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woolveren
10-27-2011, 10:36 AM
Hello,

I was going for lunch today and I stopped the car(98 Audi A4 1.8t, manual) at a traffic signal near an uphill. For a moment, something caught my attention and I forgot to apply brakes. The car was going backwards and suddenly I came to the reality and pressed the brake pedal really hard.

All of a sudden, the brake light started flashing and soon ABS light came on. The lights were there for about 45 seconds and went away when I pressed the pedal again.

Does this indicates ABS malfunctioning or something? This is the first time I am getting these kind of warnings. (Replaced 2 rear sensors 5 months before, brake pads have 50% more on it).

walky_talky20
10-27-2011, 10:55 AM
It could be speed sensor related, so you should check the codes on the module (and in the instrument cluster) as a first step.

I'd say that the vibration from the ABS pump probably just rattled the communication wire loose inside the module for minute before it regained communication. PM k0mpresd and he'll help you get that thing repaired if that's the case.

cory.smith
10-27-2011, 11:43 AM
Keep us (me) posted on the solution if you find one. I've had no ABS for I don't know how long. I'm thinking I've got a broken tone ring on my passenger axle, but I won't really know until I pull everything apart this winter.

-Cory

Seerlah
10-27-2011, 12:11 PM
If the ABS light is no longer there, don't worry about it. The ABS light resets itself once the issue gets corrected. If you are curious as to what happened, Vag Com will tell you (should be listed when you do the full scan).

woolveren
10-27-2011, 04:46 PM
BUMP!!

The light came back while I was driving back home. But this time, only the brake light came with 3 Beeps and stayed there for 10 seconds or something.

Again, same case. I was trying to pass a signal before it turns red, but didn't go through and applied a SUDDEN BRAKE.

And the brake light came with 3 beeps, pressed the pedal again and it went out. I drove another 10 miles through high way and applied sudden brake lot of times and no light came. I tried all possible sudden brakes before reaching home and no lights came.

So what does this mean? A loose connection or a speed sensor? ( I didn't change front wheel speed sensors last time. May be that's causing this?)

walky_talky20
10-27-2011, 05:33 PM
It could be that the brake fluid reservoir is *just* barely at the lower threshold. Thus, any significant g forces to the car (such as during heavy braking, trust me your car doesn't have enough power to do anything "significant" under acceleration, lol) will cause the fluid in the reservoir to run to one side, lowering the effective float level and causing the BRAKE! warning due to low fluid level.

It is normal for the fluid level to decrease over time as the brake pads wear. Actually, the system is designed so that the amount of fluid displaced by running brake pads from new to zero is enough to trip the light before the pads are able to get any metal to metal action with the rotors. So it could be that your pads are significantly worn and this is actually just working as designed. Check fluid level, and then (if low) check brake pad thickness as well.

Of course this theory does not explain the ABS light, but I am choosing to ignore that symptom for now...because I'm allowed to do that.

woolveren
10-27-2011, 05:48 PM
Actually i forgot to mention couple of things.

1. I already checked the Brake fluid level and it's perfectly at the Maximum point.

2. Two weeks ago I drove the car with Hand Brakes ON ( Not fully engaged, half way around). But it was a very short distance, from home to highway(about 0.5 miles) and another 0.5 miles on highway. Then I saw the BRAKE light and released the hand brake. I was in a hurry and didn't notice until I felt some loss of power kind of feeling..LOL

One month before i checked the brake pads and mechanic said I still have 50% on it. So driving 1 mile with hand brake cause the brake pad to wear that fast?

walky_talky20
10-27-2011, 05:52 PM
No I should think not. Thanks for shooting down my totally awesome theory and stuff. lol

I'd be checking the ABS module codes at this point. And Instrument cluster codes as well. And logging wheel speed sensor values a bit perhaps.

woolveren
10-28-2011, 07:43 AM
Yeah, I guess its something with ABS module or wheel speed sensor. I was researching about this issue and I found out something useful related to my problem.

1. The ABS light came flashing(no beeps) and after some seconds Brake light also started flashing with no beeps. The 3 beeps came the after a while ( maybe some 20 seconds later).

This condition usually indicates some fault with ABS module or a connection problem between module and the sensor. If its a brake pad or a fluid related issue, most of the time only Brake lights comes with three beeps.

Also, I forgot to mention one more thing. For the last one month, my brake pedal makes strange noises if I apply brake while turning and reversing the car in parking lot. Also I feel like something is pushing my brake pedal back and some strange noises (like stretching of steel wires..). Does this accounts for any of the problem related to ABS module?

Also, when I bought the car (2yrs ago) ABS light was ON and the previous owner said it was there for the last one year. After me buying, I didn't try to fix the ABS issue for year(I know how to pump brake without ABS.:)) and the light was there all the time. Later, I took it to the mechanic and he said the car is missing(somebody forgot to put it back after brake repair or something..LOL) rear wheel ABS sensors. I fixed it for around $150 and after that ABS started working absolutely fine. No flashing or NO yellow lights. It's been almost 8 months after the sensor repair and yesterday was the first time I saw that YELLOW light blinking again..

So my point here is, the ABS light was ON continuously for about 2 years before putting the sensors. Does this too affects the life of the module?

walky_talky20
10-28-2011, 07:50 AM
Nope, module should be fine.

You are correct: module fault or sensor signaling issue. Due to the BRAKE light and beeping, I'm leaning more toward a module issue but I'd be checking the codes and logging the wheel speeds first before I bought anything.

Seerlah
10-28-2011, 10:18 AM
FWIW, I had my ABS light come on randomly after replacing a sensor that the PO cut and splice together (did not notice this till later). Bought a used OEM replacement for $25 shipped on ebay, and that is when the light would randomly come on. Scanned with Vag Com, and it said there was a short in my wiring for my front passenger's side ABS sensor. I simply disconected it, sprayed the connectors with electrical parts cleaner, and has been fine ever since (no random ABS light).

Justin@FCP
10-28-2011, 10:49 AM
FWIW, I had my ABS light come on randomly after replacing a sensor that the PO cut and splice together (did not notice this till later). Bought a used OEM replacement for $25 shipped on ebay, and that is when the light would randomly come on. Scanned with Vag Com, and it said there was a short in my wiring for my front passenger's side ABS sensor. I simply disconected it, sprayed the connectors with electrical parts cleaner, and has been fine ever since (no random ABS light).

I had a similar issue with my B5.5 Passat. Took me a little bit of chasing wires down, but I found the short, and no no more ABS light. [:)]

cory.smith
10-28-2011, 10:52 AM
Also, I forgot to mention one more thing. For the last one month, my brake pedal makes strange noises if I apply brake while turning and reversing the car in parking lot. Also I feel like something is pushing my brake pedal back and some strange noises (like stretching of steel wires..). Does this accounts for any of the problem related to ABS module?

I am 100% having this symptom. I don't know what it is. I've never heard anything like it. My thought was that I've got a broken tone ring, which messes up the ABS. ABS makes that *TWANGGGG* sound, the pedal moves slightly, and then the ABS light comes on.

It will only do it moving forward, and it happens very early in moving. Like, say 2 rotations of the tires. It will not do it until moving forward. IE: I back out of the driveway, doesn't happen. Then, forward and Light. It only *Twangs* if you apply brakes after starting up and moving forward and within, say, 10 feet of where you parked.

Quite possibly the weirdest issue ever, which is why I've never addressed it.

-Cory

walky_talky20
10-28-2011, 12:17 PM
Mine makes a twang sound, pretty sure it does it like every time I start the car. No ABS light. It only does it after moving forward a bit, after a certain speed. Maybe there is more to it than that. My understanding was that it was merely priming the ABS pump, which is a very normal activity. If you've ever driven an older Dodge Caravan with ABS, you will be very familiar with this sound as they prime often and very loudly.

I notice that at night, the vibration from this pump activity is enough to make my factory HID's go "fuzzy" for a second. Nifty.

My guess for your twang/light activity is that this "speed threshold" for priming the pump is the same as the "test threshold" for the ABS wheel speed sensor signals. In other words, both things happen at each startup after moving forward a bit - it primes the pump and makes sure the wheel speed sensor are all up to snuff. So you get a TWANG, just as it decides one of your wheel speeds is "whack". This is my theory.

A1 A2 German
10-28-2011, 01:05 PM
Didn't read the thread so if it's been mentioned.....just a quick response to the brake light.

Mine came on, tired everything, all it was............low on brake fluid, added a little and gone.

woolveren
10-28-2011, 04:46 PM
Seems like the problem is getting worse. The brake light with 3 beeps came thrice while driving to work. The ABS flashing is random.

ABS light, along with the brake light and 3 beeps came once.

Other two times, only brake light with 3 beeps came.

I dont understand why it is behaving like this randomnly...LOL.

Any suggestions??

Seerlah
10-28-2011, 04:50 PM
Scan your ABS module and it will tell you why it's going off (there is an ABS scan during a full scan). Till then, you will basically be left guessing.

If you post in the regional section, I am sure there is someone who will be willing to let you use their Vag Com to figure this issue out. This community is really helpfull when it comes to things like that.

http://www.audizine.com/forum/forumdisplay.php/20-Mid-West

Well, just noticed that section does not have as much traffic as my regional section. But give it a try anyways.

woolveren
11-02-2011, 01:32 PM
Okay, I took the car to my trusted local mechanic today.

He figured out that there is an electrical connection problem between the ABS module and the LCD Cluster. He said all the sensors are fine and it is this problem causing the ABS Light to come on along with the brake light.

I'm having kind of a strong feeling that what he found out is true. Because, I replaced the LCD cluster one month ago with another one. But both clusters were having the same model number and everything. Not a single digit was different. There were no ABS lights or anything until last week.

So do you think whether it is something wrong with the replacement cluster? Do I need to put back the old one?

The one I replaced has lower miles(140k) and my original one has 212k. (The reason behind replacing is I got it with working center LCD screen for a cheap price on ebay).


In my other thread, you might have noticed about a CEL 17544. For this one, he found out a cracked brake hose causing vacuum leak and need to replace that complete kit.

I'm just asking, will this issue trigger the ABS and Brake light? Since the problem is related to brake, I'm curious..:)

Thanks

Seerlah
11-02-2011, 01:45 PM
I generally don't trust mechanics (pardon if I offended any mechanics with that remark). My personal mechanic is a good 25-30 min drive from me.

woolveren
11-03-2011, 07:32 AM
@ Seerlah

Yeah, i understood...:)