# '02 A6 4.2 climate control on-board diagnostic service codes



## monkeytronic (Oct 5, 2009)

After reading through the list of 61 ODB climate control codes for older Audis I'm curious if there's a list for the A6 that has 90 possible codes.
So far I've made out two of the 90 codes with the '02 A6 4.2Q:
34 = engine coolant temperature (ECT) as seen via the instrument cluster
35 = ECT as seen by the ECU
Suffice to say that these codes don't match up with the older 61 code list.


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## Snowhere (Jul 27, 2007)

*FV-QR*

How are you reading the codes? Audi A6 codes are a 5 digit number and my Bentley lists around 800 codes. When I scan ours with my VAD mobile it gives me both the code #s and a description of the code. 
If you get me the complete code I will look it up for you.


_Modified by Snowhere at 8:11 PM 10-6-2009_


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## monkeytronic (Oct 5, 2009)

The climate control unit doesn't read out OBD-II codes but it does display its associated sensor values in real-time.
In a nutshell, every so often I'm finding that when driving the instrument cluster's coolant temperature gauge will drop to "C" even when the engine's been running at normal operating temperature for quite some time. This with the oil temperature gauge showing right around 200 ºF (or about 90 ºC).
That's where the climate control unit comes in handy as during the brief time the coolant gauge blacks out, code 34 shows "-0" and "40 ºC" and code 35 shows "0" and "90 ºC", indicating an intermittent open circuit condition that lies with either the instrument cluster's ECT sensor and/or its associated wiring since the ECU is still receiving a valid ECT reading all the while.


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