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Brake and ABS light stay on...

S

stevensonmotors

New Member
Joined
Aug 27, 2006
Messages
4
I have an 02 Z71 with 42k and for some strange reason over the past 3 weeks the Break light and the ABS dash light have been both coming on at the same time every now and then.

Then when I stop the truck, do my thing and restart they will be off or maybe they won't.? ?Has anybody had this issue before? :E:

Thanks in advance.
 
my abs light and p-brake light was staying.  A traced the problem to a blown brakelight fuse.
 
Your "break" light is on because it's broken.  :)
 
bulbs, fuse and check your parking brake isn't faulty

I had that on a brand new S10 once, they asked me I if I brake torqued it to do a burnout. They said it was a faulty dump valve ? I don't have clue what a dump valve is or if the AV ABS system has one.
 
Your truck has a abs problem, get it scanned.  abs will be in-op when the light is on.
 
Another thing to check would be your brake fluid level.  I have had these lights come on in other vehicles because the brake fluid was low.  Never had it happen in the Av, but I always have checked and topped off the brake fluid at every oil change.

As your brakes wear, brake fluid level goes down.....
 
02 Z71 said:
Another thing to check would be your brake fluid level.? I have had these lights come on in other vehicles because the brake fluid was low.? Never had it happen in the Av, but I always have checked and topped off the brake fluid at every oil change.

As your brakes wear, brake fluid level goes down.....
Click to expand...

Ditto

Sam
 
I had a faulty ABS sensor cause this.  Well, the sensor was fine, but the wiring harness was almost torn out completely.  The dealership offered to jury-rig it for free, instead of replacing the sensor, and it has worked since.  Next time it happens though, it will be time for a new sensor.
 
A abs light will only come on for a abs problem, if the master is low on fluid then the red brake warning light will come on.  If your abs light is on, you have a dtc in the ebcm, scanning it is the only way to get the dtc....and i bet it will be a front hub causing your grief, replaced way to many to count....
 
I have an '02 Z66. About a month ago my ABS light and brake light came on. I took it to the dealer and they said I had bad controller. I opted not to replace it for the $800+. They said while the light was on I wouldn't have ABS brakes. Took it home and tested it out and sure enough while the light is on the ABS brakes don't work. This seems to be happening to quite a few Avalanche's.

I've had my Avalanche for 5 yrs now and have 117,000 miles on it.

 
I have the same problem.  I think there must be some problem with the wiring connections to the ABS module or one of the ABS sensors.  I believe that since the ABS light went on there must be some codes stored in the computer which could lead to a solution.  From reading other posts, the ABS module is bad only when you hear ABS pump running when you turn off the car.  I got to call a few local shops to find out if they can scan ABS codes and for how much.  I know that autoparts stores can only check "check engine" codes.
 
kgt said:
A abs light will only come on for a abs problem, if the master is low on fluid then the red brake warning light will come on.? If your abs light is on, you have a dtc in the ebcm, scanning it is the only way to get the dtc....and i bet it will be a front hub causing your grief, replaced way to many to count....
Click to expand...

noticed my abs light come on yesterday while plowing/pulling folks out of snow drifts,  could snow packed up and in and around the hubs be the cause ??  once I got to flat (under a foot deep) the light went out.
 
Mine started that last night..

I've been on a lot of rough roads lately where the truck may as well be on a vibration table.

Cheap code readers usually won't show body codes, just powertrain/emission ones.

`Wished I had a Tech 2. :( Out in the boonies here and not near my dealer is a pain. So, on with checking a large list of things.

So far I worked things around a bit, checked the module connectors and such. The fluid level is fine but the ABS light still stays on.

Other things that went nuts at the same time, so I suspect the ign switch too. (Gauge errors, engine dies, etc).

Shaking like this sometimes works the contact rivets loose in the UBEC base. That's a real bit*h to isolate sometimes.

If all else fails, I have a trusted dealer (380 miles away though) and GMPP. :)
 
Same symptoms on with mine turned out to be a faulty ABS module, dealer repaired it under warranty.
 
I feel I have several things that shook into failure. Just that many occured at the same time after many miles of the rough roads, and while on those roads. The ABS light remains on..
 
Sounds like my last truck the minute it hit 65,000-everything broke at once.

In my case the module was really easy to diagnose-the loud humming noise and vibration that stopped when the module was unplugged sort of gave it away.
 
Mine isn't doing that. That's one reason I believe it's fault is elsewhere. `Really suspecting an intermittent source now, such as the ign sw. or a loose connector/contact.

 
I'm going to check on this:

ABS Light On, DTCs C0265, C0201, U1041 Set and/or Loss of Communication with Brake Module (Reground EBCM Ground) #04-05-25-002A - (Apr 22, 2004)

2004 Buick Rainier

2002-2004 Cadillac Escalade, Escalade EXT

2003-2004 Cadillac Escalade ESV

1999-2004 Chevrolet Silverado

2000-2004 Chevrolet Suburban, Tahoe

2002-2004 Chevrolet Avalanche, TrailBlazer, TrailBlazer EXT

2003-2004 Chevolet SSR

1999-2004 GMC Sierra

2000-2004 GMC Yukon, Yukon Denali, Yukon XL

2002-2004 GMC Envoy, Envoy XL, Sierra Denali

2004 GMC Envoy XUV

2002-2004 Oldsmobile Bravada

This bulletin is being revised to update the Ground information. Please discard Corporate Bulletin Number 04-05-25-002 (Section 05 -- Brakes).

Condition

Some customers may comment that the ABS light is on. Upon further inspection, DTCs C0265 and C0201 may be set in the brake module. It is also possible for DTC U1041 to set in other modules. There may also be a loss of communication with the brake module.

Cause

A poor connection at the EBCM ground is causing unnecessary replacements of brake modules.

Important

The EBCM Ground is different for each application. Refer to the list below for the proper ground reference:

    * Midsize Utilities = Ground 304
    * SSR = Ground 400
    * Fullsize Trucks and Utilities = Ground 110


Correction

DO NOT REPLACE THE BRAKE MODULE.

Perform the following steps to improve the connection of the EBCM Ground:

  1. Remove the EBCM Ground. The EBCM Ground is located on the frame beneath the driver's side door. If multiple grounds are found in this location, the EBCM ground can be identified as the heavy (12-gauge) wire.
  2. Clean the area, front and back, using a Whiz Wheel?.
  3. Install the bolt, ground and a star washer to the frame.
  4. Install a star washer and nut to the backside of the frame.

      Tighten

      Tighten the nut to 9 N?m (79 lb in).
  5. Cover the front and back side of the repair area using Rubberized Undercoating.
 
(1) Frame
(2) Electronic Brake Control Module (EBCM) Ground (GNO)
(3) Manual Selectable Ride Ground (G302)
(4) Automatic Transfer Case/ABS Ground (G110)

 

Attachments

  • Left_frame_Grounds-1.gif
    Left_frame_Grounds-1.gif
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That was easy, but too easy. `Didn't fix mine. :(

The bolts were rather loose and they didn't clean off the frame paint! :2: `Thought sure that was it.  :E:

The motor runs briefly and stops, while the ABS light only blinks. My fingers are freezing, so, GMPP will have to foot the bill on this one.  >:D

 
After all the tries, the ABS light then went out after I moved the truck to put it inside. ???

I'm beginning to feel it may be a wheel speed sensor. The rt. front wire/connector seems to have some loose but limited play when I push & pull on it.

 
sperry said:
I'm beginning to feel it may be a wheel speed sensor. The rt. front wire/connector seems to have some loose but limited play when I push & pull on it.
Click to expand...
That's what I suggested. :D
 
The one you referred to as an "ABS sensor". :rolleyes:

Since (unless one has stabilitrack) the (front) wheel speed sensors are used just for ABS, I suppose one could refer to them as that. :)

The speedo worked OK except when I was getting a full ign shutdown too (another problem with the rough roads. :E: ). That tells me that the rear (VSS) sensor is OK.

 
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