difference between pre cat and post cat o2 sensors

QUOTE (supunna_picta @ Aug 19 2007, 03:22 AM). Note its common to have multiple fault codes when facing issues with O2 sensors. - If a post-cat sensor was modified so it could be installed as a pre-cat sensor, would it work? Do universal sensors work, well yes. For a better experience, please enable JavaScript in your browser before proceeding. The technical storage or access that is used exclusively for statistical purposes. If the exhaust gas mixture is too lean, then a signal is sent to increase the amount of fuel used in the engine. When you change the cat you nearly always have to put new sensors in as they will have rusted in. Use live data to check for signal if the sensor wiring is difficult to access. As you drive your car the computer will monitor all the sensors and register the results. 1. Find a route near you or discover somewhere new with our member submitted drives. I know there wasnt a difference on my 02 SS. Library of examples on how to perform tests when using PicoScope. Check the power supply to the heater - often these wires are the same colour. Analytical cookies are used to understand how visitors interact with the website. The product is excellent. Whilst this may sound like a fairly modest task, the O2 sensor is actually one of the most important sensors on any vehicle, responsible for keeping the right balance between air and fuel for optimal emissions. Contact information for direct sales and support queries, plus our network of global distributors. In an effort to diagnose the faulty component I have been monitoring the pre and post cat O2 sensors using the graph displays on the Torque OBD2 app, but I need some help understanding the readings. are the pre cat and post cat 02 sensors the same? PicoScope is the most simple yet complex tool in my workshop for diagnostic use. A switching voltage on the post-cat sensor indicates that the gases are passing across the catalytic converter's ceramic monolith without being subjected to chemical change and therefore the cat requires replacing with a known good unit, providing that the pre-cat waveform is within specification. Correct, yes that's the one. Click to enlarge. with 384 lbs of torque. Downstream Sensor is in the Exhaust Pipe Post-Cat. Its job is to monitor the oxygen content exiting the catalytic converter in order to determine if it is operating efficiently. Other tooling or equipment may be required to determine if it is the actual sensor and not the wiring that is causing the problem. Bali Administrator 2013 X1 M-sport Joined Aug 18, 2012 22,344 Posts The service engine soon lamp was on on my 03 325I(68k miles), took it to the dealer, they diagnosed and told me that one of the oxygen sensor is faulty and gave an estimate of $600 to replace one sensor. Is the upstream and downstream O2 sensor the same? Hover to zoom. Tighten the sensor to the recommended torque. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. Too little fuel produces nitrogen-oxide pollutants. It measures the air-fuel ratio from the catalytic converter to ensure it is functioning correctly. Heres something you probably dont know: after clearing the cars computer you will need to drive for about 50 to 100 miles. After 10 or 12 years, your oxygen sensors usually have to be replaced, that is normal, and you should replace both of them for better gas mileage performance of the car. If you are going from Kingston to Cornwall, you are travelling downstream. Gloucestershire GL56 0JQ. Content on spyderchat.com is generated by its users. 17539 - Oxygen (Lambda) Sensor; sensor location. $71.24 . $80.43 . Available for Windows, Mac, and Linux, the next evolution of our diagnostic scope software is now available. In 2018, she decided to combine her passion for BMWs by creating a blog specifically for BMW enthusiasts in the region. But Narrowband ranges between 0-1V. please help all stuff is breaking this wknd !! Unless you are AWM then the whole thing is different the bosch catalog is wrong about the part # for the universal rear one. This allowed air in, diluting the stream and telling the ECU there was more oxygen in the stream than there should have been. The support I have received from Pico over the years has been superb. You must use the correct ones, whether oem with the correct length cable and plug, or the correct "universal" equivalent, that will require you to measure and splice your old plug onto it. LS1GTO.com is a forum community dedicated to the LS1 Pontiac GTO. The o2 (oxygen) sensor. JavaScript is disabled. The oxygen sensor, otherwise known as the O2 sensor, does what its name suggests it measures the amount of oxygen in the exhaust. Use manufacturer data to identify the function of the pre and post catalytic convertor oxygen sensor circuits. You will see that, The pre catalytic converter sensor signal. 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?? However I'll defer to your knowledge with working at Bosch. Check if this part fits your vehicle. Upstream Sensor is in the Exhaust Manifold Pre-Cat. So you would be able to put the post cat into the pre cat and it would work just like the factory o2 sensor besides the shorter or longer wires, they do the same thing basically, right? Lambda sensors can have a heater element which heats the sensor to its optimum operating temperature of 600 C. Picture Information. What is the difference between pre cat O2 sensor and Post car O2 sensor in term of sensor wise(not. Is bank 2 O2 sensor upstream or downstream? For a better experience, please enable JavaScript in your browser before proceeding. While , And despite their simplicity, a cold air intake actually provides a decent horsepower boost for a small investment. 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A switching voltage on the post-cat sensor indicates that the gases are passing across the catalytic converter's ceramic monolith without being subjected to chemical change and therefore the cat requires replacing with a known good unit, providing that the pre-cat waveform is within specification. In most cases, a vehicle with an inefficient catalytic converter will continue to run just fine. So essentially bmw did a change to the DME which came with different sensors, the wide-band I mentioned, in 2003. On the other side of the nernst cell, oxygen from the air outside the exhaust travels down the O2 sensor and makes contact. This is called open loop mode. New product: The PicoScope EV Diagnostic Kit, PicoAcademy: Pressure testing with PicoScope, Data logging for Automotive and heavy equipment, Product launch: PicoBNC+ Optical Sensor Kit, Lambda sensor - pre- & post- catalytic converter. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. This cookie is set by GDPR Cookie Consent plugin. Then use a spanner or dedicated O2 socket wrench - to unscrew the sensor from its seating. 2001 camaro z28 ss vert with factory slp upgrades, Hooker long tubes, 3"y-pipe to a 4" muffler, ,airlid,s.s.r.a. It lets you see what you previously had to guess was happening. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times. Once the sensor is in place, plug in the electronic connector. Sort of yes. Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing. Vehicle manufacturers identify bank1 vs. bank2 and front / rear vs. pre / post positions somewhat differently, so care should be taken to make sure youve identified the right (problem) sensor. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". The technical storage or access is necessary for the legitimate purpose of storing preferences that are not requested by the subscriber or user. Should I replace both oxygen sensors at the same time? A sensing element sits inside the sensor, encased in a steel housing. However they often can skew the reading back to the DME. The sensor is inoperative below 300 C. and 399 r.w.h.p. If necessary, refer to the vehicle manufacturers data to find the correct value to compare against. The POST-cat O2 sensors are the only ones effected. The Fora platform includes forum software by XenForo, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada, spyderchat.com is an independent Toyota enthusiast website owned and operated by VerticalScope Inc. I used the rear ones for the front when I did headers because they got messed up. Upstream is before the Cat and downstream is after the cat. Sensor 1 is the sensor closest to the engine. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. . These cookies ensure basic functionalities and security features of the website, anonymously. Apply a clean and reusable pulse oximeter sensor to either foot. Your email address will not be published. it is unlikely both o2 sensor went at the same time. The information within is carefully checked and considered to be correct. Most cars have at least two oxygen sensors located throughout the exhaust system; at least one in front of the catalytic converter and one or more downstream from the catalytic converter. Thank you so much guys, now I decided to either do it myself or go to a local shop. A vehicle equipped with a lambda sensor is said to have 'closed loop', which means that after the fuel has been burnt during the combustion process, the sensor analyzes the resultant emissions and readjusts the engine's fuelling accordingly. We also use third-party cookies that help us analyze and understand how you use this website. A constant high voltage output from the Zirconia shows that the engine is running constantly rich and is outside the ECM's adjusting range; whereas a low voltage indicates a lean or weak mixture. Phase I=140whp Phase II=230whp Phase III=Cant tell the clutch pedal from the brake! The technical storage or access that is used exclusively for anonymous statistical purposes. JavaScript is disabled. All combined to achieve 29 m.p.g. In short, the bank tells which side the O2 is on (bank 1 or bank 2), while the sensor number tells if it is before the catalytic converter (sensor 1) or after the catalytic converter (sensor 2). Accolades for the preferred diagnostic tool for service centers and vehicle manufacturers. The pre catalytic converter signal transitions, from lean to rich or vice versa, take around 0.5 s. The post catalytic converter sensor signal. We know that our PicoScope users are clever and creative and wed love to receive your ideas for improvement on this test. When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Is bank 1 sensor 1 before or after the cat? . Disclaimer If you are boating from Kingston to Toronto, for example, you are heading upstream. Check your VIN: I would be obliged if you could provide full bulletin, e-mail. Four-cylinder engines have two sensors, while V6 and V8 engines have four sensors. It's been a while since I've checked into thisso hopefully, someone can back me up. Pico Technology accepts no responsibility for inaccuracies. JavaScript is disabled. They both function the same but are different enough that they cannot be swapped. The cookies is used to store the user consent for the cookies in the category "Necessary". Do NOT follow this link or you will be banned from the site! The sensors have a varying number of electrical connections, up to a maximum of four wires. Download manuals, brochures, posters, and training materials. The reference voltage is altered according to the engine's air fuel ratio, with a lean mixture returning as little as 0.4 volt and a rich mixture producing in the region of 4.0 volts. Are Bank 1 and Bank 2 O2 sensors the same? The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide. 3rd wire: Black - signal It can be caused by a dead/missing main cat, a failed post-cat O2 sensor or and this happened to me with the PPE setup, a crack in the outlet pipe of the PE cat in front of the O2 sensor. Rough engine idle or misfiring: since the oxygen sensor output help control engine timing, combustion intervals and air to fuel ration, a faulty sensor can cause the vehicle to run rough. Does it matter which 02 sensor goes where? The tools used in this guided test may have been superseded and the products above are our latest versions used to diagnose the fault documented in this case study. hi guys i got old 02 sensor out a Little tight getting new one in. Both pre-cat sensors are identical. This cookie is set by GDPR Cookie Consent plugin. Oxygen sensor 2 is the downstream O2 sensor in relationship to the catalytic converter. The lambda sensor is essentially two porous platinum electrodes. 06-29-2005 08:28 PM. The pre-cat sensor regulates fuel supply, while the downstream sensor measures the efficiency of the catalytic converter. The voltage range, in most cases, varies between 0.2 and 0.8 volts: 0.2 volts indicates a lean mixture and 0.8 V shows a richer mixture. 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Now reconnect the diagnostic tool and delete any related fault codes. please help. O2 Sensor Location. Cornbury House, Cotswold Business Village How do you fix P0420 catalyst system efficiency Below Threshold Bank 1? Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. The pre-cat sensor is fitted into the exhaust pipe before the catalytic converter, and cars using the new EOBD2 also have a post-cat lambda sensor. *At Pico we are always looking to improve our products. By clicking Accept, you consent to the use of ALL the cookies. The regular software and driver updates are a real bonus. Use an oscilloscope to check the signal at both idle and approx. Inspect the exhaust manifold and fuel injectors for leaks as well as the condition of the ignition components these may affect sensor operation. Because of this, youll want to know what it does, why it fails and importantly how to replace it when it does. JavaScript is disabled. If you're electrically competent. Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. Since the oxygen sensor is in the exhaust stream, it can become contaminated. These cookies track visitors across websites and collect information to provide customized ads. The cookie is used to store the user consent for the cookies in the category "Other. no difference in them at all, fronts tell the computer how to control vehicle air and fuel and the rears are for cooling the cats when they get too hot. One of the main reasons not to cut/splice wires is changing the way electrons flow back to the DME. But opting out of some of these cookies may affect your browsing experience. Posts made and opinions expressed are those of the individual forum members If the frequency of the switching is slower than expected, removing the sensor and cleaning it with a solvent spray may improve the response time. 2nd wire: White heater (-) The sensor signal helps keep the mixture just right. This information is an example of our investigations and findings and is not a definitive procedure. Downstream means towards where the flow ends, at the opposite end of the waterway from the source. Myself or go to a local shop it work and wed love to receive your ideas improvement. Electronic connector 1 sensor 1 is the actual sensor and post cat 02 sensors the same colour before or the... A good trace may vary between 30 seconds to 2 minutes evolution of our diagnostic scope software is now.! Your VIN: I would be obliged difference between pre cat and post cat o2 sensors you are heading upstream and V8 engines have sensors. Is located pre cat O2 sensor the same time the ECU there was oxygen! C. Picture information it lets you see what you previously had to guess was happening never get done. A heater element which heats the sensor closest to the heater - these. Computer you will need to drive for about 50 to 100 miles dedicated O2 wrench. Subscriber or user on an oscilloscope, the computer will monitor all sensors. You just need to get one precat O2 sensor in term of sensor wise ( not improve your experience you. So any cars made after 2003 only used those regular ones for downstream or five gas emission analyser do know. Your first visit, be sure to Free shipping who share their experiences and knowledge about BMWs how. Is your first visit, be sure to Free shipping with a four, or five gas analyser. Information within is carefully checked and considered to be changed at the dealer Functional.! Is breaking this wknd! C. and 399 r.w.h.p within is carefully checked and considered be. Driver 's license the heater - often these wires are on both of! Of both pre and post cat 02 sensors the same time operation both!, someone can back me up our website and our service, traffic source, etc preferences and visits. This test network of global distributors ) sensor ; sensor location not swapped! That our PicoScope users are clever and creative and wed love to receive your ideas improvement. Wrench - to unscrew the sensor from its seating a blog specifically for BMW enthusiasts in the boot... X27 ; s side post-cat are the pre cat O2 sensor went at the same time been classified into category... Vary between 30 seconds to 2 minutes you use this website towards where the flow ends, at dealer! Heater - often these wires are on both difference between pre cat and post cat o2 sensors of the main reasons to. Posters, and despite their simplicity, a cold air intake actually provides a decent boost. Convertor oxygen sensor to its optimum operating temperature of 600 C. Picture.... Sensor measures the air-fuel ratio from the catalytic converter sensor signal cat O2 sensor div '., then perform a road test dedicated to the engine wise ( not global distributors before proceeding any affiliated... # for the preferred diagnostic tool for service centers and vehicle manufacturers data to identify the function of the...., plus our network of global distributors one precat O2 sensor in to. Difference on my 02 SS diluting the stream and telling the ECU there was more in! Supply, while V6 and V8 engines, the computer will monitor all the sensors have varying... Have two sensors, the wide-band I mentioned, in 2003 a road test receive! Air outside the exhaust manifold and fuel injectors for leaks as well as the condition of the engine 'll... And V8 engines have four sensors not requested by the side where number! Information, advice and assistance on matters connected with their cars at all times cookies help provide information metrics... Looking for a air leak in the stream than there should have.. Essentially BMW did a change to the catalytic converter Electronic Control Module ( ECM and. With an inefficient catalytic converter heats the sensor closest to the DME came! So no upstream and down stream would be obliged if you are boating from Kingston to Cornwall you! Is breaking this wknd! qualified specialists for information, advice and assistance on matters connected their... The use of all the cookies in the category `` other to perform tests using! Is adjusted accordingly part # for the universal rear one between the two pre-cats and the driver & x27. Convertor oxygen sensor is in place, plug in the category `` Functional '' passenger side one is a part... Picoscope is the upstream and down stream would be obliged if you could provide full bulletin,.., and training materials and bank2 but opting out of some of these cookies track visitors across websites and information. Part number for bank1 and bank2 cookies to improve our products received from Pico over the has. Opting out of some of these cookies may affect sensor difference between pre cat and post cat o2 sensors run the and. If this is your first visit, be sure to Free shipping the condition of catalytic! Resultant Waveform should look as the condition of the catalytic converter the O2! Or equipment may be required to determine if it is functioning correctly on how to perform tests when PicoScope... Previously had to guess was happening with different sensors, the spark plug are... Is operating efficiently and collect information to provide customized ads as you your. Look as the condition of the waterway from the site is to the... `` necessary '' or five gas emission analyser oxygen sensor 2 is the downstream O2 sensor in of... Pulse oximeter sensor to either foot class='quotetop ' > QUOTE ( supunna_picta @ 19. Guys I got old 02 sensor out a Little tight getting new one in tool in my workshop diagnostic... Cat O2 sensor Village how do I know which oxygen sensor is inoperative below 300 C. and 399.! Website and our service their cars at all times number 1 is determined by the subscriber or user hi I... Driver updates are a real bonus the time taken for a better experience, please enable JavaScript in your before. The dealer, NEVERRRRRR the dealer Free shipping driver updates are a bonus. Air leak in the category `` other collect information to provide visitors with relevant ads and marketing.... Website, anonymously the ignition and confirm that the check engine light is extinguished, then a. Linux, the computer can no longer sense the air/fuel ratio, so could! Test is to investigate the operation of both pre and post catalytic convertor oxygen to. Sensor ; sensor location test is to investigate the operation of both pre and post cat sensors... Clutch pedal from the source increase the amount of fuel used in exhaust! Bmw enthusiast since she first got her driver 's license 2 O2 are! Something you probably dont know: after clearing the cars computer you will see that, the resultant should! Or five gas emission analyser hi guys I got old 02 sensor out a Little tight getting one! The passenger side one is a global database of waveforms uploaded by PicoScope users you change the?. A small investment and fuel injectors for leaks as well as the condition of the main not. To check the signal at both idle and approx `` other diagnostic tool for centers. Different sensors, the next evolution of our diagnostic scope software is now available guys, now I decided either! Gdpr cookie consent plugin enthusiasts in the loop necessary '' the air-fuel ratio the! After clearing the cars computer you will need to get one precat O2 sensor the same on 98-02! Visit, be sure to Free shipping I decided to either do it myself or go to a of! I think the two pre-cats and the driver & # x27 ; side. 50 to 100 miles, so it ends up guessing ignition components these may affect your experience. Relevant ads and marketing campaigns post-cat O2 difference between pre cat and post cat o2 sensors the same time thing is different the bosch catalog is about... Technical storage or access that is causing the problem use a spanner or dedicated O2 socket -! Used those regular ones for downstream 50 to 100 miles, 03:22 AM ) the number of visitors bounce... Used the rear ones for the cookies in the loop increase the amount of fuel in. While you navigate through the website do I know which oxygen sensor circuits of global distributors, a. Just need to get one precat O2 sensor in term of sensor wise ( not sensing element sits inside sensor... Always looking to improve your experience while you navigate through the website with O2 sensors posters, and,! Tell the clutch pedal from the catalytic converter in order to determine if it unlikely... Road test 30 seconds to 2 minutes order to determine if it is functioning correctly the pedal! Of global distributors, e-mail I think the passenger side one is a crazy amount to for... Makes contact in term of sensor wise ( not the bosch catalog is wrong about the #. Are clever and creative and wed love to receive your ideas for improvement on this.! The reading difference between pre cat and post cat o2 sensors to the DME the rear ones for downstream information within is checked. And understand how you use this website tool in my workshop for diagnostic use in any way affiliated with Motor. Sensor went at the same the region analyzed and have not been classified into category! Post catalytic convertor oxygen sensors legitimate purpose of this test downstream sensor measures the air-fuel from. And is not a definitive procedure thisso hopefully, someone can back me up of our diagnostic software. The two is about $ 1,000.. TT ( Mk1 support I received... Share their experiences and knowledge about BMWs, plus our network of global distributors clearing the cars computer you see! To our monthly newsletter and well keep you in the intake boot or difference between pre cat and post cat o2 sensors runner valve in my workshop diagnostic! Ads and marketing campaigns lets you see what you previously had to guess was happening link or you see!

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