Chevrolet Silverado / GMC Sierra. Manual - part 721
open/high resistance. If the circuit tests normal, replace the EBCM.
If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the
circuit tests normal, replace the EBCM.
4. Test for 4.5-5.3 volts between the 5-volt reference circuit terminal B and the signal circuit
terminal C.
If less than the specified range, test the signal circuit for an open/high resistance. If the
circuit tests normal, replace the EBCM.
If greater specified range, test the signal circuit for a short to voltage. If the circuit
tests normal, replace the EBCM.
5. Install a 3A fused jumper wire at the signal circuit terminal C. Toggle the jumper wire
between the low reference circuit terminal and the 5-volt reference circuit terminal B.
Verify the scan tool Brake Pressure Sensor Input parameter toggles between 0.2-3.2 volts.
If the specified parameter, does not toggle between the minimum and maximum values
test the signal circuit for a short to voltage, short to ground or an open/high resistance.
If the circuit tests normal, replace the EBCM.
6. If all circuits test normal, test or replace the brake booster vacuum sensor.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for EBCM replacement, setup, and programming
SYMPTOMS - ANTILOCK BRAKE SYSTEM
IMPORTANT: The following steps must be completed before using the symptom
tables.
1. Perform the ABS Diagnostic System Check before using the
symptom tables in order to verify that all of the following are
true:
There are no DTCs set.
The control modules can communicate via the serial
data link.
2. Review the system description and operation in order to
familiarize yourself with the system functions. Refer to ABS
Description and Operation (With JL4) or ABS Description and
Operation (Without JL4).
2008 Chevrolet Silverado 1500
2008 BRAKES Antilock Brake System - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Visual/Physical Inspection
Inspect for aftermarket devices which could affect the operation of the ABS. Refer to
Checking Aftermarket Accessories .
Inspect the easily accessible or visible system components, for obvious damage or
conditions, which could cause the symptom.
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer Testing
for Intermittent Conditions and Poor Connections .
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom:
ABS 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 instrument panel cluster (IPC) illuminates the Antilock Brake System (ABS) indicator by
supplying ground to the lamp. The electronic brake control module (EBCM) sends a serial data
messages to the IPC, in order to command the indicator ON or OFF.
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
2008 Chevrolet Silverado 1500
2008 BRAKES Antilock Brake System - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
ABS Description and Operation (With JL4) or ABS Description and Operation (Without
JL4)
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
Scan Tool Reference
Control Module References for Scan Tool Information
Circuit Verification
Ignition ON, observe the ABS indicator to turn ON then OFF during the IPC bulb test.
Circuit/System Testing
1. Ignition On, with a scan tool command the Scan Tool IPC display test ON and OFF. The
ABS indicator should turn ON and OFF.
If the ABS warning lamp does not turn ON and OFF, replace the IPC.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for EBCM or IPC replacement, setup, and programming
STABILITRAK 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 Description
The instrument panel cluster (IPC) illuminates the stabilitrak indicator during the IPC bulb check
2008 Chevrolet Silverado 1500
2008 BRAKES Antilock Brake System - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
or when the electronic brake control module (EBCM) sends a serial data message to the IPC
commanding the indicator ON.
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
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
Scan Tool Reference
Control Module References for Scan Tool Information
Circuit Verification
Ignition ON, observe the Stabilitrak indicator to turn ON then OFF during the IPC bulb test.
Circuit/System Testing
1. Ignition On, with a scan tool command the Scan Tool IPC display test ON and OFF. The
Stabilitrak indicator should turn ON and OFF.
If the Stabilitrak indicator does not turn ON and OFF, replace the IPC.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
2008 Chevrolet Silverado 1500
2008 BRAKES Antilock Brake System - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado