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Jake, Technician
Category: Audi
Satisfied Customers: 2428
Experience:  Over 30 years experience, 17 years with Audi, Factory trained
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Audi A6 Quattro: Hi Jake,I just recently bought a 2000 A6

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Hi Jake,
I just recently bought a 2000 A6 Quattro 4.2L After a couple of days of normal driving the check engine light came, check the codes and this is what ive got
P 1131
P 1138
P 1113
P 1136
P 0455

So... where should I start? replace both front O2 sensors? Vacuum lines?

17521/P1113 - Oxygen (Lambda) Sensor; B1 S1: Internal Resistance too High

17539/P1131/004401 - Oxygen/Lambda Sensor Bank 2 Sensor 1: Internal Resistance too High

17544/P1136/004406 - Fuel Trim: Bank 1 (Add): System too Lean

17546/P1138 - Fuel Trim: Bank 2 (Add): System too Lean

16839/P0455/001109 - EVAP System: Large Leak Detected


Thank you for choosing me with your question.

Ok, let's start with the OXS codes first. Audi's are really good about being correct when they store an OXS code. Unless the wiring is damaged going to the sensor, replace both Bank one and Bank two OX Sensors. They are both the Pre-catalyst Sensors mounted directly behind the cylinder heads. The electrical connectors will be black in color. They are the same sensor so you will need two. Audi #078 906 265M, Bosch # XXXXX ONLY USE AUDI OR THE BOSCH SENSOR I LISTED. DO NOT BUY A CHEAP AFTERMARKET SENSOR.


The EVAP large leak code is typically a gas cap that is missing, loose or failed so check that first. If it is there and tight you might even just replace it and see if the code returns as you don't have a gas cap tester and they are relatively cheap.


As far as the lean codes go they are both Add (additive). In Audi speak this means at idle. Without seeing all the fuel trim data in MVB #32 (Measuring Value Block). I can't say for certain, but that is where a vacuum leak would show up in the Add data. With the top engine cover removed inspect all the vacuum lines, especially going down the left (driver's) side of the intake manifold and going to the front of the intake manifold. These hoses typically shrink, leak, and cause other codes. Repair any problems detected. If you don't see any problems start the engine and idle, then inspect for a "hissing" sound to try and find the source of the leak and repair if necessary.


Make the recommended repairs, clear the codes, and see what returns.

I hope that I have answered your questions and addressed your concerns. If you have any more questions for me please don’t hesitate to ask. I want you to be 100% satisfied with my answer.


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Thank You!
Jake “The Audi Doctor”

Hi, checking in to see how you were doing on this and if you had any questions.

Also, something I forgot to mention on the 2000 year model 4.2s they had a pattern failure for this year model only. What it is is that the variable length runners in the intake manifold seize up. If you look at the two vacuum motors at the front of the intake manifold with the engine not running/off they will be in the relaxed mode (high RPM/long air path). When you start the engine the vacuum motors should pull the manifold flaps into the activated mode (low RPM/short air path) If they do not move freely they will not perform properly and possibly break a plastic vacuum motor link. I don't know that you would detect the performance difference, and it will not set a code, but it is something to consider if you want to get the vehicle squared away.

Best of luck and let me know if you have any questions.

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