Oxygen Sensor/Cat Problems
#21
08-13-2012, 11:59 AM
I have about 77000 miles on my car and pretty positive the O2s have never been replaced. I will go ahead and replace the post 02's first and then if the CEL disappears great else will have to replace the other 2 and check for vacuum leaks. I really appreciate all your advice and will let you know if I have more questions. Thanks
#22
08-13-2012, 01:38 PM
Wasting $ on O2's = no good
I never pay the $100 + that the actual O2 w/ OEM plug for the O2's. A $30.00 a sensor solution would be to find any Bosch "universal" O2 sensor. You simply remove the old sensor, cut the wire from the old one all the way at the bottom basically touching the sensor, and splice the wires of the new sensor with the old wire that has the plugged attached.
The Pre cat O2's are the ones that take most of the beating and will need to be changed at some point. If your post cat O2's are having problems something else is the culprit, probably your cats.
The Pre cat O2's are the ones that take most of the beating and will need to be changed at some point. If your post cat O2's are having problems something else is the culprit, probably your cats.
#23
08-13-2012, 05:25 PM
I never pay the $100 + that the actual O2 w/ OEM plug for the O2's. A $30.00 a sensor solution would be to find any Bosch "universal" O2 sensor. You simply remove the old sensor, cut the wire from the old one all the way at the bottom basically touching the sensor, and splice the wires of the new sensor with the old wire that has the plugged attached.
The Pre cat O2's are the ones that take most of the beating and will need to be changed at some point. If your post cat O2's are having problems something else is the culprit, probably your cats.
The Pre cat O2's are the ones that take most of the beating and will need to be changed at some point. If your post cat O2's are having problems something else is the culprit, probably your cats.
Yup, I'm afraid of that too
Good luck Audi9090.
#24
08-14-2012, 04:28 PM
Audi9090, not to bum you out, but I just did this dance with my A6 at 197k. Same codes, intermittently, for about 10k miles.. Replaced the cats with Billy Boats and put four new Bosch O2 sensors ($125/ea) in. Codes returned with more frequency. Installed anti-foulers. Codes returned less frequently. Now use OBDI code scanner to clear the CEL. I have noticed no performance or gas mileage issues due to the codes. Now at 206k miles.
#25
08-18-2012, 02:11 AM
Oh man - I just replaced mine 2 weeks ago but I didn't take any pictures, sorry. I have the 4.2 and the passenger side was a b*tch.
For the passenger side you need to remove the MAF/intake hose to at least have some sort of access to it. At this point you might want to disconnect the sensor already from the ECU. Get a very long extension (at least 12" or longer!) and a regular O2 socket with a swivel head. First take the socket and guide it onto the O2 by hand. This might take a while and be patient (took me 60 minutes because I dropped the socket like 10 times). Once the socket is on, get the extension and swivel head into it and start using the ratchet (use pb blaster if it is stuck). Once it is out, screw the new one in by hand, attach the socket, use the ratchet again (or preferably torque wrench). This literally took me almost 2h hours due to the roomy restrictions in that area. I'm sure now that I have done it it will be under 1h.
The drivers side takes like 10 minutes:
I used a crowfoot O2 socket for this side for easier access. First remove the coolant reservoir, disconnect the O2 connector going to the ECU and just like above guide the socket onto the sensor with your hand first, then attach the ratchet and remove it.
With both sides I used the extension and roughly the same angle from the center back end of the engine. This was the best access for both in my case.
FYI earlier in this thread there was a much more detailed list of how to attack this: https://www.audiforums.com/forum/aud...2/#post1319256
Check it out if you need additional help or simply ask more questions
Good luck
For the passenger side you need to remove the MAF/intake hose to at least have some sort of access to it. At this point you might want to disconnect the sensor already from the ECU. Get a very long extension (at least 12" or longer!) and a regular O2 socket with a swivel head. First take the socket and guide it onto the O2 by hand. This might take a while and be patient (took me 60 minutes because I dropped the socket like 10 times). Once the socket is on, get the extension and swivel head into it and start using the ratchet (use pb blaster if it is stuck). Once it is out, screw the new one in by hand, attach the socket, use the ratchet again (or preferably torque wrench). This literally took me almost 2h hours due to the roomy restrictions in that area. I'm sure now that I have done it it will be under 1h.
The drivers side takes like 10 minutes:
I used a crowfoot O2 socket for this side for easier access. First remove the coolant reservoir, disconnect the O2 connector going to the ECU and just like above guide the socket onto the sensor with your hand first, then attach the ratchet and remove it.
With both sides I used the extension and roughly the same angle from the center back end of the engine. This was the best access for both in my case.
FYI earlier in this thread there was a much more detailed list of how to attack this: https://www.audiforums.com/forum/aud...2/#post1319256
Check it out if you need additional help or simply ask more questions
Good luck
Also, I am not sure which connector is the ECU for o2 bank2 sensor 1 since I couldn't track wire from the sensor as the room is so restricted for my hand. Pictures would be great help.
Last edited by cal925; 08-18-2012 at 02:16 AM.
#26
08-19-2012, 10:52 PM
I'll check if I can take 2 or 3 pictures for you tomorrow and post them but to give you some information right now:
Bank 2 is the drivers side (so the easier one) which requires you only to remove the coolant reservoir. The wire connector is also easy to locate since it is the only one zip tied to the wall of the back side of your engine compartment. Once you have the reservoir off you should see it right away.
I would advise you to replace both bank 1 and 2 at the same time (depending on mileage and time of last replacement of both). It's best to have 2 O2 front sensor at about the same age so the engine doesn't get confused when it spots different readings for the engine (in 2 different banks).
Bank 2 is the drivers side (so the easier one) which requires you only to remove the coolant reservoir. The wire connector is also easy to locate since it is the only one zip tied to the wall of the back side of your engine compartment. Once you have the reservoir off you should see it right away.
I would advise you to replace both bank 1 and 2 at the same time (depending on mileage and time of last replacement of both). It's best to have 2 O2 front sensor at about the same age so the engine doesn't get confused when it spots different readings for the engine (in 2 different banks).
#27
08-26-2012, 02:25 AM
I'll check if I can take 2 or 3 pictures for you tomorrow and post them but to give you some information right now:
Bank 2 is the drivers side (so the easier one) which requires you only to remove the coolant reservoir. The wire connector is also easy to locate since it is the only one zip tied to the wall of the back side of your engine compartment. Once you have the reservoir off you should see it right away.
I would advise you to replace both bank 1 and 2 at the same time (depending on mileage and time of last replacement of both). It's best to have 2 O2 front sensor at about the same age so the engine doesn't get confused when it spots different readings for the engine (in 2 different banks).
Bank 2 is the drivers side (so the easier one) which requires you only to remove the coolant reservoir. The wire connector is also easy to locate since it is the only one zip tied to the wall of the back side of your engine compartment. Once you have the reservoir off you should see it right away.
I would advise you to replace both bank 1 and 2 at the same time (depending on mileage and time of last replacement of both). It's best to have 2 O2 front sensor at about the same age so the engine doesn't get confused when it spots different readings for the engine (in 2 different banks).
#29
09-19-2012, 04:47 PM
Going to resurrect this in case you havent been helped.
Ive gone through replacing 02's first also as a precaution... but they are almost NEVER the problem. I havent personally experienced this fix yet, because ive been saving money, but ive heard from tons of other Audi A6 guys, and performance dealers near by (Like NGP in Maryland).
The sensors throwing the code are Pre-cat 02's. But they are likely fine. In most cases they can go well over 100k miles. The Problem is the pre-cat itself. As the pre-cat ages the honeycomb begins to fail... but ONLY to a MINOR extent. The most minimum degradation to the pre-cats will throw the light. Ive had mine on for over a year it goes on and off every week or so sometimes it's off for almost a whole month. There is no performance or gas-mileage change. It's really just an annoying Audi thing.
The 02s are set up in the Audi almost retarded anyways. There is a pre-cat 02 then the pre-cat, then another 02 and then the MAIN CAT. The system should really only measure the 02 from before and after the MAIN CAT but Audi did not manufacture the car this way.
FIX = have your pre-cat's gutted out and welded back in so its clear (illegal, but ... you know), or you can purchase something like Piggie Pipes which is the same process already completed by Vast Performance. It relocates the main-cat 02 sensor BEHIND it (to the back end of the car exhaust) so that it prevents the CEL and the 02 sensor gets a proper reading. This is honestly how the Dealer should have built the car but they didnt.
Ive gone through replacing 02's first also as a precaution... but they are almost NEVER the problem. I havent personally experienced this fix yet, because ive been saving money, but ive heard from tons of other Audi A6 guys, and performance dealers near by (Like NGP in Maryland).
The sensors throwing the code are Pre-cat 02's. But they are likely fine. In most cases they can go well over 100k miles. The Problem is the pre-cat itself. As the pre-cat ages the honeycomb begins to fail... but ONLY to a MINOR extent. The most minimum degradation to the pre-cats will throw the light. Ive had mine on for over a year it goes on and off every week or so sometimes it's off for almost a whole month. There is no performance or gas-mileage change. It's really just an annoying Audi thing.
The 02s are set up in the Audi almost retarded anyways. There is a pre-cat 02 then the pre-cat, then another 02 and then the MAIN CAT. The system should really only measure the 02 from before and after the MAIN CAT but Audi did not manufacture the car this way.
FIX = have your pre-cat's gutted out and welded back in so its clear (illegal, but ... you know), or you can purchase something like Piggie Pipes which is the same process already completed by Vast Performance. It relocates the main-cat 02 sensor BEHIND it (to the back end of the car exhaust) so that it prevents the CEL and the 02 sensor gets a proper reading. This is honestly how the Dealer should have built the car but they didnt.
#30
01-12-2013, 08:57 PM
Hello ,
I have a 2003 Audi A6 3.0L FWD could anyone tell me whats the bosch part number for Oxygen sensor Bank1 sensor 2?? or could some give me a link where I can order it I will really appreciate it. also can I get my audi repaired for cheap some where in or around Phoenix, Arizona.
Please let me know.
THanks
I have a 2003 Audi A6 3.0L FWD could anyone tell me whats the bosch part number for Oxygen sensor Bank1 sensor 2?? or could some give me a link where I can order it I will really appreciate it. also can I get my audi repaired for cheap some where in or around Phoenix, Arizona.
Please let me know.
THanks