difference between pre cat and post cat o2 sensors

Common sources of contamination include an excessively rich fuel mixture condition or oil blow-by in an older engine and engine coolant being burnt in the combustion chamber as a result of an engine gasket leak. The code P0420 can be caused by the catalyst, O2 sensors before and after the catalyst. A vehicles (bank 2, sensor 2) O2 sensor will be located behind or downstream of the catalytic converter on the bank which corresponds to the engines second cylinder. If you are going from Kingston to Cornwall, you are travelling downstream. Each vehicle may be different and require unique test 232/234 .595,.598 +2 comp cam with ported and polished stock heads with .650 lift dual springs and a bowl grind. If you need assistance having this checked or repaired, a qualified pro from YourMechanic can come to your location to inspect the system and replace any O2 sensors that are faulty. These can all affect the oxygen sensors response characteristics, resulting in an extended response time or a shift in the sensor voltage curve and in the long run reduced sensor performance. Are the sensors indeed the same functionally? 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. For a better experience, please enable JavaScript in your browser before proceeding. These cookies track visitors across websites and collect information to provide customized ads. The Fora platform includes forum software by XenForo, http://www.realoem.com/bmw/showparts.do?model=ET37&mospid=47720&btnr=11_2181&hg=11&fg=50&hl=3, https://www.youtube.com/watch?v=21E5_u6dz0s, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Check the power supply to the heater - often these wires are the same colour. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned. As I understand it, the pre cat voltages should swing between around 0.2v - 0.8v per second (mine appear to do that just fine) and the post cat . 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. Pre Cat and Post Cat O2 Sensors For Suzuki Swift Sport RS416 1.6L M13A M16A . The difference between the two is about $1,000.. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". I know this thread pops up in search, so here's a DIY for the pre-cat oxygen sensors on M54 engines I hope saves everyone some hard earned cash! So any cars made after 2003 only used those regular ones for downstream. There is no different part number for bank1 and bank2. Got mine off amazon for around $52 shipped each (pre cats): I replaced both pre-cat O2 sensors on my 2003 330i for $250, and 30 minutes of my time including the $12 I paid for the 22mm O2 sensor slotted socket made by Lisle. The O2 sensor is part of the emissions system of your car that measures the proportion of oxygen in your engine. . Copyright 2022 Machine Matrix L.L.C. The Fora platform includes forum software by XenForo, https://turbobricks.com/resources/O2sensors.pdf, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Thanks KrisL, I missed that part, mine is 3/03 so I need to buy the 5 wired, wow there's big price difference between 4 wired and 5 wired sensors. Cornbury House, Cotswold Business Village 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). tuned with EFI Live. Is a brake light and running light the same? Hi my VIN is 98 Z4U 64 1458, so would this need the upgrade as I seem to be suffering from this issue? However they often can skew the reading back to the DME. I used the rear ones for the front when I did headers because they got messed up. Upstream Sensor is in the Exhaust Manifold Pre-Cat. . Contact information for direct sales and support queries, plus our network of global distributors. This enables the sensor to be located further away from the heat source at the manifold to a 'cleaner' location. Information can be obtained from the operator or the white pages. Honestly, with narrow band sensors, it WILL work. Once the sensor is in place, plug in the electronic connector. 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. There is no difference between the pre and post O2 sensors. Required fields are marked *. This allows measurement of a much wider air/fuel ratio. 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. Too much fuel produces hydrocarbons and carbon monoxide. 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. 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. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. On the other side of the nernst cell, oxygen from the air outside the exhaust travels down the O2 sensor and makes contact. Tighten the sensor to the recommended torque. Where as before 2003, they were like yours using all 4 regular. hi guys i got old 02 sensor out a Little tight getting new one in. For a better experience, please enable JavaScript in your browser before proceeding. O2 Oxygen Sensor Kit For Mazda CX-7 2006-2012 2.3 Turbo Petrol (both sensors) New . On an oscilloscope, the resultant waveform should look as the illustration above. Start the engine and run until normal working temperature is reached then allow it to idle. When the vehicle accelerates, the ECM allows overfuelling and ignores the lambda signals. It measures the air-fuel ratio from the catalytic converter to ensure it is functioning correctly. Thanks! These cookies will be stored in your browser only with your consent. Whereas wide-band is 1V -5V, allowing for more detail when not at ideal operating conditions. Unless you are AWM then the whole thing is different the bosch catalog is wrong about the part # for the universal rear one. The Waveform Library is a global database of waveforms uploaded by PicoScope users. The cookie is used to store the user consent for the cookies in the category "Other. 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. . Poor fuel economy: a faulty oxygen sensor will upset the air to fuel mixture resulting in increased fuel usage. To protect against the sensor becoming welded into its threading, Delphi sensors come with anti-seize compounds either pre-applied or included in the box. Top wire: White heater (+) Connect a diagnostic tool, such as Delphis DS, select the correct vehicle and read the fault code(s). Lambda sensors have an internal heater, so check the resistance of the heater it will usually be quite low. The ECU wont be able to adjust fuel trims properly. If you are boating from Kingston to Toronto, for example, you are heading upstream. How do I know if its my upstream or downstream O2 sensor? Reading the trouble codes will tell you exactly which sensor is in need of replacing either the upstream (top) or downstream (bottom) sensor and on what bank (side) of the engine. Where is the downstream oxygen sensor located? How do you fix P0420 catalyst system efficiency Below Threshold Bank 1? The Titania Oxygen sensor differs from the Zirconia sensor in that it is incapable of producing its own output voltage and is therefore reliant on a 5-volt supply from the vehicle's ECM. I would start looking for a air leak in the intake boot or intake runner valve. 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. Its job is to monitor the oxygen content exiting the catalytic converter in order to determine if it is operating efficiently. You will see that, The pre catalytic converter sensor signal. The difference in the amount of oxygen between that present in the outside air, and that present in the exhaust promotes the flow of oxygen ions and produces voltage. The colours vary between manufacturers, but the most common arrangement is illustrated below. The difference in the amount of oxygen between that present in the outside air, and that present in the exhaust promotes the flow of oxygen ions and produces voltage. 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. Use live data to check for signal if the sensor wiring is difficult to access. Inspect the electrical connector for damage or dirt. We know that our PicoScope users are clever and creative and wed love to receive your ideas for improvement on this test. Upstream is before the Cat and downstream is after the cat. All Rights Reserved. New . - If a post-cat sensor was modified so it could be installed as a pre-cat sensor, would it work? That's where my misconfusion came from. 27 sold . The Club assumes no responsibility for any effects arising from errors or omissions. If you decide to do this long term, you will experience problems. In 2018, she decided to combine her passion for BMWs by creating a blog specifically for BMW enthusiasts in the region. Bank 2 Sensor 1 is the first sensor closest to the engine. 06-29-2005 08:28 PM. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. If both O2 sensors and catalyst was replaced then you may have an exhaust leak at the manifold or pipes. This also happens during initial warm-up. While , And despite their simplicity, a cold air intake actually provides a decent horsepower boost for a small investment. Is upstream pre or post cat? It is also exposed to extremely high temperatures, and like any component can wear over time. 2001 camaro z28 ss vert with factory slp upgrades, Hooker long tubes, 3"y-pipe to a 4" muffler, ,airlid,s.s.r.a. Click to enlarge. Sensor 1 is the sensor closest to the engine. They reacts to the oxygen content in the exhaust system and produce a small voltage depending on the air/fuel mixture seen at the time. The pre-cat sensor regulates fuel supply, while the downstream sensor measures the efficiency of the catalytic converter. 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. In most cases, a vehicle with an inefficient catalytic converter will continue to run just fine. Come join the discussion about M performance, turbo kits, engine swaps, builds, modifications, classifieds, troubleshooting, maintenance, and more! read the wiki, all common air leask are there, hi y have 2 codes po155 heated oxygen sensor bank2 sensor 1 (ho2s21) sensor heater circuit and po135 heated oxygen sensor bank 1 sensor 1 (ho2s11) sensor heater some vary can tell me the locations on this sensor and part #s or were i can buy it cheap thanks. We have good news! It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible. This page could not be found. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times. Since the oxygen sensor is in the exhaust stream, it can become contaminated. Because many late model vehicles have multiple oxygen sensors, be sure you correctly identify the bad sensor so you do not mistakenly replace the wrong one. The pre-cat sensor regulates fuel supply, while the downstream sensor measures the efficiency of the catalytic converter. Use an oscilloscope to check the signal at both idle and approx. Free shipping . . Necessary cookies are absolutely essential for the website to function properly. 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. A lambda sensor is also referred to as an Oxygen or O2 sensor, or a Heated Exhaust Gas Oxygen (HEGO) sensor, and plays a very important role in control of exhaust emissions on a catalytic-equipped vehicle. This is a TSB regarding the P2096 problem. 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. Use of the Forum is subject to the Terms and Conditions. But opting out of some of these cookies may affect your browsing experience. Oxygen molecules from the exhaust gas pass through tiny slots or holes in the sensors steel shell to reach the sensing element, or nernst cell. Check engine light: whilst the check engine light can come on for many reasons, it is normally down to an emission related issue. Analytical cookies are used to understand how visitors interact with the website. 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? Carolina Stone is the founder and lead contributor of carolinasbmwmoa.org, a popular blog dedicated to all things about BMWs. 2,500 rpm engine speed. The sensor signal helps keep the mixture just right. This help topic is subject to changes without notification. Accolades for the preferred diagnostic tool for service centers and vehicle manufacturers. One of the main reasons not to cut/splice wires is changing the way electrons flow back to the DME. ,t.c.bypass,descreened m.a.f. This information is an example of our investigations and findings and is not a definitive procedure. Check if this part fits your vehicle. What is the difference between pre cat O2 sensor and Post car O2 sensor in term of sensor wise(not. are the pre cat and post cat 02 sensors the same? Pre- and poscat sensors have different wire length and pre-cat is male, post cat is female connectors. A4 (B5 Platform) Discussion. It is what tells your cars ECU when the AFR goes rich, stoic, or lean. Do universal sensors work, well yes. 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. 3rd wire: Black - signal SpyderChat Forum is a community for Toyota MR2 Spyder Enthusiasts to discuss specs, reliability and more! Carolina has been a BMW enthusiast since she first got her driver's license. A typical Zirconia lambda sensor has four wires. carolinasbmwmoa.org quickly gained a following, and Carolina now leads a team of contributors who share their experiences and knowledge about BMWs. When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing. 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. As you drive your car the computer will monitor all the sensors and register the results. Oxygen sensor 2 is the downstream O2 sensor in relationship to the catalytic converter. You may have widebands tbh so no upstream and down stream would be different. The downstream oxygen sensor detects the change and informs the vehicles computer. Available for Windows, Mac, and Linux, the next evolution of our diagnostic scope software is now available. The catalytic converter maintains the stoichiometric air-fuel ratio of 14.7:1. The technical storage or access that is used exclusively for statistical purposes. The technical storage or access that is used exclusively for anonymous statistical purposes. 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. with 384 lbs of torque. Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you. with unbelievable performance for the money. Check the O2 sensor is reading correctly by confirming the O2 value with a four, or five gas emission analyser. Once unscrewed, discard the old sensor and replace with the new unit. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Bank 2 Sensor 2 is the second sensor on the engine's exhaust pipe, usually behind the catalytic converter. Tally how many spark plug wires are present. I have two new original postcat sensors. It lets you see what you previously had to guess was happening. 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. All combined to achieve 29 m.p.g. Downstream Rights means the rights that are acquired from the Downstream Operator by a User or the Downstream System counterparty user, in order to receive the Regasified LNG at a Regasified LNG Delivery Point. I think the two pre-cats and the driver's side post-cat are the same on the 98-02 fbodies. *At Pico we are always looking to improve our products. If the exhaust gas mixture is too rich and there is too little oxygen in the exhaust, a signal is sent to the engines Electronic Control Unit (ECU) to decrease the amount of fuel added into the cylinder. Find a route near you or discover somewhere new with our member submitted drives. JavaScript is disabled. Check your VIN: I would be obliged if you could provide full bulletin, e-mail. Titania is also used in the manufacture of another type of lambda sensor that offers a faster switching time than the more common Zirconia 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. 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. $89.05 .