Chevrolet Silverado / GMC Sierra. Service manual — part 709

Conditions for Running the DTC

C0055 00

The ignition is ON.

Ignition voltage is greater than 9.5 volts.

C0055 5A

The ignition is ON.

Ignition voltage is greater than 9.5 volts.

The brake pedal is not pressed.

A DTC is not set for the other wheel speed circuit on the same axle.

Conditions for Setting the DTC

C0055 00

An open is detected on the rear wheel speed sensor signal circuit.

A short to ground is detected on the rear wheel speed sensor signal circuit.

A short to voltage is detected on the rear wheel speed sensor signal circuit.

C0055 5A

The EBCM detects an erratic rear wheel speed signal.

Action Taken When the DTC Sets

The EBCM disables the Antilock Brake System (ABS)/Traction Control System (TCS) for
the duration of the ignition cycle.

The electronic brake distribution (EBD) does not function optimally.

The ABS indicator turns ON.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

The EBCM automatically clears the history DTC when a current DTC is not detected in 100
consecutive drive cycles.

Diagnostic Aids

2008 Chevrolet Silverado 1500

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

If 2 or more wheel speed sensors are inoperative diagnose each wheel speed sensor individually.

An ECE 13 response may be required, after repairs are made, and DTCs are cleared, operate the
vehicle at speeds greater than 13 km/h (8 mph) to complete the self test, and the EBCM will turn
off the ABS indicator.

C0055 5A, 00

If the customer comments that the ABS indicator is ON only during moist environmental
conditions: rain, snow, vehicle wash, etc., inspect the wheel speed sensor wiring for signs of
water intrusion. Also, a condition may result in a stored history DTC C0055, this DTC can set if a
customer turns the ignition key from the RUN position to the ACCESSORY and leaves it for
more than 1 second. The DTC may be stored in history due to a software condition in the EBCM,
and no repairs are necessary. If the ABS indicator illuminates intermittently, clear all DTCs and
simulate the effects of water intrusion by using the following procedure:

1. Spray the suspected area with a 5 percent saltwater solution. To create a 5 percent saltwater

solution, add 2 teaspoons of salt to 8 fl oz of water (10 g of salt to 200 ml of water).

2. Test drive the vehicle over various road surfaces: bumps, turns, etc., above 40 km/h (25

mph) for at least 30 seconds.

3. Rinse the area thoroughly when completed.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Circuit/System Testing

1. Use a scan tool in order to clear the DTCs. Cycle the ignition to OFF and then start the

engine. A current failure will set a DTC.

If the DTC does not reset, go to Diagnostic Aids.

2008 Chevrolet Silverado 1500

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

2. Turn OFF the ignition and disconnect the EBCM harness connector. At the EBCM harness

connector terminal 31 W/JF3 or terminal 20 W/JH6, test for 10 volts on the vehicle speed
signal circuit.

If the voltage is below 10 volts, test for an open or short to ground on the vehicle
speed signal circuit. If all circuits test normal, replace the EBCM.

3. Ignition ON, verify that a test lamp does not illuminates between the vehicle speed signal

circuit terminal 31 W/JF3 or terminal 20 W/JH6 and ground.

If the test lamp illuminate, test the vehicle speed signal circuit for a short to B+. If the
circuit tests normal, replace the EBCM.

4. If all circuits test normal, replace the PCM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM/BPMV or PCM replacement, setup, and programming

DTC C0110

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.

DTC Descriptor

DTC C0110 00

Pump Motor Circuit

DTC C0110 03

Pump Motor Circuit Voltage Below Threshold

DTC C0110 04

Pump Motor Open Circuit

DTC C0110 61

2008 Chevrolet Silverado 1500

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

Pump Motor Circuit Actuator Stuck

Circuit/System Description

The pump motor is an integral part of the brake pressure modulator valve (BPMV), while the
pump motor relay is integral to the electronic brake control module (EBCM). The pump motor
relay is not engaged during normal system operation. When antilock brake system (ABS) or
traction control system (TCS) operation is required the EBCM activates the pump motor relay
and ground circuit is provided to the pump motor.

Conditions for Running the DTC

The ignition switch is in the ON position.

Initialization is complete.

Conditions for Setting the DTC

The EBCM motor drive circuit detects a short to battery positive, or open ground circuit,
and a continuously on or off motor.

The pump motor continues to rotate briefly after activation creating a feedback voltage. The
EBCM sets the code if the measured feedback voltage indicates a binding or stalled pump
motor.

Action Taken When the DTC Sets

The EBCM disables the ABS/TCS/VSES for the duration of the ignition cycle.

The ABS indicator turns ON.

The Traction Control and VSES indicators turn ON.

The Traction Control and StabiliTrak displayed on the DIC.

Conditions for Clearing the DTC

The condition for the DTC is no longer present.

The EBCM automatically clears the history DTC when a current DTC is not detected in 100
consecutive drive cycles.

Reference Information

Schematic Reference

Antilock Brake System Schematics

2008 Chevrolet Silverado 1500

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