Content .. 720 721 722 723 ..

Chevrolet Silverado / GMC Sierra. Service manual - part 722

Control Module References for EBCM or IPC replacement, setup, and programming

TRACTION OFF INDICATOR MALFUNCTION

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The Low Traction indicator is controlled by the instrument cluster via serial data messages from
the electronic brake control module (EBCM). When the traction control system (TCS) is active
for 0.5 seconds, the EBCM commands the instrument cluster to flash the Low Traction indicator.

The electronic brake control module (EBCM) sends a serial data message to the instrument panel
cluster (IPC) to illuminate the Traction Control indicator when the EBCM has disabled the
traction control system (TCS) due to a DTC. The Traction Control indicator will also turn ON
during the instrument cluster bulb check. When the ignition switch is turned to ON, the Traction
Control indicator will turn ON for approximately 3 seconds and then turn OFF.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation (With JL4) or ABS Description and Operation (Without
JL4)

Electrical Information Reference

Circuit Testing

Connector Repairs

2008 Chevrolet Silverado 1500

2008 BRAKES Antilock Brake System - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool Reference

Control Module References for EBCM and IPC

Circuit/System Verification

1. Turn OFF the ignition for 5 seconds.

2. Turn ON the ignition, with a scan tool, select instrument panel special functions Display

Test. Command the instrument panel lamps ON. Verify the traction control off lamp
illuminates for at least 2 seconds and then turns off.

Circuit/System Testing

1. Ignition OFF for 5 seconds, Igniton ON, observe that the traction off indicator functions by

illuminating for 2 seconds then turns OFF.

If the traction OFF indicator does not illuminate, with the scan tool, select instrument
panel special functions Display Test. Command the instrument panel lamps ON and
OFF. Verify the TC lamp turns ON and OFF.

If the TC warning lamp does not turn OFF, replace the IPC.

If the TC warning lamp does turn OFF, replace the EBCM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM or IPC replacement, setup, and programming

Repair Validation

Ignition OFF for 5 seconds, Igniton ON, observe that the traction control off indicator functions
by illuminating for 2 seconds then turns OFF.This is the bulb self test that operates upon every
ignition key start cycle.

IMPORTANT: Diagnose all vehicle DTCs before using this diagnostic.

The malfunction must be present during diagnosis in order to
prevent unnecessary parts replacement.

2008 Chevrolet Silverado 1500

2008 BRAKES Antilock Brake System - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

REPAIR INSTRUCTIONS

ANTILOCK BRAKE SYSTEM AUTOMATED BLEED PROCEDURE (WITH JL4)

1. Install a scan tool to the vehicle.

2. Start the engine and allow the engine to idle.

3. Using the scan tool, begin the automated bleed procedure.

4. Follow the instructions on the scan tool to complete the automated bleed procedure. Apply

the brake pedal when instructed by the scan tool.

5. Turn the ignition OFF.

6. Remove the scan tool from the vehicle.

7. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11®,

GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean,
sealed brake fluid container.

8. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Pressure)

or Hydraulic Brake System Bleeding (Manual) .

9. With the ignition OFF, apply the brakes 3-5 times, or until the brake pedal becomes firm, in

order to deplete the brake booster power reserve.

10. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.

11. If the brake pedal feels spongy, repeat the automated bleeding procedure. If the brake pedal

NOTE:

When adding fluid to the brake master cylinder reservoir, use only
Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or
equivalent DOT-3 brake fluid from a clean, sealed brake fluid
container. The use of any type of fluid other than the recommended
type of brake fluid, may cause contamination which could result in
damage to the internal rubber seals and/or rubber linings of
hydraulic brake system components.

NOTE:

Refer to BRAKE FLUID EFFECTS ON PAINT AND ELECTRICAL
COMPONENTS NOTICE .

IMPORTANT: The base hydraulic brake system must be bled before performing

this automated bleeding procedure. If you have not yet performed
the base hydraulic brake system bleeding procedure, refer to
Hydraulic Brake System Bleeding (Pressure) or Hydraulic Brake
System Bleeding (Manual) before proceeding.

2008 Chevrolet Silverado 1500

2008 BRAKES Antilock Brake System - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

still feels spongy after repeating the automated bleeding procedure inspect the brake system
for external leaks. Refer to Brake System External Leak Inspection .

12. Turn the ignition key ON, with the engine OFF; check to see if the brake system warning

lamp remains illuminated.

13. If the brake system warning lamp remains illuminated, DO NOT allow the vehicle to be

driven until it is diagnosed and repaired. Refer to Symptoms - Hydraulic Brakes .

14. Drive the vehicle to exceed 13 km/h (8 mph) to allow ABS initialization to occur. Observe

brake pedal feel.

15. If the brake pedal feels spongy, repeat the automated bleeding procedure until a firm brake

pedal is obtained.

ANTILOCK BRAKE SYSTEM AUTOMATED BLEED PROCEDURE (WITHOUT JL4)

1. Install a scan tool to the vehicle.

2. Start the engine and allow the engine to idle.

3. Depress the brake pedal firmly and maintain steady pressure on the pedal.

NOTE:

Refer to BRAKE FLUID EFFECTS ON PAINT AND ELECTRICAL
COMPONENTS NOTICE .

IMPORTANT: This procedure may be performed on all vehicles EXCEPT those

equipped with option code JL4, Vehicle Stability Enhancement
System (VSES).

IMPORTANT: The base hydraulic brake system must be bled before performing

2008 Chevrolet Silverado 1500

2008 BRAKES Antilock Brake System - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Content .. 720 721 722 723 ..