 Volt over a very small Lambda (or AFR) range. 24 V * 30 seconds or more, Estimated sensor temperature Less than 750C (1382 F) P0137 - Low Voltage * Heated oxygen sensor impedance 15 kΩ or more * Output voltage always less than 0. 21 Upstream Heated Oxygen Sensor Voltage Grounded. The mechanism in most sensors involves a chemical reaction that generates a voltage (see the patents below for details). im trying to save some $ , and have to take it to a shop. Anyway, I will try and replace a new air fuel ratio sensor and see if p0420 goes away. To give you an idea how stuck it is, I didn't jack the car up. The difference in oxygen levels between the exhaust and outside air within the sensor causes voltage to flow through the ceramic bulb. CEL is still illuminated. If there is too much oxygen in the exhaust, the fuel mixture is too lean, but too little oxygen indicates a rich fuel mixture. 0 is a rich reading. An O2 sensor voltage above 0. 8v and back around once per second. Once the sensor is hot, it will produce a voltage based on how much oxygen is left in the exhaust. Oxygen O2 Sensor spacer Extender extension Header Straight 0 /90 degree /Bung HHO Adapter Pipe Angle Kit M18 x 1. 100 Volts to 0. The typical range of the signal voltage (displayed as a waveform) varies from about 0. balanced (about 14. Buttoned everything back up and no reading (stuck at 0. With this code, the technician will primarily be interested in the data for the indicated O2 sensor. P2273-O2 SENSOR 2/2 SIGNAL STUCK RICH. Can't get car to complete emissions check without O2 sensor reading to pass state inspection. The front heated oxygen sensor (or O2 sensor 1) is placed into the exhaust manifold.