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A8 D3 - ABS - Handbrake malfunction - Brake wear warnings

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Old 10-16-2017, 03:44 PM
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Default A8 D3 - ABS - Handbrake malfunction - Brake wear warnings

Please can someone help. I am in the UK (Derby)
I have taken my beloved 2006 A8 D3 (3.7 V8 petrol) to a reputable Audi Specialist who was extremely helpful and spent a good few hours fault finding the numerous warning lights but in the end advised me to take the car to the main dealer for a plug in diagnostic. This I did last week and parted with £120 only to be told that they could not be certain what the problem is and would have to have the car in to do some 'exploratory' work and part with £168 per hour for them to 'try' various parts options in hopes of finding a fix.

After much sympathetic and guiding discussion I left, totally dejected and facing the possibility of having to progressively part with anything up to £5000 to keep my car on the road beyond its next MOT in January 2018. Alternatively, I could hand it over to a breaker and hope to get £1000-2000 for it.

The car has covered approx 130,000 miles and runs like a dream apart from these annoying brake related fault messages.

Here are the symptoms.

Start the engine and usual dashboard checks are completed and lights all go out except brake wear which remains on. After driving about 5 miles (at approx same spot on the A38 every day) the ABS lights, brake wear symbol and handbrake malfunction warnings beep at me then go off again only to come on again after a further minute or so. The ABS lights stay on for the remainder of the journey and brake wear and handbrake malfunction messages alternate and beep at me for the remainder of the journey.

I had the front brakes replaced 3 weeks ago and the rears were done just last weekend - all the lights still do as described above.

I have pampered this car and absolutely LOVE driving it but it is now driving me nuts.

Any help and guidance would be very much appreciated by me AND my A8 !!!

Thanks,
Mick
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Old 10-16-2017, 04:46 PM
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Welcome. You will need to report what the scan says for any educated help here. It may be as simple as the brake pad thickness is not correctly entered, coupled perhaps with a bad ABS electronic module. Pad thickness resetting is a common Audi stumbling block, and Audi ABS modules have been failing with age going back 20 years. Detailed scan info will likely pin it down better from just percentage guessing.
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Old 10-16-2017, 06:47 PM
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"Scan, scan, scan". I was told the same thing by members on this forum. I don't have a VAG scan tool and found the real solution. Here's an explanation: The ABS function compares the speed of wheels. If one wheel is going slower (or sliding on ice), the ABS modulates (pumps real fast) your brakes.

My symptoms were the same as yours. When you start your car, everything is cold and you don't have any warning lights. Driving five miles and it heats up under the hood. If the outside temperature is colder (in winter time) it might take more than five miles before all the lights come on. When you get the ABS warning light, do you also get the ESP. (electronic stabilization program) warning? In the UK, ESP might show as a "delta" which is a little triangle. The "hand brake warning light and beep you mention might be a matter of US terms vs UK. When you say "hand brake" do you mean the parking brakes which are electric and activated by a switch on your console? If so, then we are on the same page.

The same thing happened to me more than a year ago. At first, it was very intermittent. Some days lights would come on, but not others. It progressively got worse till it regularly failed in 4 or 5 miles. Also, my speedometer would stop working. The beep was from the parking brake (same as hand brake?). Other than the annoying lights and beep, I could still drive the car. The beep was the worst. Since the "hand brake" or "parking brake" warning are lit, you don't have the parking brake function anyhow. My temporary solution was to pull the two, 30 amp fuses for the brakes. they are located in the trunk behind the panel over the battery. It might be a different layout for a UK car but my fuses were the last two at the bottom of the fuse panel. This turns off the parking brake function. On my car, it also displayed a "BRAKE" light near the ABS. Again, this only applies to the parking brake. normal foot brakes are not affected.

ABS, ESP and the parking brake have one thing is common in this warning mode. That is the speed signal which comes from the left front wheel speed sensor. Of course the speedometer needs this signal also. Most people with these symptoms see an scan error pointing to the speed sensor. That may indeed be the problem but for me, it wasn't. Being intermittent and coincidental with the heat of the engine (driving 5 miles), points to the same speed signal but it is being lost along the way. The speed signal goes through the ABS module (electronic thing attached to the side of the brake modulator (pump). Vibration from the pump, the engine and especially heat from the engine can cause the tiny electronic contacts inside the module to loose contact. This is a common failure with the module made by Bosch.

As I said, you can drive the car with all these warnings lit. Of course, you don't have ABS function, but then you didn't have ABS on any car 20 or so years ago. You can drive without it but be careful on ice and snow. You can also drive without a speedometer. I'm pretty sure there wasn't a speedometer on the model T Ford, etc. You just have to estimate your speed.

the problem is in the electronic module. You can buy a new ABS module for about $450. (not sure what that is in "L". Alternative to buying a new module is to have your module repaired. There is a guy who you send the module to and for $125. he fixes it and warrants for ever. Taking the module off is somewhat difficult but can be done. A shop might want to remove the modulator and disconnect the brake lines. (this adds labor to the job, plus the brakes lines need to be bled when attaching. It takes 10 days (maybe more from the UK) to get your repaired module back. Do you leave it at the shop with the brake lines off,? Or do you pay labor to have them attached so you can drive, then go through the same removal and attach when you get the module back?

the module can be removed without removing the modulator. It is not easy and it's a tight fit to get your hands down there, especially near the exhaust so do it when the engine is cold. The trick is to loosen the mounts of the modulator and move it slightly (brake lines allow some movement). Doing it this way, allows you to drive the car while waiting for the repaired module to come back.

It can be done. I did it and I'm a fat, 72 yr old guy. Once reinstalled, I haven't had a warning light in 7 months.
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Old 10-16-2017, 06:52 PM
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I read your post again and picked out a few other terms. Guest guessing but handing it over to a "breaker" is what we call a "junk yard', right? I don't know what you meant by "MOT" I also don't know if the "L" next to a figure is a pound or a Euro?
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Old 10-16-2017, 07:12 PM
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Who did the rear brakes?
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Old 10-16-2017, 09:32 PM
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Scan tells you if module is defective. Simple. OP also said it was scanned but we don’t have any info. Or, throw parts and $$$ at it with dice rolls. Many more possible variables too than ones mentioned thus far, including wheel sensors, bad wiring in back upstream from sensors, bad wiring below ABS unit area in harness. Sometimes even just a crap battery, more so if a secondary issue like the pad wear has not been set correctly. Scan helps sort reality from speculation.

MOT reference is about getting an inspection in order to renew registration. Mostly we think of smog inspection, but some states are more and some countries pretty comprehensive.
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Old 10-16-2017, 10:40 PM
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I’m an English native so will translate a couple of terms:

The “L” is actually a “£” which is a pound sign and the symbol for Great British Pounds (GBP), like $ is the symbol for Dollars (not necessarily USD though!)

“Breakers” is short for breakers yard, aka junk yard.

Hand brake means parking or emergency brake.

MOT is short for “Ministry of Transport” Test which is an annual vehicle safety, emissions and road worthiness inspection required by UK law. Similar to emissions/smog tests in the USA but much stricter and with a focus on vehicle condition and safety. I estimate 50% of vehicles on US roads would fail an MOT test, so lackadaisical is the average US motorist with respect to the safety and condition of their vehicles.

Last edited by dvs_dave; 10-16-2017 at 10:42 PM.
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Old 10-16-2017, 11:12 PM
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Anyway, if you can post scan results, it will help at least rule some items out. A faulty ABS module is a possibility, but that’s kind of the nuclear option at this stage. There are many other much simpler options to explore beforehand.
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Old 10-17-2017, 06:53 AM
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Scan will tell you the speed sensor signal is missing. It will not tell you why it is missing or whether due to a bad sensor, hub ring, wires or the module itself. If I have a scratchy throat, tickle in my breath, etc, I know from experience I'm getting a cold. There is no need to get an MRI, CAT (or DOG) scan and 90% of the time even go to a doctor.

I am not marketing for the guy who fixes ABS modules. However, he has seen enough failed Modules to know there is a common problem in the modules due to the contact welds. My own experience with module fails both in my wife's 98 and my 05 plus a few (50+) of driving, common sense and automobile knowledge tell me this is a major cause and affect outcome. If I were a betting man and AW could legally set up a wagering system, my bet would be on Mickmellors final repair to be as I have described.

As a final observation, Mickmellors post indicated that he did indeed have it scanned (by a "main" dealer) and it was not definitive, requiring more "exploratory" work. Perhaps that would include completely unwrapping bundle of wires in the loom and visually inspect everyone and check for continuity. Obviously at a dealer that's going to me a lot of bucks (or "L"s)

I hope we hear back from him as to a final solution.
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Old 10-17-2017, 11:39 AM
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Originally Posted by audijim113 View Post
Scan will tell you the speed sensor signal is missing. It will not tell you why it is missing or whether due to a bad sensor, hub ring, wires or the module itself. If I have a scratchy throat, tickle in my breath, etc, I know from experience I'm getting a cold. There is no need to get an MRI, CAT (or DOG) scan and 90% of the time even go to a doctor.

I am not marketing for the guy who fixes ABS modules. However, he has seen enough failed Modules to know there is a common problem in the modules due to the contact welds. My own experience with module fails both in my wife's 98 and my 05 plus a few (50+) of driving, common sense and automobile knowledge tell me this is a major cause and affect outcome. If I were a betting man and AW could legally set up a wagering system, my bet would be on Mickmellors final repair to be as I have described.

As a final observation, Mickmellors post indicated that he did indeed have it scanned (by a "main" dealer) and it was not definitive, requiring more "exploratory" work. Perhaps that would include completely unwrapping bundle of wires in the loom and visually inspect everyone and check for continuity. Obviously at a dealer that's going to me a lot of bucks (or "L"s)

I hope we hear back from him as to a final solution.
or logic like you... You do need an MRI and DOG because the DR. is not sure... LOL.
Cheers,
Louis
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