ABS Light After Brake Job, VAG-COM: Hydraulic Pump Implausible Signal Intermittent

Hi guys, had my car for almost 4 years now, but still sort of a NOOB when it comes to some things. Hope you can help!

I did a full brake job with new pads and rotors and a bleed at a small local TDI club meet last month. The pedal felt kinda soft after leaving, but the brakes grabbed pretty well so I wasn't concerned.

About 50-75 miles and two days later the ABS light comes on while driving around town. Now it comes on within a minute of moving the car every single time I drive it. However, if I just sit there it will take much longer to come on.

I brought it back to the guy's house where we did the brake job and we scanned it and VAG-COM said, "ABS Hydraulic Pump, Implausible Signal - Intermittent." We were recommended to bleed the ABS pump, following the Ross Tech procedure. However, the procedure on Ross-Tech's site doesn't say what to do after you push "Go!" and the on-screen instructions were not very helpful, so after a while it would just say "N/A" all the way across...

After searching, it seems like I may not have been holding the pedal down long enough??? I saw another thread that said you have to hold it down for a while until the pump comes on.

Do you think that bleeding the ABS pump should take care of this issue?? Is there some way to check the signal other than Vag-COM???

Also, since my car is a 2002 model year and some of them had a recall on ABS pumps, I asked the dealer about the date of manufacture and they told me it was 10/2001, which puts me just outside of the recall period. But couldn't they still have been using the same part numbers for another month??

i have just replaced my pump/module for a similar reason. my fault code was 00004.

I would try bleeding it as per the procedure, but it didn't help me.

Dang. I don't know the fault code, but I'll double check.

I've got an extended warranty, and the hydraulic pump isn't covered.

Why do you suppose the pump going bad might coincide with a brake job??
Yatzee, how was your situation similar? Did yours go bad after a brake job as well? How much was the new pump?

When depressing the caliper pistons, if the bleed screws weren't open enough, could fluid have possibly gone backwards through the system damaging the ABS pump??

I started getting the codes after a non-vw garage replaced my rear calipers. They messed up, and didn't bleed it properly. I had to get it rebled. I lived with the light on and off for months until came on permanently. Then i got a used pump and changed it. Dealer price was over $800

Hmm... the pedal is still kinda soft, even after bleeding them, but they grab just fine.

Does the ABS just come out? Or does it require major modification to make an ABS car into a non-ABS one? If its going to be too expensive, I might as well just remove the system altogether.

I haven't tried the ABS to see if its really not functioning or not.

Also, since the signal said intermittent, maybe it could just be a wiring issue?? Anyone had a problem with the wiring to these pumps?

Bump, nothing else for me guys??

if the abs light is on, the abs is inactive. I would just install a used part, once you've concluded that bleeding the system won't repair it. You'll also want to take a look at the connections on top of the battery for corrosion and the main connector onto the module.

FirstOrbit84 said:

I brought it back to the guy's house where we did the brake job and we scanned it and VAG-COM said, "ABS Hydraulic Pump, Implausible Signal - Intermittent." We were recommended to bleed the ABS pump, following the Ross Tech procedure. However, the procedure on Ross-Tech's site doesn't say what to do after you push "Go!" and the on-screen instructions were not very helpful, so after a while it would just say "N/A" all the way across...

After searching, it seems like I may not have been holding the pedal down long enough??? I saw another thread that said you have to hold it down for a while until the pump comes on.

Click to expand...

I did the ABS pump bleed procedure after doing my ASR/ESP upgrade. I don't recall the exact messages that come up on the screen, but I can give you the general idea.

Once you hit GO! the screen says to depress pedal and hold
You have to press the pedal HARD. Seriously, pound the pedal like you're about to drive over a cliff.

The pedal will drop, the pump runs briefly, then the pedal comes back up.

Take your foot off the pedal.

I think it wants you to click on OK at this point.

The screen says something like FR/FL bleed screw OPEN.

Open both front bleed screws.

Click on OK (or DONE or something like that).

Pump runs for 10 seconds, pushing fluid out of the bleeders into your catch jars.

Screen says something like: Depr. pedal 10X; bleed screw CLOSED

Depress pedal firmly 10 times, then close both bleed screws.

Click OK.

You then go back to depress pedal and hold and repeat the cycle. It goes on for like 10 or 15 cycles. I never got a finished message, I just did it until the screen said N/A.

It is easier with two people. One in the car pressing the pedal and working Vag-Com, the other outside opening and closing bleeders and making sure the master cylinder doesn't run dry (very important!).

RacerTodd said:

I did the ABS pump bleed procedure after doing my ASR/ESP upgrade. I don't recall the exact messages that come up on the screen, but I can give you the general idea.

Once you hit GO! the screen says to depress pedal and hold
You have to press the pedal HARD. Seriously, pound the pedal like you're about to drive over a cliff.

The pedal will drop, the pump runs briefly, then the pedal comes back up.

Take your foot off the pedal.

I think it wants you to click on OK at this point.

The screen says something like FR/FL bleed screw OPEN.

Open both front bleed screws.

Click on OK (or DONE or something like that).

Pump runs for 10 seconds, pushing fluid out of the bleeders into your catch jars.

Screen says something like: Depr. pedal 10X; bleed screw CLOSED

Depress pedal firmly 10 times, then close both bleed screws.

Click OK.

You then go back to depress pedal and hold and repeat the cycle. It goes on for like 10 or 15 cycles. I never got a finished message, I just did it until the screen said N/A.

It is easier with two people. One in the car pressing the pedal and working Vag-Com, the other outside opening and closing bleeders and making sure the master cylinder doesn't run dry (very important!).

Click to expand...

wow. thanks. i didn't understand it was that involved, and the on-screen instructions are practically useless. you should work for Ross-Tech.

why is it SO important to have all 4 wheels off the ground like everyone says, if the procedure is just for the front bleeders?

FirstOrbit84 said:

wow. thanks. i didn't understand it was that involved, and the on-screen instructions are practically useless. you should work for Ross-Tech.

Click to expand...

When I did this I only had a procedure that someone posted for the VAG1552 machine, but that gave me the general idea of what to expect and so I was able to interpret the somewhat cryptic messages Vag-Com uses.

FirstOrbit84 said:

why is it SO important to have all 4 wheels off the ground like everyone says, if the procedure is just for the front bleeders?

Click to expand...

I haven't seen any indication in my VW manual that you have to have all four wheels off the ground when bleeding the pump. I didn't and it seemed to work fine.

ok cool, thanks for the info. i'll give it another shot this week