Need help with GM ABS on a truck

[Fencer]

Gear heads, Rad you out there?

I just got back in from picking up one of my kids at practice and the ABS has F-ed up. The motor (ABS) is still running even though the Yukon XL (2001 if that helps) is shut off. I pulled the under dash fuse labled ABS, but that did not kill it and I figure the big fuse under the hood prob works ALL brake stuff. Right now I have disconnected the battery so it won't run down.

Question: how to bypass ABS and leave other systems up till I can put it in the shop in the morn?

 

[radman]

Just seeing this now, a little late to help. Doesn't sound to me like it's the ABS motor operating if the fuse is yanked. More like a electric ps and brake booster pressure motor, if they use this sytem on the Yukon rather than traditional vac booster and engine driven ps hydraulic pump. If so, thats where you need to look, as this system is always hot due to needing to provide boost in the event of engine shutdown etc in emergencies. Not real familiar with the system, so I can check up on it if help still needed. Also, if the ABS is indeed constantly cycling, could be a stuck relay-pull the connector at the ABS unit, it'll trip the light, but you'll still have brakes minus the ABS. Several recalls on that Yukon, with ABS being one of them, a shorted battery pos cable at the steering column being another.

 

[Wingman]

Just seeing this now, a little late to help. Doesn't sound to me like it's the ABS motor operating if the fuse is yanked. More like a electric ps and brake booster pressure motor, if they use this sytem on the Yukon rather than traditional vac booster and engine driven ps hydraulic pump. If so, thats where you need to look, as this system is always hot due to needing to provide boost in the event of engine shutdown etc in emergencies. Not real familiar with the system, so I can check up on it if help still needed. Also, if the ABS is indeed constantly cycling, could be a stuck relay-pull the connector at the ABS unit, it'll trip the light, but you'll still have brakes minus the ABS. Several recalls on that Yukon, with ABS being one of them, a shorted battery pos cable at the steering column being another.

I may be wrong here, but I believe that the ABS module in question also controlls the front/rear brake bias. It may not be advisable to just unhook it. It could result in much longer braking distances. That being said, I believe there are two or possibly three fuses. Look in the engine compartment and passenger compartment for the fuses, but I would recommend finding someone who knows how to peoperly diagnose and fix this problem. If radman is right about recall, it might be fixed at no charge.

Good luck,

David

 

[radman]

After further review, this truck usually has a electric motor driven vacuum motor, which then powers a conventional vacuum brake booster. Depends on where the actual noise was coming from-underhood/vacuum pump motor. Right kick panel area, EHCU/ABS valve motor. Pulling the ABS Maxi-Fuse underhood in the elec center should have killed if the latter. And, for what it's worth, disabling any ABS system function will not affect brake operation on any vehicle I'm familiar with, only the ABS function will be affected. This is so that any failure in the ABS system does not render the brakes inoperative in any way.

 

[vectervp1]

:grin:

 

[Fencer]

Pulling the ABS Maxi-Fuse underhood in the elec center should have killed if the latter.

I ended up disconnecting the battery last night, and pulled the Maxi-fuse this morning.

Problem: Bad EBCM $1100.00 at dealer, Replaced once before 2 years to the day! That time it was under warranty. My warranty Just ran out on Dec 31. and I only have 74,600 on this truck :angry:

Rad What was the ABS recall? can you point me to it? I am trying to get them to cover this since it was done once before. But get this, since I took my GMC to (the same) Chevy dealer who repaired it before. Chevy is saying that (paraphrase)- Well, if it were a Chevy, we could prob cover it under good customer/faith. But, since its a GMC I don't know if we can.- different parts.

Different parts my ass- the Chevy dealer put the "Chevy part" on last time. and I'll wager HUGE sums of money that they are stamped GM and will work fine on either brand. For those of you who don't know what a GMC Yukon XL is think Chevy Suburban with a diff name tag.

 

[radman]

Pulling the ABS Maxi-Fuse underhood in the elec center should have killed if the latter.

I ended up disconnecting the battery last night, and pulled the Maxi-fuse this morning.

Problem: Bad EBCM $1100.00 at dealer, Replaced once before 2 years to the day! That time it was under warranty. My warranty Just ran out on Dec 31. and I only have 74,600 on this truck :angry:

Rad What was the ABS recall? can you point me to it? I am trying to get them to cover this since it was done once before. But get this, since I took my GMC to (the same) Chevy dealer who repaired it before. Chevy is saying that (paraphrase)- Well, if it were a Chevy, we could prob cover it under good customer/faith. But, since its a GMC I don't know if we can.- different parts.

Different parts my ass- the Chevy dealer put the "Chevy part" on last time. and I'll wager HUGE sums of money that they are stamped GM and will work fine on either brand. For those of you who don't know what a GMC Yukon XL is think Chevy Suburban with a diff name tag.

The recall concerned unwarranted ABS activation, unconnected to your issue. It was the result of bad wheel sensors, not unheard of in GM vehicles. And, as far as the Chev dealer, he cannot repair GMC's under warranty in most situations. Generally, it's all dependent on the warranty admin at the dealership whether it will fly or not. A good story gets it done, but at 75 thou, it would be very very iffy. Now you know why Toyota is becoming #1 though.

 

[Fencer]

I'm Happy

Chevy/ GM covered the bill!!!!!!

It prob helped that my last 6 vehicles have been Chevy trucks and get the service at this dealer