2009 Audi Q5 Brake Malfunction? Abs Fuel Gauge Speedo

[Q5-sLine]

Afternoon folks, I’m wondering if anybody could help me with this problem I have. I bought a Accident Damaged Q5 exactly a year ago which I then repaired... all was good. Then driving a little brought up a number of faults that don’t seem to go. The Abs, Traction, Glow plug (flashing), brake and Engine light are all on... along with the Speedo not functioning and things like ESP Off, Parking sensors, hill descent all not working! The drivers rear door, the drivers door and the drivers side wing was all replaced. Doing more reasearch I’ve found out this car was Auctioned on Copart, were it had all the same dash lights on, meaning the two lads I bought it off somehow temporarily disabled them? I’ve been to multiple mechanics and tried speed sensors, Air flow sensors, dpf sensors, break bleeding basically the whole lot, I’ve got a few photos linked which may help someone with this but right now I’m baffled, I’ve tried all the ways others have told me (fuses,relays) but still nothing.

Regards, Ryan

[GreenV8S]

Sounds as if you have thrown parts at it rather than diagnosed the problem(s).

If you have warning lamps on, there will be fault codes stored to indicate why. You need to get those codes and work out what they mean, then diagnose the fault that is causing them.

Some fault codes are only reported after a number of drive cycles which may be why you didn't see any warnings initially i.e. the sellers cleared the codes without fixing the underlying fault. If this was a trade sale, you should have some recourse against the sellers. If it was a private sale I suspect you're out of luck unless you can prove the sellers lied and are willing to take them through the courts to recover your losses.

[Q5-sLine]

It’s been a private sale, so no luck there. There’s no communication and I can’t clear the faults using VCDS or Dealer level diagnostic tools... any ideas?

[robbocop33]

I agree with previous comments, throwing parts at it just on the strength of fault codes isn't the right way to go, do you really think all these sensors would bugger up at the same time, or my idea below, a ground 'all' these sensors share is damaged!
This sounds like a ground wire issue or a wire shorting against the chassis since it's affecting so much. Your ecu/pcm is showing codes which shows it's doing it's job. Maybe a wire got pinched during the accident, guy you bought it off maybe knew this and just moved the harness temporarily knowing it was dodgy, now it's moved again?
Concentrate on harnesses around the accident damaged area, have someone in car with ignition on while you are tugging on all the wiring harnesses in that area and see if anything changes on the dash, doesn't cost you anything and it's worth a try and might narrow it down a bit? !
Whereabouts are you based roughly?

Edited by robbocop33 on Saturday 30th March 18:36

Edited by robbocop33 on Saturday 30th March 19:18

[Q5-sLine]

I’m based in Birmingham and is there any way I can get a map of the side wiring harness?

Thanks for the help guys it’s much appreciated

[Q5-sLine]

It once had previously gone back to normal a little after repairing it and it has a rough idle which temporarily goes with redex... VCDS says it’s the mounts but I’m focused on getting the electrics sorted yet

[drdino]

What damage did it have? Do you have a list of the codes stored in the various modules?

[robbocop33]

Q5-sLine said:

I’m based in Birmingham and is there any way I can get a map of the side wiring harness?

Thanks for the help guys it’s much appreciated

Looking at your codes they are all based on damage/faults on the side of the car that was hit! (cylinder 1,2 fault etc) and most include the causes of the codes as 'wiring'! Which tells you a lot!
Even the mixture fault codes are on cylinders 1 and 2,and guess what side of your engine they are?? :-) Im going for a harness that's had a battering.
What engine is it?

Edited by robbocop33 on Saturday 30th March 19:28

Edited by robbocop33 on Saturday 30th March 19:45

[Q5-sLine]

It’s a 2.0 TDI manual

[Q5-sLine]

Drdino click on the photo and there should be an photo with the codes written on them 👍

[robbocop33]

Yes i've seen the faults, the p1588 one is you engine mounting control solenoid bank 1 and 2 open circuit, which could mean a completely cut wire, pointing to harness damage. Might be worth trying to find this component and following wire from it, see if there's damage down the line. Here's a pic of it below. Might lead you somewhere?
The p2452 code could be a wiring fault too, this is your diesel particulate pressure sensor, says 'circuit malfunction' again could be wire damage.
Mounting solenoid;



DPF sensor;

[robbocop33]

Dpf sensor location, follow wiring down from it!number 3

[robbocop33]

Your engine mounting solenoid is fuse number f5, 10 amp in the fuse/relay box below(might be worth checking it) , your dpf pressure sensor just goes straight to your ecu.And for the record the u0121 code is a loss of communication with the abs control unit, more specifically the can-bus has no communication with the electronic brake control unit, again i think a wiring issue.

Edited by robbocop33 on Saturday 30th March 21:21

[Q5-sLine]

Where would you think the wiring would be travelling from? My guess is under the wing? I’d bring it over to my mechanic to take the wing off and have a look

[robbocop33]

The reason i gave you the locations of some of the components that are showing fault codes, is if you follow wiring down from them you might find some wiring damage(your dpf sensor, your Abs module communication fault etc) . The fact you've got so much going haywire altigether makes me think the wiring from them all might meet at a common point, and this point may have been damaged in the collision.
Over on your driver side you have a main wiring ground point as well on the A pillar, a few things might share this ground and again,this is where the car was hit.
Sorry i can't find any main harness diagrams(that's why i told you to folliw wiresdown from things that are damaged) , some data sites show them, some don't.

[Q5-sLine]

I got the dpf sensor for £8 on eBay and it worked! Well pleased all the dash lights on on though... I’ll have to find more information on this a pillar ground point, thanks for all the help so far!

[robbocop33]

As i said before, there's no way anyone would get all those faults all at the same time, without all the wiring all being in the same area and being hit, bad grounds can do some really freaky stuff! Things can go haywire!
I had esp lights, abs lights, mil lights etc on my little rs225 megane, it was just one bad ground wire!!
Just a reminder what i said before, have soneone sit in the car and start wiggling wiring looms roundabout where the accident damage was,with the ignition on and see if anything on the dash disappears or changes.

[Q5-sLine]

I have no idea where I’d start because looking at the Q5 with all its panels on there’s no harnesses showing lol

[robbocop33]

Q5-sLine said:

I have no idea where I’d start because looking at the Q5 with all its panels on there’s no harnesses showing lol

Don't know if you're getting aywhere yet with yoyr car. This electronic course i'm on is actually covering an audi s5. He mentions there was a fault with the engine mount solenoid, same as yours, but he mentions that on the s8 a fault with the engine mount solenoid cuts of the high pressure fuel pump!!
Don't know if your cars running just now?

Edited by robbocop33 on Saturday 13th April 13:29

[Q5-sLine]

It has always run and drove, just with all the dash lights, no speedo and weird fuel gauge... I’m gonna start diagnosing issues starting Monday but I’ve tired tugging on the harness nothing happened sadly. Thanks for keeping in touch