4.2 beast

HI there ,

I am trying to test the throttle potentiometer on my 95 Audi s6.I found all the info here and in the Audi 200 20v Bentley and while doing all the resistance measurments I found out that the WOT resistance is only 2500 ohms instead the 3600 ohms per the Bentley.I do have a spare potentiometer that I measured also at WOT and it says arround 2450 ohms.Can anybody tell me if the 2500 value is acceptable or better yet if some of you can do the test on your potentiometer and let me know if it is the same or not I would really appreciate that. I want to know this before I go and spend 150 $ for a new one.

Thanks in advance

Igor.

UrS4boy

The pin-out on the connector for the 078133154 potentiometer/idle switch (Based on Pg. X56 in Vol.3 of the Bentley) and the G60/F60 is as follows:



Pin 1: A red wire that also connects to T12/55 in the ECU which provides 5V+ to the G69/F60 combination as well as the F96 Barometric Pressure Sensor and the G40 Cam Position sensor. (Note: The Bentley incorrectly calls the Pressure Sensor the "G16" but there is no such "G16" device for the AAN).

Pin 2: Green wire with a Black stripe - goes to ground connection 5 in the engine harness.

Pin 3: Gray wire connected to pin T53/55 in the ECU - the signal is the 5V+ modified by the variable resistor in the throttle position switch which tells the ECU the degree to which the throttle body is open, which helps the ECU compute "load".

Pin 4: Brown wire with a red stripe, goes to ground connection 2 in the engine harness.

Pin 5 - not used

Pin 6 - Violet (purple) wire that connects to pin T52/55 in the ECU that tells the ECU that the throttle is closed (via the microswitch in the diagram shown above).

Testing the F60 Closed Throttle (Idle) Switch is as follows:

Across Pins 4 and 6 on the switch:
Closed = 0 ohms (continuity)
Open throttle (slightly) = infinite ohms (open)
If either fails, adjust switch as per procedure above.

Testing the G69 Throttle Position Potentiometer:

Across Pins 1 and 2 on the switch:
Must be 1500 to 2600 ohms

Across Pins 2 and 3 on the switch:
Throttle closed = 750 to 1300 ohms
As throttle is opened from closed to WOT = increase to 3600 ohms
If NO, replace sensor.

The 078133154 was used on the 20VT inline fives, the C4 V6s and V8s and even the S6plus V8 so finding a good used one to test should be possible.

4.2 beast

Yeah ,I guess I have a two bad potentiometer on my hands then.

Thank you for the quick response.

Igor.

4.2 beast

Also can you tell me if this might be the reason why sometimes the car does not go to full boost (14-15psi) unless I back off the throttle and press on it again hard.

UrS4boy

If the throttle potentiometer does not provide the correct resistance and/or wide open throttle (WOT) switch information to the ECU, the ECU isn't going to provide the correct signals to the fuel injectors, the waste gate frequency valve and ignition timing to give you what you expect of WOT performance.

You should see 17 psi briefly as the max boost on a properly running stock AAN. 14 is a bit low.

4.2 beast

What you are saying makes a lot of sense.About the boost I might have a boost leak or inaccurate gauge I guess.

Anyway ,thanks for the help.