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HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 Fuse

Posted: Sat Jun 11, 2016 10:43 am
by PeePeeV
Hello,

I have just purchased a PPV from out of state, and have a bit of an issue. When it came to me, the ABS/Stabilitrak lights were on, and the underhood F5 fuse was blown. After replacing the fuse, the car would drive normally under regular driving circumstances. When under heavy load (wide open throttle), however, the car will blow the F5 fuse, and the lights reappear, presumably because of the loss of connection to the ABS valves. Additionally, I should mention, that although I have never driven a PPV before, the brake pedal feels like there is no pressure for the first inch or so of travel then becomes very stiff.

What could this problem be? ABS module? EBCM? Shoddy removal of upfitting? all opinions and knowledge are appreciated. Thanks!

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 F

Posted: Sat Jun 11, 2016 2:02 pm
by smwalker
Here is a link to a description of the ABS system: ABS Description

Would seem to me when the system does a self test it is OK but when you floor it you are activating the traction control and something is causing resistance on the motors enough to blow the fuse. I would think if it was just an electrical short it would blow during the self test. But not to sure. Do you have a scanner to see if any ABS codes are present?

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 F

Posted: Sat Jun 11, 2016 3:23 pm
by PeePeeV
I just used a Solus to pull codes, when the fuse was blown it would not communicate with the ABS module whatsoever. After the fuse was replaced, the solus was able to communicate with the ABS system, no codes were present. In the transmission section, code U0121 was present. To test the ABS system, i used the solus to cycle the ABS , which caused a slew of lights on the dash and a blown fuse yet again.

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 F

Posted: Sat Jun 11, 2016 5:53 pm
by smwalker
Well Think you are in for a new Electronic Brake control module. Nothing is serviceable inside them as far as I can read.

The fuse you are blowing is the ABS VLV circuit and it is just a wire going to the module. What's actually blowing the fuse inside the module is anyone's guess. Here is the wiring diagram, but there is not a diagram for anything inside the module.

Image

Check around for ABS module re-builders in your area. At the shop I work at we just exchange them for rebuilt units. not sure how popular the one on the caprice is you may have to wait for them to go through it and replace any defective relays or circuits if they can at all. Cheaper than getting a new one from GM.

Then you may have to get the new module re flashed by a dealer using a tech2. I think that is what I read.

EDIT: And GM recommends replacing the entire unit as it seems taking the module off the valves can lead to trouble:

GM's Note: If the electronic brake control module (EBCM) or brake pressure modulator valve (BPMV) is to replaced under manufacturer's warranty, do not disassemble the EBCM/BPMV assembly. If the EBCM or BPMV is faulty, replace the EBCM/BPMV as an assembly.

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 F

Posted: Sat Jun 25, 2016 7:47 pm
by PeePeeV
Well, i think i might have a short instead of a bad ebcm. For a while, the car had no lights on, although the f5 fuse was blown. Then, upon replacong the fuse, the loghts lit again, but thos time the fuse did not blown. Not sure if this new info points more to a bad ebcm or a short.

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 F

Posted: Sat Jul 09, 2016 9:37 pm
by PeePeeV
UPDATE: For those who may have this problem in the future, It was a short. I found that the two wires shown on the wiring diagram above for the ABS motor and valves (red and orange respectively) had melted on the exhaust manifold and were shorting out. Spliced in an extra foot of wire and rerouted, problem has been solved.

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 F

Posted: Sat Jul 09, 2016 10:01 pm
by smwalker
THanks for the update. Could we get a picture of where it got into contact on the manifold? That would help future folks.

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 Fuse

Posted: Tue Nov 26, 2019 9:52 am
by Capeasy
I think I'm having the opposite problem. I cant disable the traction control . Pressing the button does nothing, which was fine a few weeks ago. I checked all the connections at the brakes. Not sure if it's a blown fuse or bad switch? Where do I start?
All these ponys and no way to unleash the beast lol.
I wish it was as easy as just pulling a fuse and completely turning it off like I've heard some Corvette owners have done.
Open to all suggestions.
Thanks

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 Fuse

Posted: Thu Nov 28, 2019 1:24 am
by Capeasy
Just spent 2 hrs troubleshooting everything and it was the darn switch went south, at the same time as the diff swap. Never even thought to look at the switch, kept blaming the gear ratio swap. all is well :D

Re: HELP! ABS/StabiliTrak Fault Light on, keeps blowing F5 Fuse

Posted: Thu Sep 02, 2021 3:16 pm
by andrewquant
Sorry to resurrect an old post, but how did you figure out it was the switch? I'm having a similar problem but just no blown fuse.