New EPC light today...P2535

A6 All/ S6 All
#1

EPC light came on today. Ran AutoScan in VCDS and the only code from today was:

009525 - Ignition Switch; Run/Start Position Circuit
P2535 - 001 - Short to Plus
Freeze Frame:
Fault Status: 01100001
Fault Priority: 2
Fault Frequency: 4
Reset counter: 255
Mileage: 177315 km
Time Indication: 0
Date: 2018.02.06

Next time I keyed the car up there was no EPC light. Any thoughts? Does any of this fit with the codes I got ~1200mi on January 17? Those related to throttle body position issues and a few voltage codes in a lot of different modules (see my other thread: http://audirevolution.net/forum/index.php?topic=4678.0) Is this pointing to a bad connector or control module somewhere?

#2

The fault code wouldn’t be one that would trip a code usually or it would trip it right at start up if the car even started. It in the case of your code would be no communication from the ECU to the dash but you have had that happen more than once from what the code says.

It could have just been a cold weather thing where it was intermintent and went away or cleared itself.

#3

As always, thanks for the input, Justin!
Very much appreciate you “eyes” on this board.

#4

Follow up question:
I assumed that was the culprit of the EPC light since it was the only code that had the date and time it happened. So, did the EPC light come on because that fault reached a threshold frequency?

#5

Could be cam position adjuster O ring/s. They are located in the V at back of valve cover gaskets in a deep well.
Read some about them here
https://www.audiworld.com/forums/a6-s6-c6-platform-discussion-58/2007-s6-5-2-v10-oil-leak-2930521/
These fail causing epc light and a seeming mystery oil leak.
Ask me how I know… haha
IMVHO all the 5.2 sealing gaskets/o rings should be changed at 100k.
They literally turn into hard plastic and crumble into pieces.
If you have epc light and smoking oil leak at engine rear, this is probably the culprit.

#6

Its hard to say. There are fault priority and frequency. Priority dictates when a CEL will come on. Frequency won’t.