Help Please Electronic Parking Brake Malfunction

[Saxem]

Hoping someone can help!

I'm having a problem with the electronic parking brake on the right rear not working and getting a electronic parking brake malfunction on the dash.

Initially, thought it was the parking brake motor so changed that but still not working. Tested the original motor on a 12v battery (should have done this first) and that it works fine. Checked the voltage at the plug and wasn't getting anything when engaging/releasing the handbrake. So changed the module and still nothing from the right side.

Finally managed to get it scanned with vcds and got the following:
Address 53: Parking Brake Labels: 8K0-907-801-V1.clb
1 Fault Found:

02433 - Supply Voltage for Right Parking Brake Motor (V283)
007 - Short to Ground - MIL ON
Freeze Frame:
Fault Status: 11100111
Fault Priority: 1
Fault Frequency: 1
Reset counter: 58
Mileage: 166275 km
Time Indication: 0
Date: 2009.11.08
Time: 15:28:46

Freeze Frame:
Voltage: 11.50 V
Count: 33
Speed: 0.0 km/h
Hex Value: 0x0263
Hex Value: 0x0001
Hex Value: 0x1004

I guessing this means there might be a split in a wire somewhere? Couldn't see anything exposed wires around the module, but I guess it could be somewhere else. The module looks to have two 12v feeds into it (guessing one for left motor and one for right motor). Both are giving the same voltage.

Also got the following when doing advanced measurements (with handbrake engaged):

Info1 - Info2 - Actual
Battery Voltage - (Terminal 30) - 11.50V
Shut-Off Current - Left (Calculated) - 17.100A
Shut-Off Current - Right (Calculated) - ERROR

Does anyone have a wiring diagram for the module to help trace the wires?

Any help/pointers would be massively appreciated.
Thanks

 

[spartacus68]

Can you trace the wiring back. Any plastic connectors? I just did my rear discs and pads, so can remember unclipping wires. It's all done with VCDS to retract the piston, but I'd be looking at anything that's on a clip on the subframe or chassis for chaffing.

 

[Saxem]

I tried but it goes straight into a sleeve, which looked intact. On the right hand side it looks like it goes straight up into the boot next to the module, but behind the arch liner, so I should probably remove that and have a better look.

I did also try unplugging the module and sending 12v down the pins which made the motor move, so I'm not sure if that rules out a break in the cable or not.

I could probably try splicing the cable just outside the module and running a new wire to motor to see if that's any better, but wondering if I'm missing something obvious.

 

[audiwaterpump]

Some history of the car may help.
Miles, owners, how long you had it, audi service history, year etc

Has anyone ever messed about changing the brake pads on it? They may not of done it properly and caused some damage.

I assume it's been working ok until now?

And check fuses.

 

[spartacus68]

Just looked at your error code. Battery voltage looks a little low? Have you tried charging the battery? Also look at the piston on the caliper. Is the dust sleeve intact, no tears? Look at the back of the motor to make sure the motor case isn't cracked. From what I've read they can crack, water ingress, etc.

 

[Dippy]

Not only was the battery voltage low but the fault occurred in 2009. Clear the DTC and get a new scan.

 

[Saxem]

Thanks for the replies.

Have tried to clear the fault code has a couple of times but comes back instantly.

Some background would have been helpful. Cars a 2010 plate with 103k, which I've owned around 3 years. I know the previous owner and the brakes have only been done by mechanics since he/I had it.
The parking brakes had been working fine. I'd just done a 25 minute journey, parked up for less than 5 minutes, got back in and got the error and right side had jammed on. RAC came out and tried to run the brake cycle procedure with their diagnostics, which had no effect on the right side so the guy manually unwound it then removed the motor. After replacing the motor, took it to a garage to clear the DTC (thinking it was fixed) and realised it still wasn't working, but they got a communication error when trying to cycle the handbrake. They'd only seen something like that previously with a split wire.

Back of the motor looked fine but the O ring for the motor looked a little rubbish and it was a bit dirty inside, motor still works fine when I tested it though. It was wet that day though so water could have got in somewhere else. From the amount of sleeve I could see, that looked fine too. I'll take the arch liner which should help me get a better look at it.

I did think the battery voltage was a little low but dismissed it as both parking brake sides are getting same voltage if you measure at the pins into the module, so would have thought it would have effect both sides if it was a battery voltage issue, but will charge the battery to be sure

 

[audiwaterpump]

@Saxem When was the battery replaced?
A weak battery will cause all sorts of weird faults, especially with the electronics.

Thanks for the detailed reply. Hope you get it sorted soon.

Some mechanics don't have the vcds to change the brake pads properly, and some of the unorthodox methods can sometimes cause damage especially to electronic parts.
And try swopping similar fuses over, even if they look ok. It can sometimes affect the voltage.

 

[Saxem]

Cheers, will try a new battery. I'm not sure how old that one is without looking. I did try swapping the fuses (was getting desperate at that point) but still the same.

The mechanic I use doesn't have VCDS but does use a snap on diagnostics kit, which seemed to have the procedure for the brakes which he used while the read pads were done last. He did say the caliper was a bit stiff though, not sure if that would have any impact if it's starting to give in.

 

[audiwaterpump]

The mechanic I use doesn't have VCDS but does use a snap on diagnostics kit, which seemed to have the procedure for the brakes which he used while the read pads were done last. He did say the caliper was a bit stiff though, not sure if that would have any impact if it's starting to give in.

What's the time span between rear pads being replaced and this fault occurring?

If you can, try fully charging the battery first. And if it works it may save you a few pounds.

You also need to clear the fault codes.

 

[Saxem]

What's the time span between rear pads being replaced and this fault occurring?

Probably about a year now, think it was advisory on last mot which is November.

 

[Diesel bob]

If the caliper is stiff or partially seized the the motor will have to work harder. This means the voltage at the motor could drop to such a level the car thinks the supply is shorted, giving the error. Could be worth checking out especially if the battery is on the way out.

 

[Diesel bob]

If the caliper is stiff or partially seized the the motor will have to work harder. This means the voltage at the motor could drop to such a level the car thinks the supply is shorted, giving the error. Could be worth checking out especially if the battery is on the way out.

 

[Saxem]

Good shout. I did try to clear the codes with the brake unplugged but it still came back on. It might see that as a completely open circuit though and not be happy about it. I could try the spare motor detached from the caliper though...

I've got it booked to go in, but the garage has a 4 week wait so will check the battery before then. I don't think I'll go cutting wires just yet, don't think they'd be very happy trying to figure it out a mess of wires.

 

[rum4mo]

Trying to clear any smart system faults with part of that system still faulty or unplugged will never work.

 

[Saxem]

No, you're right. I was hoping it might show a different code with it unplugged so I could start to rule things out