if it were before the front sensor you would get a similar code on. As the cat degrades, the voltages starts to fluctuate and mirror that of the up stream sensor switching between rich and lean. Common OBDII Codes. This means the sensor is operating properly. With engine fully warmed, data stream for sensor one is -0. A downstream O2 will not oscillate rapidly. 8 Volt: Payment Shipping Returns Contact Us. 3 volts and rich readings range from. I have found the TaN / WHite sensor wire where it goes into the PCM. This causes less oxygen to be sensed by the sensor tricking the fuel computer into thinking the air:fuel mixture is richer than it is. 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. 0-5 volt analog output compatible with most any data logger or engine controller. If the O2 sensor is a traditional zirconia type sensor, the voltage output drops to about 0. Fits Except Automatic trans. Again, it may have a relay in the circuit as well. 1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. What down stream sensor detects is O2, if the level of O2 read by the upstream and downstream sensor is the same then ECU interprets it as bad cat. Does this indicate that the cat is working as required or is this voltage too high ?. Oxygen Sensor Output Voltage Bank 1-Sensor 1(V)0. A standard oxygen sensor measures neither oxygen nor fuel content in exhaust gasses. POSSIBLE CAUSES -O2 SENSOR BELOW 2. 1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. Bank 1 upstream reading lean, to normal, but a bit lean, while the downstream bank 1 O2 sensor is stuck at. 8 volts, so its doing its job. However, if the O 2 sensor harness voltage shows battery voltage on both heater wires (with the light still connected), locate the possible open circuit in the sensor’s negative wire. 9 volts (rich). For optimum catalyst operation, the air-fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The goal of the PCM is to keep O2 voltage moving across the 0. On a downstream O2 sensor, the heating element should be checked in the same manner as the upstream O2 sensor. Always lowest price on B Bosch. 1 Sensor no. ) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a. The voltage output range is 2. In response to the amount of oxygen found in the exhaust, the oxygen sensors output a voltage which can be read with a multi-meter, oscilloscope, or scan tool. Also, I can tell you that. 9 volts like the upstream sensor. The downstream O2 sensor is considered to be protected from extreme environments by the catalyst. This excess air reaching the catalytic converter confuses the upstream and downstream O2 sensors , and the on-board computer thinks there is a problem with the "oxygen storage" of the catalytic converter and it trips a trouble code. O2 thing supplies voltage--so find out what voltage=good, make up some kind of reducer/regulator that reduces 12 to that small number. Unlike the front O2 sensor, whose voltage varies. Find many great new & used options and get the best deals for 234-4703 Oxygen Sensor Downstream O2 02 for 2000-2003 Nissan Xterra 3. My LTFT is always at 0. 2pcs O2 Oxygen Sensor Up Downstream For 1998-2002 Honda Accord 2. Before the 1987 model year the O2 sensor was a single wire unit and it relied on the hot exhaust gases to heat the O2 sensor. Therefore, the downstream oxygen sensor (sensor 2) should produce a steady voltage of approximately 0. What Does an Oxygen Sensor Do in a Car? All cars that were manufactured post-1980 feature an oxygen sensor. CASE 2: The O2 sensor voltage was stuck above 0. All I can tell you is you have to play with that downstream EFIE. this sensor usually trips P0420 code if it works bad (could be also a bad cat converter too if sensor is OK). ² Set Condition: The oxygen sensor signal voltage is below 1. com http://1aau. The voltage was ~0. HOWEVER, the downstream, although new, did endure a lot of coolant when the motor blew. Newer vehicles will have accurate air fuel sensor voltages. Check Base Engine Idle, EGR, Fuel System and Air Induction System. According to my readings, an O2 sensor is actually a battery using the air going through as its fluid element!. 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. 0 Ohms resistance to the middle lead of the voltage regulator). New O2 Oxygen Sensor For. As I understand it, this sensor does not affect fuel trim but only monitors exhaust. ) For a good sensor, voltage should fluctuate constantly between 0. 6V within 20 seconds, if not, the most likely cause is an internal open circuit or lead fouling. NEW UPSTREAM DOWNSTREAM 02 O2 Oxygen Sensor for Acura Honda Accord Civic 2pcs. I have checked the downstream O2 sensor and i am 100% sure its working good, as i put it in a friends car (same as mine) and it was reading 0. The sensor's output ranges from 0. Would a clogged or bad fuel filter give the same code? I will check the wires and connector. If you were to unplug the O2 sensor and measure voltage on the O2 signal wire, you would see it. EX-O2-25V-O - Macurco Ex Series Explosion Proof Electrochemical Gas Detector for detection of Oxygen (O2) 0-25% vol. 5 volts for 3 seconds after starting engine. Check Base Engine Idle, EGR, Fuel System and Air Induction System. The DTC must be retrieved using a scanning tool. 0-5 volt analog output compatible with most any data logger or engine controller. With engine fully warmed, data stream for sensor one is -0. Basically, the PCM is looking for a steady reading of about. P0137 code definition. With the engine running, the O2 sensor signals are viewed in graphing mode on the scan tool. My question is if there is a small exhaust leak a foot downstream of the rear O2 sensor (at most a pin hole) AND outside air was going upstream that foot to the sensor wouldn't it simply read high all the time?. You guys have the o2 sensor backwards. The problem didn't move with the sensor. What my issue boiled down to is the ECU was getting a reading of incredibly lean mixture from the O2 sensor. The ECM's responsibility is to keep the oxygen sensor voltage switching between high and low voltage for optimum fuel efficiency, lowest emissions and highest miles per gallon. Ram Upstream Oxygen Sensor Goal Voltage From Star Center News #5, February 2000 - tests for those who have access to OBD II or OBD III code readers. My plan is to use feedback from my 1v output on my wideband setup to simulate the downstream sensor. I have found the TaN / WHite sensor wire where it goes into the PCM. An o2 sensor (not Wideband o2) cannot accurately measure HOW rich or HOW lean the exhaust is. New O2 - $512. (Use back probe method, DO NOT pierce the wire. 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. Since the introduction of OBDII with both upstream and downstream O2 sensors, the downstream O2 sensor has been used to evaluate catalytic converter operation and to control converter efficiency. If your Chevy Silverado is racking up miles, you might notice a significant decrease in fuel economy and engine power. Downstream O2 sensor circuit volts high. Testing O2 Voltage with a Meter. The converter now starts to clean the exhaust and remove the pollutants. From what I can tell you can run with downstream O2 always at 0. Upstream sensors actually control the air to fuel ratio, downstream sensors only purpose is to check catalyst performance (used to check effeciency of the catalytic convertor) if the converter fails or is removed both upstream and downstream will. It doesn't hurt if the total voltage goes above 1. An O2 sensor is a galvanic battery that provides the PCM with a voltage signal (0-1 volt) inversely proportional to the amount of oxygen in the exhaust. The upstream sensor should produce a signal pattern that switches between 0. 0 volts on the scan tool with the connector disconnected. Making the fuel mixture artificially rich by feeding propane into the intake manifold should cause the sensor to respond almost immediately (within 100 milliseconds) and go to maximum (0. After all, the "post catalytic" O2 sensors are now outputting 0. It will read an accurate mixture, usually, but not necessarily, a voltage of 0. (or O2 sensor 1) is. It has original O2 sensors and catalytic converters. This is not coming from the O2 sensor, but rather the computer. As fuel quantity decreases we return to a lean mixture, and sensor voltage drops. Best Answer: Hi Josh,it means that your O2 sensor # 1 (before the cat convertor) is showing high voltage. The ECM's responsibility is to keep the oxygen sensor voltage switching between high and low voltage for optimum fuel efficiency, lowest emissions and highest miles per gallon. I am confused about finding the signal ground BlacK / Light Blue. This is the 2nd sensor and its giving a PO137 and also the guy said something about another code=heater. Do not replace just one sensor replace them in pairs only. It should move very slowly in its voltage range indicating the catalytic converter is successfully reducing the amount of HC’s (hydrocarbons) emitted from the exhaust. POSSIBLE CAUSES -O2 SENSOR BELOW 2. 0 Oxygen Sensor Voltage (Bank 1 Sensor 1) 0. has anyone ever heard of an o2 sensor reading more than 1 volt? and does anyone have any direction to go with this? thanks. Repair the short to battery voltage in the (K141) O2 Sensor 1/2 Signal circuit. Oxygen O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2) What does that mean? This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. If an engine has suffered a recent head gasket failure, the O2 sensors may need to be replaced because of contamination. Order today by 4 P. An O2 sensor is a galvanic battery that provides the PCM with a voltage signal (0-1 volt) inversely proportional to the amount of oxygen in the exhaust. this sensor usually trips P0420 code if it works bad (could be also a bad cat converter too if sensor is OK). 4: Notice that the rear or downstream oxygen sensor is producing about 0. When the car got turned off it took minutes for the voltage to drop to 0 so I figured that changing a sensor on a 10 year old car isn't that crazy. Bank 1 upstream reading lean, to normal, but a bit lean, while the downstream bank 1 O2 sensor is stuck at. You guys have the o2 sensor backwards. Still has a slight miss but no SES light. 7:1, gives a reading of around 0. New O2 - $512. 3L F23A1 F23A5 | eBay. Changed out front sensor with another new Bosch unit and both still read 0 voltage. 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. An O2 sensor voltage above 0. Upstream sensors actually control the air to fuel ratio, downstream sensors only purpose is to check catalyst performance (used to check effeciency of the catalytic convertor) if the converter fails or is removed both upstream and downstream will. The upsteam sensor was reading a pretty steady 0. 1 v) to near maximum (0. Here are the Competition Sensor in stock ready to ship today. 3L F23A1 F23A5 | eBay. 500v is considered stoichmetric (the proper amount of fuel). The sensor should cycle between 0. Does this indicate that the cat is working as required or is this voltage too high ?. code p0420 has appeared. Again, it may have a relay in the circuit as well. As I understand it, this sensor does not affect fuel trim but only monitors exhaust. The higher the number of O2 cross counts, the better the sensor and other parts of the computer control system are working. 2 volts when the fuel mixture is lean (more oxygen in the exhaust). This also means that the high voltage the downstream O2 sensor is reporting is being caused by a genuine Rich condition. You will need a scan tool with accurate enhanced data. 0 volts on the scan tool with the connector disconnected. Replacing Oxygen Sensors 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. For a complete wiring diagram Refer to Section 8W. The Jaguar X Type is fitted with 4 O2 sensors one up-stream and one down-stream on each of Bank 1 and Bank 2 in line with OBDII requirements. You should see a DC voltage of at least 0. The O2 sensor just reads oxygen content in the exhaust, THAT’S IT. You can also find other images like images wiring diagram, images parts diagram, images replacement parts, images electrical diagram, images repair manuals, images engine diagram, images engine scheme diagram, images wiring harness diagram. 0 Oxygen Sensor Voltage (Bank 1 Sensor 1) 0. Re: DIY: Replacement Of Downstream (bank 1 Sensor 2) O2 Sensor On 03-07 Accord 4cyl by Piyke : 5:06pm On Jan 04 , 2015. The upstream sensor should produce a signal pattern that switches between 0. Chevrolet Silverado 1999-2006: How to Replace Oxygen (O2) Sensors. What is the most important emissions control device on a vehicle today? The catalytic converter, because it cleans up any exhaust pollutants that exit the engine. Using a jumper wire, jump the (K141) O2 Sensor 1/2 Signal circuit to the (K904) O2 Downstream Return circuit in the O2 Sensor harness connector. 0 Volt fluctuating voltage range. 5 V, and a lean mixture will cause a low voltage output, around 0. 15 volts at upstream sensor. This sensor measures the pollutants making it through the converter and out of the tailpipe. Typical lean voltage readings are between 0 and. 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. 5 Volts DC and this is what your looking for (in a normally operating catalytic converter, the rear O2 sensor should report a steady voltage between 0. Don't thgink a resistor is the way--you want something regulated. Not a O2 sensor for pre cat. processing orders both local and international. 9 while for bank 1, sensor 2 I get a nearly constant voltage of about 0. Should the downstream sensor stay at the same voltage? Or can they swing a little bit?. I replaced both sensors (upstream and downstream) with new Bosch sensors from. So is my O2 sensor bad (too low - rich fuel/low O2)? Why I am asking. On rare occasions, the signal voltage can drop below 0. 8 volts, so its doing its job. Downstream O2 sensors work? 2002 Dodge Dakota, 3. 0 volts roughly three times per second if you're using an analog meter. With engine fully warmed, data stream for sensor one is -0. The range at idle was between 0. 78 once the engine is warm it moves slowly as I accelerate, but never oscillates up and. Step by step instructions on how to change the Oxygen O2 Sensor in your car. Testing the oxygen sensor (commonly referred to as O2 sensors) on your 4. Since this is a wideband A/F sensor, I do expect voltage above 1V. The signal from most O2 sensors varies between 0 and 1 volt. The voltage will drop a bit at idle and raise a little when running but should always be stable and not varying like the front sensor. As far as CAT temps, no, the scanner has no selectable entry for anythign related to the CAT. 3 volts or less to 0. 0 volts on the scan tool with the connector disconnected. HOWEVER, the downstream, although new, did endure a lot of coolant when the motor blew. 4Pack Oxygen O2 Sensor Up/Downstream for Ford Lincoln Town Car 3. 2 volts when the fuel mixture is lean (more oxygen in the exhaust). The catalytic converter works to maintain the stoichiometric air-fuel ratio 14. The post-catalyst sensor does not suffer this problem because most of the excess fuel and oxygen is consumed in the catalyst. When the mixture is lean, the voltage tends to drop down to about 0. When the catalytic converter fails the downstream O2 sensor will report a continuous fixed voltage above. P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2) Approx. The downstream sensor should read only lower amounts of O2 due to the oxidation taking place inside the cat. 11 v; sensor 2, 0. I'm not sure where to go from here. If the O2 sensor only produces a low- or high-voltage signal, either you have an engine performance issue or the oxygen sensor stopped working. Rich to lean threshold voltage. The dealership carrys 2 A/F sensors for the 2005 X depending on build date. Basically, the PCM is looking for a steady reading of about. As the cat degrades, the voltages starts to fluctuate and mirror that of the up stream sensor switching between rich and lean. 662 on three different dates. The time taken for the voltage to change from 0. It only checks to see if its above or below. Sometimes the sensor with show 0. 0 Oxygen Sensor Voltage (Bank 1 Sensor 1) 0. 0 volts on the scan tool with the connector disconnected. P0151-O2 SENSOR 2/1 CIRCUIT LOW LX ENGINE ELECTRICAL DIAGNOSTICS 9 - 153 ² When Monitored: Engine running for less than 30 seconds and the O2 Sensor Heater Temperature is less than 251°C (484°F) with battery voltage greater 10. Magnum EZ CEL Fix Oxygen sensor simulator is available to all cars, trucks and SUV's fitted with 1 up to 4-wire narrowband zirconia exhaust o2 sensors working in the standard 0 up to 1. What down stream sensor detects is O2, if the level of O2 read by the upstream and downstream sensor is the same then ECU interprets it as bad cat. It definetaly ran WORSE than before and was drinking gas like never before. I don't recall the CEL code, but it was the passenger side (ie. (Use back probe method, DO NOT pierce the wire. This means the sensor is operating properly. P0136 O2 Sensor Circuit Low Voltage (B1S2) Technical Description. 9V in Gen 1 and no codes will be thrown, but you will probably be throwing way too much gas down the cat. 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. When the fuel mixture is rich (less oxygen in the exhaust), the sensor's output jumps up to a high of about 0. The downstream sensor should read only lower amounts of O2 due to the oxidation taking place inside the cat. With the engine idling, the sensor voltage should be cycling from low voltage to high voltage. I've discovered that it looks for a slightly leaner mixture then the upstream sensor, and also for testing the cat is looks for a response time. The downstream O2 has only one job, that is to monitor the catalytic converter. Unplugged, the PCM shows default. P1621-O2 SENSOR REFERENCE VOLTAGE CIRCUIT LOW Theory of Operation Normally, the O2 Sensor signal voltage will fluctuate between 0. 500v is considered stoichmetric (the proper amount of fuel). Bank 1 Sensor 2 O2 Sensor X-Type Lambda Sensor Jaguar X-Type petrol (all years) Part Number C2S38497. 2007 Jeep Grand Cherokee 5. 035 or so volts but nothing compared to the same sensor on bank 1 which is. If the O2 sensor only produces a low- or high-voltage signal, either you have an engine performance issue or the oxygen sensor stopped working. P013A-O2 SENSOR 1/2 SLOW RESPONSE - RICH TO LEAN. 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. An oxygen sensor (O2 sensor) measures the amount of oxygen in the exhaust gases, sending the signal to the engine computer. ) For a good sensor, voltage should fluctuate constantly between 0. An O2 sensor is a galvanic battery that provides the PCM with a voltage signal (0-1 volt) inversely proportional to the amount of oxygen in the exhaust. On a downstream O2 sensor, the heating element should be checked in the same manner as the upstream O2 sensor. Data stream for second sensor is positive and appears normal. Standing facing the Flywheel end of the engine, Bank 1 is located on the right 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. 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. However, if the O 2 sensor harness voltage shows battery voltage on both heater wires (with the light still connected), locate the possible open circuit in the sensor's negative wire. * Registered users of the site do not see these ads. On rare occasions, the signal voltage can drop below 0. The O2 voltage will be exactly 450. "O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor2)" Checked the sensor, it was indeed high-ish 0. The PCM cuts the fuel to the engine upon deceleration, and O2 sensors should respond accordingly by a voltage output lower than 0. I'm getting an intermittent P013C code for passenger side downstream O2 sensor slow to respond rich-lean. If possible, avoid probing through the insulation to connect a meter to the wire. If the sensor is sluggish or reads low, it needs to be replaced. This continuous feedback loop is the heart of the fuel control system. Buy Chevy GMC Buick Pontiac Olds Isuzu O2 Oxygen Sensor - AM-4060167476 now at AM-AutoParts! Always Free Shipping. Expected voltage for downstream lambda sensor Car seems to be running well now, the odb2 diagnostics show a fairly regular 0. 4L upstream O2 sensor issue 2 Answers. RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. 445 v with ignition on and initial start of vehicle. Replacing Oxygen Sensors 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. With engine off, sensor 1 reads -0. 0 : Battery voltage BELOW NORMAL (< 7. An o2 sensor (not Wideband o2) cannot accurately measure HOW rich or HOW lean the exhaust is. Before I go any further, know that I have read the threads regarding O2 sensors before I posted this. When their is a lean condition, the voltage drops, when there is a rich condition, the voltage increases. The signal will however not flip-flop from 0. A "cold" engine makes the computer change the fuel air ratio so the output voltage of the o2 sensor switches between about 100 and 850/900 mV and after a while the sensor may output a switch voltage between about 200 and 700/750 mV, for turbocharged cars even less. This sensor measures the pollutants making it through the converter and out of the tailpipe. Code P0137 references a circuit voltage issue with the downstream oxygen sensor located after the exhaust catalyst. The computer doesn't detect how high the voltage goes. Therefore, the downstream oxygen sensor (sensor 2) should produce a steady voltage of approximately 0. 0-5 volt analog output compatible with most any data logger or engine controller. If any of the tests fail, then the upstream O2 Sensor should be replaced. It's constantly reporting 0. 9 volts but sometimes passing 0. 450 volts) and lack of it will send the voltage signal high (over 0. Backprobe the connector near the O2 sensor to connect the voltmeter to the sensor signal wire. 1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. Theory of Operation. This month, we're moving downstream to diagnose a bad O2 sensor. your downstream oxygen sensor (bank 2) is going bad. Unlike narrow band sensors that communicate to the computer by means of a voltage on a single wire, the wide band sensor uses two wires and signals the computer by means of a current flow. When replacing a sensor, don’t miss the opportunity to use the test above on the replacement. ) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a. Now an oxygen sensor outputs a voltage between 0 and about 1 V depending on the difference between the amount of oxygen in the exhaust and the amount of oxygen in normal air. 800 mV, which is slightly high for a post-catalyst sensor. Data stream for second sensor is positive and appears normal. 7L GM vehicle is not that hard to do. For optimum catalyst operation, the air-fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. However, you can clearly see that the average cruise value is about 600 mV, indicating that this converter is oxidizing. Downstream NOx sensor reports O2 open wire. This product is small size, easy to. 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. 9 volts (rich). What my issue boiled down to is the ECU was getting a reading of incredibly lean mixture from the O2 sensor. Order today by 4 P. The sensor's voltage reading should also be fairly steady (not changing up or down), and average 0. The oxygen, or O2, sensor reads the percentage of oxygen in the exhaust coming from the engine and sends this information to the computer. Is the voltage above 0 volts? Yes. O2 Sensor Reading 0 5v Bad ECU?? - Volvo Forums. I don't see any issues with exhaust system. In the example below, the downstream sensor voltage uses almost the whole 0-1 Volt range during a test drive. HOWEVER, the downstream, although new, did endure a lot of coolant when the motor blew. P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2) Approx. 45 volts as a lean exhaust. 2 volts indicates a lean mixture and 0. 9-volts indicates a rich mixture. The time taken for the voltage to change from 0. I have a code P0420 in my '04 Civic Si. 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. When the fuel mixture is rich (less oxygen in the exhaust), the sensor's output jumps up to a high of about 0. This sensor measures the pollutants making it through the converter and out of the tailpipe. Also if the cat was failing you would have P0420 and P0430 associated to your o2 codes. 0 volts roughly three times per second if you're using an analog meter. Turn the ignition off, disconnect the O2 sensor harness connector. I am confused about finding the signal ground BlacK / Light Blue. An O2 sensor voltage above 0. With engine fully warmed, data stream for sensor one is -0. From there I tested my theory by cutting and using wire-nuts to run some temporary wire to the O2 sensor. ) For a good sensor, voltage should fluctuate constantly between 0. For the best answers, search on this site https://shorturl. CASE 1: The downstream O2 sensor's voltage decreased to. Oxygen 1 Sensor 4xUp+Downstream 2500HD 6. 5L 4-Wire O2 Oxygen Sensor. The downstream sensor should read only lower amounts of O2 due to the oxidation taking place inside the cat. The sensors are usually abbreviated as O2S1B1 (O2 Sensor, Bank 1) Sensor 1 output should be very active and oscillate rapidly from approximately 0 to less than 1 volt. It can be mounted anywhere close to the throttle body. The downstream O2 sensors are also pretty low voltage wise, they generate around 2. 7:1, gives a reading of around 0. Excess oxygen in the form of regular ambient air will send the O2 sensor voltage signal low (under 0. My 2001 PT Cruiser (2. This month, we're moving downstream to diagnose a bad O2 sensor. The sensor voltage should cycle or fluctuate within the 100 mV-900 mV (0. 45 volts as a lean exhaust. It definetaly ran WORSE than before and was drinking gas like never before. 5 volts for 3 seconds after starting engine. So is my O2 sensor bad (too low - rich fuel/low O2)? Why I am asking. I got a P0420 code on my Altima so I began looking at my O2 sensors with a diagnostic tool that showed me the waveforms and voltages. The voltage produced should swing from app 0. The sensor's voltage reading should also be fairly steady (not changing up or down), and average 0. P0136 "O2 Sensor Circuit Malfunction (Sensor 2). The ECM's responsibility is to keep the oxygen sensor voltage switching between high and low voltage for optimum fuel efficiency, lowest emissions and highest miles per gallon. Can clear code and it takes a long time to come back on. Magnum EZ CEL Fix Oxygen sensor simulator is available to all cars, trucks and SUV's fitted with 1 up to 4-wire narrowband zirconia exhaust o2 sensors working in the standard 0 up to 1. Does this indicate that the cat is working as required or is this voltage too high ?. 6 volts and behaving as it should, not bouncing around. What down stream sensor detects is O2, if the level of O2 read by the upstream and downstream sensor is the same then ECU interprets it as bad cat. P0140 code - the Downstream O2 sensor no activity diagnostic monitor is intended to diagnose Downstream O2 sensoe that is not moving or is stuck in a voltage window. Lean to rich threshold voltage. By narrowing the scope of the data stream to include only pertinent data, you will get a faster data response. 45 volts or higher. The oxygen sensor’s voltage signal is monitored by the onboard engine management computer to regulate the fuel mixture. Therefore, the downstream oxygen sensor (sensor 2) should produce a steady voltage of approximately 0. The sensor's voltage reading should also be fairly steady (not changing up or down), and average 0. 0 Volt fluctuating voltage range. 3L New at the best online prices at eBay!. I still have the same problem. 9 but not up to 1. 5 volts with the jumper wire in place. Is you check engine light on because of a bad oxygen sensor? You don’t have to spend your life savings to replace a defective O2 sensor. Code P0137 references a circuit voltage issue with the downstream oxygen sensor located after the exhaust catalyst. Real sensors go over 1. The Jaguar X Type is fitted with 4 O2 sensors one up-stream and one down-stream on each of Bank 1 and Bank 2 in line with OBDII requirements. The oxygen, or O2, sensor reads the percentage of oxygen in the exhaust coming from the engine and sends this information to the computer.