For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2008 🢒 Chevy Suburban - 2WD 🢒 Brakes 🢒 Antilock Brake System - Hybrid 🢒 DTC C1122 or C1123

DTC C1122 or C1123 for Chevrolet Chevy Suburban - 2WD 2008

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 Descriptors

DTC C1122 00: Right Front Brake Hydraulic Circuit Blocked

DTC C1123 00: Right Front Brake Hydraulic Circuit Leaking

The electronic brake control module EBCM) activates the valve relay to supply voltage to the valve solenoids. This voltage is referred to as the system voltage. The EBCM activates individual valve solenoids by grounding the valve solenoid control circuits.

Conditions for Running the DTC

•	Ignition ON.

•	The ignition voltage is greater than 10 volts.

Conditions for Setting the DTC

C1122 00

The EBCM is commanding a valve solenoid to release brake pressure. The wheel that is commanded to release brake pressure has a speed less than 5 km/h (3 mph) for 1.25 seconds.

C1123 00

The pressure change of the accumulator indicates the volume of fluid used which is compared to expected fluid used during a brake apply. Too much fluid usage indicates a leaking circuit

Action Taken When the DTC Sets

•	The EBCM disables the antilock brake system (ABS), traction control and the vehicle stability enhancement system (VSES) for the duration of the ignition cycle.

•	A DIC message and/or a warning indicator may be displayed.

Conditions for Clearing the DTC

•	The condition for the DTC is no longer present.

•	The EBCM clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles.

Reference Information

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/System Verification

Ignition ON, verify that DTC C1120 or C1121 are not set.

⇒	If the DTC is set, replace the brake pressure modulator valve. If the DTC resets, replace the EBCM..

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Brake Pressure Modulator Valve Replacement

•	Control Module References for EBCM replacement, setup, and programming