View Full Version : electrical gremlin is back

01-09-2010, 01:00 PM
its been two months with no problems. things have been going too good to be true. and i was right. the past couple days the problem that i THOUGHT i fixed two months ago is back. i vag'd my car and this code came up again...

17972 - Throttle Actuator (J338): Under-voltage during basic setting
P1564 - 35-10 - - - Intermittent
17853 - Throttle Valve Controller: Malfunction
P1545 - 35-10 - - - Intermittent

Two months back i got a new TB and the problem went away. but now its back. Any time i boost above 5psi, or get on the gas in a high gear low rpm EPC kicks on.

2001 a4 1.8tqm
93 oct APR burn

both changed 2 months ago

01-09-2010, 01:40 PM
Try a Throttle Body Adaption.

-Remove negative cable from battery for roughly 10-15min to be sure
-Place cable back and place key in starting positon (all lights on dash lit up and one click from cranking)
-Let it sit there for 5-10min to be sure
-Crank the car and let her turn over

After you do this, erase the fault codes and see if they come back. Your issue could be faulty TB wires, seeing how you already replaced the TB itself.

01-09-2010, 01:50 PM
dont bother with the cable off etc
just go into adaption in vcds and adapt that way

01-09-2010, 01:54 PM
IF it is bad TB wires, where would i get the new harness? or is that something id just have to get from a parts car?

and i have been trying the VAG way to adapt the TB. but that still doesnt get rid of the problem that ive been having.

01-09-2010, 05:37 PM
i tired unplugging the negative terminal on the battery, it worked for about a mile or two. but once i pulled off from a light, getting a little hard on the gas to see if it would trip on me. and it did, EPC kicked in short after takeoff.

01-09-2010, 05:47 PM
Then I would say it is an issue with your TB wiring, which the second code in your first post wad directed to.

01-09-2010, 05:55 PM
ive been checking different places on the net of harness' like mjm. im havin no luck though. is that a harness ill only be able to get from a junk yard or parts car from here?

01-09-2010, 06:10 PM
Generally speaking, you would just repair the harness: find which wire(s) is open/shorted/high resistance/bad ground/etc and either repair it or replace the wire or wires. The coil-pack harness is a special case - if 1 wire is heat damaged, they all are. So that is why a partial new-harness replacement is done for that repair.

To find what is wrong, you would test the wires between the throttle body connector and ECU connector. Test for resistance of each wire and any continuity between them or to ground. If the problem is apparently wiring, but the problem cannot be positively identified, you may elect to just run all new wires between the ECU and TB. You could run the new wires alongside the original harness with whatever tape, insulation, or split-loom tubing you deem necessary. Just a suggestion. I suppose you could source a replacement part of a harness from a junkyard if you like. It's up to you.

Usually the wiring harness, either from Audi or aftermarket, will be the entire engine harness, not a piece of it. Again, due to problems with heat damage of the coil pack harness that was made available from VW as a repair harness for a few of the transverse cars, and from 034 (I believe) as an aftermarket repair solution.

01-09-2010, 06:38 PM
that was extremely helpful. thanks walky talky

01-09-2010, 06:46 PM
i seem to remember a technical service bulletin about throttle body harness and having to rewire it, but i cant for the life of me remember what chassis/body/engine it was for.

if your vehicle sits outside overnight, the problem could also be rodent damage, as ive seen this a few times in the past. you dont want to know how much an oem engine harness is for d3 (new a8).....

01-09-2010, 06:59 PM
nah, it gets babied, it sits in a garage on a carpet every night