Denali and AWD Traction Control. Seems to work more than I would like to..

[retiredsparky]

I agree with the above posters who think you have a sensor or cable connection that has an intermittent connection that is affected by the rough road. Look for corrosion on the cable connectors. A sensor may have come loose inside of it's plastic case or in the hub.

Jack your truck up and wiggle the tires to see if you have worn bearings in the hubs. The reluctor wheel wobbling (attached to the hub internally) can cause various problems with the ABS and traction control.

 

[Searay45db]

TECHNICAL

Bulletin No.: 03-05-25-007D

Date: May 01, 2009

Subject: Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface)

Models:
2002-2006 Cadillac Escalade, Escalade EXT
2003-2006 Cadillac Escalade ESV
1999-2006 Chevrolet Silverado
2001-2006 Chevrolet Suburban, Tahoe
2002-2006 Chevrolet Avalanche
2003-2006 Chevrolet Express
2007 Chevrolet Silverado Classic
1999-2006 GMC Sierra
2001-2006 GMC Yukon, Yukon Denali, Yukon XL, Yukon Denali XL
2003-2006 GMC Savana
2007 GMC Sierra Classic
2003-2006 HUMMER H2


Supercede:This bulletin is being revised to add the 2007 Silverado/Sierra Classic models. Please discard Corporate Bulletin Number 03-05-25-007C (Section 05 - Brakes).


Condition

Some customers may comment on ABS activation at low speeds, usually below 8 km/h (5 mph). Upon investigation, the technician will find no DTCs set.

Cause

The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.

Correction

Measure AC voltage and clean the wheel speed sensor mounting surfaces.

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Manual.
2. Disconnect both the front wheel speed sensor connectors at the frame and harness.
3. Place a Digital Volt Meter (DVM) across the terminals of each wheel speed sensor connector.
4. Rotate the wheel clockwise approximately one revolution per second. The minimum reading should be at least 350 ACmV's. If the reading is less than 350 ACmV's, remove the wheel speed sensor. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual.
5. Plug the wheel speed sensor bore in order to prevent debris from falling into the hub during service.
6. Clean the wheel speed sensor mounting surface using a wire brush, sand paper, emery cloth, scotch brite, or other suitable material. Be sure to thoroughly clean the wheel speed sensor surface. There should be no rust or corrosion.
7. Check the sensor head to determine if it has been warped/distorted due to the corrosion build up or other causes. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinists scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple (minimum 3) positions/directions. If the sensor head is distorted, replace the sensor.
8. Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats. Use ONLY Rust Penetrating Lubricant, P/N 89022217 (in Canada, P/N 89022218).
9. When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a thin layer of bearing grease to the hub surface and sensor O-ring prior to sensor installation. Use ONLY Wheel Bearing Lubricant, P/N 01051344 (in Canada, P/N 993037).
10. Install either the original sensor or a new one in the hub. Ensure that the sensor is seated flush against the hub. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual.
11. Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel. The voltage should now read at least 350 ACmV's.

 

[Searay45db]

Bulletin No.: 04-08-49-006C

Date: January 05, 2005

TECHNICAL

Subject:
Service Stability Message Displayed, DTC C0550 Set (Reprogram EBCM)


Models:
2004-2005 Cadillac Escalade, Escalade ESV, Escalade EXT
2004-2005 Chevrolet Avalanche, Suburban, Tahoe
2004-2005 GMC Yukon, Yukon Denali, Yukon XL


Supercede:

This bulletin is being revised to correct the Subject line. Please discard Corporate Bulletin Number 04-08-49-006B (Section 08 - Body and Accessories).

Condition

Some customers may comment that while driving downhill and making a turn, the Service Stability message will display in the Driver Information Center (DIC). This will occur prior to ABS activation and once stopped, the message will go off.

Upon investigation, the technician may find DTC C0550 stored in history.

Cause

The cause of this condition may be that the "Long Accel Gain" parameters in the EBCM are sensitive to certain driving conditions.

Correction

Technicians are to reprogram the EBCM with an updated software calibration. This new service calibration was released with TIS satellite data update version 9.5 available September 20, 2004. As always, make sure your TECH 2(R) is updated with the latest software version.

Warranty Information

 

[Searay45db]

Ok, so now that you have them....thoughts?

 

[Rocket Man]

Do you think your ABS is activating at slow speed or is the Service Stability message showing up in the DIC? These TSB's are specific to these , and I didn't see you mentioning these exact issues in your previous posts.

 

[retiredsparky]

I can see where both of these TSB's are logical in certain situations. A dirty surface at the sensor location would only be a problem if the sensors had been r & r'd without cleaning that surface. So it does make sense to check the sensor voltage as recommended.

Rough roads causing intermittent activation sounds more like a corroded connection or faulty sensor/worn hub bearings. Rough roads cause a lot of G-force (especially on trucks with large diameter rims and short sidewall tires) on the un-sprung part of the suspension where the sensors are mounted.

 

[05alive]

Replace your ABS sensors. It's like 40 bucks for both. Easy job if you have access to a jack and some simple tools. If you feel up to it, clean the surface rust off your cv's.

 

[MikeLade]

I had the same issue on my 03 Escalade.

After replacing all of the brake calipers and doing a brake fluid flush, the problem is gone. While I was at it, I upgraded to GMT900 brakes up front.