Exhaust Leak At Downstream Oxygen Sensor

Also make sure there is not an exhaust leak and that the cat is bolted squarely to the turbo. Plugged fuel injectors, a bad fuel pressure regulator, and a bad fuel pump can also cause a lean condition. O2 Sensor Wiring goes bad. Alternatively, one could check for exhaust leaks and correct them, if any. Its voltage depends on the amount of oxygen in the exhaust stream. To ensure your vehicle has optimal performance and fuel economy while producing minimal emissions replace a defective O2 sensor with one backed by the aftermarket's most rigorous testing process. I just got the Mass Airflow Sensor changed out since that was bad and did an entire tune-up on it. I was always told that if there is an exhaust leak after an O2 sensor that it wouldn't usually contribute to a problem but given the proximity of this O2 sensor to the leak could it be the reason for my idle issues? There is no downstream O2 sensor on this car. This will help you remove it later by making it significantly looser. A second oxygen sensor is mounted "downstream" or behind the converter to compare oxygen levels in the exhaust before and after the converter. Positioned in the exhaust manifold, the Chevrolet Aveo Oxygen Sensor forwards oxygen levels present in the engine's fuel system to the computer. P2099: Post catalytic converter fuel trim (FT), bank 2 -too rich and there are no exhaust leaks, a downstream oxygen sensor that is known to be good will generate. And if it's "after the O2 sensor" I'm assuming their referring to the downpipe to midpipe connection (if they're not bullspitting you). 25) Technician A says that oxygen sensors can have one, two, three, four, or more wires, depending on the style and design. The ECM would interpret that as a bad catalytic converter. But now there's no way I think the sensor is bad. ' Inline 4 cyl's only have one bank. I swapped the downstream sensors and the code went to the other side. Most emission-controlled cars have two to four oxygen sensors, depending on the amount of cylinders and exhaust pattern. 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? I am pretty sure this would be the case. O2 (Oxygen) Sensor Signal Stuck Lean Bank 1 Sensor 3 This is a downstream O2 sensor and is exclusively used to it is common for a mechanic to miss vacuum leaks or exhaust leaks that will. Further to my video about upstream sensors, he. Be sure to confirm the issue isn't related to exhaust leaks, the exhaust gas recirculation (EGR) system, vacuum leaks, the MAF sensor, etc prior to replacing the O2 sensor. The lambda sensor determines the remaining oxygen content in the exhaust emission, and provides the engine control with an electric signal to control the air-fuel ratio. Install new oxygen sensor and torque to specs. Apply anti-seize to rear O2 sensor threads, carefully put it on and tighten it. A more complete list of oxygen sensor symptoms and their causes can be found here. Finally, the other most common issue is an exhaust leak. 0 V6 4WD for months now. How Does an O2 Sensor Work. Step 4 - An exhaust leak will allow fresh air to enter the system on the negative pressure side of an exhaust event, this will cause an oxygen sensor to produce a lean reading. Keep in mind that the down stream sensor is only reporting that the drop of CO is not with in specified range or that the heater element is not working. Hooked a scan tool up and the new sensor is showing a voltage of between. That causes the upstream O2 sensor to see a continually lean exhaust and it adds fuel to compensate. Tech A says that this indicates a slow reacting oxygen sensor. converter and that the same O2 sensor that was right there was bad to but they could not fix and I would have to take it to a muffler shop. the upstream sensor was bad, i replaced it. 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. P0136 - HO2S Sensor Circuit Malfunction (HO2S-12) The downstream HO2S sensor(s) are continuously checked for maximum and minimum voltages. Easy to use parts catalog. A fault code for an O2 sensor will indicate the sensor location by sensor number (1, 2, 3 or 4) and by cylinder bank (1 or 2). If it was the culprit I'd expect both sides to be affected. The downstream O2 sensor in or behind the catalytic converter reacts to the exhaust gases as they exit the converter. Are you getting a P0430 code because Bank 2 catalyst isn't cleaning the exhaust. The P2270 DTC refers to downstream sensor (after the catalytic converter), sensor #2 on bank #1. If the MAF sensor has been cleaned and you still get the code, inspect all vacuum and PCV hoses for leaks. 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. The downstream O2 sensor is considered to be protected from extreme environments by the catalyst. You would be able to audibly hear an exhaust leak. With the vehicle running and at normal operating temperature, use the digital multimeter to check the voltage reading of the downstream O2 sensor. I have my old manifold/Cat from when it got a crack in it a few years ago. The first sensors on both banks were reading 0. Step 4 - An exhaust leak will allow fresh air to enter the system on the negative pressure side of an exhaust event, this will cause an oxygen sensor to produce a lean reading. This is done by removing a large vacuum hose and checking to see if the downstream oxygen sensor reports the vacuum leak. The conditions that caused this diagnostic to fail is when the upstream O2 Sensor biased from an exhaust leak, O2 sensor contamination, or some other extreme operating condition. I had a bad O2 sensor code, so I replaced the sensor. Often, the oxygen sensor is the cause of P0430. 2 Oxygen Sensor Installation The oxygen sensor should be mounted at a point where it can read a good average of all the cylinders on one bank. This means that an Oxygen sensor in bank 1 detected a lean condition: there's too much oxygen in the exhaust. I have a 2004 Camry 220,000 miles - check engine code indicates downstream oxygen sensor problem among others - exhaust system leak, etc. The upstream sensor was replaced, twice with a generic sensor, then with a hyundai sensor, the downstream sensor was also repl. It would be a good idea to check the exhaust for leaks first. The rich-to-lean sensor switch time is 0. ?Check for exhaust leaks at the manifold, pipes, catalytic converter. I talked to a fast rep and he claims that it will affect the sensor, I just don't see how if it's downstream. How O2 sensors react to exhaust leaks: '01 Audi A4 In this diagnosis and repair of a blown flexpipe on an '01 Audi A4 Quattro we observe how an exhaust leak upstream of an oxygen sensor can. P0136 is a generic code for types of trouble with oxygen sensors on "Bank One" of an exhaust system (FYI, if you have true dual exhaust Bank One will be dr. Without a scope/DSM/scan tool to see the signal in real time, it is hard to say whether to sensor is working well or not. Unfortunately, cleaning the O2 sensor will not fix the issue. My exhaust leak is downstream from all O2 sensors. What brand of O2 sensors should I use for replacements? Pay close attention to this one so you can do it once and do it right! The Jeep Wrangler TJ is extremely sensitive to all oxygen sensors other than NGK / NTK. 2 Oxygen Sensor Installation The oxygen sensor should be mounted at a point where it can read a good average of all the cylinders on one bank. The performance of the O2 sensors can be measured using a scan tool, a DVOM or a ­labscope. During this warm up period the computer would disregard the O2 sensor and function strictly off of the other sensors. This is a costly repair, but common with a p0420 code. The O 2 sensor typically screws into the vehicle's exhaust system, either in the exhaust manifold or a pipe downstream. My Subaru still runs fine with a very slight decrease in MPG. Oftentimes, a P0171 means that your Toyota is having trouble with a dirty or faulty mass air flow (MAF) sensor, or a vacuum leak downstream of the MAF sensor (perhaps in the PCV line or in the valve itself). Our mini oxygen sensor converter can only solve the Problem of P0420 codes-faulty Catalytic converter. Greetings all, I've got a 2013 Suburban with the 5. The more the downstream sensor switches in relation to the upstream sensor, the less efficient the converter is at storing and releasing oxygen. The oxygen sensor is an important part of a car engine. Engine light refuses o go out 37 Answers. is the one after the cat a downstream or upstream? and will putting a downstream o2 sensor on a upstream mess it up and vice versa?. Absolutely it can, the bogging is probably from the computer misinterpreteing the information from the o2 sensor, fix the leak, maybe replace the sensor (downstream o2 sensors often break upon removal, also check the sensors resistance while you're under there to make sure it's within normal range) and you'll probably be good to go. Each element is incredibly. Contaminated or damaged sensor. The trick is in both removing and installing the sensor. If it keeps on switching like the upstream sensor, it tells you the catalyst is probably bad and the converter needs to be replaced. The voltage signal is proportional to the amount of unburned oxygen in the exhaust. Using an oxygen sensor socket, remove oxygen sensor from exhaust pipe. If the MAF sensor has been cleaned and you still get the code, inspect all vacuum and PCV hoses for leaks. A leak in the exhaust system before the O2 sensor will also cause incorrect readings. The heated oxygen sensor senses the oxygen concentration in the exhaust gas and, converts it into a voltage which is sent to the ECM. This will help you remove it later by making it significantly looser. P0420 code definition Catalyst System Efficiency Below Threshold (Bank 1) What the P0420 code means The purpose of the catalytic converter is to break down If the downstream oxygen sensor is. I'm using band clamps about 24" downstream from o2 sensor so they do leak enough that I can see the black soot where they leak. If you want more help on how to diagnose the P0420 code, you can check out our P0420 Troubleshooting article. Downstream means the O2 sensor is "downstream" of the catalytic convertors, meaning after the catalytic convertors. Replace as necessary. Bank 2 is the bank of the engine that does not contain cylinder #1. Should this go out again within a year. To understand why an exhaust leak is so detrimental to O2 sensor (also known as a wideband sensor) performance, one must first understand how an O2 sensor works. Rather like a battery, the sensor produces a voltage between 0. This fluctuation (waveform) is first measured by the upstream (pre-cat) oxygen sensor. Acura TL 2004-2008: How to Replace Oxygen (O2) Sensor. The engine light went on and was triggered by a 'faulty' oxygen sensor. Can an exhaust leak cause your car to give bad readings? such as O2 sensors are bad? I have been having issues with my 99 Jeep Grand Cherokee 4. Grand Cherokee oxygen sensor locations for 4. Oxygen sensors (3, 13) are provided upstream and downstream of a three-way catalytic converter (10) in an exhaust passage (9) of an internal combustion engine (1). Catalytic Converter is clogged. There could also be a vacuum leak in the engine causing this code. Details about 2x Oxygen Sensor Upstream & Downstream for GMC Chevy Savana Silverado For Buick. Adult Content Warning. They also told me that there was an exhaust leak after the headers but before the cat. It has to be something else causing that code to be generated. Exhaust Leaks Before or Near Heated Oxygen Sensor (HO2S) Gasket Leaking Harness Connections Incorrect Harness or Heated Oxygen Sensor (HO2S) Short to Voltage Heated Oxygen Sensor (HO2S) Heated Oxygen Sensor (HO2S) Circuit Open Oil Overfull Positive Crankcase Ventilation (PCV) System Leaking or Valve Stuck Open Powertrain Control Module (PCM. fault is downstream from exhaust manifold. Slide the oxygen sensor wrench over the sensor and twist it counterclockwise to unscrew it from the pipe. Most exhaust manifolds will get up to 600° but it wouldn’t happen until the engine had been running for several minutes. A fault code for an O2 sensor will indicate the sensor location by sensor number (1, 2, 3 or 4) and by cylinder bank (1 or 2). Diagnostic Test 1. I change the rear O2 sensor: take connector off, cut the clip to the engine block, use a wrench to take the rear oxygen sensor off. I talked to a fast rep and he claims that it will affect the sensor, I just don't see how if it's downstream. converter and that the same O2 sensor that was right there was bad to but they could not fix and I would have to take it to a muffler shop. Does post cat oxygen sensor affect gas mileage? This is a discussion on Does post cat oxygen sensor affect gas mileage? within the General Help forums, part of the LSx Technical Help Section category; My car has 210,000 miles now and I just realized that I still have the original O2 sensors. When the signal from the O2 sensor is detected by the PCM as being stuck lean or biased lean, this DTC is set. The Oxygen Sensors (O2S) are attached to, and protrude into the vehicle exhaust system. I had a bad O2 sensor code, so I replaced the sensor. I talked to a fast rep and he claims that it will affect the sensor, I just don't see how if it's downstream. ^ (side tracked) and can't see the downstream sensor =\. For a good quality gasket you're looking at about $20 for an OEM donut gasket, 2. The Bosch oxygen sensor utilizes a mix of zirconium and yttrium oxides and other elements to form a tough base that withstands the intense stress to which oxygen sensors are subjected. If you have a massive exhaust leak at the flange, the outside ambient air would consist partially of exhaust and give a bad reading. Upstream O2 is used to determine the A/F ratio of the mixture burned in the engine. This is how an exhaust leak can hurt your car. Disconnect the harness connected to the sensor and remove the sensor. You'll have to check o2 storage of the cat to rule it out. so the code is for a voltage problem in the front downstream O2 sensor. Usually, an exhaust leak will simply make your car louder and could allow you to smell exhaust fumes in the cabin of your car. A controller (2) performs feedback correction of an air-fuel ratio of an air-fuel mixture burnt in the engine (1) by proportional/integral control based on the output of the upstream oxygen sensor (3). A General Motors vehicle is being checked using mode $06 for the proper operation of the oxygen sensor. and upstream O2 sensor, which I replaced (after mkt Cat. You should also inspect the exhaust system and converter for leaks. The more the downstream sensor switches in relation to the upstream sensor, the less efficient the converter is at storing and releasing oxygen. Often, the oxygen sensor is the cause of P0420. The sensor produces a voltage that changes when the amount of unburned oxygen in the exhaust changes. Do NOT mount the sensor far back in the exhaust as this will negatively impact closed loop operation response. The oxygen sensors are threaded into the exhaust manifold and/or exhaust pipes on all vehicles. Before you start replacing the oxygen sensor we need to identify which oxygen sensor needs to be replaced. It is necessary to clean the sensor to ensure that performance is not negatively affected. They also told me that there was an exhaust leak after the headers but before the cat. There are a number of threads on here that are about this trouble code and iirc none of them required replacing the cat or O2. The upstream oxygen sensor also provides an input to determine catalytic converter efficiency. 800V My reading for Bank 1 sensor 1 (Wide Range O2) Equivalence Ratio is 1 and not changing. The performance of the O2 sensors can be measured using a scan tool, a DVOM or a ­labscope. The escape is seems like it is running great but now both downstream 02's are reading extremely rich under idle and extremely lean under load. A leak before the first O2 sensor can cause it to read incorrectly and and incorrectly adjust the A/F mixture. Oxygen sensors detect the amount of oxygen content in the exhaust stream. In that case, your OBDII scanner should be reading a lean 0. The downstream or diagnostic sensors only monitor the exhaust leaving the catalytic converter and will not cause such an issue. It is a feedback sensor used by the Engine Control Module (ECM) to perform closed loop control of engine fueling and, if a post catalytic converter sensor is present, monitor catalytic converter function. It would be a good idea to check the exhaust for leaks first. Using an oxygen sensor socket, remove oxygen sensor from exhaust pipe. P013A-O2 SENSOR 1/2 SLOW RESPONSE - RICH TO LEAN. This is the third time I've had both that code, and the P0133 code which indicates bank 1 sensor 1. ?Check for exhaust leaks at the manifold, pipes, catalytic converter. So the upstream sensor voltage should switch with mixture changes, but the downstream sensor voltage should be fairly steady. P0420 is either a leak in your exhaust or a bad catusually its a bad cat. An alternative to the Mopar air checking fluid is bubble solution (Mr Bubbles) or a mixture of Meguiar's car wash soap (the one in the purple jug) and water in a spray bottle. The powertrain control module constantly flip-flops between rich and lean air-fuel mixtures due to the input from the upstream oxygen sensor (sensor 1). Which technician is correct?. 4 L four-cylinder Kia engines, there are two oxygen sensors. Set Condition: The conditions that cause this diagnostic to fail is when the Upstream O2 Sensor becomes biased from an exhaust leak, O2 Sensor contamination, or some other extreme operating condition. Replacing an aging O2 sensor that has become sluggish can restore peak fuel efficiency, minimize exhaust emissions and prolong the life of the converter. Follow the exhaust pipe (called the down tube) from the manifold to the large oval catalytic converter that bolts to the pipe. But, don't be surprised if it's not. P0420 code definition Catalyst System Efficiency Below Threshold (Bank 1) What the P0420 code means The purpose of the catalytic converter is to break down If the downstream oxygen sensor is. All O2 sensors are vented to the atmosphere which contains Approximately 21% oxygen. A fault code for an O2 sensor will indicate the sensor location by sensor number (1, 2, 3 or 4) and by cylinder bank (1 or 2). The PCM compares the readings of the upstream and downstream O2 sensors to see how well the converter is reducing pollutants in the exhaust. p0430 catalytic or o2 sensor Silverado Car Forums exhaust leaks, faulty oxygen sensors, and a faulty catalyst. Also make sure there is not an exhaust leak and that the cat is bolted squarely to the turbo. An alternative to the Mopar air checking fluid is bubble solution (Mr Bubbles) or a mixture of Meguiar's car wash soap (the one in the purple jug) and water in a spray bottle. It is constructed from high quality stainless steel, porous polytetrafluoroethylene, fluorine rubber, aluminum oxide, high-grade platinum and ceramics. > Oxygen Sensor wiring and connector: perform a meticulous visual inspection of the upstream and downstream O2 sensor wiring and connectors. converter and that the same O2 sensor that was right there was bad to but they could not fix and I would have to take it to a muffler shop. These sensors are broken down into two categories, upstream and downstream. Any sign of exhaust leaks, overheating or excessive corrosion may be an indication of replacement. I talked to a fast rep and he claims that it will affect the sensor, I just don't see how if it's downstream. 1 is usually the one in the exhaust manifold, while sensor No. Check for leaks as far a 2 feet behind the Downstream O2 sesnsors. A leak downstream before the catalytic converter can trick the oxygen sensor into thinking the engine is running lean. Check the area for leaking oil and anti-freeze. A leak in the exhaust system before the O2 sensor will also cause incorrect readings. Oxygen sensors in general are normally located before and/or after the catalytic converter. To diagnose a P0420 trouble code we begin by checking for exhaust leaks under the vehicle. The rich-to-lean sensor switch time is 0. If this doesn't work, try checking for dirty fuel filter and see that proper fuel pressure is observed. As it is prone due to the fact that it is right next to the hot exhaust at all times. The P2270 DTC refers to downstream sensor (after the catalytic converter), sensor #2 on bank #1. Before you start replacing the oxygen sensor we need to identify which oxygen sensor needs to be replaced. Just finished install of the new pipe and gasket yesterday, so far no leaking and the truck runs smoother. The PCM cuts the fuel to the engine upon deceleration, and O2 sensors should respond accordingly by a voltage output lower than 0. The O2 sensor is located on the exhaust pipe, close to the engine. But now there's no way I think the sensor is bad. A more complete list of oxygen sensor symptoms and their causes can be found here. I have no exhaust leaks. An exhaust leak can cause your O2 sensor to read incorrectly. The O2 sensor he said wasn. The O2 sensor in question is the one in the top of the exhaust manifold nearest the firewall. The downstream O2 sensor is located in the exhaust path behind the catalytic converter, and is monitored for proper response to assure optimum catalytic converter efficiency. The performance of the O2 sensors can be measured using a scan tool, a DVOM or a ­labscope. There could also be a vacuum leak in the engine causing this code. Anytime Exhaust can leak out of the system before crossing the O2 sensor you lose some signaling power at the sensor, corresponding to this, air may be sucked into the exhaust system between exhaust pulses due to negative pressure, further contaminating the reading. The upstream sensor was replaced, twice with a generic sensor, then with a hyundai sensor, the downstream sensor was also repl. When the signal from the O2 sensor is detected by the PCM as being stuck lean or biased lean, this DTC is set. is there a difference between downstream and upstream o2 sensor? i have a honda accord 2001 v6. There are a number of threads on here that are about this trouble code and iirc none of them required replacing the cat or O2. You would be able to audibly hear an exhaust leak. Exhaust Leaks Before or Near Heated Oxygen Sensor (HO2S) Gasket Leaking Harness Connections Incorrect Harness or Heated Oxygen Sensor (HO2S) Short to Voltage Heated Oxygen Sensor (HO2S) Heated Oxygen Sensor (HO2S) Circuit Open Oil Overfull Positive Crankcase Ventilation (PCV) System Leaking or Valve Stuck Open Powertrain Control Module (PCM. One is upstream of the catalytic converter, and one is downstream. 95 volts if the catalytic converter is doing its job properly and there are no problems. I had a malfunctioning rear 02 sensor last year and it was a P0136 code, replaced the sensor and it went away. Weld at O2 sensor leaking (Use Soapy Water test to determine). 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. NOTE: Check connectors - Clean/repair as necessary. Does that suggest a weak O2 sensor needing replacement?. Condensation buildup can destroy a sensor very quickly, so mounting the sensor between 9 o’clock and 3 o’clock protects it from water build-up at the bottom of the exhaust pipe. This is the second O2 sensor gasket on this vehicle and I must say that it seems to be of a much higher quality than the standard gaskets available which do not have a metallic coating as this one does, the potential for continued compression and eventual leaking. 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. There is a leak in the junction of the exhaust pipe to the driver side catalytic converter. Any O2 sensor that is defective obviously needs to be replaced. 2 Oxygen Sensor Installation The oxygen sensor should be mounted at a point where it can read a good average of all the cylinders on one bank. It will produce a relatively stable. Hello everyone. 500 volts) and it should hold this reading as long as the engine idles; If the downstream oxygen sensor fluctuates in a similar manner to the upstream oxygen sensor, the catalytic converter is most likely faulty. That causes the upstream O2 sensor to see a continually lean exhaust and it adds fuel to compensate. The tiny hole is downstream and equidistant. Failed emissions test? Check engine light on? You may need to replace your catalytic converter. The parts and labor required for this service are. It would be a good idea to check the exhaust for leaks first. This leak will allow air to be pulled into the exhau st and cause a false lean concern at the post O2 sensor. Downstream means the O2 sensor is "downstream" of the catalytic convertors, meaning after the catalytic convertors. Many of these symptoms could be related if the O2 is reading different than the actual reading and adjusting the A/F mixture. 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. Front cylinders are 2-4-6 so that is bank 2. The O2 sensor has a green wire extending from it; the sensor is white and it looks almost like a spark plug. The oxygen sensor is an important part of a car engine. Bank #1 is the side of the engine that contains cylinder #1. Toyota Camry Oxygen Sensor Replacement costs between $133 and $672 on average. What would the recommended fix be??. Thus a damaged O2 sensor wiring can cause p0420 Toyota Prius trouble code. Locate the faulty O2 sensor which should be positioned in the exhaust manifold just before or just after the catalytic converter. Check to see if the O2 sensor responds correctly to rich and lean fuel conditions. Make sense? _____. The heated oxygen sensor senses the oxygen concentration in the exhaust gas and, converts it into a voltage which is sent to the ECM. Read more to find out more about these symptoms and how to correctly diagnose and replace a failing oxygen sensor. Now O2 sensor Sensor 2 is a sin wave from 0. Further to my video about upstream sensors, he. When the engine is first started, the downstream O2 sensor's output will mirror that of the upstream O2 sensor, and flip-flop back and forth between rich and lean. Remember, any deviation from. As the oxygen content changes at the downstream sensor, the PCM calculates how much air-fuel ratio change is required. But there may also be benefits to replacing the O2 sensor periodically for preventive maintenance. Thus a damaged O2 sensor wiring can cause p0420 Toyota Prius trouble code. A low reading could indicate a vacuum leak or possibly a leaking EGR valve. Looks like the truck has 2 or 3 sensors. Show Full Signature. 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. RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Step 4 - An exhaust leak will allow fresh air to enter the system on the negative pressure side of an exhaust event, this will cause an oxygen sensor to produce a lean reading. Engine Temp Sensor is bad. Thanks for your question. One option is to use some spark plug defoulers to set the o2 sensor out from the exhaust a few inches. Take the digital multimeter and check the voltage of the downstream o2 sensor. A leak farther downstream before the catalytic converter can trick the oxygen sensor into thinking the engine is running leaner than it really is, which will cause the computer to dump more gas into the cylinders. It is constructed from high quality stainless steel, porous polytetrafluoroethylene, fluorine rubber, aluminum oxide, high-grade platinum and ceramics. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING). Then I cleared the codes and it came back. But air can also be sucked into the pipe at the same leak. If you think your oxygen sensor is malfunctioning, there are a few factors to look into. Check for leaks as far a 2 feet behind the Downstream O2 sesnsors. Any ideas, please prey-tell!! I'm at my wits end here. •Pinched, shorted, corroded wiring or pins The code will set when the voltages•Crossed sensor wires fail to meet the calibrated limits. The parts and labor required for this service are. The tiny hole is downstream and equidistant. But there may also be benefits to replacing the O2 sensor periodically for preventive maintenance. Position: Downstream. 5 in exhaust gasket, and 30 minutes tops of your time to replace it. Positioned in the exhaust manifold, the Chevrolet Aveo Oxygen Sensor forwards oxygen levels present in the engine's fuel system to the computer. 3L and about 90k Miles. Specifically it'll usually be the O2 sensor(s) on the downstream side of the catalytic converter. My exhaust leak is downstream from all O2 sensors. The rich-to-lean sensor switch time is 0. EXHAUST LEAK ENGINE MECHANICAL PROBLEM 1/2 O2 SENSOR (K141) O2 SENSOR 1/2 SIGNAL CIRCUIT (K299) O2 1/2 HEATER CONTROL CIRCUIT (K904) O2 DOWNSTREAM RETURN CIRCUIT FUEL CONTAMINATION Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. The O2 sensor has a green wire extending from it; the sensor is white and it looks almost like a spark plug. If code P2096 returns then the problem is NOT with the downstream oxygen sensor. A fault code for an O2 sensor will indicate the sensor location by sensor number (1, 2, 3 or 4) and by cylinder bank (1 or 2). The conditions that caused this diagnostic to fail is when the upstream O2 Sensor biased from an exhaust leak, O2 sensor contamination, or some other extreme operating condition. For a complete wiring diagram Refer to Section 8W. The converter now starts to clean the exhaust and remove the pollutants. If the PCM does not detect a rich to lean switch within a specific time during a decel fuel shutoff event, the monitor will fail. To ensure your vehicle has optimal performance and fuel economy while producing minimal emissions replace a defective O2 sensor with one backed by the aftermarket’s most rigorous testing process. This demand causes a voltage to build up, due to transportation of oxygen ions through the sensor layer. Such a swing in A/F ratio is a sign that an upstream or control sensor is faulty. Oxygen Sensor is bad. The downstream O2 sensor is considered to be protected from extreme environments by the catalyst. Hello everyone. The only other possibilities are wiring issues, and computer concerns. The downstream O2 sensor should slow down and go flat when the converter lights off (if the catalyst is working). 2L F150 because I was getting a P0136 (Bank1 Sensor 2) code that I couldn't get rid of by cleaning the connector or fixing wires. How Does An O2 Sensor Work To understand why an exhaust leak is so detrimental to O2 sensor (also known as a wideband sensor) performance, one must first understand how an O2 sensor works. P0133, P0135, P0141: Oxygen Sensor Trouble Codes And The Cause. (If it's not too close to it). Oxygen sensors detect the amount of oxygen content in the exhaust stream. The escape of hot gases can also burn nearby spark plug wires and plug boots. Dealer wants over $300 to replace and says if the sensor is not replaced, damage will occur to catalytic converters. Federal Emissions Package (4. Labor costs are estimated between $61 and $78 and the parts are estimated between $97 and $190. Sensor 2 is "downstream" O2 sensors behind the catalytic converter. I don't hear any exhaust leaks from what I can tell. One option is to use some spark plug defoulers to set the o2 sensor out from the exhaust a few inches. Engine Temp Sensor is bad. The PCM monitors converter efficiency by comparing the. The downstream oxygen sensor should find a reading near center (about. The powertrain control module constantly flip-flops between rich and lean air-fuel mixtures due to the input from the upstream oxygen sensor (sensor 1). This is the third time I've had both that code, and the P0133 code which indicates bank 1 sensor 1. The conditions that caused this diagnostic to fail is when the upstream O2 Sensor biased from an exhaust leak, O2 sensor contamination, or some other extreme operating condition. Also make sure there is not an exhaust leak and that the cat is bolted squarely to the turbo. Downstream means the O2 sensor is "downstream" of the catalytic convertors, meaning after the catalytic convertors. Focus is misfiring or the exhaust timing is off. Once establishing how far downstream in the exhaust system to position the wideband O2 sensor, the bung should be mounted between 9 o’clock and 3 o’clock. O2 Sensor Gasket. Now O2 sensor Sensor 2 is a sin wave from 0. Induce a lean condition to see if the downstream oxygen sensor reports it. The newer type of lambda sensor (titania) work on a different principle, changing a supplied voltage as against creating one, but they still measures the Oxygen differences. (If it's not too close to it). ACTIVE DTC. Possible Causes EXHAUST LEAK (K141) O2 1/2 SIGNAL CIRCUIT (K904) O2 RETURN DOWNSTREAM CIRCUIT 1/2 O2 SENSOR. The downstream sensor should read only lower amounts of O2 due to the oxidation taking place inside the cat. I replaced the downstream O2 sensor and tested the MAF, which seems OK. The symptoms of a bad oxygen (O2) sensor include a check engine light, bad fuel economy, engine hesitation, increased emissions and rough idle. With the vehicle running and at normal operating temperature, use the digital multimeter to check the voltage reading of the downstream O2 sensor. If one or both of your upstream sensors are bad, and they failed in such a way that it isn't obvious to the computer, all it will know is that its readings from the downstream sensors don't line up with its expectation, hence the cat codes, rather than upstream O2 codes. Downstream O2 is used to verify the cat is burning off hydrocarbons. Then reroute the wiring harness and connect the electrical connector. The rich-to-lean sensor switch time is 0. Toyota Camry Oxygen Sensor Replacement costs between $133 and $672 on average. The downstream oxygen sensor functions the same as the upstream oxygen sensor in the exhaust manifold. P0136 is a generic code for types of trouble with oxygen sensors on "Bank One" of an exhaust system (FYI, if you have true dual exhaust Bank One will be dr. There may be a third sensor downstream, if that is the problem, a P2274 is set. Unfortunately, cleaning the O2 sensor will not fix the issue. Apply SNOOP leak finder liquid or a mixture of liquid dish soap and water to the following areas: - All welded joints from the exhaust manifold to 152.