[Biturbos4] HELP!!! Troubleshooting DTCs w/ EPC light

Michael Benno mbenno at yahoo.com
Sun Nov 28 11:42:16 EST 2004

the fault codes associated with the O2 sensor and the exhaust gas temp are a result of the lean conditions on the cyclinder banks, not that the 02 sensors are failing. The fact that you have the lean conditions on both banks would indicate that you have a mixture problem. At this point I would think that you have a boost leak. I have seen the 17522 and 17866 together on boost spikes and leaks. I would certianly check to make sure 
However the fact that you have EPC issues would lead me to suspect you have an issue there. A malfunctioning throttle valve will also cause mixture issues. Do you know how to reset/test the throttle valve? I would suggest you start there. If you don't shoot me an email and I can look up the process using vag com.
Mike Benno
A6 2.7t

Adam Jansen <aedan1 at hotmail.com> wrote:
As I was driving over the Cascades to visit family for the holiday, the EPC 
light comes on the the power cuts out (not fun coming up Snoqualmie Pass!)

I dont have my Bently or family albumn with me, but luckily I did have the 
laptop and pulled these codes:

17526 - Oxygen (Lambda) Sensor Heating: B1 S2: Open Circuit
P1118 - 35-00 - -
17522 - Oxygen (Lambda) Sensor: B1 S2: Internal Resistance too High
P1114 - 35-00 - -
16524 - Oxygen (Lambda) Sensor B1 S2: No Activity
P0140 - 35-00 - -
17866 - Exhaust Gas Temp Sensor 2 (G236): Short to Ground
P1458 - 35-10 - - - Intermittent
17536 - Fuel Trim: Bank 1 (Mult): System too Lean
P1128 - 35-00 - -
17538 - Fuel Trim: Bank 2 (Mult): System too Lean
P1130 - 35-00 - -
17579 - Angle Sensor 2 for Throttle Actuator (G188) Implausible Signal
P1171 - 35-10 - - - Intermittent

I am replacing the O2 sensor in the morning (driver's side rear correct?) 
but I am worried about the Throttle Actuator and the System running lean!

I stopped when the light came on and then started off again as the light 
turned off... it seems that the EPC light with the above codes (expect the 
O2 sensors readings) come on only after the engine has been running on the 
highway for 30-45 mins, which just adds to the frustration of trying to fix 

ANY help would be appreciated!

00 S4
Spokane, WA but current stuck in Olympia and hesitant to crawl over the 
cascades under limited power

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