difference between pre cat and post cat o2 sensors

An ECM will only control the fuelling in 'closed loop' when the appropriate conditions allow, which is normally during idle, light load and cruise operations. The support I have received from Pico over the years has been superb. Both pre-cat sensors are identical. 27 sold . This help topic is subject to changes without notification. Posts made and opinions expressed are those of the individual forum members Information can be obtained from the operator or the white pages. Unless you are AWM then the whole thing is different the bosch catalog is wrong about the part # for the universal rear one. We know that our PicoScope users are clever and creative and wed love to receive your ideas for improvement on this test. The sensors have a varying number of electrical connections, up to a maximum of four wires. 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. For a better experience, please enable JavaScript in your browser before proceeding. This is called open loop mode. The product is excellent. I was very impressed as to the speed and ease of ordering. 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. Top wire: White heater (+) Minimize the help page. 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The difference is the wire length. Automotive diagnostic scopes and equipment. LS1GTO.com is a forum community dedicated to the LS1 Pontiac GTO. Fantastic products and support with unbelievable performance for the money. For a better experience, please enable JavaScript in your browser before proceeding. Heres something you probably dont know: after clearing the cars computer you will need to drive for about 50 to 100 miles. These cookies track visitors across websites and collect information to provide customized ads. Your email address will not be published. $89.05 . I think the passenger side one is a different part number because of longer wires. 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 2018, she decided to combine her passion for BMWs by creating a blog specifically for BMW enthusiasts in the region. Are the sensors indeed the same functionally? 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. Check your VIN: I would be obliged if you could provide full bulletin, e-mail. for diagnostic use. TT (Mk1 . Sign up and subscribe to our monthly newsletter and well keep you in the loop. Use of the Forum is subject to the Terms and Conditions. Hi my VIN is 98 Z4U 64 1458, so would this need the upgrade as I seem to be suffering from this issue? Anyone else wonder if the OP was able to do any modifications (lights, drop, wheels, interior trim, grilles) but can't figure out how to swap out the 02 sensors? A typical Zirconia lambda sensor has four wires. Check the condition of the probe element protective tube for signs of damage and contamination. It lets you see what you previously had to guess was happening. 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. 06-29-2005 08:28 PM. O2 Oxygen Sensor Kit For Mazda CX-7 2006-2012 2.3 Turbo Petrol (both sensors) New . 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. Where as before 2003, they were like yours using all 4 regular. Confirm the fault code by selecting live data and comparing the value of the suspect faulty sensor to that of a known working sensor. Use live data to check for signal if the sensor wiring is difficult to access. Our garage has checked leaks and wiring and this is what they have done. . All Rights Reserved. I used the rear ones for the front when I did headers because they got messed up. Contact the seller. Copyright 2022 Machine Matrix L.L.C. I tried a couple of them and got codes before I even started the car. Hover to zoom. Poor fuel economy: a faulty oxygen sensor will upset the air to fuel mixture resulting in increased fuel usage. JavaScript is disabled. The ECU wont be able to adjust fuel trims properly. This page could not be found. Wide band O2 sensors have an additional O2 pumping cell to regulate the amount of oxygen present in the sensing element. If this is your first visit, be sure to We also use third-party cookies that help us analyze and understand how you use this website. If the voltage of the downstream oxygen sensor drops and fluctuates like the voltage of the upstream oxygen sensor, it is a sure sign that the oxygen levels are too high, and the PCM will display the P0420 code. Most oxygen sensors come with a special electrically conductive anti-seize compound applied to the threads, so its merely a matter of threading the new sensor into the void left by the old one. The cookies is used to store the user consent for the cookies in the category "Necessary". Their bodies are identical, so the threads. Switch on the oximeter and connect the applied probe to the oximeter. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide. Check if this part fits your vehicle. Our support forum where 16,000+ users (including Pico staff) discuss all things PicoScope Automotive. Disclaimer It lets you see what you previously had to guess was happening. AU $309.99 + AU $45.00 postage . If you're electrically competent. Gloucestershire GL56 0JQ. What is the difference between pre cat O2 sensor and Post car O2 sensor in term of sensor wise(not. The Club assumes no responsibility for any effects arising from errors or omissions. i.e. Other than the connector, is there a difference? 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. carolinasbmwmoa.org quickly gained a following, and Carolina now leads a team of contributors who share their experiences and knowledge about BMWs. Pre Cat and Post Cat O2 Sensors For Suzuki Swift Sport RS416 1.6L M13A M16A . The "pre-cat sensor" regulates fuel supply, while the downstream sensor measures the efficiency of the catalytic converter. Come join the discussion about Bimmerfest events, production numbers, programming, performance, modifications, classifieds, troubleshooting, maintenance, and more! Sensor 2 is the downstream oxygen sensor. Second difference: (and most important) There is a reason why the Upstream O2 sensor is about 2-3x more expensive than the downstream sensor. Apart from that, they work on the same principles and do same job - measuring O2 level. The outer electrode surface is exposed to the exhaust gases and is coated in a porous ceramic, with the inner coated surface exposed to fresh air. These known good waveforms have the following characteristics: Go to the drop-down menu bar at the lower left corner of the Waveform Library window and select, Oxygen / O2/ Lambda sensor. It is also exposed to extremely high temperatures, and like any component can wear over time. The code P0420 can be caused by the catalyst, O2 sensors before and after the catalyst. Both Titania and Zirconia sensors, when working correctly, switch approximately once per second (1 Hz) and will both only start to switch once the normal operating temperature has been achieved. 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. Picture Information. $71.24 . 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. The sensor signal helps keep the mixture just right. A typical Zirconia lambda sensor has four wires. These Remove passenger side front Use the factory wire retainers i Upstream is before the Cat and downstream is after the cat. Necessary cookies are absolutely essential for the website to function properly. Real-life case studies show how the professionals use PicoScope to diagnose vehicle faults. Do NOT follow this link or you will be banned from the site! 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 post cat is a different P/N and has a different wiring length but the fact that you ran CEL-less for a year means you indeed had the two remaining sensors wired correctly. 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. It's been a while since I've checked into this.so hopefully, someone can back me up. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. However, bank 1 has two sensors, of which sensor 1 is located near the engine before the catalytic converter, an upstream sensor called pre-CAT, and sensor 2 is located after the catalytic converter called post CAT, a downstream sensor. I think the passenger side one is a different part number because of longer wires. I then tried a front universal and all was well. The Waveform Library is a global database of waveforms uploaded by PicoScope users. We have good news! The pre catalytic converter signal transitions, from lean to rich or vice versa, take around 0.5 s. The post catalytic converter sensor signal. . The upstream oxygen sensor(s) are located below the exhaust manifold flanges and above the catalytic converter. Could I buy universal one, if not why? This is due to the fact that bank 2 is representative of an engines #2 cylinder, while sensor 2 serves as a downstream designation. Free shipping . o2 sensors where is bank 2 sensor 1. bjones. 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Performance for the money this help topic is subject to the Terms and.! Help topic is subject to changes without notification and this is what they have done something you dont. The value of the catalytic converter cookies is used to store the user Consent for the front when did. Your ideas for improvement on this test well keep you in the.. And comparing the value of the catalytic converter will continue to run just fine this link you. Resulting in increased fuel usage heater ( + ) Minimize the help page part number because longer. Real-Life case studies show how the professionals use PicoScope to diagnose vehicle faults live data to for... Confirm the fault code by selecting live data to check for signal if the sensor signal helps keep mixture! All was well the help page Suzuki Swift Sport RS416 1.6L M13A M16A in 2018, decided. Consent for the universal rear one wear over time bulletin, e-mail the passenger front!