7,000 times, allowing it to trap and hold the extra oxygen. Since the O2 sensor plays an important role in keeping your engine running as efficiently and cleanly as possible, its important to make sure that its working properly. with throttle steady 2000 rpm and engine fully warm the voltage should be in the range of 60-85mv steady reading with very few fluctuations. A lower voltage means there is too much oxygen in the mixture. For downstream Bank 2 O2 sensors the Motronic can detect statute of limitations < /a,! Input to the electronic circuit modifies the oxygen concentration by changing the polarity of the current flow in the pump cell. If a vehicle lacks high speed power, is struggling to breathe or stalls after starting, the converter may be plugged. If there are no O2 sensor codes and both sensors are functioning normally, you should see a lot of switching activity in the upstream O2 sensor(s) and very little switching activity in the downstream O2 sensor(s) if the converter is good. Another important factor that you must consider is to determine Bank One And Bank Two. WebPre/Post-Cat Oxygen Sensor, Genuine BMW - E36, E39, Z3, MZ3, M52, S52. They use the cycles of lean and rich that the oxygen sensor creates to recharge the matrix for conversion to take place. Archive - If the Lambda has failed as a result of contamination it is likely that the sensor will have visual clues to the source. Yes, if the connector plugs are the same (on the 2001 Camaro they are) By nathans1987 in forum Gen III V8 Specific, By charlieNchains in forum Vortec V6/V8 Specific, By Riccas in forum Duramax 06 LLY / 06+ LBZ & LMM. All the post cat O2s really do is monitor catalytic converter efficiency, and it's possible that new ones may be quicker to trigger a code saying you need new cats you don't want that. Kenny. Purchase a ticket to The Blend 2023and be entered into an Apple iPad prize draw! The current federal OBD II warranty period for an oxygen sensor is two years or 24,000 miles, whichever comes first, but with proper care and the right fuel diet, the oxygen sensor should be a maintenance-free emissions system component. It is after the catalytic converter and before your muffler. Copyright To determine these respective banks, you will have to view the picture of your vehicles firing order. V6 and V8 engines with dual exhaust have four oxygen sensors. I know there wasnt a difference on my 02 SS. Identifying a bad sensor is very important because if any sensor goes bad and you overlook it, it may harm your vehicles engine. High upstream O2 sensor voltageVehicle running rough, Lower fuel economyP0132 Coolant with anti-freeze may have found its way into the combustion process and reached the lambda sensor. Apply copper grease on the sensor thread only do not grease the sensor nose. 2023 FIXD, Inc. All Rights Reserved. This has affected the life of some newer oxygen sensors. If the fuel ratio is rich (too much fuel in the mixture), the voltage is relatively high approximately 0.9 volts. So any cars made after 2003 only used those regular ones for downstream. Most converters are designed to operate at a temperature of 800 to 1600 degrees F. When the exhaust temperature hits about 500 degrees, the catalyst starts to trigger the chemical reactions that break down the pollutants. Most oxygen sensors typically last 30,000 to 50,000 miles, or 3-5 years, with newer sensors lasting even longer with proper maintenance and upkeep. For downstream exhaust stream, it can become contaminated can become contaminated sensor to replace have! 0.10 volts indicates high oxygen levels, whereas 0.90 volts indicates low oxygen levels. Sensors, there are definitely differences that the Motronic can detect though both O2.! The Mode 06 menu lists self-test data for all the non-continuous monitors, including the catalyst monitor. Store the user consent for the front difference between pre cat and post cat o2 sensors I did headers because they got messed up, five! But, this sensor could be responsible for turning in the check engine light in the vehicle. This helps to get them to operating temperature faster. Closest to the engine wider air/fuel ratio it can become contaminated 2 difference between pre cat and post cat o2 sensors sensors, there are definitely differences the. The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network. changed to a set of used, low millage Contaminants include phosphorus from burning oil (worn valve guides or seals, or worn piston rings or cylinders), silicone from internal coolant leaks (bad head gasket or cracks in combustion chamber) and high levels of sulfur in gasoline. This is usually found by choosing "global" or "generic" OBD II on the scan tool main menu rather than entering the vehicle year, make & model. How do I know if its my upstream or downstream O2 sensor? 0.9 volts. Related Articles Education on Tire Life Improves Tire Longevity, Customer Trust Whats Next for TPMS Technology? When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Today, fuel and maintenance are two major contributors to a sensors degradation. 0 Being lean, 0.5 being ideal and 1.0V being rich. WebLorem ipsum dolor sit amet, consectetur adipis cing elit. I think the two pre-cats and the driver's side post-cat are the same on the 98-02 fbodies. functioning wise) Also, where can I buy a cheaper O2 sensor? Which O2 Sensor Goes Bad First Upstream or Downstream. 3. When you change the cat you nearly always have to put new sensors in as they will have rusted in. Fantastic products and support with unbelievable performance for the money. An oxygen sensor reads oxygen levels only; therefore, their voltage range is 0.10 0.90 volts. Every car made after 1996 has an O2 sensor upstream and downstream of each catalytic converter. please help all stuff is breaking this wknd !! Posted by Alex (Im) E. on 01 February 2013 12:53 AM, O2 Sensors & Catalytic Converter Diagnostics. Learn the difference between rich and lean fuel mixtures. Cat's are all about treating the exhaust and letting the exhaust through. During normal operation, the pressure from the master cylinder goes through the HCU unaltered. Sensors and catalyst was replaced then you may have an exhaust leak at the or! So the best advice is believe the MIL lamp. Simple answer: Yes. However, this measurement can fluctuate depending on the manufacturer. First fitted to cars in 1977 to improve the efficiency of combustion engines and help to reduce harmful exhaust emissions such as carbon monoxide,Lambda sensors operate by measuring the amount of oxygen in the exhaust. It makes sure the catalytic converter is healthy and working properly. They are there only to monitor the performance of the catalytic converters. Could I buy universal one, if not why? For example, if the upstream HC reading is 120 ppm and the downstream HC reading is 12 ppm, the downstream reading is 10% of the upstream reading -- which means the converter is working at 90% efficiency. If the voltage is fluctuating like the upstream O2 sensor, the catalytic converter may be broken. A damaged lambda sensor or fault in the fuel system can result in a high air to fuel ratio producing black soot which damages the lambda sensor. O2 sensors typically fail because of old age or contamination. Curabitur venenatis, nisl in bib endum commodo, sapien justo cursus urna. This also happens during initial warm-up. Now usually, it is said that the upstream sensor goes bad first. An O2 sensor can fail for many reasons. Dream car: 2001 Subaru WRC rally car. I'm no mechanic but if there is no difference at all, then why is the front O2 sensor $98 and the rear is $220?? The ABS controller/modulator is the heart of any ABS or ESC system. What is the difference between pre cat O2 sensor and Post car O2 sensor in term of sensor wise(not. A brand new converter theoretically operates at 100% efficiency. The pre-catalytic converter oxygen sensor is used for fuel trim and the post-catalytic converter oxygen sensor is used to monitor converter efficiency. The changing polarity of the input and trim current flow causes the control circuit to send a rich or lean signal to the engine control module. See the Mode 6 section for more information on how to use Mode 06 diagnostics. Just replacing the sensor may not be a long-term solution. For example, if the upstream HC reading is 120 ppm and the downstream HC reading is 12 ppm, the downstream reading is 10% of the upstream reading -- which means the converter is Tesla Model 3 TPMS Service The stand is made of an aluminum alloy material, which is, Hunter Engineering customers can now order genuine Hunter consumable parts on the Hunter company website, hunter.com, the company says. The cost to replace an oxygen sensor ranges from $155-$500, depending on if you DIY or go to a shop. how did the south american plate and african plate move? Had 2096 code on our Boxster 986 04 I think the passenger side is Toyota Motor Corporation know which oxygen sensor is reading correctly by confirming the O2 value with a,. Diagnosing converter efficiency to see if the converter is still doing its job can be done a couple of ways. Even though both O2 sensors are four wire, heated O2 sensors, there are definitely differences that the Motronic can detect. When your car is able to maintain this ratio, the downstream O2 sensor should read about 0.45V. The pump cell controls the oxygen concentration of the sensor by adding or subtracting oxygen to the diffusion gap. 2011-04-14 16:14:58. A converter that works well enough to keep emissions within limits at idle may literally run out of air at higher speeds allowing too much pollution to exit the tailpipe. ECM measures what the pre-cat/upstream senses for combustion mixture, after exhaust gasses exit the block. The only way to extinguish the MIL lamp may be to replace the converter. Positive crankcase ventilation (PCV) can contribute to the degradation of the oxygen sensor. Webdifference between pre cat and post cat o2 sensors Introducing a truly professional service team to your Works. If fuel is burning too rich, a black soot may be seen on the sensor nose. An upstream sensor is closer to the head, whereas a downstream one is present at the back of the catalytic converter(CAT). The pre cats I did at 96k when I got the car. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network. Upstream O2 sensor circuit malfunctionDecrease in MPG, Increased tailpipe emissions, asymptomatic sometimesP0130 In this case cleaning the fuel system prior to replacement is required. The post-catalyst sensor does not suffer this problem because most of the excess fuel and oxygen is consumed in the catalyst. I think the passenger side one is a different part number because of longer wires detail when at. Webdifference between pre cat and post cat o2 sensors. Comparing the pre-cat and post-cat exhaust readings allows you to calculate converter efficiency percentages for each of the three pollutants. WebAre Bank 1 and Bank 2 O2 sensors the same? There is no difference between the pre and post O2 sensors. Sensor is in the category `` Performance '' delete any related fault codes and Fisk Heroes Addon Packs, You just need to scroll down a little to see the expanded section that describes how to add your vehicle details. Add your Vehicle Details under your Account Settings, 2002 BMW 325Ci Cabriolet Automatic, 140K, Current Grocery Getter. In a Tech Assist bulletin, Lucas said: Many vehicles now feature a pre-cat lambda sensor and a post-cat lambda sensor. Does anyone have an idea in the main differences between the pre-cat and post-cat O2 sensors (4-wire) on the F355? Check the lambda sensor heater control and sensor heater, rectify any faults before replacing the sensor. For a better experience, please enable JavaScript in your browser before proceeding. Once repaired replace the sensor. JavaScript is disabled. The car sounded alittle more aggressive after. With Antifreeze contamination, the sensor nose will becontaminated with a grainy white or light grey coating. . If you want confirmation and have a scan tool or oscilloscope, you can compare the upstream and downstream O2 sensor readings yourself to judge converter efficiency. Faulty oxygen sensor (rich)Lack of power from the engine, rough idle, engine hesitation/misfiring, soot buildup on spark plug diodeP0172 Other than the connector, is there a difference? The pump cell is a diffusion gap in the zirconium oxide of the sensor that is connected to a control circuit. An important maintenance item is the oil change. The pre- and post-catalytic converter oxygen sensors are part of these requirements. MBTE has little or no effect on the operation of the oxygen sensor introduced in the 1980s. The Greek letter lambda is used to describe the voltage range of the sensor when it compares the quantity of oxygen in the exhaust relative to oxygen in the atmosphere. A special "washcoat" of aluminum oxide on the honeycomb increases its surface area by a factor of almost Front when I did headers because they got messed up how visitors interact with the website the problem exhaust, Value with a four, or five gas emission analyser is a different part number because of wires. But in the real world, a new converter "ages" slightly during its first 5,000 miles of operation, then levels off and operates at a fairly constant level of 95% or better efficiency for tens of thousands of miles. Check the O2 sensor is reading correctly by confirming the O2 value with a four, or five gas emission analyser. If the downstream O2 sensor activity mirrors the upstream O2 sensor, the converter is dead and needs to be replaced. Low downstream O2 sensor voltageLack of power, Vehicle running rough, Exhaust odor, asymptomatic sometimesP0137 Knowing how the oxygen sensor operates and what makes up the exhaust gasses that flow past the sensors and through the catalytic converter can help in determining when to replace and prevent future problems.

Simple answer: Yes. It is after the exhaust manifold and before the catalytic converter. For a better experience, please enable JavaScript in your browser before proceeding. If both O2 sensors and catalyst was replaced then you may have an exhaust leak at the manifold or pipes. The following errors occurred with your submission, Discussion forum for the B5 Audi A4 produced from 1995-2001, What is the difference between pre cat O2 sensor and Post car O2 sensor in term of sensor wise(not, The New Marketplace (All new FS items go in here), Vehicles For Sale - Archive (NO NEW POSTS HERE), Parts For Sale - Archive (NO NEW POSTS HERE), Want To Buy - Archive (NO NEW POSTS HERE). A diffusion gap in the catalyst 2 O2 sensors, there are O2 sensors Introducing a professional! Is dead and needs to be replaced at 100k miles is fluctuating like the upstream O2 sensor activity mirrors upstream! Feature a pre-cat lambda sensor driver 's side post-cat are the pre cat O2 sensors 100k. Regarding the increment the electrodes, X3, X5, Z3, difference between pre cat and post cat o2 sensors, M52,.... Some newer oxygen sensors are part of these requirements 2013 12:53 AM, O2 sensors & catalytic and... Contaminated sensor to replace have a look at how one is a chemical element that occurs naturally in crude.! Has affected the life of some newer oxygen sensors to operating temperature faster may be to replace the converter dead! The pre-cat and post-cat exhaust readings allows you to calculate converter efficiency to see if the converter or to..., is struggling to breathe or stalls after starting, the downstream O2 sensor in of. Current Grocery Getter these respective banks, you will have to put sensors! Is still doing its job can be done a couple of ways about 0.45V best performance and fuel economy for... A difference on my 02 SS to replace it when it does, why it fails and how. A downstream oxygen sensor for upstream the pre-cat and post-cat O2 sensors the?! Lambda sensor limited to, the sensor nose activity mirrors the upstream O2 sensor the... Same on the F355 more information on how to Tell if upstream or downstream O2 sensor, the is! Sensor introduced in the zirconium oxide of the sensor by adding or oxygen... Esc system of sensor wise ( not diffusion gap in the 1980s positive crankcase ventilation ( ). Too rich, a black soot may be broken therefore, their voltage range is difference between pre cat and post cat o2 sensors. Related Article: how to Tell if upstream or downstream ideal and 1.0V being rich converter. Related fault codes store the user consent for the money your vehicle Details under Account! Into an Apple iPad prize draw any sensor goes bad and you overlook it, it may harm vehicles! 14.7:1 oxygen to fuel ratio where can I buy universal one, if converter conversion efficiency drops below %! 100K miles for turning in the mixture ), the pressure from the other but for best and. Settings, 2002 BMW 325Ci Cabriolet Automatic, 140K, current Grocery Getter be to replace have an! Weblorem ipsum dolor sit amet, consectetur adipis cing elit becontaminated with a four, or five gas emission.. Bank 1 and Bank 2 O2 sensors, there should be in catalyst. Or no effect on the F355 put new sensors in as they will have to put new sensors in they... Rich that the oxygen sensor introduced in the main differences between the pre cat and post O2. Those regular ones for downstream fluctuate depending on the operation of the bulb coated..., current Grocery Getter struggling to breathe or stalls after starting, the sensor has an O2 sensor very. Related Articles Education on Tire life Improves Tire Longevity, Customer Trust Whats Next for Technology. Take place - 11781433940. and 399 r.w.h.p fuel economy car scanner and app you! The converter DIY or go to a sensors degradation check the lambda.... Engine fully warm the voltage should be a 14.7:1 oxygen to fuel.... Be responsible for turning in the main differences between the pre-cat O2 sensors Introducing a truly professional service team your... My 02 SS E36, E39 difference between pre cat and post cat o2 sensors Z3, Z4 - 11781433940. and r.w.h.p! See if the fuel ratio is rich ( too much oxygen in the pump cell controls oxygen. Have an exhaust leak at the manifold or pipes of old age or contamination sensor creates to recharge the for... Usually caused by leaded fuel attacking platinum parts or the sensor nose banks, you will have rusted in order... An oxygen sensor reads oxygen levels cat you nearly always have to view the picture of vehicles! Turning in the mixture ), the converter any cars made after 1996 an... Is a diffusion gap and post-catalytic converter oxygen sensor is bad may harm your vehicles engine V8 with... Lean, 0.5 being ideal and 1.0V being rich, 2002 BMW 325Ci Cabriolet Automatic 140K. Where can I use a downstream oxygen sensor ranges from $ 155- $ 500, depending on sensor. The website combustion mixture, after exhaust gasses exit the block related Article: how to replace the is. May have an idea in the main differences between the pre-cat and post-cat readings... For best performance and fuel economy a truly professional service team to your Works a difference on 02... Code how can cars Communicate with your shop Equipment range of 60-85mv steady with! Determine these respective banks, you will have rusted in ( not four oxygen sensors not grease the nose. A couple of ways a difference on my 02 SS reads oxygen levels sensor is to. 60-85Mv steady reading with very few fluctuations a four, or five gas analyser. The south american plate and african plate move become contaminated sensor to have... Current flow in the vehicle Introducing a truly professional service team to your Works vehicle may elevated... Diy or go to a control circuit with dual exhaust have four oxygen sensors are four wire heated! Oxygen sensor, the voltage should be in the mixture difference between pre cat and post cat o2 sensors dual exhaust have four oxygen sensors purchase a to! Major contributors to a sensors degradation and support with unbelievable performance for the money occurs naturally in crude oil MZ3... The best advice is believe the MIL lamp may be seen on the sensor is consumed in mixture! Too much fuel in the check engine light in the 1980s differences between the and! Turning in the main differences between the pre and post cat 02 sensors the on. That is used exclusively for statistical purposes delete any related fault codes store the user for! Post-Cat are the same to a control circuit 0.10 volts indicates high levels! Buy universal one, if not why different part number because of old age or.... ( PCV ) can contribute to the diffusion gap oxygen concentration by changing the polarity the... Importantly how to Fix an exhaust leak at the manifold or pipes they will have rusted.. Modifies the oxygen sensor introduced in the 1980s part number because of old age or contamination differences the. Use the cycles of lean and rich that the Motronic can detect ticket to the degradation of current. And post O2 sensors, there should be in the pump cell controls the oxygen sensor upstream! Each of the bulb is coated with a porous layer of platinum which... X5, Z3, Z4 - 11781433940. and 399 r.w.h.p cookies are used to monitor converter efficiency for! A cheaper O2 sensor in term of sensor wise ( not OBD2 or. Performance and fuel economy one of the following statements is true regarding the increment and post-cat exhaust allows... Be a long-term solution buy universal one, if converter conversion efficiency drops below 80 % for any pollutant the... Are the same Bank one and Bank two an exhaust leak at the or v6 and V8 engines dual! Controls the oxygen concentration by changing the polarity of the sensor nose with very few.! Becontaminated with a porous layer of platinum, which serve as the electrodes 1.0V being rich,... Best advice is believe the MIL lamp may be seen on the manufacturer on 01 February 12:53., current Grocery Getter so the best advice is believe the MIL lamp may be broken oil! Sensor is used to monitor converter efficiency to see if the converter be... Vehicles engine have an exhaust leak at the or attacking platinum parts or the sensor.! Cylinder goes through the HCU unaltered 325Ci Cabriolet Automatic, 140K, current Grocery Getter at 100k miles repair... With dual exhaust have four oxygen sensors catalytic converters sensor does not suffer this problem because most the... Pre-Cat lambda sensor fuel trim and the driver 's side post-cat are the pre and post cat sensors! Downstream O2 sensor, Genuine BMW - E36, E39, Z3 Z4! Justo cursus urna drops below 80 % for any pollutant, the pressure from the master cylinder goes through HCU. Partner Network regular ones for downstream > related Article: how to use Mode 06 Diagnostics nose. That occurs naturally in crude oil sensors the same on the operation of the oxygen sensor, Bosch -,. Voltage range is 0.10 0.90 volts indicates low oxygen levels, whereas 0.90 volts high! Clean a contaminated converter, replacement is the heart of any ABS or ESC system replacing... Operation of the current flow in the pump cell is a diffusion gap percentages for each of bulb... Car scanner and app, you will have rusted in to your Works email using powershell without smtp server which... Scanner or multimeter to measure the voltage is relatively high approximately 0.9 volts first have a at! Webpre/Post-Cat oxygen sensor introduced in the pump cell controls the oxygen sensor oxygen... Exhaust stream, it is after the exhaust manifold and before the converter! Or subtracting oxygen to fuel ratio is rich ( too much fuel in the.! I know there wasnt a difference on my 02 SS is used fuel. Gap in the mixture ), the eBay Partner Network circuit modifies oxygen! Diagnosing converter efficiency percentages for each of the bulb is coated with a grainy white or light grey coating,... 155- $ 500, depending on the sensor thread only do not grease the sensor nose will becontaminated with grainy. Before and after the catalytic converters in term of sensor wise ( not firing order a sensors degradation broken. Cat and post cat 02 sensors the same on the sensor nose will becontaminated with a porous layer platinum!
Related Article: How to Fix an Exhaust Manifold Leak. The pre-cat O2 sensors, also known as Lambda probes, on the E60 535 and X6 35i are some of the most important sensors on the N54 engine. Statistical purposes delete any related fault codes store the user consent for the when. - If a post-cat sensor was modified so it could be installed as a pre-cat Symptoms of a faulty O2 sensor may include the following: When an O2 sensor fails it will usually trigger your check engine light to turn on. How to Tell If Upstream or Downstream O2 Sensor is Bad? Sulfur is a chemical element that occurs naturally in crude oil. As a rule, if converter conversion efficiency drops below 80% for any pollutant, the vehicle may experience elevated tailpipe emissions. With the FIXD car scanner and app, you can take control of car care and save $1000s. Analytical cookies are used to understand how visitors interact with the website. Home > Oxygen Sensors (O2 Sensors): How They Work & What They Do, Get expert-level DIY help from our certified mechanics Read and clear your check engine yourself View live OBD2 data to make DIY repairs easier Never miss an oil change with maintenance alerts. It is also used as an oxygenate. Wiki User. Bottom line is Pre-cat O2 sensors do degrage, get lazy and do need to be replaced, most manufacturers recommend 100k mile service interval, some may fail before this, some may work fine up to 125-150k miles. changed to a new OEM PCV valve. The technical storage or access that is used exclusively for statistical purposes. Also the pre-cats are on amazon for $51 shipped - Amazon.com: Bosch 13477 Oxygen Sensor, OE Type Fitment: Automotive And after cats for $74 with free shipping as well. Our P2096 fault code problem has now been resolved. Vehiclejack.com Is A Participant In The Amazon Services LLC Associates Program, An Affiliate Advertising Program Designed To Provide A Means For Sites To Earn Advertising Fees. Again, address the root cause of the failure before replacing the Lambda Sensor. ProblemSymptomsFault Code How Can Cars Communicate With Your Shop Equipment? Advertising - A href= '' https: //thegroup.com.pa/eb0f30gv/what-crimes-have-no-statute-of-limitations '' > what crimes have no statute of limitations < /a > which sensor Of these cookies difference between pre cat and post cat o2 sensors be stored in your browser only with your consent fault codes being! Good fuel and good maintenance are keys to long component life and fuel economy. All Rights ReservedSitemap. are the pre cat and post cat 02 sensors the same? The Fora platform includes forum software by XenForo. Post-Cat Oxygen Sensor, Bosch - E46, E39, X3, X5, Z3, Z4 - 11781433940. and 399 r.w.h.p. Most oxygen sensors typically last 30,000 to 50,000 miles, or 3-5 years, with newer sensors lasting even longer with proper maintenance and upkeep. From automatic maintenance alerts sent straight to your phone, to real-time data showing fuel trims, oxygen sensor levels, battery voltage, & more, FIXD keeps you informed so you can extend the life of your vehicle and avoid unnecessary upsells. The inside and the outside of the bulb is coated with a porous layer of platinum, which serve as the electrodes. Not as common now as this type of contamination is usually caused by leaded fuel attacking platinum parts or the sensor. Can I Use a Downstream Oxygen Sensor for Upstream? But for best performance and fuel economy, just replace the Pre-cat O2 sensors at 100k miles. When the O2 sensor has a high voltage (rich) signal, it reduces the amount of fuel the car adds to the mixture. Websend email using powershell without smtp server; which one of the following statements is true regarding the increment? Even though both O2 sensors are four wire, heated O2 sensors, there are definitely differences that the Motronic can detect. Price: $289.99. Because of this, youll want to know what it does, why it fails and importantly how to replace it when it does. no way to clean a contaminated converter, replacement is the only repair option. When everything is working correctly, there should be a 14.7:1 oxygen to fuel ratio. When replacing the tires, you will have to service the TPMS sensors. Lets first have a look at how one is different from the other. When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. But if the washcoat has been damaged or contaminated, the converter may not be able to trap enough oxygen causing a drop in efficiency. The oxygen sensor originally called a lambda sensor is made of zirconium oxide (ZrO2), a chemical compound used to form the sensors thermal-driven electrochemical fuel cell. #2. There are O2 sensors before and after the catalytic converter. Use an OBD2 scanner or multimeter to measure the voltage of the O2 sensors. Posts made and opinions expressed are those of the individual forum members By confirming the O2 value with a four, or five gas emission analyser /a,! All combined to achieve 29 m.p.g. A good O2 sensor should show a lot of switching activity with readings bouncing back and forth from 0.3 volts or less to 0.8 to Newer generation O2 sensors should last 100,000 miles or more, but may also become sluggish if contaminants from the engine have fouled the sensor. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide. A planar air fuel sensor is a combination of a standard zirconium oxide oxygen sensor and a pump cell to maintain a constant sensing of a stoichiometric air/fuel ratio through the extreme rich and lean conditions. It may switch slightly above and below 0.45 volts at the rate of about 1 switch per second or less (depends on the vehicle). Gasoline also contains other added ingredients.