MY 2004 D3 electrical gremlins
 

I think my D3 is telling me its time to be sold, I have had her for 4 and half years now.

Latest problem.

Driving in stop and start traffic, out of the blue up will pop a series of faults on the DIS in the following order.

Headlight range control defective
Parking Brake Fault
And another I cannot remember.

ABS and ESP lights then come on in addition to the warning, and you cannot engage ACC cruise control.

The parking brake still works perfectly fine, if you turn off the engine before engaging.

I drove for three hours yesterday morning in regular traffic, and the car drove perfectly with no faults. I got stuck in traffic going to work, and within just a few minutes up pop the faults. The only thing I can think of is that in traffic the brake pedal is being used a lot more than when in motion, can a faulty brake switch cause this?

Yes it can - and has done to my D3 - or at least the ABS and ESP lights part can be (I think that the Headlight range and Parking brake may well be seperate faults)
and the brake switch isn't too expensive or difficult to change so I'd definitely start with that first +++

Your adaptive cruise won't work of there is known issues with the ABS and ESP for safety reasons I would have thought

I agree with Neil, first stop would be VCDS scan to see what errors are logged as brake switch defects will be logged in that

I've got an old dodgy copy of vcds, I'll try and scan the car later and post the results.

I'll be down to Beaulieu at the weekend on Sunday at the show otherwise Manny and will happily catch up and plug in my vagcom for you somewhere if that helps, just let me know +++

I wouldn't be certain about the brake switch, when mine went the gearbox went into limp mode. I drove it to the garage thinking the gearbox was toast. I was thrilled to be told it just needed a brake switch.

Today I finally got around to scanning the car. Sorry i am not Beulieu, I've got a job application to finish off and my CV as unemployment looms.

I have attached the log, but aside from the usual issues my D3 has and those relating to low battery as the car is hardly used one stands out like a sore thumb.

Address 03: ABS Brakes Labels: 4E0-910-517.lbl
Part No SW: 4E0 910 517 A HW: 4E0 614 517 A
Component: ESP 5.7 allrad H29 0420
Coding: 0008597
Shop #: WSC 02313 000 00000
VCID: 214DE1B78159

1 Fault Found:
00290 - ABS Wheel Speed Sensor; Rear Left (G46)
012 - Electrical Fault in Circuit - Intermittent

That is the obvious stand out, how easy is that sensor to sort or check the wiring connections?

Perhaps if someone else could review the whole log I would feel happier.

With the fault present I can clear the ABS sensor fault but as soon as you close the controller it returns. However after the car has gone fully to sleep the fault is no longer current and will drive fine again until it recurs.

Well as you suspect I'd say most of that will clear ok other than the abs sensor and level control pressure and temp warning I would be too concerned.

the abs sensor may be faulty but worth checking the contacts for grime or corrosion.

The door handles quite possibly are dragging down the battery.

The rear parking sensor can be changed assuming its it at fault without removing the bumper, well it can be on the S8 bumper.

Once you sort the the abs out the headlight and acc should start behaving too.

The level control pressure sensor one I had before, and I had the bagpipingandy rebuild kit fitted more than 4 years ago. The cause then was low pressure output from the compressor.

The overtemp must be caused by the system trying to build up pressure after not being run for nearly 2 weeks. Whilst left for this long the car does drop a little.

I maybe selling the car soon, but I do want to have a car that does not beep loudly in slow or stationary traffic. As it stands now, it may well fail the MOT as it is unpredictable how long the ABS light remains off after starting the car, and the next MOT is due soon.

Wheel bearing?

Another possibility of course, but that one was changed several years ago as the original whined a lot.

The first time I got all those lights on was not long after driving through a large puddle during the very wet winter and its been regular ever since.

I can almost predict when it's going to occur, the abs fault came up whilst I was scanning the car and the car was not even moving.

I wonder if there is a measuring block that can read each wheel speed sensor.

Given the choice would you go for a brand new third party sensor or a used 14 year old sensor from the forum sponsor (They are both the same price).

I am out of work from Friday, so will have plenty of time to work on the D3.

That reminds me, must finish CV. Working for the same company for 30 years means I didn't really have one.

I would use A8Parts, I've always had great service from them, and wouldn't have a problem using a used good sensor.

There is this new Bosch sensor,

https://www.ebay.co.uk/itm/302150530146?

Hopefully it's original and not a Chinese copy. Who knows!?!

Measuring Block 1 in ABS will display each wheel speed, not so useful in this case. Measuring Block 7 is Installation position, either invalid / ok / not ok. It would be interesting to see if yours displays invalid or not ok. Not ok would indicate a working sensor but inserted wrong with too much gap, bad bearing, axle tolerance (incorrect tyre size on that corner etc..). My guess now would be an invalid reading due to the puddle and the sensor may have water ingress.

All the best with CV, job, A8 +++

Neither, I would try to check connectors and replace the cable on the old one first as it is usually the problem because conductors break inside cable from all the bending over time going over bumps so 14 year old is likely to get the same fault soon and aftermarket could be questionable quality.

I have replaced all of the twisted pairs of ABS wires to each sensor all of the way back to the ABS unit on my D3 A8L, this was due to the external casing getting brittle and cracking / breaking away in a number of places and the twisted pairs making random contact and setting of the beeps of doom on the dash :rolleyes:

I really hope is just a connection problem, with the connector itself. I drove the D3 50 miles yesterday with no problem at all, but I did not get stuck in low speed traffic which is what tends to trigger the fault, for example in a queue or sitting at traffic lights.

I had a water ingress problem with one of the air suspension electrical connections not long after getting the car, which caused all kinds of issues with the suspension. Since having that resolved it's been fine ever since.

Well as I am now unemployed, I took advantage of the time to remove the rear wheel and investigate the wheel speed sensor.

After disconnecting the wiring to the sensor, there was no apparent issues with either the car wiring connectors or the sensor itself.

I disconnected and reconnected the connector a few times and then clicked it back into place and went for a drive.

The drive was fine, but whilst sat in the car outside my house doing zero mph the fault recurred and has recurred again since.

I am assuming I checked the correct wheel (UK passenger side, rear).

I've been driving the D3 today, and no problem to report with the ABS until whilst sat idling outside my house doing 0mph the fault triggered.

Tomorrow I am going to hook up VCDS and connect to the ABS controller and look at measuring block 1 which should show me what all 4 wheel speed sensors are seeing and then start a log, and hopefully when the fault recurs I may catch something in the log.

I may even try going for a drive to see if that sensor is returning consistent readings compared to the other three sensors.

The attached picture is taken looking up at the sensor with the wiring disconnected, no sign of water ingress at this end.

Ok,

So today I've been out in the D3 with my laptop and did some logging with VCDS.

I've attached the results to this post, as you can see all is well and there are no problems at all for a while. All four wheel speed sensors read the same, and no faults until once again I was sat in the car not moving when the fault occurred. VCDS was logging at the time, so right down the end of the log you can see a blue section, just before that is when the fault occurred. The dark blue section is after the fault occurred, and you can see that the left rear sensor is no longer reporting data and the logged fault code cannot be cleared at this point.

Annoyingly you get kicked off the ABS controller once your road speed exceeds 20kmh.

im wondering if this is anything to do with a faulty brake switch hence it happening when you stop? relatively cheap one to replace if it could be that??

If the fault was occurring when moving I would say broken conductors in ABS sensor cable but since mostly happens when stationary I am leaning towards dry solder joint in ABS unit. Sitting in traffic etc results in heat buildup under bonnet, cracked solder joint expands and looses connection, start driving or leave car alone for a while it cools down joint contracts and makes contact again. Common problem for many cars, I think I have heard it happen on several D3's before. You can remove electrical part from pump and send it off for repair or you could have a go repairing it yourself, I did it once for friends Volvo, just cut it open, re-flow all big solder joints for plugs/solenoids and glue the cover back on.

I've found a company in Exeter who will sort the ABS whilst you wait, in around 2 hours. I am going to call them in the near future and see what they say.

wow that will be a useful find if they can sort it +++
Let us know how you get on Manny

I've had an email conversation with the company (actually in Collompton) and they have said that they can fix the ECU. I am calling them next week to book the car in and then drive from Blandford to Collompton in the D3, and they will remove the ECU, fix it and reinstall it whilst I wait. Not sure on lead times yet but will keep you posted.

I could do without spending any money right now, but I need this sorted before the MOT runs out otherwise it will fail

Well the D3 is going in on Monday to have the ABS ECU fixed, after speaking with them on the phone they are going to.

1) Remove the ECU
2) Disassemble the ECU
3) Using a Microscope examine and repair faulty connections
4) Reassemble, refit and test.

I then have a choice of them bleading the brake system and renewing the fluid leaving as is. Fluid change is due, so may get them to do that as I believe it is included in the price.