I have been having some problems with my ABS pump lately.

To start off with I had a calliper hanging up on the right side. I changed out the caliper and the break lines and it still was hanging up, however the ABS was working great. I would get the moan when I started moving and it would engage whenever it was supposed to. I finally gave up trying to find the problem with the caliper and took it into a mechanic. They said that they though the ABS pump was acting up, and it would be $1500.00 for a new one.

I thought this was an outragious price, so I checked on ebay and found one for $40.00 that was guaranteed for 30 days, so I bought it.

Once I had the new one installed I checked to see if the calliper was hanging up, and it wasn't! So the problem was fixed, but a new problem showed up. Now the ABS does not work. I changed out all of the relays and even the wiring harness and even cleaned all the wheel sensors. I also found a cheap ECBM on ebay and got that and installed it. None of these things worked, so I figured I had a bad pump. I called the guy I bought it from and he sent me another one. I put this one in and the exact same thing happens.

When I turn the car on I can hear clicking coming from the ABS pump's relays, and everything seems fine. Then when I move and the self test is supposed to start all's I get is an anti-lock light that stays on until I turn off the car.

I have been told that these pumps are majorly over engineered, so they very rarely have problems, so it seems to me that having a total of 3 bad pumps is just impossible.

Anyone have any ideas?

Thanks in advance,
Steve

 

The ABS can't make only one caliper hang up! You have a defective caliper or caliper piston seal or some other problem with the caliper mount, pad guide pins, pad clips, etc. I recommend that you look at the caliper inside and out. Put your original ABS pump back!

 

When driving, what symptoms lead you to the hanging caliper? Odd that it would still hang after a new caliper is installed.
I don’t have my factory service manual in front of me, but Isn’t there an ABS control module somewhere?
:cheers:

 

When the caliper was hanging I would get a severe pull while driving it... I then had the car aligned after we did some suspension work and they said the caliper was hanging. I then tested it myself by lifting the car up spinning the tire and applying the brakes. It would stop the wheel, but would not release it until after about a minute. After we replaced the caliper we tested it again and figured it was a flapping brake line, so we replaced those.

There is an EBCM module in the back that I have replaced. that didn't seem to make a difference, still had the same problem.

I am thinking it is time to try and find someone who has the equipment to diagnose the problem.

I forgot to mention that I had to put my old pump back in to get the new one from the guy I bought it from. When I put my old pump back in the caliper started to hang up again...

Thanks!
Steve

 

K, im to lazzy to run out and look at mine, but can the ABS brake each wheel individually, or only the front and back independently?

I ask because you should be able to use T-fittings to bypass the pump all together.
Just for testing purposes, this way the pump is out of the loop all together or you could disconnect the power, and connectors to the pump, but im not sure how the pump would react to this???

 

I suspect you are dealing with an 88, but which relays have you changed? There are 3, a motor relay, solenoid relay both on top of the motor and a power relay to the side of the ECU. Now with the light going of after start up I would suspect the power relay is working and seeing how the light comes on only after you start driving, I would suspect you may have a problem with either one or more wheel speed sensors, or motor or motor relay. I suspect it either tried to do a motor test and failed or one or more speed sensors did not get picked up by the ECU. I would start with an ohm check of every sensor at the sensor then do the checks again at the ECU, that way you are able to check wiring and sensor. Another good test would be to get two Fluke meters and a pinout and do some sensor tests on the road testing Hz and A/C voltage you may find one now working at low speeds.

David Fulcher

 

The two front brakes are independent of each other, but the back brakes work together. I have completely unhooked the ABS pump, and the brakes work fine, but then I get the antilock light as soon as the car is powered on...

 

I have replaced all 3 relays with the relays out of the pump that was working. Two were under a clippy thing that was holding them down and one was inline of a few wires. I am not very skilled with electrical stuff, but I was thinking it could be a bad wheel sensor. I will probbably have to take it in to someone for all those tests...

Yes, it is an 88...

Thanks for your help!
Steve


[Modified by Steve_88, 5:27 PM 9/24/2003]

 

If you can get a hold of a simple digital volt ohm meter, just start with checking ohms at the sensors, they should all be real close to one and other.

David Fulcher

 

Steve, its possible your ABS is fine. Check for a loose wheelbearing. If one gets sloppy it can open the gap at the abs sensor, turn on the light. Just a guess but it costs nothing to check.