ABS Pump continuously running

[pharpe]

I just got a 2002 Yukon and I'm trying to sort out a few issues. I have an ABS light and the Traction light on. (ABS does not work) I ran my Android ODB2 scanner and got no related codes so I took it to a shop to see if a better scanner might see something. They tried two different scanners and found nothing. I've read about bad grounds or wiring being an issue so I got under there and investigated. Turns out the wiring harness was disconnected from the ABS pump. When I plugged it in the pump started running really loud and continuously. See video I shot

Even with the pump plugged in and continuously running I did not see any codes. I didn't leave it like that long though.

Does this mean a bad ABS Control module?

 

[rockola1971]

The ABS pump is fed directly from a fuse. It is given a ground from the EBCM (Electronic Brake Control Module). I dont know if that ground switch is a internal relay or a transistor. It is quite possible that if a relay the contacts are welded together and giving a constant ground to the pump. Also possible a transistor is shorted if the switch is electronic.

 

[pharpe]

The ABS pump is fed directly from a fuse. It is given a ground from the EBCM (Electronic Brake Control Module). I don't know if that ground switch is a internal relay or a transistor. It is quite possible that if a relay the contacts are welded together and giving a constant ground to the pump. Also possible a transistor is shorted if the switch is electronic.

Gotcha. So most likely something internal to the EBCM is causing this then? I guess I will pull that out and see check it.

 

[swathdiver]

Gotcha. So most likely something internal to the EBCM is causing this then? I guess I will pull that out and see check it.

It was common for the pumps in other GM cars around this generation to have bad solder joints in the EBCM that would turn the pump on like that. Used to be lots of youtube videos on how to fix them.

 

[rockola1971]

It was common for the pumps in other GM cars around this generation to have bad solder joints in the EBCM that would turn the pump on like that. Used to be lots of youtube videos on how to fix them.

Very possible. I would have to see the internal logic of the module to be able to rule out that possibility. I dont believe Ive ever seen an internal schematic for one. Just a very basic block diagram.

 

[swathdiver]

Very possible. I would have to see the internal logic of the module to be able to rule out that possibility. I dont believe Ive ever seen an internal schematic for one. Just a very basic block diagram.

Me neither, just guys opening them up and resoldering joints on youtube.

 

[Fless]

A run-of-the-mill scanner will not read the ABS codes. With the pump unplugged you should have, at the least, an ABS circuit code (which is likely why the ABS light is on). You'll need a scanner capable of reading the ABS codes, if you want to see them.

 

[DBacon]

Please use a jack stand, not just a floor jack. You are too valuable to this forum...
-Dave