ABS Module not responding in VAG-COM

For your 99 you need the cluster from a 99. No other year will work.

IMO if you can talk to other modules the cluster is not at fault. Want to confirm? Unplug the cluster.

-Jason

compu_85 said:

For your 99 you need the cluster from a 99. No other year will work.

IMO if you can talk to other modules the cluster is not at fault. Want to confirm? Unplug the cluster.

-Jason

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Is there a source for used clusters for this model year... or am I gonna have to throw away $600?

Joeviocoe said:

I can only connect to 01, 09, 15, and 17.
03, 16,and 19 I cannot!

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A 99.5 has no #09, so that can't be true. Are you maybe talking about #08?

03 should be the ABS, that was standard - so that you should have. #16 was the steering column control module which was only installed if you have a multi-function-steering-wheel, doubt you have one so take that off the list. #19 would also not be in a 99.5, so that shouldn't be an issue either I guess.

Sebastian said:

A 99.5 has no #09, so that can't be true. Are you maybe talking about #08?
03 should be the ABS, that was standard - so that you should have. #16 was the steering column control module which was only installed if you have a multi-function-steering-wheel, doubt you have one so take that off the list. #19 would also not be in a 99.5, so that shouldn't be an issue either I guess.

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I don't have a multifunction steering wheel.
So that means that the ABS (03) is the only module that I cannot connect to but should.

So you believe that the Instrument panel (K-line) is NOT to blame??

I will be heading through Orlando to Polk City this weekend. Could I be of assistance?

Lots of modules are on the K line. If the line got shorted nothing would work.

FWIW no 99.5 has a factory steering wheel with buttons.

-Jason

DanG144 said:

I will be heading through Orlando to Polk City this weekend. Could I be of assistance?

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I have a Vagcom to run this auto-scan. But the car is still in the shop until I pick it up tomorrow.

Unless you know of some other diagnostic procedure that you could do, I don't know what else to do, other than replace the Instrument Cluster and hope for the best.

compu_85 said:

Lots of modules are on the K line. If the line got shorted nothing would work.

FWIW no 99.5 has a factory steering wheel with buttons.

-Jason

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So what would the Instrument cluster have to do VAGCOM not being able to communicate with the ABS module? I know from frightening experience too, that the ABS does, in fact, NOT WORK. The ABS module is NOT the cause since it has been replaced by multiple units, and has been sent away for rebuild, the connections for communication, power, ground have all been tested.

And this problem started shortly after battery failure and replacement, and around the same time my TB slipped a gear tooth on my IP sprocket, causing a non-start (now fixed). Intermittent at first, but now consistent.

I am not real big on Easter Egg hunts. But it is not my money or time, either.

It seems to me that we should ensure continuity on the communication lines. Trust but verify.
I can try to pick out some test points in my Bentley, though sometimes the electrical drawings foul me up.

That post was written before I could read the post above it. Just ignore it, I guess.
The ABS module is not functioning. That changes things from a communication issue .

DanG144 said:

That post was written before I could read the post above it. Just ignore it, I guess.
The ABS module is not functioning. That changes things from a communication issue .

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I thought that if the ECU and the ABS could not talk, the ABS would not function. Would that not be considered a "communications problem"??

Either way... I already paid a lot of money to have the continuity checks of the communication lines.

compu_85 said:

On a 99.5 the cluster shouldn't have anything to do with the ABS module.

-Jason

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If I am reading my Bentley correctly (and that is a big IF) then in figure 9/5 it does show a connection between the K line, the ABS module and "J285 Control Module with indicator unit in instrument panel Insert." And there is a wire junction A76 where they all tie together. I think you are correct that if the K line was stuck you could not communicate with anything, but what if the one wire to the ABS from the K line had come loose? (I know Joe has paid to have this checked.)

There is a signal type wire from the ABS T25/16 to the cluster T32/19 that could also be an impact. figure 9/5.

There are also two wires that I have not run down yet, that seem to go to the instrument harness on figure 9/3 to connections A133 and A134.

I would go with Jason, and if I was troubleshooting, I would unplug the 32 pin connector on the instrument cluster.

I would also try removing the battery leads and shorting the positive and negative leads together for about 20 seconds. It actually makes a difference in a few cases.

If the ECU could not communicate with the ABS, then it should give an error code for that, correct? (I am not sure about this vehicle, but on others you can sometimes see an error message on both sides ABS says it cannot communicate with the ECu and the ECU says it cannot communicate with the ABS.

And the AUTO SCAN could potentially help a lot, show the coding, etc.

My ignorance is vast, I am always willing to learn. I just thought I would bring this up.

Thanks Dan... I will try the Battery Leads thing and run Auto-Scan tomorrow.

Thanks everyone for you help.

2x. Be sure the module is getting power.

Yes, the cluster has some connections to the ABS module. They share the common K line, and if your 99 is like mine there are probably CANbus wires going to the cluster too (though they are unused at the cluster). The ABS will work just fine without the engine computer talking to it. Won't even trip a fault light, though it will trip a fault code for no communications.

Note that the light in the cluster is normally ON, the abs unit turns it OFF.

Have you removed the plug from the ABS unit and verified that power is there on all the pins where it belongs? I can look that up if you don't have a wiring diagram.

-Jason

compu_85 said:

2x. Be sure the module is getting power.

-Jason

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When I first had the problem, I took it to ESwanson, who made sure the module got power. It checked out, so I got a replacement ABS Module (refurb). Didn't work. So we thought that maybe the refurb was bad, so we sent it back and got another. Still nothing.

Took it to a VW specialist shop. Of course, the first thing was to check power and grounding. They didn't trust the previous 3 modules, so they sent mine to Module Masters and had it rebuilt. Got it back, and nothing. Rechecked the power, and checked the entire harness, checking continuity.

I know for a fact that the ABS does not work when wheels lock up. I have to pump the brakes manually to get good stopping distance.

The VW tech said that, in my model, the Instrument cluster is the "gateway" and that it may be the cause of non-communication. Are you saying this is impossible? Or just unlikely?

Thanks for everything, your insight is very helpful.

On a 2000 the instrument cluster does have the CAN Gateway, which is quite important. Your 99.5 does not.

There should be power coming in on multiple pins. I'll take a look at the manual tomorrow and let you know which ones should be hot. Something you could do now is check the big fuses on the top of the battery.

-Jason

compu_85 said:

Something you could do now is check the big fuses on the top of the battery.

-Jason

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Those were checked and rechecked.

compu_85 said:

On a 2000 the instrument cluster does have the CAN Gateway, which is quite important. Your 99.5 does not.

-Jason

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Would it matter if the cluster had been changed in the past, perhaps from a different model year? I bought this car used. And this odometer reads over 230k miles.

Because it sounds to me like you're saying that the cluster could not affect the operation of the ABS system. And as long as the power is good, the module is good, the wheel sensor are good, then the ABS should actuate when needed (when a wheel locks up from braking) ???

Would it matter that the ECU was swapped in 2007 for another ECU with a Rocketchip flash. It did run fine for over a year. But what I am asking is, could some incompatibility be throwing off our troubleshooting efforts?

No, wouldn't matter if the cluster were changed in the past. Only a 99.5 cluster works in a 99.5. The ECU can not disable the ABS. The only thing it can do is make the ABS cranky and throw a powertrain data bus missing error code.

I can't think of any way the cluster could affect JUST the abs computer. But why not pull the cluster and check, it's super easy to do. Remove the trim above the steering column (pull straight forward) to reveal the 2 screws that hold the cluster in place. Flip the lever on the connectors to remove them. The 2 plugs are color coded so you can't mix them up.

-Jason

This is similar problem I had in mine old 99.5 vw jetta before I sold it, had abs light solid, and blinking brake light, I couldn't connect with ABS module at all using original vagcom, I wasted money on everything that everyone was pointing me to do, I had abs module fixed , didn't work, bought used unit from junk yard and same issue, someone suggested cluster was an issue, replaced that nothing helped, then I got help from friend that had same model and year and we swapped parts to test it, first we tested the cluster abs light and brake light was there, then we swapped with his abs module, lights on dash were gone, at that time back in 2001 only option for me was to buy new abs from dealer, bought it installed it and problem solved.
I have strong feeling that abs module faulty, even thou module master fixed they don't run it or test it if it communicates or if even responds , someone told me that it is possible that abs eeprom module got faulty, some power surge happened and damage the abs eeprom module and file got erase possible I don't know, if your cluster was faulty you would have more then abs light on and brake like on, usually all the lights light up if cluster fails.

Try to contact local junk yards and see if you can find these parts and at least you should able to return them in case they don't work

I have the original ABS only module from my 99.5 somewhere if you need it...

vwtdi04 said:

Try to contact local junk yards and see if you can find these parts and at least you should able to return them in case they don't work

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I have tried 3 modules already. 2 from Michael's auto salvage in Orlando, and one rebuilt by Module Masters.

I don't know anybody willing to remove their ABS module to test swap.

Is it possible the ABS Modules I have received are simply incompatible with my 99.5?? And that my original (working before it broke) module has been returned for a core charge?

Auto part dealers often don't understand the 99.5 year for VW and simply catalog modules by A3 or A4 or A5

Can anybody give me the EXACT P/N for the ABS module that works with my 99.5?

Any Mk20 ABS module should work. Even one from a late Mk3 without canbus.

I really think you have broken wire(s) somewhere. And there aren't many on that abs system. Probably around 15 if my guesstimate is correct.

-Jason

compu_85 said:

Any Mk20 ABS module should work. Even one from a late Mk3 without canbus.

I really think you have broken wire(s) somewhere. And there aren't many on that abs system. Probably around 15 if my guesstimate is correct.

-Jason

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It does seem like there are only a finite amount of possibilities. I am hearing the same stuff over and over.

Replace the module - Done 3x
Check the power to the module - Done 2x
Check the fuses on top of the battery - Done 3x
Check all the communications lines - Done 1x (very labor intensive)

It would seem "replace Instrument Cluster" is not part of the troubleshooting system for my car. Yet I have been told that it is the source of my trouble. And that vwtdi04 was also told the same.

Am I missing anything?

if you got different module, from different year , you be able to communicate with vagcom but you won't be able to change or reprogram because might not be compatible with your car existing modules, I know these days they rarely repair your existing module and they ship presumably same one that they repaired it, so it is hard to say

try to find used cluster from 99.5 vw , then you can test it when power on if the light is still present at least you can eliminate

another thing you can do, take your cluster apart and look at the circuit board for possible burn out traces , it is easy to spot,

I can drop by with yet another spare ABS module, from an 01, but I doubt that would help. I will throw it in the car. Call me if you want me to come by.

While I felt that the ABS should have most of its functionality without ECU input, or communication, I was not positive.

But my money would be on faulty power supply or ground wiring. Perhaps failing under load - able to pass enough voltage for a multimeter to show 12 volts, but dropping drastically when it is loaded.

I would clean the grounds, not just check them.
I would consider disassembly of the fuse block above the battery. They sometimes get badly corroded on the inside.
I would put a pin through the supply wiring (all 4 power sources) and check that the voltage did not drop when it was plugged in.

DanG144 said:

I can drop by with yet another spare ABS module, from an 01, but I doubt that would help. I will throw it in the car. Call me if you want me to come by.

While I felt that the ABS should have most of its functionality without ECU input, or communication, I was not positive.

But my money would be on faulty power supply or ground wiring. Perhaps failing under load - able to pass enough voltage for a multimeter to show 12 volts, but dropping drastically when it is loaded.

I would clean the grounds, not just check them.
I would consider disassembly of the fuse block above the battery. They sometimes get badly corroded on the inside.
I would put a pin through the supply wiring (all 4 power sources) and check that the voltage did not drop when it was plugged in.

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Curious....

Exactly WHEN IN THE DRIVE CYCLE do folks with bad ABS modules (or even bad power to the module) get the ABS light solid on, brake light blinking, and 3 tones???

I can start the car just fine, the lights will NOT yet come on nor will it beep.... UNTIL I start moving forward a few feet. If I am backing up in reverse, it will not happen... only when I move forward a few feet.

Is that expected? Or could this be a symptom?

yes,
When you power up the car, both light come on, abs solid, brake flashing, as soon you put to drive or reverse it starts to beep 3 times and then just brake light continue blinking
You can still drive the car, just your ABS will not kicking for you when you needed, if you don't have money, start saving , when driving just keep distance so in case stopping you have time to react

here is a abs pump on ebay http://cgi.ebay.com/ebaymotors/ABS-...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

You can buy this one and he has return policy, in case doesn't work return it

vwtdi04 said:

yes,
When you power up the car, both light come on, abs solid, brake flashing, as soon you put to drive or reverse it starts to beep 3 times and then just brake light continue blinking
You can still drive the car, just your ABS will not kicking for you when you needed, if you don't have money, start saving , when driving just keep distance so in case stopping you have time to react

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It does not happen that way for me. No lights, no beeps on startup. Nothing when reversing either. Only when I roll forwards a few feet.