O2 Sensor Stuck At 0 Volts

When diagnosing this DTC, only diagnose the O2 Sensor that set the DTC. 8 volts, it can be done. If so, replace the o2 sensor, it's shorted internally. Honda Accord: How to Test and Replace Oxygen Sensor. So, O2 should respond, EGO will only respond if MegaSquirt ® has: been on for more than 30 sec, the current rpm (adjusted on the stimulator) above the EGO 'active above' rpm threshold, EGO step and limit do not equal 0, and. EZ CEL Fix oxygen sensor eliminator outputs the Engine computer with mimicked, fluctuating voltage signal and tricks the Electronic Control Unit into thinking the emissions are within allowance. 600 deg F). the O2 sensor or circuit is shorted to low by checking for a lean condition during steady state throttle and during power enrichment (PE). This is neither rich nor lean. There could be a vacuum leak downstream of the MAF sensor Possible cracked vacuum or PCV line/connection Faulty or stuck open PCV valve Failed or faulty oxygen sensor (bank 1, sensor 1) Sticking/plugged or failed fuel injector Low fuel pressure (possible plugged/dirty fuel filter!) Exhaust leak between engine and first oxygen sensor. If you have a scope the voltage should oscillate between about 0. 2 volts to above 0. I'm trying to figure out why my car is stalling out after clutching-in while driving. The engine control module (ECM) takes readings of oxygen sensor voltage to learn whether there is a fault. Verify engine is not overheating, and correct any cooling system related problems first. It's constantly reporting 0. Measuring the activity of the broadband oxygen sensor using the volt drop method accompanied with Ohm's law removes the need for expensive milliamps clamp to measure tiny current values ranging from 0. 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. 45 volts is recognized by the PCM as a rich exhaust; below 0. Since the ECM sees a rich signal, it will try to correct with a lean command and try to lower the oxygen sensor high voltage signal. It then relays this information to the ECU to adjust the fuel mixture. Repair as necessary. The red top (skinny) i believe works on resistance from a power source sent from the ecu and can be measured in ohms from 1000-20,000ohms I was using the fat o2 from the black top and i was getting the Mv reference but it had no effect on my wide band readings I would start out at. If you have a scope the voltage should oscillate between about 0. The voltage reading should now be about 0. For example, when the ho2 sensor voltage does not decrease to less than 0. P2270 O2 Sensor Signal Stuck Lean Bank 1 Sensor 2is caused by wiring error, an issue in the HO2S, fuel pressure, injectors, or an intake leak. Other tests:. At WOT, even tho your O2 sensors do nothing to control fueling, your after cat sensors should rise from low 0. When I pulled the oxygen sensor it was partially melted. 1A Auto has a large selection of aftermarket O2 Sensors for many makes and models, including Upstream (Front) Sensors, Downstream (Rear) Sensors, and more. P0133 (M) 1/1 O2 Sensor Slow Response: Oxygen sensor response slower than minimum required switching frequency. O2 Sensor Output Voltage-- The actual voltage being generated by the oxygen sensor (should be 0. If the air-fuel mixture becomes rich (more fuel and less air), there is less oxygen in the exhaust, so the oxygen sensor will generate more voltage (around 0. For wide-band O2 sensors and linear O2 sensors, the value may be higher, or it may be converted to a zero to one volt scale. downstream sensor output is alternating voltage from near 0V up to 1V based on readings where generally below 0. 310 ($09EB) 0. With this code, the technician will primarily be interested in the data for the indicated O2 sensor. O2 sensors basically sniffs the exhaust and outputs voltage between 0 and 1 volt indicating how much oxygen is in the exhaust. If the sensor is sluggish or reads low, it needs to be replaced. 9 volts like the upstream sensor. This is neither rich nor lean. 5 volts may not be enough to set the code, but it depends on the vehicle) and you don't have any other o2 sensor codes present in the PCM, then it's a good bet that the sensor is bad. Most will operate down to 10. 8 volts) or a lean reading (0. Differences between an oxygen sensor and an air-fuel sensor: The exterior appearance of the air-fuel ratio sensor and oxygen sensor may be very similar but that's where the similarity stops. 00 volts and 1. The upstream heated oxygen sensor reading should vary between 100 millivolts and 900 millivolts, once the engine reaches its optimal temperature. My scanner says 0 volts. AUTOMOTIVE OXYGEN SENSOR DEVELOPMENT STAGES There are thousands of Internet web pages that deal with oxygen sensors each trying to explain the total functionality of the oxygen sensor as it applies to the automobile industry. 0 is a lean reading, while 1. ANY O2 sensor that will generate 0. It seems to hang around 0. Oxygen sensor failure can often be traced to one of three common factors: Age and high mileage, an internal contaminant (poisoning) or an electrical issue. 15V), and short-term and long-term fuel trims track close to zero, consistently less than +/- 5%. The HO2S sensor senses the oxygen content in the exhaust flow and outputs a voltage between zero and 1. With the engine idling, connect the voltmeter from the sensor case to the sensor ground wire on the computer. I put my scan tool on it and at idle [if it stays running] the upstream o2 sensors are returning values of 0. Rang out harness wiring and found no opens. 9 volts or more when heated, show 0. To give you an idea how stuck it is, I didn't jack the car up. MITSUBISHI ERROR CODE and Self DIAGNOSTIC approximately 0. 9v at the top. Just wanted to share my experience and maybe get some. A good O2 sensor should show a lot of switching activity with readings bouncing back and forth from 0. I do not hear any exhaust leaks before the downstream O2 sensor. An O2 sensor voltage above 0. the O2 sensor or circuit is shorted to low by checking for a lean condition during steady state throttle and during power enrichment (PE). During Closed Loop, the input from the Oxygen sensor(s) is used by the ECU to calculate fuel delivery adjustments or Adaptations. 1V etc) the rear oxygen sensor is at fault. It lead to too rich fuel. 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. Learning how to check an oxygen sensor (O2) will help you confirm a potential problem with the sensor in your vehicle before you spend time and money replacing a unit that might not even need a replacement in the first place. The voltage reading should now be about 0. This is neither rich nor lean. The up-stream sensors are located on the engine side of the catalytic converter, these are the main sensors for control of the fuel air mixture. You'll note that these voltage trends are exactly the opposite of those we expect from a conventional O2 sensor. It then relays this information to the ECU to adjust the fuel mixture. Note that you must have the same sensor type for both O2 sensors, and to take full advantage of this, you must have each bank on a separate injector output. Its voltage depends on the amount of oxygen in the exhaust stream. With engine off, sensor 1 reads -0. Where you might see a steady voltage of. Most cars have narrow band sensor meaing they can only measure accuratly around stoich A/F (14. 4 volt and a rich mixture producing in. If the o2 sensor reading remains high (0. 2 ms then there is an unmeterd air leak where not enough fuel is being supplied to the system or an erroneous signal from the air. I went back and checked the O2 plug and it was 0 volts. 9V & LED AFR Gauge 19 / 11 LEAN and RICH +1* O2 Sensor. This process repeats for as long as the engine is running. 6 volts and behaving as it should, not bouncing around. An o2 sensor (not Wideband o2) cannot accurately measure HOW rich or HOW lean the exhaust is. An oxygen sensor will typically generate up to about 0. 9 volts or more when heated, show 0. With KOEO (Key on engine off) disconnect the o2 sensor and look for signs of corrosion or water intrustion. 9 volts when the fuel mixture is rich and there is little unburned oxygen in the exhaust. 00 volts and 1. The upstream heated oxygen sensor reading should vary between 100 millivolts and 900 millivolts, once the engine reaches its optimal temperature. I am not sure why it would read that way unless the sensor is bad. O2 SENSOR TEST 1: Inducing a Rich Condition to see if Oxygen Sensor is BAD or not. An oxygen sensor will typically generate up to about 0. 9 volts, with a value of about 0. If the heated oxygen sensor output voltage is 0. This slight reduction in voltage forces the ECU to add additional fuel. P2195: O2 Sensor Signal Biased/Stuck Lean (Bank 1 Sensor 1) 0x2D34: 11572. When the mixture is rich the oxygen content is low and the voltage signal will remain on the high side of the 450 mV mid-range. Bad oxygen sensor? Voltage goes to 0. Have you done the resistance check on the o2 sensor yet?. It is as if the circuit between the sensor and computer is not complete. Time necessary to complete sample is based on engine speed. 45 volts or higher. This is neither rich nor lean. 7:1), the sensor will generate around 0. It should have, as the voltage is only 0. The mid point is about 0. Still has a slight miss but no SES light. Jeep Cherokee 1984-2001: How to Read OBD Trouble Codes. If this comparison shows little or no Oxygen in the exhaust manifold, a voltage is generated. Some O2 sensors have three wires and an internal heating element to help the sensor reach operating temperature more quickly. The signal can vary from a low of about 0. 9 volt does not apply all the times. With this code, the technician will primarily be interested in the data for the indicated O2 sensor. Learning how to check an oxygen sensor (O2) will help you confirm a potential problem with the sensor in your vehicle before you spend time and money replacing a unit that might not even need a replacement in the first place. The downstream O2 has only one job, that is to monitor the catalytic converter. 45 volts, fluctuating a bit up and down. Learning how to check an oxygen sensor (O2) will help you confirm a potential problem with the sensor in your vehicle before you spend time and money replacing a unit that might not even need a replacement in the first place. For Nissan to go back to an O2 sensor for pre cat would be like going back to vacuum tubes. 2 volts to above 0. Read more about C4 Diagnostic Trouble Codes at CC Tech. The code may not include the "P". light the propane torch and hold the tip of the inner blue cone on the oxygen sensor. Also a bad sensor or connection can cause low voltage. In many cars, the computer sends out a bias voltage of 0. 47 [volt] because it is not reached light-off temperature, so ECU recognize lean fuel control and add injection time. I’m sure mountainbike knows that an O2 sensor generates its own voltage. First 15 minutes highway drive all monitors except O2 heater sensor and Evap ran. The O2 sensor acts as a small battery as it has the ability to produce a low voltage signal (between 0. CASE 1: The O2 sensor signal voltage moved up and down the as the engine idled. 45 through the O2 sensor wire. What is the life expectancy of an oxygen sensor? Heated oxygen sensors should be checked or replaced every 60,000 miles, while unheated or one wire oxygen sensors should be checked or replaced every 30,000 miles. You may have to increase the RPM to a fast idle to check the voltage of the bank 2,2 sensor. I just replaced the CATALYTIC CONVERTER but the scanner STILL shows a P0420 code. If you see the front sensor fluctuating normally and in range, and the rear oxygen sensor fluctuating as well, and within 80% of the front sensor voltage for more than 12 seconds or so, the catalyst is failed. Login with Google Login with Facebook Login with Facebook. Discover over 1855 of the best Selection Rate Voltage on Aliexpress. Refer to the WBO2 sensor pin-out (in this link), to verify your wiring is correct:. 5 volts may not be enough to set the code, but it depends on the vehicle) and you don't have any other o2 sensor codes present in the PCM, then it's a good bet that the sensor is bad. The output of the sensor is usually between 0 and 1. (which i think may indicate it is faulty?) you can see in the image below that Sensor 2 has a constant voltage and does not change where as sensor 1 jumps all over the place. I unplugged front 02 sensor on R side (bank 1) and it pegged to zero. Check the wiring and connections to the sensor. Code 14- Coolant sensor circuit-high temperature indicated. A fully warm O2 sensor *will not spend any time at 0. The O2 sensor signal should fluctuate under normal conditions. Start the engine. Is this negative voltage reading symptomatic of a faulty oxygen sensor, or. 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. It detects the amount of oxygen in the exhaust gas compared to the outside air. 1 volts with a HOT, neutral idle engine. The rear o2 still says 0 volts. If it did, check for water intrusion or other connector problems. It's constantly reporting 0. Oxygen sensor before catalytic converter, system check: Signal fixed at lean: The diagnostic function monitors the voltage of the pre-catalyst oxygen sensor and compares it with the voltage of the oxygen sensor behind the catalytic converter (at lambda = 1). Rang out harness wiring and found no opens. Supply voltage can be checked at terminal C with the ignition on. 45 volts is recognized by the PCM as a rich exhaust; below 0. At operating temperature the oxygen sensor signal varies between 0 and 1,000 mV. In operation, the sensor is connected to the power supply and monitoring circuit via the electrical connector, and the gas sample is supplied via the pressure connector. Output voltage of heated oxygen sensor remains at 0. The sensor can tell the computer when it’s stoic. and richer the longer you stay stuck to the. The ECU would add more fuel and get a rich voltage back rom the sensor,except the ECU is programmed. 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. (Use back probe method, DO NOT pierce the wire. This is neither rich nor lean. 1 volt, to about 0. A fully warm O2 sensor *will not spend any time at 0. With KOEO (Key on engine off) disconnect the o2 sensor and look for signs of corrosion or water intrustion. What is an oxygen sensor? Oxygen sensors work by burning some of the unburned oxygen in the exhaust, producing voltage which varies by the percentage of oxygen in the exhaust, thereby telling the computer how rich or lean the mix is. A reduced amount of oxygen means there is too much fuel in relation to the amount of oxygen. It detects the amount of oxygen in the exhaust gas compared to the outside air. Sensor 2, Bank 1 & 2 (after-cat) read aprx. An oxygen sensor that has failed completely can't be fixed without fully replacing it, but you can follow these maintenance tips to keep your oxygen sensor in tiptop shape for as long as possible:. How Do I Dial In The Right Air/Fuel Ratio For Today’s Oxygenated Fuels Using A Wideband O2 Sensor? Q. The oxygen sensor in your vehicle outputs a voltage to your car’s computer based on the amount of oxygen in your combusted air fuel mixture. The O2 sensor codes will be set if the O2 sensor readings remain low (lean), or high (rich), or do not change quickly enough, or do not change at all. Read more to find out more about these symptoms and how to correctly diagnose and replace a failing oxygen sensor. 5 Volts and up to 19. 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. Your oxygen sensor, sometimes called an O2 sensor or air-fuel ratio sensor, measures the oxygen level in your exhaust gases. 66 "constantly. 45 volts or so. Maximum sensor voltage for test cycle N/A N/A Volt CAN MODE $06 TEST RESULTS CHEVROLET MID Monitor Name TID Test Results Value Min Max Units $01 OXYGEN SENSOR MONITOR BANK $01 PASS 1-SENSOR 1 RICH TO LEAN SENSOR VOLTAGE-B1S1 0. When there is low voltage, the mix is lean — not enough oxygen. 45 through the O2 sensor wire. Voltage there should be 5 volts + or - 0. The oxygen sensor after the catalytic converter is a diagnostic sensor which monitors the efficiency of the converter. 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 oxygen sensor signal will then measure a rich signal which causes the DME to compensate for the problem by making the mixture lean. Don't thgink a resistor is the way--you want something regulated. Fuel trim make no sense for a downstream O2 Sensor. If so, replace the o2 sensor, it's shorted internally. Don't confuse EGO and O2 voltage. Use a 10-megaohm digital voltmeter. Unleaded fuel is essential to the proper and continued operation of the O2 sensor. 0 volts nominal. The on-board computer or Powertrain Control Module (PCM) monitors the voltage from the oxygen sensor. Innovate Motorsports LC-2 builds upon the legacy of the LC-1 by adding simplicity and leading edge technology. Maximum sensor voltage for test cycle N/A N/A Volt CAN MODE $06 TEST RESULTS CHEVROLET MID Monitor Name TID Test Results Value Min Max Units $01 OXYGEN SENSOR MONITOR BANK $01 PASS 1-SENSOR 1 RICH TO LEAN SENSOR VOLTAGE-B1S1 0. If you have 4 wires they will be: " Heater 12 Volts + " Heater ground " Oxygen sensor signal + " Oxygen sensor signal ground. 1A Auto has a large selection of aftermarket O2 Sensors for many makes and models, including Upstream (Front) Sensors, Downstream (Rear) Sensors, and more. 475 volt all the time. My conclusion is that if you are getting a Bosch Universal Oxygen Sensor, they are all the same , except the heater wattage, and how they electrically hookupactual construction is the same. Hey guys, My truck is a 1996 Nissan Truck IMAGE. Check connection to O2 sensor for corrosion as well as wire degradation. We have a complete list of Mustang DTC check engine codes located in one place! No more scouring the internet to find what that “service engine soon” code means. 2 volts when the fuel mixture is lean (more oxygen in the exhaust). Look at the PID for the front oxygen sensor. But you just learned how to replace an oxygen sensor without damage to the exhaust manifold, catalytic converter, or exhaust pipe. 45 volt rich/lean switch point for optimum fuel efficiency and emissions. If the voltage isn't stuck low and the o2 sensor seems to be operating fine, it's likely sticking low. circuit or the MAP sensor. This is neither rich nor lean. If the voltage is stuck high then the engine is probably running rich for some other reason. The post cat o2s will stay and no switch if the car has cats on it and if they are working correctly. "Sensor 5" stays consistently at around 0. 48 volts is Stoichiometric, 14. The most important function of the MAP sensor is to determine barometric pressure. The mid point is about 0. To verify the fault (whether the fault is internal or external) disconnect the AFR sensor and either measure the continuity between the ECM AFR wires and the AFR connector or apply a varying voltage (O2 sensor simulator – 0. 100 Volts and 0. Typically 1 to 4-wire sensors are narrowband. Revving the engine should cause the sensor's voltage to change (react). Rang out harness wiring and found no opens. I have a 98 neon DOHC that has just over 100k miles on it. Part no: 2112B012501. As the O2 sensors heated up the voltage increased to roughly. A good sensor will oscillate from below 0. The rate of change that the O2 sensor detects is called the big slope. You can try replace 2/2 O2 sensor. 0 Volt or 0 up to 5 Volt fluctuating voltage range. Never use cleaning solvents of any kind on the O2 sensor, solvents can permanently contaminate the sensor element. 8 volts, so its doing its job. ) For a good sensor, voltage should fluctuate constantly between 0. 3 volts consistently even when unplugged. 5volts then fall to about 47. It is widely applied in many water quality applications, such as aquaculture, environment monitoring, natural science and so on. But before the O2 sensor can produce a voltage output signal, it must be hot (approx. I'm now getting a voltage signal from the rear O2 sensor again. ­Nissan says the rear heated oxygen sensor we replaced should read above 0. Oxygen sensor voltage after. 45 volts is recognized by the PCM as a rich exhaust; below 0. 6 volts most of the time, but the front O2 sensor is all over the board, when idling it jumps anywhere from 0-. Lean of stoichiometric (air/fuel ratio of approximately 14. 2001 F150, 4. 5 volts may not be enough to set the code, but it depends on the vehicle) and you don't have any other o2 sensor codes present in the PCM, then it's a good bet that the sensor is bad. i had p0134 primary a/f sensor no activity, and p1298 ELD High voltage. When there is low voltage, the mix is lean — not enough oxygen. 310 ($09EB) V $01 OXYGEN SENSOR MONITOR BANK $02 PASS 1-SENSOR 1 LEAN TO RICH SENSOR. This is neither rich nor lean. Modular V8 (4. 8 V (very RICH) for 10 seconds even though voltage output of the heated oxygen sensor output voltage is less than 0. They are both stuck between 0. This is one of the more common failures of an A/F sensor – its voltage sticks at the lean (or oxygen-rich) side of it’s range. Output voltage of heated oxygen sensor remains at 0. 9 x 2 Power / Signal Harness (1’ length) Oxygen Sensor Harness (10’ length) x 2 Installation instructions Connect the 6-pin Oxygen Sensor Harness Left and Right to the Zt-4 “O2 Sensor” ports. 0 volts for a conventional zirconia O2 sensor). Other tests:. If the 0, voltage is lower than 0. When the O2 sensor wears out, it does report the changes in the exhaust, but very slowly. 00 volts) to the AFR circuit. Any oxygen sensor that produces higher voltages, is determined to be a wideband oxygen sensor. The voltage produced should swing from app 0. In many cars, the computer sends out a bias voltage of 0. The lag time in the sensor makes it useless for correctly reading a surging engine. We have all heard them make scratchy noises as you turn them up or down. 9 volts when the fuel mixture is rich and there is little unburned oxygen in the exhaust. 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. 060 V at higher rpms (+2500) B1 S1 will start switching properly between 0. I took the oxygen sensor out again and put the torch to it to clean it off. The 450 mV value (GM) is called a bias voltage and it is not the same for all manufacturers. wire by testing. If the o2 sensor reading remains high (0. Start the engine. EGO is a kind of integrator function that acts on the O2 voltage. 7 parts air to 1 part fuel), the oxygen sensor produces 0. 6 V or (min) always above 0. The mid point is about 0. A GM O2 sensor signal stuck at 450 mV is an indication of an open O2 sensor circuit (signal wire) or faulty O2 signal ground. 445 v with ignition on and initial start of vehicle. Understanding the O2 Sensors' Voltage. This is a new type of oxygen sensor which is not yet widely used. 45 through the O2 sensor wire. With the engine warm, connect a multimeter set on a fairly low "volts" range (between 1 and 12) with one lead to the these tabs and the other to a good ground. Don't thgink a resistor is the way--you want something regulated. If no problem is found, replace sensor. I do not hear any exhaust leaks before the downstream O2 sensor. A fully warm O2 sensor *will not spend any time at 0. If the o2 sensor reading remains high (0. If an engine has suffered a recent head gasket failure, the O2 sensors may need to be replaced because of contamination. For wide-band O2 sensors and linear O2 sensors, the value may be higher, or it may be converted to a zero to one volt scale. Look at the PID for the front oxygen sensor. The mid point is about 0. Location: Bank 1 Sensor 1: P0132. I tested the voltage on the appropriate pins and had 12 volts there too. In many cars, the computer sends out a bias voltage of 0. 5 Volts as the engine idled. Most will operate down to 10. (which i think may indicate it is faulty?) you can see in the image below that Sensor 2 has a constant voltage and does not change where as sensor 1 jumps all over the place. Thimble type sensors feature a ceramic element that projects into the exhaust system and becomes electrically conductive at high temperature. We have worked hard to design a site that caters to everyones Nissan Versa Oxygen Sensor needs. P0133 (M) 1/1 O2 Sensor Slow Response: Oxygen sensor response slower than minimum required switching frequency. In oxygenated and iron replete cells, HIF-α subunits are rapidly destroyed by a mechanism that involves ubiquitylation by the von Hippel–Lindau tumor suppressor (pVHL) E3 ligase complex. What is the life expectancy of an oxygen sensor? Heated oxygen sensors should be checked or replaced every 60,000 miles, while unheated or one wire oxygen sensors should be checked or replaced every 30,000 miles. 9v at the top. need help with CIRCUIT ECU controlled O2 sensor enhancer If you want to go from 2 to 4 volts (wideband A/F O2 sensors) to 0. 2 volts) when the fuel mixture changes. If you have 4 wires they will be: " Heater 12 Volts + " Heater ground " Oxygen sensor signal + " Oxygen sensor signal ground. If you get a check engine light with an O2 sensor code, you've interrupted the circuit. It keeps posting code P0140, which basically states that the rear o2 sensor stays stuck at the middle of the range. The PCM needs to know if the vehicle is at sea level or at a higher altitude, because the air density changes with altitude. i had p0134 primary a/f sensor no activity, and p1298 ELD High voltage. 8 V (very lean condition) for 15 seconds, despite the HO2 sensor output. downstream sensor output is alternating voltage from near 0V up to 1V based on readings where generally below 0. You may have to increase the RPM to a fast idle to check the voltage of the bank 2,2 sensor. 450 volts) and lack of it will send the voltage signal high (over 0. 4 L four-cylinder Kia engines, there are two oxygen sensors. A fully warm O2 sensor *will not spend any time at 0. 52mm Digital Volt 0. For this test you will need a. 1 volts (lean) to 0. Add plugs to power wires to make each hookup quick and easy. If an engine has suffered a recent head gasket failure, the O2 sensors may need to be replaced because of contamination. Plus they don't cover replaceable items like the O2 sensors been down that street before with. Repair as necessary. Check for wiring and connections problems from the O2 sensor back to the ecm. The voltage then remained constant at the. The sensor's output ranges from 0. Time necessary to complete sample is based on engine speed. Wanted to check the wiring, so I applied 12 volts from the battery directly to the rear O2 heater circuit with the connector disconnected from the. 90 volts indicating proper a/f ratio. You can unplug one O2 sensor and read the trouble codes with an OBD2 scanner to see what the trouble code is saying. A perfectly balanced (stoichiometric) fuel mixture of 14. A good sensor will oscillate from below 0. This is neither rich nor lean. COMPONENT DESCRIPTION. If the Oxygen Sensor signal ever goes to a negative voltage or above 1 volt, this alone is enough to condemn the sensor. It should have, as the voltage is only 0. EZ CEL Fix oxygen sensor eliminator outputs the Engine computer with mimicked, fluctuating voltage signal and tricks the Electronic Control Unit into thinking the emissions are within allowance. This code definition indicates that either the oxygen sensor has failed, there is an exhaust. The voltage on the scanner moved slow and would get stuck at times or stay fixed.