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Jef

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Tech working with a 2013 A8, no infobus action (no radio, media player, dead display, ect). Optic Bus testing shows the radio is electrically dead. So I touch on the "holy trinity", so make sure powers/grounds/data are good... and if so, bad module.

Calls back few days later, says everything checked out, so replaced hardware, no change. Optic Bus testing still shows an electrically dead radio. OK, lets get to the radio in the right rear if the car and double check power/grounds.

.... right rear.... I replaced the thing in the dash.

That would be the 5F Information Electronics. Went to right rear of car, found radio module (a bit hidden it seems). So fuse SF11 ST6 (7.5A) any good? We don't need Paul Harvey to tell you the rest of the story.
 
   #42  

Jef

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2011 Q5, the Steering Wheel Electronics (J527) was replaced. New from Audi dealer, part number checks out good. It looked like some one has been into this before, but no know history. Was able to Auto-Scan with "original" J527 and then copy the coding value over to the new one. Can not get G85 to relearn.:

Address 16: Steering wheel (J527) Labels:. 8K0-953-568.clb
Part No SW: 8K0 953 568 M HW: 8K0 953 568 M
1 Fault Found:
00778 - Steering Angle Sensor (G85) 005 - No or Incorrect Basic Setting / Adaptation

Go through the steps, but nope. Can see live data for the G85 in 16-08-033.3 and it is good.

Turns out there DTCs in other modules for no comm with J527 and G85. Fresh Auto-Scan submitted.... so while the J527 talks, several modules have DTCs for no communication. Address 10-Park/Steer Assist is dead as well.

The CAN Gateway has just 1 fault code:

Address 19: CAN Gateway (J533) Labels:. 8T0-907-468.clb
Part No SW: 8T0 907 468 AD HW: 8T0 907 468 K
1 Fault Found:
00576 - Terminal 15 008 - Implausible Signal

So what I find kind of interesting here, the Park/Steer assist module is dead as it can be, but no code for that... just Terminal 15 concern.

J533 has two fuses, SD8 ST1 and SD5 ST2. Visual inspection, fuses are good. Tech goes to get a test light... turns out none of the SDx ST1 fuses have any power! This dead fuse block gets power from SC15 ST1, a 25A fuse.... and it is missing.


Noted that there were some janky "fuse taps" hanging out there in fuse panel C and dash camera installation of the highest caliber. But with fuse replaced, everything falls into place, G85 relearn performed, no warning lights and a load of codes cleared out.
 
   #43  

Jef

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2018 A4 (2.0T CYMC) Owner of the vehicle called up dealer to price out a replacement battery. $$. Owner is like no way, I can do this myself for less money. Owner proceeds to hook up a replacement battery backwards and fries a lot of stuff... crispy modules and crispier wiring harnesses. Tech has been weeding through this A4 for some time and everything is just about sorted out... down to a crank no fire issue.

Just two codes in ECM ever getting flagged:

P068A 001674 VCDS-EN-210405 ECM Power Relay Load Circuit: Opens Too Early
P02F0 000752 VCDS-EN-210405 Cylinder 3 - Injector: Implausible Signal

ECM had been replaced and matched up, same issues.
We ohm tested the injectors, no red flags.
Test and check wiring for J271 relay, all good. Relay swapped out, no change.

When checking operation of the the J271 relay, it powers fuses SB ST1. So far things are checking out good, fuses getting power. Fuses SB14 to SB16 are just to the left of the other fuses... the tech found them, but there are only two fuses there, not three. SB16 is out of here!

.... SB16, 30A, this is what powers the J538 Fuel Pump Control Module.... popped in a 30A and the engine fired right up.

Not for nothing, but might of been nice if the ECM would of maybe pointed out the damn J538 wasn't there, missing or something. I wonder how much that battery swap ended up costing the customer?
 
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