Audi A3 8v technical help

[Cultus]

Hi I’ve bought an Audi A3 8v facelift with light front passenger side damage, damage was to headlight and behind, no chassis leg damage but has damaged the upper inner wing also the fuse box was hit and damaged and Ecu knocked battery tray ect ect

I have replaced the fuse box under bonnet, battery tray and have a replacement inner wing to weld in. Originally I had a lot of faults on the dash, power steering wasn’t working airbag lights Esc fault ect ect. Since fitting the new fuse box the power steering working again and it solved most of the faults. I’m scratching my head about the remaining faults and was hoping you guys would be able to point me in the right direction.

Firstly when I bought the car the person I got it from had bridged constant power in fuse box to the fuel pump wire! Without this bridge the car won’t start and when ignition is off the fuel pumps on and the fan kicks in but when you turn the key to ignition on the fan turns off? With wire removed there’s no fuel pump prime with ignition? I’m using an obdeleven pro and it’s giving me fault code P068900 PCM power relay sensor circuit de energised to slow? Also have a fault for no basic settings for dash. Is there some sort of fuel cut safety system in this car so when it senses impact it cuts of fuel? Or is it a power replay fault? I have the diagram for the fuse box’s but it does not tell me what relays are what just the fuses. It’s a 2017 1.6tdi Audi A3 8v 3door if anyone can help me out I would really appreciate it.

 

[Khufu]

it might be worth signing up and paying for a session here:

https://erwin.audi.com/erwin/showHome.do

you can get access to wiring diagrams and relays/fuses etc.

I've never used obdeleven so i dont know if its as comprehensive as VCDS in its functions for basic settings.

Could either be a sensor issue that causes the car to think the temp is too high and is trying to cool it or the power is short to ground via a wiring short?

My car was accident repair (side) but only accident related action was ABS was activated due to collusion.

 

[Cultus]

Thank you khufu I will get on that site tonight.

There is a fault code for engine oil temperature sensor circuit low also. I think because the previous owner wired a constant battery supply to fuel pump wire under fuse box that’s setting of fan. When this wire is disconnected the everything still works car ignition ect ect just won’t start. I’ve never used vcds and this is first time using obdeleven what could the P068900 fault be caused by? It shows with or without fuel pump bridge wire I have swapped all the relays? Is there a fuel cut on these that is activated when crashed?

 

[Cultus]

Fixed stripped loom wrapping and found broken wire reconnected and car starts as it should. Only things left is the airbag light the faults are for the sensors I’ve tried clearing them but the just keep coming back?

I can’t see any more broken wires so is there something different I must do to clear the sensor faults?

 

[Cultus]

Oh and airbags have not deployed sorry should of said that before.

Thanks

 

[Khufu]

there is a pedestrian sensor on the front bumper and the seat belt pretensioners that could be causing airbag light. what airbag error is coming up?

 

[Cultus]

It’s the passenger and driver side pedestrian crash protection sensor/ b+ short circuit open circuit ?


Will this be a case of just replacing those sensors?

 

[Cultus]

there is a pedestrian sensor on the front bumper and the seat belt pretensioners that could be causing airbag light. what airbag error is coming up?

It’s the passenger and driver side pedestrian crash protection sensor/ b+ short circuit open circuit ?


Will this be a case of just replacing those sensors?

 

[Khufu]

i sent my seat belts off to get fixed properly. I guess you could put a resister across them...

 

[Mo-S3]

It’s the passenger and driver side pedestrian crash protection sensor/ b+ short circuit open circuit ?


Will this be a case of just replacing those sensors?

Sensors can easily be resued. You need to check the bonnet actuators as they have probably fired and need replacing. A proper scan is needed instead of guess work.

 

[Ivaylo Vladov]

Fixed stripped loom wrapping and found broken wire reconnected and car starts as it should. Only things left is the airbag light the faults are for the sensors I’ve tried clearing them but the just keep coming back?

I can’t see any more broken wires so is there something different I must do to clear the sensor faults?

Hi Cultus,
Do you recall which wire was broken? I replaced the fuse on the positive terminal. Now the car cranks but doesn't start I have the same error as you on the ECU - power relay deenergized too fast.