Have I Fried my Electronics?

[Guffy]

Prior to changing Audi SQ2 rear discs and pads, I applied 12 Volts to retract the electric parking brake, but didn’t release I was still connected to the CAN bus and I appear to have fried everything judging by all these faults:



Has anyone experience of this? I’ve checked all the fuses that I can find, cleared the codes, even changed the battery.

The car is just about drive-able, but the speed isn't displayed, the power steering has a mind of its own and lots of other things no longer work.

Any help would be greatly appreciated.

(I did try to use the VCDS to retract the parking brake, but I had connectivity issues, obviously I regret that now..)

[LordLoveLength]

I’m guessing you connected 12V to the handbrake motor without disconnecting it? Rather than put 12V on the CANBUS which will upset it but shouldn’t damage anything.

It looks like you have damaged the abs module - it’s status is the only one that ‘cannot be reached’
I think your other codes will be other modules complaining about no comms with abs module, or possibly corrupt CAN data coming from the damaged module.

Double check abs module fuses, then try unplugging it and see what errors there are - this may not work as many modules pass CANBUS through them, so anything ‘downstream’ of the abs module cannot then communicate.

[Guffy]

Thanks LLL, appreciate that feedback and it makes sense to me, off to investigate further.

[tux850]

I'm not familiar with Audis and their scan codes however I can't help but feel surprised that a generic '0010' code for so many modules is the best it can come up with as it does sound like they are at least responding. Are you able to interrogate modules individually? If so see if they can the report something more specific and, hopefully, something more indicative of what the problem might be (my gut feeling is something fairly benign like low battery voltage).

Edited by tux850 on Saturday 8th July 12:29

[Guffy]

Still no further forward..

I managed to borrow a professional scanning tool yesterday, but of the 6 ways it offered to down the file, none worked, so had to resort to pics!





None the wiser tbh

[Polly Grigora]

You could think back to when you applied voltage to something and attempt to verify what circuit you supplied that voltage to

Could you have possibly applied a voltage to a circuit that it wasn't meant to be applied to?

[guards red]

LordLoveLength said:

I’m guessing you connected 12V to the handbrake motor without disconnecting it? Rather than put 12V on the CANBUS which will upset it but shouldn’t damage anything.

It looks like you have damaged the abs module - it’s status is the only one that ‘cannot be reached’
I think your other codes will be other modules complaining about no comms with abs module, or possibly corrupt CAN data coming from the damaged module.

Double check abs module fuses, then try unplugging it and see what errors there are - this may not work as many modules pass CANBUS through them, so anything ‘downstream’ of the abs module cannot then communicate.

I agree with this. This is (in my opinion) your best bet to start to understand what you have and have not. Most modern cars have "rings" of data on various buses depending on what the modules functions are. So the powertrain ring will have the engine ECU, the ABS/traction control, auto gearbox/ rear differential control EPAS etc. Other rings will have other components as part of the overall tree. If one goes down and is severely damaged it may corrupt the digital communications on all of the components of the ring bringing it all down. If it's one of the fundamental rings the car will barely run if at all.

You need to isolate the handbrake ECU or ABS ECU from the ring so the other ECUs can start using the ring again to communicate.

[LordLoveLength]

You are further forward - you know the majority of faults are missing communication messages.
You have confirmed that the engine ecu can no longer communicate with the abs controller.

You have an interesting message under ‘Electronic central electric’ about no power on terminal 30.
Almost certainly a blown fuse - possibly a high current link-type on or around the battery positive terminal.
Start there looking for a broken link, then other fuse boxes, then look at disconnecting the abs controller.

[Guffy]

Thanks for your responses, it's much appreciated.

Obviously i'm out of my depth, so the car is booked into the local auto electrician this week who think they can help rather than just scan the car...

I would have liked to have at least identified the rout cause, but i've checked all the fuses in the two main fuse boxes, not sure where others might be without some sort of wiring diagram.

[Polly Grigora]

Ok then

If you're sure that it was the motor/actuator that you supplied voltage to I doubt very much that you could have damaged any communication circuits

All being well the auto electrician will find the problem is a simple fix

[Guffy]

Polly Grigora said:

Ok then

If you're sure that it was the motor/actuator that you supplied voltage to I doubt very much that you could have damaged any communication circuits

All being well the auto electrician will find the problem is a simple fix

Not 100% sure, instead of disconnecting directly at the brake motor, I disconnected shown in the example pic below, which could be an ABS line?

[E-bmw]

OK, so I am confused.

You say you didn't disconnect at the actuator, but you were operating the actuator, and you clearly know which is the actuator.

Why?

[stevemcs]

Have you attempted to clear the codes in the abs module - not scanning the whole car and clearing them but going into the specific module.

[Guffy]

E-bmw said:

OK, so I am confused.

You say you didn't disconnect at the actuator, but you were operating the actuator, and you clearly know which is the actuator.

Why?

Sorry for the confusion

I originally tried to use VCDS to retract the parking brake, but the software wouldn't connect to the car. So i unplugged the connector circled above and incorrectly applied 12v, nothing happened but had created the 20 or so fault codes i have now. Later in the week i disconnected the plug directly on the actuator and successfully retracted the piston, allowing me to fit new discs and pads.

[Guffy]

stevemcs said:

Have you attempted to clear the codes in the abs module - not scanning the whole car and clearing them but going into the specific module.

I tried various things like that, although the scanner could not connect to the brake control module.

[E-bmw]

Guffy said:

E-bmw said:

OK, so I am confused.

You say you didn't disconnect at the actuator, but you were operating the actuator, and you clearly know which is the actuator.

Why?

Sorry for the confusion

I originally tried to use VCDS to retract the parking brake, but the software wouldn't connect to the car. So i unplugged the connector circled above and incorrectly applied 12v, nothing happened but had created the 20 or so fault codes i have now. Later in the week i disconnected the plug directly on the actuator and successfully retracted the piston, allowing me to fit new discs and pads.

So, in that case was this the actual start of the issue & is unrelated to what you think is the fault?

[Guffy]

E-bmw said:

Guffy said:

E-bmw said:

OK, so I am confused.

You say you didn't disconnect at the actuator, but you were operating the actuator, and you clearly know which is the actuator.

Why?

Sorry for the confusion

I originally tried to use VCDS to retract the parking brake, but the software wouldn't connect to the car. So i unplugged the connector circled above and incorrectly applied 12v, nothing happened but had created the 20 or so fault codes i have now. Later in the week i disconnected the plug directly on the actuator and successfully retracted the piston, allowing me to fit new discs and pads.

So, in that case was this the actual start of the issue & is unrelated to what you think is the fault?

No, it just needed a reinstall, works fine now.

[Guffy]

Just to close this one out, the ABS module was replaced and everything is working fine now.

I might be £1800 lighter of pocket, but sometimes you need a slap in the face with a wet fish...

[paintman]

Ouch!

Isn't modern technology wonderful.

[Sheepshanks]

Makes me feel less guilty about using garages - I find modern cars terrifying! I either break something on the car or hurt myself.