ABS, traction control, and Stabilitrac MIL

[davester]

Are you certain the trailer brakes are disabled by the abs system and that they aren't working for some other reason? And is the the TBC an integrated GM one or from a third party (if it's a GM built-in one, you may be able to get a code from the TBC with a more advanced code reader)?

[sdeeter19555]

The trailer brake controller is the OE installed...and I'm getting the same DIC messages, service TC, service Stabilitrac, service Trailer brakes that were caused by the faulty wheel sensor and stored a code.

 

Trailer brakes were working fine just before these MIL and codes started popping up...

 

Just for giggles, I unhooked from that trailer, and hooked to another...same thing, acknowledges the trailer connected but no brakes.

 

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[sdeeter19555]

And further, the only way you get that "trailer connected" message is if it detects trailer brakes...if the brakes aren't hooked up or if the trailer doesn't have brakes; you will not get that message.

 

Therefore, one can deduce the system is reading the trailer correctly, but the fault (suspected wheel sensor) is causing the system to not allow power to flow to the trailer brakes.

 

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[Coby7]

Trailer brakes will still function for the duration the truck engine is running after the MIL comes ''ON'' but the second you turn off the engine and turn it back on you will not have trailer brakes.

[sdeeter19555]

Trailer brakes will still function for the duration the truck engine is running after the MIL comes ''ON'' but the second you turn off the engine and turn it back on you will not have trailer brakes.

Not true...I never shut the truck off between when the light came on and I hooked the trailer up, trailer brakes were non-existent.

 

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[Coby7]

Yeah but trailer wasn't hooked at the time of the MIL. GM still has safety in the circuit, Same with blowing an ignition fuse or a BCM fuse, truck will still run perfectly until next start-up.

[sdeeter19555]

Still a safety issue in my opinion...

 

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And a reason to consider another option...

 

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[sdeeter19555]

ABS module appears to be bad...going to have it replaced.

 

Traced all wiring to the trailer module and then to ABS module, everything was fine. Continuity was fine in all wiring. Tone ring is clean, and free of any damage checked all the grounds.

 

Everything points to the ABS module, which is a part that GM has to program...so off to the dealer.

 

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[sdeeter19555]

Final fix - wiring issue above the spare tire on the right frame rail.

 

Seems the local shop missed it the first time, even the dealer missed it the first time through. Something chewed on the wiring a "while ago", and that was the break causing the intermittent issue. The good thing was that it completely failed before I took it to the dealer where it was an intermittent issue for the local shop. They actually pulled the harness to inspect it because they couldn't find it installed in the truck.

 

So far, 40 miles and no lights...will report back if that doesn't fix it.

 

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[davester]

thanks for posting the fix. intermittent wiring problems suck to find.

[sdeeter19555]

I think that's why the local shop narrowed it to the module, the wiring still "worked" when they had it.

 

I'm glad the break failed completely because that would have meant throwing parts until one stuck.

 

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