Post Cat O2 Sensor Voltage

The other three are at. Sensor 1x2 (post-cat) should offer a stable reading if the cat has done it's job. What does Oxygen Sensor Post-Cat and Pre-Cat mean?  oxygen sensor circuit voltage high. 5 which is the size on 99% of vehicles produced. The engine RPMs should raise to around 1400. I currently have the stock tune. Now O2 sensor Sensor 2 is a sin wave from 0. o Example 2: A small exhaust leak upstream of the exhaust oxygen sensor is causing a false lean indication to the ECM. What on earth is fault Code P0130 O2 Sensor circuit Malfunction?!! Discussion in 'Astra, Corsa, Zafira, Meriva, Adam, Cascada, Agila, Viva, Tigra & Nova [Includes AstraVan & Combo Van] owners forum' started by Astrawoman, Mar 31, 2009. Order MINI Cooper Oxygen Sensor online today. On early OBD II systems, the post-cat O2 sensor should show little or no voltage fluctuations on a scope waveform, since all the mixture fluctuations are being absorbed by the catalytic converter. I would try replacing the O2 sensor. The o2 sensor is a four wire sensor. Catalytic Converters & O2 Sensors Download PDF. It's a hot job (literally) that operates at temperatures of 600 to 1000 degrees F. I wouldnt go throwing money at a new sensor until you know for sure that its at fault. You may have to register before you can post: click the register link above to proceed. Bank 1 Sensor 1 (Upstream) (pre-cat) P0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1) P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1) P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1) P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) P0134 O2 Sensor Circuit No. Is it also the case that the voltage on the post-cat sensor must cross 0. This resulted in excessively rich fuel delivery to bring oxygen sensor voltage back to normal operating range. The air/fuel ratio is measured in the exhaust stream by the oxygen (O2) sensors. 5V) for reference voltage to the sensor through one wire, and sensor ground to the other wire. 45 volt mark O2 cross counts. Sensor Type Depending on your vehicle you may have standard or wide range O2 sensors. Ml250 nox sensor fault. It will read an accurate mixture, usually, but not necessarily, a voltage of 0. While a pre-cat oxygen sensor switches voltage from rich to lean, the air-fuel sensor stays at a steady voltage. Can you read live data of the O2 sensors? The pre-cat O2 sensors should be jumping between high and low voltage constantly and the post-cat O2 sensors should be steady high voltage. Again, it may have a relay in the circuit as well. The high voltage readings on the Pre Cat sensors indicate the engine is running very. Would the down stream/post cat sensors play a role in the mixture? Edited February 10, 2014 by chas0218. I would swap the O2 sensors and see if you see the same fault. Ml250 nox sensor fault. Hence why you can 'map out' the post cat. When you gave it no accelerator both drops to around 0. 1-3: voltage monitoring  The same OBD2 code could be triggered by several different BMW codes. The dark green/orange wire should have 12 volts. On V6 and V8 applications with dual cat exhausts, you'll have upstream O2 sensor readings for each side of the engine and downstream O2 sensor readings for each converter. from the post-catalyst O2 sensor. If the downstream O2 sensor activity mirrors the upstream O2 sensor, the converter is dead and needs to be replaced. To over simplify: a post-cat sensor's main job is to monitor catalyst efficiency, not control fuel management (although they can have a measure of influence over the front o2 sensor's operation). 0, independent of Lambda fluctuations pre-cat. P0130 O2 Sensor 1 Circuit Voltage Low C-30 P0130 O2 Sensor 1 Open Circuit C-30 P0130 O2 Sensor 1 Incorrect Signal C-30 P0170 P0170 Rich Exhaust C-30 P0170 Lean Exhaust C-30 So does this mean the O2 sensor is the faulty? Also does my astra have one or two O2 sensors ? So which sensor does Bank 1 Sensor 1 represents, the one near the engine or. Slow signal of precat exhaust oxygen sensor may prevent the post oxygen sensor emulator from working. Bank 2, control value. Sensor 1x2 (post-cat) should offer a stable reading if the cat has done it's job. Prior to 2000, the post-cat 02 sensor was mainly used to gauge cat efficiency. The ECU would add more fuel and get a rich voltage back rom the sensor,except the ECU is programmed. Well if you are gonna eliminate the catalytic converter and do have an existing O2 sensor after the cat, you will throw a code if you dont put it back in. If anyone has been following my threads on getting this S600 escaped from a refugee camp in Sudan, you might remember I've not been able to get a correct mixture on one bank of the engine, as evidenced by the Lamda reading, and a direct voltage reading off the O2 sensor. Oxygen sensor simulator is a racing part. Field 1 is post-cat sensor voltage. Some vehicles have pre and post catalytic converter sensors (upstream and downstream). Purchased the Bosch OEM O2 sensor up front and in an effort to save money, got the 'universal' Bosch O2 sensor for the aft spot. Your automotive DIY guide to replacing your car's oxygen sensor. Make sure the rear O2 goes through it's voltage range. When the voltage is outside of the range, the code sets. The ECU doesn't operate the heater until 35 MPH or thereabouts. That makes it quite different from a conventional oxygen sensor that produces a voltage signal that. The sensors were first installed in vehicles in the 1970s, when the Environmental Protection Agency introduced exhaust regulations. i know from experience that the o2 sensor can be ruined from running too rich. I currently have the stock tune. These sensors have been proven to work on BMW, VW, Saab, and a list of other. The universal oxygen sensor does not come with a connector which makes splicing necessary for installation. Faulty O2 sensors can lead to converter efficiency failure too. Ohms are basically the resistance that goes on between two points of a specific conductor. They are there only to monitor the performance of the catalytic converters. Because on an O2 sensor rich = high voltage and lean = low voltage. Order MINI Cooper Oxygen Sensor online today. Bank 1 Sensor 1 (Upstream) (pre-cat) P0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1) P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1) P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1) P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) P0134 O2 Sensor Circuit No. 4 volts If they do set a po136 code then its more than likely the sensor at fault not the wiring but of course it can be just that. 1 V due to the difference compared with the oxygen content of the ambient air. 350ºC: Dynamic Factor of O2 Sensor Pre Cat: Max. M (Power train Control Module) compares the post-cat o2 sensor to the pre-cat o2 sensors to measure the cat's efficiency. The heating element should have battery voltage on one wire with key on engine off and ground should be present on. Never use cleaning solvents of any kind on the O2 sensor, solvents can permanently contaminate the sensor element. Get a volt meter and check the voltage right at the O2 sensor. O2 Heating Period Bank 1/2: This shows the oxygen heater period for cylinder bank 1/2. Reset ECU after upstream oxygen sensor replacement? If this is your first visit, be sure to check out the FAQ by clicking the link above. Water getting inside the heated oxygen sensor connector can caused the heated oxygen sensor fuse to blow. The baseline voltage is 0. Physically, there's no difference between front and back O2 sensors. MODE 06 CATALYST CHECKS. Air-fuel sensors are only used for fuel control, so they are always a pre-catalytic converter sensor, not a post-catalytic converter sensor. Pre cat sensor switches between 0. It is my hope that this short oxygen sensor article will open your mind on the subject. According to the amount of oxygen in the exhaust stream. 3)Dual exhaust, four O2 sensors, (OBD II) In this install you would need one more DIY Dual O2 Sensor circuits, hooked up both sides 1 & 2, with one dual pot. Water getting inside the heated oxygen sensor connector can caused the heated oxygen sensor fuse to blow. This O2 Simulator is threaded 18mm x 1. The downstream sensor should read a more steady voltage, usually somewhere above 0. If you were to measure the actual amount of time the post-cat O2 is used during. Yup a mistake trying to save money I learned. 87 but the value for O2 sensor 2 gives a constant voltage of 0. 6 V8 SVT Bypass Kit Exhaust Kit CEL. In general, after year 2000 most car manufacturers uses the post-cat O2 sensor to provide additional emission feedback to the ECU. Well, that is interesting. has a 2003 chevy s10 4. sensor, and the computer does not use the post cat. Which of the following is the most likely cause of the original lean O2 sensor reading? A. Upstream and downstream. Signs of an O2 sensor failure include worse fuel economy, lack of torque, and fault codes for the. The rear sensor can be made to alter it's voltage by simply snapping the throttle open and therefore commanding a rich mixture. So then I replaced the Post CAT O2 sensors and my SES light, again went away by itself, but it came back like the first time. 45 volts is interpreted by the ECM as a rich exhaust, and an O2 sensor voltage signal below 0. Precat or before cat is used for closed loop fueling. A typical Zirconia lambda sensor has four wires. See here for a step-by-step guide on how to diagnose and fix check engine light code P0138. Bank 2 sensor voltage. 7 volts Plugs all look to be running slightly lean. They can start going back and not throw a code - ie, it'll not be performing as efficient as a new one can but not be out of spec to cause the code. I've been looking at the voltage readings from the o2 sensors on bank 1 (pre-cat) and bank 2 (post-cat) and the voltage from the pre-cat/manifold lambda/o2 sensor fluctuates from. Usually post-cat sensors aren't used for engine tuning, only as a 'confirmation' the cat is working. This sensor will be present on most modern engines of six cylinders or more. If you've been dealing with the symptoms of a bad oxygen sensor, a new sensor can make your car's emission control and fuel consumption right again. Any of my search term words; All of my search term words; Find results in Content titles and body; Content titles only. Result [g/s] [V] [V] Text:Test ON/Test OFF/ Sys OK/Sys. So BN cats too. Light the torch and place the torch flame to the probe end of the o2 sensor (the perforated end) in such a way as to touch the blue flame cone tip to the. Air-fuel sensors are only used for fuel control, so they are always a pre-catalytic converter sensor, not a post-catalytic converter sensor. My question is, the o2 sensor that was connected to my exhaust manifold is just sitting by my valve cover. I had a diagram of the four sensor assignments several years ago, when I had to replace another one, but cannot locate that diagram now. If its B2 S2 that means Bank 2 (opposite Bank to Bank 1) and the downstream after cat o2 sensor. The voltage is transmitted to the engine's computer. Sensor 2 seems to sit at a constant 0. 9 volt range. What does Oxygen Sensor Post-Cat and Pre-Cat mean?  oxygen sensor circuit voltage high. The high voltage readings on the Pre Cat sensors indicate the engine is running very. Which of the following is the most likely cause of the original lean O2 sensor reading? A. If there is no reading or if the sensor voltage is not changing, then it indicates a bad or sluggish O2 sensor that needs replacing. INTRODUCTION. P0135-1/1 O2 SENSOR HEATER FAILURE When Monitored: The O2 Heater Monitor runs during O2 sensor cool-down period, after a hot drive cycle, when engine is shut down with the ignition key turned OFF. Slow signal of precat exhaust oxygen sensor may prevent the post oxygen sensor emulator from working. the sensor before the cat is NOT an O2 sensor but a HO2S sensor ( two different sensors with different operations). 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. The computer only needs a reading of 50 ohms from the o2 sensor to keep the 'check engine ' light off. In your car, a functioning O2 sensor ensures that your engine is running at top performance. The post-cat oxygen sensor was added to OBD II-compliant vehicles primarily so the PCM could compare upstream and downstream oxygen sensor activity and use that information to deduce the catalytic converter's efficiency and state of health. The computer then uses this information to recalculate the fuel delivery depending on what is needed. due to the way the O2 sensor A/D channel is setup, there is no pull-up or pull-down resistor connecting the O2 sensor's channel up or down to a known value with it disconnected. Oxygen sensors detect the amount of oxygen content in the exhaust stream and turn this information into a voltage signal. To see 5+V on the output of an O2 sensor suggests a failed O2 sensor or bad wiring/connector between the O2 sensor and the ECU. It is located within the emissions control system. Bank 2 sensor voltage. The customer concern is a sudden decrease of 20% in fuel economy. P0420 Catalyst System,Bank1 Efficiency Below Threshold Ok so I've searched all over and seems like everyone that gets this code had an aftermarket exhaust. Air-fuel sensors reflect a lean condition when their voltage INCREASES and a rich condition when their voltage DECREASES. 6V; it doesn't cross 0. You'll then get your socket wrench with the O2 sensor attachment to unscrew it. I've been looking at the voltage readings from the o2 sensors on bank 1 (pre-cat) and bank 2 (post-cat) and the voltage from the pre-cat/manifold lambda/o2 sensor fluctuates from. So, as discussed, the pre-cat sensor signals are oscillating between 0. P0138 is the OBD-II generic code indicating the O2 sensor for bank 1 sensor 2 fails to have a lower voltage output below 1. It will take some force, especially if anit-sieze wasn't used. Remember, since it's after the cat, it doesn't switch constantly like sensor 1, it basically just measures the oxygen content of the post cat exhaust, which varies based on engine operation (running, idling, decelerating) all are burning very different. In regards to other "sensors and stuff" are there any other O2 sensors to check? I believe I only have 1 sensor but I have seen the term of Oxygen sensor and Heated Oxygen sensor and they are side by side descriptions on how to pull either one from this book. #2 sensor is less likely to fail than the #1 A/F sensor. 4 v8 and runs well except for a lumpy idle. 67 mustang coil wiring diagram together with s stang mustang forums attachments ignswwiring 220602 together withstrategiccontentmarketing co wp content uploads 2018 08 ignition coil wiring diagram enticing reference ford motor inside exceptional distributor 1 on chevy 350 ignition coil wiring diagram furtheraveragejoerestoration resources mustang wiring and vacuum diagrams 1967 mustang wiring. Another point that can trip up an unwary technician is that the A/F value displayed on a scan tool can be misleading. Make sure the rear O2 goes high, the cat monitor won't run unless it does. Im using the torque app on my android and connected it via a BAFX bluetooth OBD-2 scanner. What the Home Mechanic Needs to Know about O2 Sensors Download PDF. I think the O2 sensors generaly make the car run rich when they are going out. Replaced MAF, Egr Valve, fuel filter, fuel pump, pov valve, o2 sensor S2B1, fuel injectors and have done a smoke test and still getting the codes and it runs worse everyday. Do you reset the code on your own or does it go away when you replace the o2 sensor?. Bank 2 sensor voltage. The PCM (Powertrain Control Module) then compares the post-cat reading to the pre-cat readings to determine if the catalyst is working properly. Sensor 2 seems to sit at a constant 0. Turns out the actual fault/issue's source is with the after cat o2 sensor. 4 (both positive values). & Post Cat Oxygen O2 Sensor 1,Sensor 2 For 10 11 Toyota Camry L4 2. Usually post-cat sensors aren't used for engine tuning, only as a 'confirmation' the cat is working. Dallas1215 I have a 2003 Ford Escape 3. the post cat sensor is there as a cat check basicaly from what I understand, by checking pre and post cat emissions it can detect when the CAT is no longer working / failling. I understand that the voltage on the pre-cat O2 sensor must cross 0. 8 pin wiring diagram wall jack moreover learnabhi wp content uploads 2018 11 functions of 8 pins in rj45 port together withs ponents101 sites default files ponent pin rj45 connector pinout together withsmarthomeideas images wiring9 gif as well assimplepilgrimage org wp content uploads 2018 09 beautiful of surface mount data jack wiring diagram cat 5 wall plate rj45 rca cat5 with ether wiring. For Nissan to go back to an O2 sensor for pre cat would be like going back to vacuum tubes. How to Change an Oxygen Sensor. The air fuel imbalance test uses the sensors amplitude frequency over a period of time to calculate the air fuel ratio which is given as a voltage reading. Two wires are dedicated to the heating element and two wires are dedicated to the sensor. 4 v8 and runs well except for a lumpy idle. They are used to trim the fuel a little to maximize catalyst effiency. Sub O2 Signal The sub-sensor signal will make slow transitions in voltage, however, they occur over long periods of time (several seconds). ones are post and the. To see 5+V on the output of an O2 sensor suggests a failed O2 sensor or bad wiring/connector between the O2 sensor and the ECU. #2 sensor is less likely to fail than the #1 A/F sensor. This will reduce the level of emissions your vehicle puts into the atmosphere. On early OBD II systems, the post-cat O2 sensor should show little or no voltage fluctuations on a scope waveform, since all the mixture fluctuations are being absorbed by the catalytic converter. upstreamexhaust oxygen sensor has to work flawlessly. 800V That sounds spot on. Bank 2 sensor voltage. My 850GLT is running too rich, which I believed initially was due too a defective primary o2 sensor. I have used my generic OBD2 scanner to check live data, and can see voltage for the post cat sensors, but not for the pre cat ones. 2 LSU Wideband O2 Sensor with Connector Bosch 4. Simply threading your O2 sensor from the exhaust pipe, using a 18mm wrench. Check engine light codes associated with a bad oxygen sensor. In some instances, Sensor 2 can be pre-catalytic and thus making Sensor 3 post-catalytic. I am Getting this code P0138 HO2S Circuit High Voltage Bank 1 Sensor 2 on my 2005 N/A base  PT Cruiser Forum. A more complete list of oxygen sensor symptoms and their causes can be found here. A P0144 definition:a fault at the post-cat o2 sensor, indicating that the signal voltage is too high. This article describes how to test an O2 Sensor while it is still on the vehicle. This may vary by model and the computer won’t registered a bad sensor until it fails a few times. 18mm wrench will take out the sensor. My question is, the o2 sensor that was connected to my exhaust manifold is just sitting by my valve cover. They usualy last about 100K miles. P0141 and P0137 are both rear O2 codes, heater circuit , and low voltage respectively. I understand that the voltage on the pre-cat O2 sensor must cross 0. Also, A bad or failing O2 sensor can also cause you to fail your emissions test. current sensor, Wholesale Various High Quality current sensor Products from Global Sodium Tripolyphosphate Suppliers and current sensor Factory,Importer,Exporter at Okchem. Lotus Esprit World was unaware of a way of Removing the Cataylic converters from a V8 without the causing the ECM to go into 'limp' mode, due to the reading from the Oxygen sensors. Voltage for that sensor is (low). 4 Front Rear 4ZOS743, O2 Oxygen Sensor, O2 Sensor at Walmart. Threads Tagged with o2 sensor faults. The Vacuum leak code can also be because the o2 sensors are reading to much oxygen in the exhaust. I didn't think that the post cat sensor is supposed to switch rich/lean unless there is something wrong with the cat. My gas mileage is horrible after the headers were put on. The o2 sensor is a four wire sensor. O2 Heating Pre Cat Bank 1/2: This shows the oxygen heating value for the pre cat sensor on cylinder bank 1/2. They can start going back and not throw a code - ie, it'll not be performing as efficient as a new one can but not be out of spec to cause the code. The vehicle had repeatedly returned with a code of P0031—O2 sensor B1S1 low current flow heater circuit failure (open circuit). 45 volt (450 mv). 74v mainly). For optimum catalyst operation, the air-fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. An oxygen sensor placed after the cat on certain cars is a verification of the the cats performance Their voltage reading if everything is normal will be stable around. 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. The post cat sensor (bolted to the end of the cat) only measures emissions and throws up the light. If you were to measure the actual amount of time the post-cat O2 is used during. Threw an engine Code 5, which points to the O2 sensor. If the output wire of the O2 sensor is open, the input on the ECU may float high, thus the high reading. You agree not to post any copyrighted material unless the. 1 On August 4th, 2007, steven said:. The ECU basically ignores it until you get into the catalyst monitor test range MPH. 3l with a post cat o2 sensor. According to the amount of oxygen in the exhaust stream. Air-fuel sensors reflect a lean condition when their voltage INCREASES and a rich condition when their voltage DECREASES. My 850GLT is running too rich, which I believed initially was due too a defective primary o2 sensor. ­Th­e oxygen sensor is positioned in the exhaust pipe and can detect rich and lean mixtures. P112C - seems to be O2 sensor pre-cat, line fault. It moved a little but overall it was stable here (0. The red indicator LED is in the middle. If the cat is doing it's job the pre cat sensor wil jump and the post cat shouldn't move much. So that is good. INTRODUCTION. The computer then uses this information to recalculate the fuel delivery depending on what is needed. the post cat sensor is there as a cat check basicaly from what I understand, by checking pre and post cat emissions it can detect when the CAT is no longer working / failling. The dark green/orange wire should have 12 volts. 5 which is the size on 99% of vehicles produced. I would think that it is more of a problem with the O2 sensors, than the maf sensor. Have a P0138 code on 2006 Rav4 (secondary O2 sensor). DTC Library. Usually post-cat sensors aren't used for engine tuning, only as a 'confirmation' the cat is working. Reason I ask, the post sensor is about $100 higher than the pre, they are both 4 wire, heated and look the same. And we are going to talkabout how to know when to change your O2 sensor. so, with no sensor connected, you have a small antenna that will show voltage via induction(i think). BMW documentation says they use post cat sensors on some engines to make fuel trim adjustments but nobody replaces post cat sensors unless they have cat efficiency codes. Usually rear o2 sensor problems won't cause drivability issues since they are an input that measures catalyst efficiency (unlike front o2 sensors). Primary fuelling on a wideband car is done by the pre cat wideband sensor. The rear sensor can be made to alter it's voltage by simply snapping the throttle open and therefore commanding a rich mixture. Oxygen Sensor Control Pre Cat: O2 Sensor Reg Pre Cat-10. They are relatively cheap, can run anywhere from 20-40 bucks. The reason I'm thinking about going this route is that I get one of the codes every so often from this linked write up. My intention was to compare the O2-1 (pre cat. With the rear O2 sensor completely removed, you can modify it on your work table or where ever you want, instead of cutting and splicing while underneath your rig. Any of my search term words; All of my search term words; Find results in Content titles and body; Content titles only. In regards to other "sensors and stuff" are there any other O2 sensors to check? I believe I only have 1 sensor but I have seen the term of Oxygen sensor and Heated Oxygen sensor and they are side by side descriptions on how to pull either one from this book. It's likely a faulty o2 sensor. What kind of simulator do I need or can I just remove the whole sensor. Replaced MAF, Egr Valve, fuel filter, fuel pump, pov valve, o2 sensor S2B1, fuel injectors and have done a smoke test and still getting the codes and it runs worse everyday. Conv, Bank 2 voltage 0. The O2 or Oxygen sensor works like a tiny voltage generator. Just look behind the engine. I understand that the voltage on the pre-cat O2 sensor must cross 0. I was reading a thread in the BenzWorld site. 5 which is the size on 99% of vehicles produced. 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. Sensor 1, Bank 1 & 2 (pre-cat) toggled between. P0138 code definition. A fuel Injector leaking fuel. 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. Testing the O2 Sensor. Testing the oxygen sensor (commonly referred to as O2 sensors) on your 4. Why does my OBD-II scanner show the O2-#2 sensor reading in milliamps, not volts? I use am OBD-II scanner to read my O2 sensors. 99v and doesnt change at all. However after replacing the two Pre CAT O2 sensors my SES light went away by itself, then came back with a P2096. has anyone experienced this before?. When I first bought the car I scanned it and found the codes might have been cleared previously, and I was getting a P0137 O2 circuit low voltage on Bank 1 Sensor 2 (driver side post cat). Another is that the voltage signal is coming from the PCM, not the sensor itself, so you can’t read an A/F sensor’s output voltage directly with a digital storage oscilloscope (DSO) like you can with a conventional O2 sensor. I can find a cat if I need to. What you can do is wire up an O2 simulator in place of the sensor and tie it into the wires that the O2 sensor ran off of. The ECU basically ignores it until you get into the catalyst monitor test range MPH. The O2 sensor sends an electric signal directly in proportion to the oxygen content in your vehicle's exhaust stream. So all a post-cat O2 sensor has to do is to monitor that Lambda stays steady at 1. I replaced an O2 sensor on my TJ in an attempt to fix a check engine light. 825  Would the down stream/post cat sensors play a role in the mixture?  The best way to look at an o2 sensor. #2 sensor is less likely to fail than the #1 A/F sensor. See our oxygen sensor page. Am I able to use Diagbox or PP to measure pre. The higher the voltage, the richer the AFM. 2 LSU Wideband Sensor Connector Kit. Have P0420 code on 2001 Tacoma 2. FWIW Speed density vehicles still use an O2 sensor for af ratio calcs. In fact I pointed out the difference between. The oxygen sensor which is placed before the catalytic converter/s is used by the ECM to adjust the air/fuel ratio. The downstream sensor should read a more steady voltage, usually somewhere above 0. Reason I ask, the post sensor is about $100 higher than the pre, they are both 4 wire, heated and look the same. Upstream (pre-cat) and downstream (post-cat) are found in reference to the catalytic converter. Both of them are the same in every other aspect. Threw an engine Code 5, which points to the O2 sensor. WHAT IT MEANS WHEN YOUR GET A CODE READ OF PO420 OR PO430. Q - I do not have a bung in my new pipes, will this work for me? A - No, you must have a working sensor in the system. As these two graphs show, the post-cat barely crosses 0. For Nissan to go back to an O2 sensor for pre cat would be like going back to vacuum tubes. The rear O2 sensor voltage fluctuates from around a peak of nearly 1 volt at WOT, to nearly 0 on decel. It can also adjust the air fuel ratio to compensate for a degraded Catalyst. Vehicles '96 (OBD II )and newer, have two O2 sensors, one right after your exhaust manifold (pre) and one after your catalytic converter (post). This is an old trick on the MKIII engine but has not been tried on MK4 Jetta, Golf, and GTI models. P0138 Meaning The Heated Oxygen Sensor 2 (HO2S) (Rear O2 Sensor), after three-way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. This is a Genuine Bosch O2 Sensor from an Australian distributor for Bosch. sensor, and the computer does not use the post cat. Always follow the instructions in your owner’s manual for oxygen sensor replacement. 0%: Voltage of O2 Sensor Before Catalyst: 0. Post cat is aftercat, these are for catalytic working yes or no ONLY. 1963 C10 with a LT1/4L60E from a 95 Impala. I have just bought a D3 4. Hey guys, Strange issue that I've been trying to figure out for a while and I'm at a loss. BA BF Falcon, Fairlane, XR6, XR6 Turbo, XR8 – same sensor pre and post cat; FG Falcon, XR6, XR6 Turbo, G6, G6E Turbo (pre Nov-2010) – same sensor pre and post cat; Territory SX, SY, SZ 6 Cylinder, Territory Turbo; and many others matching the below Bosch part number. The post-cat oxygen sensor will be a straight line if the catalytic converter is good in most cases. I would say to pull it, clean and retry, but it sounds like pulling it out is a sure way to break it physically. The heating element should have battery voltage on one wire with key on engine off and ground should be present on the. It serves no fuel control purpose. The downstream O2 sensor produces a relatively steady voltage reading of approximately 0. 9 volt at idle. It is a four wire sensor. my friend in the auto tech class at the trade school we go to swears up and down that you dont need your oxygen sensors and that your engine wont run any. Sensor 2 seems to sit at a constant 0. So, as discussed, the pre-cat sensor signals are oscillating between 0. In your car, a functioning O2 sensor ensures that your engine is running at top performance. It must fluctuate slightly between 0 and 1V. I had a two Cel's for bank 1 sensor 1 no activity and heater out. Afterwards, P1113 has disappeared - the front O2 sensor seems to be working. Today's computerized engine control systems rely on inputs from a variety of sensors to regulate engine performance, emissions and other important functions. Production vehicle/sensors, Constant rpm and Lambda = 1. Toggle navigation Close Menu. Bank 1 Sensor 1 (Upstream) (pre-cat) P0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1) P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1) P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1) P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) P0134 O2 Sensor Circuit No. 2 LSU Wideband Sensor Connector Kit. So BN cats too. You agree not to post any copyrighted material unless the. Remember, silver bar on the edge of the diode is on the ECM side, not the sensor side. He suggested genuine senors are about 150-160/each, so potentially a fairly expensive job for something that should be straightforward. Most cat manufacturers will insist that you have new post-cat O2 sensors when you install new cats.