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VW / Audi Oxygen Sensor Replacement
 
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Pelican Technical Article:

VW / Audi Oxygen Sensor Replacement

Peter Bodensteiner

Time:

20 minutes20 mins

Tab:

$100-170 per sensor

Talent:

**

Tools:

O2 sensor socket (22mm), flat-blade screwdriver

Applicable Models:

 
Audi A4 (1997-01)
Audi A4 Quattro (1997-01)
Audi TT (2000-04)
Audi TT Quattro (2000-04)
VW Beetle (1999-02)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Passat (1996-00)

Parts Required:

New O2 sensor(s)

Hot Tip:

Easy to swap the front sensor, very difficult to get to the second sensor; make sure you really need to replace the rear sensor before you dive in

Performance Gain:

A properly-operating O2 sensor is essential to the efficient performance of the engine management system.

Complementary Modification:

Remove turbocharger, replace downpipe

The oxygen, or O2 sensor is one of the cornerstones of modern motoring technology, and thus it is found in every production car today. The O2 sensor sits in the car's exhaust system, downstream of the combustion process, where it senses the composition of the engine's exhaust gases. It relays the results of the engine's operation to the car's engine computer. The computer uses this data to adjust the engine's air/fuel ratio and ignition timing, optimizing it to different driving conditions and demands.

As such an important component, you can imagine that if an O2 sensor isn't working properly, it's difficult for the engine as a whole to work properly and efficiently. The upside of this is that it's a plug-and-play operation to replace an oxygen sensor. The downside is that these sensors are usually buried deep in the engine bay, and gaining access to the sensor with the kind of specialized socket needed to remove it can seem next to impossible.

The later 1.8T engines are equipped with two O2 sensors, one just after the exhaust manifold and turbo, and the other after the catalytic converter. The first sensor is fairly easy to access, while the second one is not. I'll show you how to remove the first sensor, which is the easiest to see (and photograph). The second sensor is buried behind the engine and requires the removal of the downpipe and/or the removal of the passenger-side front axle heat shield to get enough access to remove it.

This is the forward O2 sensor, upstream of the catalytic converter.
Figure 1

This is the forward O2 sensor, upstream of the catalytic converter. In reality, both O2 sensors are installed within the segment of the exhaust system that incorporates the converter; the other sensor is in the rear portion of the cat, where it reduces its diameter to meet up with the rest of the exhaust system.

The best tool to use to remove an oxygen sensor is an oxygen-sensor socket.
Figure 2

The best tool to use to remove an oxygen sensor is an oxygen-sensor socket. This is a somewhat generic special tool, in that oxygen sensors are relatively standard-issue from one car brand to another. Most auto parts stores will carry something like this. Essentially it is a 22mm deep socket with a gap in the side to accommodate the cable extending from the tail of the sensor.

The wiring for each O2 sensor connects to the car's wiring harness at connectors mounted to the firewall on the driver's side of the engine compartment.
Figure 3

The wiring for each O2 sensor connects to the car's wiring harness at connectors mounted to the firewall on the driver's side of the engine compartment. The cables leading to the sensors are the ones on the bottom; the top leads go to the engine computer. The red connector to the left in the photo goes to the rear sensor and the black connector canted to the right leads to the front O2 sensor.

The connectors are similar to others found around the car.
Figure 4

The connectors are similar to others found around the car. Use a small screwdriver to manipulate the internal clasp of the connector up and over the raised notch that holds it in place.

After disconnecting the end of the sensor lead, the cable will still be held in place by a couple of plastic zip ties.
Figure 5

After disconnecting the end of the sensor lead, the cable will still be held in place by a couple of plastic zip ties. Cut these to free up the wire. This first one is just behind the cylinder head at the rear of the engine compartment.

The second zip tie connects to this tab at the rear of the valve cover.
Figure 6

The second zip tie connects to this tab at the rear of the valve cover.

It's best to free up the wire first, because as you unscrew the O2 sensor, the wiring can then wrap around the socket freely.
Figure 7

It's best to free up the wire first, because as you unscrew the O2 sensor, the wiring can then wrap around the socket freely. Note the angle of the socket and extension, which lines up just behind the airbox.

Here's the business end of the O2 sensor.
Figure 8

Here's the business end of the O2 sensor. When you reinstall the sensor (or install a new sensor, 40 ft-lb) you can apply some high-temperature anti-seize compound to the threads of the sensor, but don't get it near the slots in the sensor itself as this can affect its operation.

The complete sensor and wiring lead, removed from the car.
Figure 9

The complete sensor and wiring lead, removed from the car.

In this photo I've got a crow's foot-style wrench on the rear O2 sensor, but the photo is a bit misleading in that the sensor is much deeper in the engine bay than it would appear.
Figure 10

In this photo I've got a crow's foot-style wrench on the rear O2 sensor, but the photo is a bit misleading in that the sensor is much deeper in the engine bay than it would appear. I was unable to get any leverage on the sensor here.

Improved access to the rear O2 sensor and/or the rear set of nuts and bolts for the catalytic converter can be gained by removing this heat shield that resides over the passenger-side axle.
Figure 11

Improved access to the rear O2 sensor and/or the rear set of nuts and bolts for the catalytic converter can be gained by removing this heat shield that resides over the passenger-side axle. It is held to the transmission with three 6mm socket-head bolts. Unfortunately it's quite easy to strip out these bolts. Please, please don't ask how I know.

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Comments and Suggestions:
Brooke Comments: I have a 2004 VW Jetta 1.8T wagon. OBD codes say Bank 1 Sensor 1 is faulty. I know that is the upstream sensor, I just can't find it. Some sites say just behind manifold by firewall, others say at front on catalytic converter...Help!
July 29, 2016
  Followup from the Pelican Staff: it is at base of exhaust manifold right before catalytic converter. - Nick at Pelican Parts  
Veeeedubbb Comments: Hi, I own a 2004 Volkswagen Jetta 2.0 I put a cold air intake on the car and the first start the epc and check engine light were on. The car drove fine can't figure out how to shut the lights off and resolve the problem.
July 10, 2016
  Followup from the Pelican Staff: You will need a VW scan tool to clear the fault codes. - Nick at Pelican Parts  
Bernie Comments: I have a golf 5 1.6. Idling irregular. Replaced spark plugs within 3 weeks. Seems to be over fuling because the plugs are wet with petrol. Breaks down on acceleration. Idling irregular. The only error i see is the skid control light that autmatically comes on including the engine and aircon fans. Could the O2 sensor be the problem.
June 19, 2016
  Followup from the Pelican Staff: You would likely have an o2 sensor fault code if so. Could be an issue with the fuel pump. I would perform a fuel delivery system test. Check fuel pressure, volume and quality.
- Nick at Pelican Parts
 
Otoyo Comments: I do have VW jetta 2007 of late its been losing power I was told Oxygen Sensor which i replaced. The was some improvement but the problem again could you please advice
May 9, 2016
  Followup from the Pelican Staff: Could be an issue with the fuel pump. I would perform a fuel delivery system test. Check fuel pressure, volume and quality. - Nick at Pelican Parts  
Bry Comments: Hi I have a 1997 Audi a4 Quattro 2.8 30V an since no one make a exhaust system for it can I cut out the catalytic converters with out having a issue with the way my motor will run?
April 26, 2016
  Followup from the Pelican Staff: No, it is against US law to remove catalytic converters or tamper with any emission system. - Nick at Pelican Parts  
roxy Comments: Which O2 sensors would i buy for an 2004 vw passat 1.8t 4 door. I ordered the bos 17733 they told me to also get the bos 17351 bt im not one hundred percent sure if they are the right ones
March 13, 2016
  Followup from the Pelican Staff:
I’m not the best with part numbers.

Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need. - Nick at Pelican Parts
 
Trav Comments: Hi I have a 2000 Audi A4 quattro 2.8l non turbo v6 was wondering how many O2 sensors there was please
February 26, 2016
  Followup from the Pelican Staff: four. - Nick at Pelican Parts  
mike Comments: 1998 1.8 volkswagon golf looks like one of the springs in down pipe exhaust is broke it moves around can I replace the springs or do you have to replace the whole down pipe
December 28, 2015
  Followup from the Pelican Staff: You should be able to replace the hardware. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
Angelsnow Comments: I have a 2009 jetta tsi 2.0L,check engine light came on and with it lost of power,went to autozone and the give me to codes,p0171 and p2239, I did change the fuel filter,fuel pressure regulator and clean manifold,still with the problem,Any comment will be appreciated thanks.
December 10, 2015
  Followup from the Pelican Staff: It could be a faulty mass air flow sensor, vacuum leak or faulty fuel pump. - Nick at Pelican Parts  
covack 505 Comments: i have a2002 vw passat 1.8 turbo automatic i have replaced timing belt and turbocharger and cam sensor and maf sensor car hesitates on takeoff fuel pressure is 50+ at idle and rises to 60 on acceleration catylitic convertor is clear getting a p0341 code and po300 code no other codes engine revs up on freeway but car doesnt move transmission shifting as it should i am stumped?? help anyone also when i plug in scanner it will not read whenengine is running only with key on engine off have reset timing 3 times and tried 3 different cam sensors
November 25, 2015
  Followup from the Pelican Staff: I would check if mechanical engine timing is correct. - Nick at Pelican Parts  
Montana Comments: Also checked the fule pressure and the booste pressure valve. both were good.
November 21, 2015
  Followup from the Pelican Staff: Ok, got it. - Nick at Pelican Parts  
Montana Comments: I have 2006 passat 2.OL TSI. No accelaration. Seems to run OK above 2000 rpm. Had a low boost and misfire code. The exhaust manifold was cracked so I raplaced it and the turbo unit, put in new spark plugs, checked the coils, the old pluges were white indicating lean mixture, found 2 vacuum leaks and repaired them. Still no power, no trouble codes, could this be an O2 sensor?
November 21, 2015
  Followup from the Pelican Staff: The cat may be plugged. The cracked manifold points that direction, for overheating. - Nick at Pelican Parts  
jhonatan Comments: so it is the catalyst can it be the 2 02 sensor i have a bad turbo seal im putting new turbo on saturday
November 19, 2015
  Followup from the Pelican Staff: P0420 indicates a catalyst that is not meeting the efficiency spec. The o2 has to pass a test before that test runs, so likely not the o2. - Nick at Pelican Parts  
jhonatna Comments: got an a4 audi 1.8t quattro o2 sensor is bad im trying to change but it said the model has 2 but went i scan it this code come up p0420 bank 1 im guessing is the one by the turbo am i right???
November 18, 2015
  Followup from the Pelican Staff: P0420 points to a faulty catalyst. - Nick at Pelican Parts  
luis Comments: I have a 2001 Audi A4 quattro Avant 2.8 tiptronic. Where EXACTLY should the post cat downstream, S2 oxygen sensors be located? It has 2 cats per side. Should they be after the front cats or after the rear cats? CA law says that all 4 cats need monitoring, so does this mean that the downstream O2 sensors really need to be AFTER the rear cats? Please help me because I'm really LOST here with so much conflicting info! If you look at a picture of the original Audi pipe with 2 cats it has a hole for the o2 sensor on the pipe past the rear cat.
November 15, 2015
  Followup from the Pelican Staff: On the 2.8, they are behind the cats, in the middle of the trans tunnel. - Nick at Pelican Parts  
Maleana Comments: I have a VW Polo 1.6 petrol 2010 model. It is very heavy on fuel since I purchased it although it runs well. I was told it could be the CO2 sensor. Please advise.
November 14, 2015
  Followup from the Pelican Staff: We don't have that vehicle here, so I am not familiar with the system. However, check for fault codes, that is a good place to start. If none are stored, check fuel trim. - Nick at Pelican Parts  
Kevin Comments: I have a 2001 A4 and the cel just recently came on. It had come on before a few months back and went away soon after but I had a quick scan by a friend and it read O2 sensor bank 2. Would this also cause a sulfur smell? I do also have the stock cat at ~185000 miles. any help is appreciated. Thanks.
October 10, 2015
  Followup from the Pelican Staff: No, a sulfated cat would cause a sulfur smell. - Nick at Pelican Parts  
trini Comments: how many oxegen sensors does the 2008 Audi Q7 3.6l gas v6 premium sport utility carry
August 30, 2015
  Followup from the Pelican Staff: Four. - Nick at Pelican Parts  
Tostao Comments: I have a jetta 2004. I bought a universal O2 sensor of 4white,white,gray and black wires and the wiring harneses of my old O2 sensor has 5 wireswhite,red,yellow,black and grey. How can I correctly connect this universal sensor with this harneses. Regards
August 24, 2015
  Followup from the Pelican Staff: As far as I know, you can't. You will have to get the right sensor. - Nick at Pelican Parts  
Lexi1291 Comments: Hi I have a 2005 Audi a4 quattro 2.0 Check engine light has been on since I bought the vehicle a couple months ago..A shop recently hooked the computer up, im not sure what the code was, but it said 02 sensor Bank 1..As ive been researching this im finding theres two 02 sensors, front and back?? If so which one do I need to repair?? Im lost please help lol..
August 15, 2015
  Followup from the Pelican Staff: bank 1 would be the sensor closest to cylinder 1. - Nick at Pelican Parts  
Phillip Comments: Hey I have 12 vw cc check engine lights on and epc lights,rough idle, sluggish on low rpm, autozone ran the codes p0300- p0304 misfires in all four cylinders. I change spark plugs, and clean injectors? Need a little help.
August 8, 2015
  Followup from the Pelican Staff: I would check spark, fuel and compression on all cylinders. Plugs rarely cause misfires. - Nick at Pelican Parts  
Derick Comments: This is a followup on previous comment. Nick we replaced all 4 plugsgenuine vw.New petrol filter, air filter, pollen filter, oil filter.Did compression test 1n 4 was at 120.We have twice cleaned the injectors. We have also checked both oxygen sensors and reinstalled them.Petrol pum cleaned out.Trottlebody cleaned. Now ESP light comes on intermittently, car now all of a sudden does not start up first time as it has done all a long regardless of problems. Any other suggestions and recommendation Nick?
August 6, 2015
  Followup from the Pelican Staff: 120 sounds low for compression.

When the vehicle will not start, see what is missing, fuel, spark, etc. Whatever is causing the starting issue is related to the lower issue for sure. - Nick at Pelican Parts
 
Derick Comments: I have golf 5 1.6. The car seems to hesitate when i accelerate, and it feels like there is a slight missfire. I have thusfar cleaned the injectors, the MAF sensor, the throttle body, new spark plugs, fuel filter. Still problem persists. No check engine light. Though EPC light did come on, but i replaced the brake switch, which took care of that. What else could be the problem?
August 4, 2015
  Followup from the Pelican Staff: If it feels like a misfire, I would focus on that diagnosis. I would check spark, fuel and compression on all cylinders. - Nick at Pelican Parts  
Dennis Comments: Hi,
i have a 2010 a5 sportback
error code Bank 1 system too rich,
occasionally cranking becomes very long.

error code P2178
Bank 1 System 1 Too rich off Idle

i changed out the front O2 sensor and air intake sensor.

any light you can shed on my case?

thank you so much
August 4, 2015
  Followup from the Pelican Staff: This fault is usually the throttle body or an issue with the high pressure fuel system. - Nick at Pelican Parts  
pete Comments: i have an 02 passat 1.8t what is the cause of code po030
July 29, 2015
  Followup from the Pelican Staff: The front oxygen sensor heater circuit, if faulty. - Nick at Pelican Parts  
Mario Comments: Hi: this is regarding my 2009 passat wagon 2.0 L 4 cyl TSI turbocharged. Not sure if I should replace the o2 sensor. The problem is that I have been getting the problem code P0171 lean fuel/air mixture. Freeze frame data suggests that the code was set at low rpmprobably idling. Have changed the following components: MAF sensor, fuel pressure ssensor on the fuel rail, fuel filter in the fuel tank, spark plugs, crankcase air breather, did a chemical flush on the fuel injectors. I am not getting any trouble code regarding the O2 sensor but I decided to change it because it is part of the same fuel air mixture control. Your helpful advice would be much appreciated. Forgot I am also getting the P12a2 code if that can give any clue. Did a smoke test to check if there any air/vacuum leaks-none found. Couple of visits to the dealership produced nothing of value but aggravation.
July 28, 2015
  Followup from the Pelican Staff: A lean code will usually be a vacuum leak or mis-metered air. Not the sensor. I would check for duct or intake leaks. - Nick at Pelican Parts  
SM Comments: I have a 2005 gti with 1.8T L4. I had a new turbo installed in a couple months ago. I got a fault code 420, I went through a check list and have changed both o2 sensors, MAF. sensor and plugs. After plugs it ran great but 420 code came back. I then changed down pipe and catalytic converter now I have 133 code o2 sensor circuit 1 slow response. My question is if cat was bad would it by chance screwed up the new sensor or is there another underlying problem? I have read that i should not feel or notice anything but it has a slight hesitation and a slight miss when at idle. Again it ran great before new catalytic converter.
June 12, 2015
  Followup from the Pelican Staff: Unlikely. The sensor may have been damaged during the cat repair. A cat monitor will not run unless the o2 sensor passes it's monitor first. - Nick at Pelican Parts  
Duvik Comments: I have a 1998 1.6 VW Passat - lately the engine is stuttering. The mechanic told me it's a oxygen sensor problem base on the car's computer, the malfunction code is 00537. After replacing the oxygen sensor the problem doesn't solved the same problem and malfunction code appears. Is there a second oxygen sensor to replace?
May 17, 2015
  Followup from the Pelican Staff: Is the check engine light on? Sounds like an engine misfire. I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 
TerryFinchAuto Comments: got a 2003 audi a4 quatro rough idle runs great other than that extreme vacuum on oil cap, cannot pull it off when the car is running
April 22, 2015
  Followup from the Pelican Staff: Could be collapsed breather hoses, I have seen that quite a bit on those engines. - Nick at Pelican Parts  
jitandraz Comments: My VW Polo is misfiring and I changed the plugs but still misfiring what could be the problem?

March 28, 2015
  Followup from the Pelican Staff: Could be many things. I would check spark, fuel and compression on all cylinders. - Nick at Pelican Parts  
Sky Comments: Is there a way to fix the throttle . I can't get it out of the driveway to get it to the shop
March 15, 2015
  Followup from the Pelican Staff: You can try a throttle adaptation. That will require a VAG scan tool. - Nick at Pelican Parts  
Sky Comments: I have a 99 audi a4 quattro battery was dead replaced the battery and now the car will not idle. It ran fine if I jumped the old battery. When I get it started it will not rev above 1500 rpm.
March 14, 2015
  Followup from the Pelican Staff: Check the DME for fault codes. It is possible the throttle body was confused during the process. - Nick at Pelican Parts  
Blake Comments: Kinda lost... keep failing emissions for high nox. using obd2 on the elm 327 interface with torque i found that my pre cat sensor is giving out no readings while post cat seems fine. No engine codes or even pending codes. Replaced the sensor and still no readings or codes. I can get pending code P0134 only if i unplug sensor 1 while the cars running but otherwise i cant get it to tell me anything is wrong.
March 13, 2015
  Followup from the Pelican Staff: What vehicle are you working on?

Nox is only caused by high cylinder temperatures and cats that can't clean it up. - Nick at Pelican Parts
 
trlangevain Comments: Also curiously enough on my 97 a4 2.8 the o2sensor on mine has three wires? I wonder if the previous owner screwed up when he replaced it or what?
February 25, 2015
  Followup from the Pelican Staff: They should have four wires. - Nick at Pelican Parts  
trlangevain Comments: Hey nick I have a 97 Audi a4 2.8 5spd can u please tell me where the o2 sensor relay is located? What #relay it is too please.
February 25, 2015
  Followup from the Pelican Staff: There is no o2 relay on your vehicle. The heaters get power from the fuel pump relay through fuse 20. - Nick at Pelican Parts  
Pete Comments: Hello from the UK
I am thinking I have a problem with my pre cat lambda, i get the following code;

17524 - Oxygen Lambda Sensor Heating; B1 S1: Open Circuit
P1116 - 35-00 -

Your write up made things a lot clearer although I haventt looked under the car yet, Im slightly worried the pre cat sensor is going to be a pig to reach?
February 21, 2015
  Followup from the Pelican Staff: Not rich, open circuit. You are on the right track. Check the voltage at B1s1. - Nick at Pelican Parts  
biza Comments: hi i have an audi a4 1.8, suddenly it does want gear two. only 1.3.4.5 are working. so i dont know whether i should buy a new gearbox or it can be fixed.
February 20, 2015
  Followup from the Pelican Staff: With the shift linkage removed, can you manually shift into second? - Nick at Pelican Parts  
jeff Comments: hi i have vw golf 5 1.6,my problem is the car can't run accordingly and they say its a oxygen sensor from the diagnostic machine,so how must i replace it and be sure about it as its two cables and which one must be replaced or fixed as also the gas dont last.As later they where sugesting that its a trottle body problem after i hav diagnose it and get the oxygen sensor proble.Please assist.
February 17, 2015
  Followup from the Pelican Staff: I would need the fault code to be able to advise you which sensor may be at fault. - Nick at Pelican Parts  
jeff Comments: i have a vw polo and I took the car for a diagnostic test and they said o2 sensor and a intact manifold leak ,are there a kit for the intake manifold and can I do it at home
December 27, 2014
  Followup from the Pelican Staff: Sure is. Give our parts specialists a call at 1-888-280-7799 and they can help figure out which part or repair kit you need.
- Nick at Pelican Parts
 
Raph Comments: I have a 2004 Audi A4 quattro with code p0171 replaced egr valve, pvc, check valves, maf, checked hoses and all good.. After all that Still have same code.. Any suggestion?????
December 12, 2014
  Followup from the Pelican Staff: What engine does it have? - Nick at Pelican Parts  
Ras Comments: - 2004 A4 1.8T
-Car ran very rough so I unplugged mass air flow senor and it ran, but somewhat rough.
- put in a new sensor, but still now it quits after Iplug it in and so I put the old one back in and it quits again within seconds.
- Put in a new O2 Sensor on the intake, but ran a little better, but still rough.
- new bypass valve for the turbo
- Plug the connector back on to the air flow sensor and car still quits within seconds. Unplug it and it runs again.
- Gas mileage sucks.

Could it be a bad connection on the wire housing connector itself? Should I try new wires? Any other thoughts. Code comes up as mass air flow sensor. Thank You.
December 2, 2014
  Followup from the Pelican Staff: You could have a faulty connector or replacement sensor. Is that the only fault code you get?

Be sure to check the system for air leaks. - Nick at Pelican Parts
 
Passat Comments: What brand of O2 sensor should be used when replacing the old one , I've heard Bosch is one of better ones
November 15, 2014
  Followup from the Pelican Staff: I prefer OE. However, Bosch is usually just that. Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
toby f Comments: if i puch out the guts out of my cadilac converter on my 00 passat how will that effect the o2 sensor or is there a code to make it run smooth
October 13, 2014
  Followup from the Pelican Staff: You should not remove the catalyst material. Your emissions will increase. - Nick at Pelican Parts  
Charlie Comments: Hi I have a 1997 audi a4 1.8 quatrro. I failed my smog test at idle. The CEL codes are P3004. I have changed out the plugs, coil packs,MAS. The car cold starts and stubles until it hot. Once hot the car runs fine. My mechanic check out the car for leaks and general connectons wire etc. Suggestions where i should look now based on the issue only being a cold start.
August 14, 2014
  Followup from the Pelican Staff: Sounds like an engine misfire. I would check spark, fuel and compression on all cylinders. - Nick at Pelican Parts  
Matt Comments: Hi, I have an 1999 Audi A4 1.8t Quattro Automatic where the check engine light turns on and off. The problem with the car is that when it's driven and it's in 3rd gear, the engine feels like it hesitates/stalls for a few seconds before it shifts again. Even though I can hear the engine revving the car isn't moving any faster. I took it to a shop earlier today and the code was for an oxygen sensor. I just want to know if this could be the issue or if it's a transmission slip or catalytic converter problem. Is there an exact way of determining what could be the cause, because most of these parts are not cheap and I don't have the luxury + money to trial and error it.
Big Thanks
July 29, 2014
  Followup from the Pelican Staff: Unlikely related. This could be a slip caused by low fluid or low pressure. Start by checking your fluid level. If it is OK, you may have worn parts causing a pressure drop and slip. I would have it checked before it gets much worse.
- Nick at Pelican Parts
 
John Comments: I have a 1998 Audi A4 Quattro 2.8L...which O2 sensors are "Oxygen Sensor - Bank 1 - Sensor 2" and "Oxygen Sensor - Bank 2 - Sensor 2"....I am getting two check engine codes and want to replace them. Thanks...John
July 23, 2014
  Followup from the Pelican Staff: These are the oxygen sensors behind the catalytic converter. - Nick at Pelican Parts  
doredani Comments: I have the code P0411 on my 2003 Passat 1.8T, it is telling me that it is related to a vaccum leak or the SAI punp, but this is functioning, I am going to replace the O2 sensors anyways as they haven't ever been replaced in over 135K miles and as the smell out of the exaust it's realy bad just like rotten eggs, any taughts on that please?
July 22, 2014
  Followup from the Pelican Staff: P0411 is a flow code for the secondary air. I would test the secondary air components. One is causing the air from the pump to not make it to the exhaust. - Nick at Pelican Parts  
chels Comments: Would replacing only the upstream sensor and not the down stream cause my 02 vw golf to "bog out" if I push the gas to hard ...we replaced the upstream sensor a few weeks ago and since then every once in awhile if my rpms go above 4 in 1,2,or3rd great seems like its just gonnastraight stall out .... help lol replaced a and done so much on this stupid thing already lol
Thanks
chels
June 25, 2014
  Followup from the Pelican Staff: NO, you do not have to replace o2 sensors in pairs. It is recommended, but it won't cause a drivability issue. I would perform a fuel delivery test and check the vehicle for fault codes.- Nick at Pelican Parts  
BillyG627 Comments: Outstanding description. Thank you for providing. I'm not a mechanic, and I don't do my own repairs. I'm a regular guy who angsts whenever I take my car to a shop. I'm trying to decide whether I'm bamboozled or not. Your description helps me to understand. Keep up the good work.
June 24, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
JKM Comments: Thanks Alan

Very useful information
June 20, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
Danny Comments: Have a 2003 Passat GLX wagon V6 since new. Been servicing at a VW/Audi only shop. The check engine light has been on and off for 3 years but passed CA inspection last Fall. Now the check engine light is on most of the time. Is this an O2 senors issue?
June 16, 2014
  Followup from the Pelican Staff: Could be any emission component. I would start by checking the DME for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing.
- Nick at Pelican Parts
 
VW Chick Comments: I have a 2010 Jetta Wolfsburg 2.0Turbo. Oxygen sensor light came on. Went to local auto parts store and got codes. Will I be able to do this myself ?
June 8, 2014
  Followup from the Pelican Staff: Not sure,it depends on your technical ability. - Nick at Pelican Parts  
jimmy Comments: I went an replaced turbo, injectors of A4 tdi 2006 model diesel and then since I now have this problem: Car cant start, cnt idle and I do not know what happened
May 19, 2014
  Followup from the Pelican Staff: IS there air in the fuel rail? I would try bleeding it. If it is bled, check fuel pump operation. - Nick at Pelican Parts  
mlmorris2605 Comments: I have a 03 passat. I bought it with the check engine light on. I had it checked and was told not to more. Well now on the dash display where it shows dprn123 and the above that the temp and above that the mpg..well this is what I have about my temp...I have a o with a line through it and the mpgs are stuck at 22.5 and then there is a 2? This just started...please help what does this mean???
March 17, 2014
  Followup from the Pelican Staff: Sounds like the cluster is not getting data to display the right information. I would start by checking the vehicle for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing.
- Nick at Pelican Parts
 
JJ Comments: wondering if this write up is good for 02 a4 Quattro 3.0
February 26, 2014
  Followup from the Pelican Staff: Applicable Models:
Audi A4 (1997-02)
Audi TT (2000-04)
VW Passat (1996-00)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Beetle (1999-02) - Nick at Pelican Parts
 
VWFAN Comments: Hello,

I have a 2001 Jetta 1.8T Wolfsburg Edition and I was told by my mechanic that I needed to replace both O2 Sensors. Is the 17014 the one in the front and the 16978 the rear one?
February 25, 2014
  Followup from the Pelican Staff: Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
New Jetta owner Comments: I have a 2001 Jetta GLS 1.8T and I need to replace the secondary o2 sensor. When I went to buy the part there are two types, AWW and AWD, how do I know which one is the right one.
January 20, 2014
  Followup from the Pelican Staff: Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
Frustrated Passat owner Comments: Have been advised that the sensor could be faulty due to the following problem: at approx 2500 rpm, the turbo seems to kick in and the car has power BUT it does not always happen this way. I was advised to change the fuel filter before any thing else, which I have done, but there is still no change in the performance. It was suggested that the sensor could be the problem - is it likely to be the issue for the lack of power?? The car stood for 9 months without any starting etc hence the changing of the filter. Hope this makes sense as any guidance would be appreciated.
January 17, 2014
  Followup from the Pelican Staff: Are you stating the turbo-charger doesn't always work? COuld you describe the symptom a little more? - Nick at Pelican Parts  
Chrisgee Comments: Good night sir, I have a jetta 2000 1.8t and i have a problem in which i think is the oxygen sensor. Everytime i stop at a red light I hear and feel the car like if it wants to acelerate! I look at the dashboard and the RPMs are bouncing just a bit but its the only thing that is moving on my dashboard also if I put my AC full blast the rpms will move faster and more
December 30, 2013
  Followup from the Pelican Staff: I would check the engine for vacuum leaks. This sounds more likely. It wouldn't hurt to check for fault codes, as there could be an issue with the throttle housing. - Nick at Pelican Parts  
Greg Comments: Very good tutorial. Thank you for posting!
December 27, 2013
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
eric Comments: i have a audi a4 2001 quattro. How many o2 sensors?
December 9, 2013
  Followup from the Pelican Staff: 4-cylinder models have 2.- Nick at Pelican Parts  
tiger Comments: I have an 2003 vw passat 1.8. The problems I have out of it are: 1. When I am driving and increase speed it hesitates and acts as if it does not want to go. 2 my check engine light will not go off and when it does do number 1 my check engine light blinks and two more lights pop on which is and explanation point with an arrow circling around it and the other an A if I'm not mistaken. By the way my gas burns out much faster then it should I took it to advance auto parts to let them hook it Up and it read o2 sensor another guy told me when I told him what it was doing that its an MAF I don't know which part it is or which to buy
December 2, 2013
  Followup from the Pelican Staff: I would start by checking the DME for fault codes. The generic code reader at a parts store does not necessarily give useful information. Best to visit a shop that specializes in these advanced electronic vehicles. For example, there may be a turbo problem with your vehicle. Fault codes will be your best bet when diagnosing. - Nick at Pelican Parts  
KMU Comments: I have a 2009 2.0T that runs EXTREMLY rough the first couple miles after sitting. Not sure if this is a carbon build up issue or bad O2 sensors. I have only run 91 or higher and used Seafoam for 6 straight fill ups but nothing. Check engine light stays on and fuel mileage is reduced but oower still there.
November 20, 2013
  Followup from the Pelican Staff: Sounds like a vacuum leak. There is an updated intake manifold and seal kit for a problem like yours. I would check if your has had these parts replaced. Give our parts specialists a call at 1-888-280-7799. They can help you find the right parts.


- Nick at Pelican Parts
 
Jim Comments: I have a problem with my 79 Type 2 CA model. Very sluggish, no real power. When I disconnect the O2 sensor, the idle speed guoes up to about 1800rpm. The performance improves slightly. Initially, the vehicle hesitates when putting it in gear and letting up on the clutch. Bad sensor ? Replaced last one about 2500 km ago, vehicle passed smog with good results about 6 months ago. Tnx vy much. I would appreciate an e-mail reply. Jim Green
October 14, 2013
  Followup from the Pelican Staff: I have seen the o2 relays fail creating idle and performance issues. Usually an o2 sensor will result in a slight power difference, but not no power. Check the o2 with a multimeter, see if it is switching from 0 to 1 volts when the engine is hot, with engine RPM raised.
If you have low power, I would start by check fuel pressure and volume and exhaust backpressure. - Nick at Pelican Parts
 
Audi Comments: Hi, I have a Audi a4 1.8t 1997, my check engine light is on and im guessing its a o2 sensor code p1136 but how do i find out which one without having to take a 50/50 chance since mine has two 02s.?
September 17, 2013
  Followup from the Pelican Staff: P1136 is a lean fuel trim fault code, not an oxygen sensor code. You will have to determine when the engine is running lean and find the source of the problem. If at idle, it could be a vacuum leak. If off idle it could be the MAF sensor. - Nick at Pelican Parts  
Manics Comments: By removing the heat shield mentioned for the rear O2 sensor what tool did you then use to remove the sensor? Is there then enough leverage to use a 22mm wrench or would you still need the crows foot or O2 socket as you used on the front sensor?

Did you complete this through the engine bay or from underneath the car? Thanks for the info!
September 4, 2013
  Followup from the Pelican Staff: You still have to use a crowsfoot, you will be working through the right from wheel well instead of from the top of the engine. - Nick at Pelican Parts  
beginner Comments: I have a 2003 vw passat back 02 sensor is a BIG problem will this work?! Please help!!
July 25, 2013
  Followup from the Pelican Staff: If your Passat has a 1.8, this tech article should help you. - Nick at Pelican Parts  
pete Comments: I have a 2003 passat back sensor BIG problem would this work pleasse!!!!¡¡¡¡ Help!¡
July 25, 2013
  Followup from the Pelican Staff: If your Passat has a 1.8, this tech article should help you. - Nick at Pelican Parts  
Kiwisurfer Comments: If you have a V6 or V8 with two seperate exhaust manifolds and catalytic converters, will it not have 4 sensors? My range rover does.
July 25, 2013
  Followup from the Pelican Staff: A US market Audi with the mentioned set up will have four osygen sensors. - Nick at Pelican Parts  
Nolaroo Comments: Thank You for the information - I have the 100 sedan
June 14, 2013
  Followup from the Pelican Staff: Your vehicle has two oxygen sensors. - Nick at Pelican Parts  
Nolaroo Comments: I have a 1994 Audi - an auto repair shop told me there are 4 oxygen sensors can you let me if this is correct and where they may be located. Do you carry the parts?
June 13, 2013
  Followup from the Pelican Staff: Since I don't know which model you have I cannot answer your question. What I can say is OBD-II started in 1996 and requires a pre and post O2 sensor. You probably only have one. Call one of our parts specialist and they can point you in the right direction - Nick at Pelican Parts  

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