Makes 🢒
Chevrolet 🢒
2009 🢒
Avalanche - 4WD 🢒
Driver Information and Entertainment 🢒
Cellular, Entertainment, and Navigation 🢒
DTC C056D, C120C, C121C, C121E, C121F, C123A-C123F, C1255, C1256, C126E, C126F, C127E, C12A7, C12C2, C12C5, C12C6, C12C8, C12CC, C12CF, C12D0-C12DF, or C12E0
Diagnostic Instructions
DTC Descriptors
DTC C056D 00: ECU Hardware Performance
DTC C120C: ECU Hardware Performance
DTC C121C: ECU Hardware Performance
DTC C121E: ECU Hardware Performance
DTC C123A: ECU Hardware Performance
DTC C123B: ECU Hardware Performance
DTC C123C: ECU Hardware Performance
DTC C123D: ECU Hardware Performance
DTC C123E: ECU Hardware Performance
DTC C123F: ECU Hardware Performance
DTC C1255: ECU Hardware Performance
DTC C1256: ECU Hardware Performance
DTC C126E: ECU Hardware Performance
DTC C127A: ECU Hardware Performance
DTC C127B: ECU Hardware Performance
DTC C127C: ECU Hardware Performance
DTC C12A7: ECU Hardware Performance
DTC C12C2: ECU Hardware Performance
DTC C12C5: ECU Hardware Performance
DTC C12C6: ECU Hardware Performance
DTC C12C8: ECU Hardware Performance
DTC C12CC: ECU Hardware Performance
DTC C12CF: ECU Hardware Performance
DTC C12D0: ECU Hardware Performance
DTC C12D1: ECU Hardware Performance
DTC C12D2: ECU Hardware Performance
DTC C12D3: ECU Hardware Performance
DTC C12D4: ECU Hardware Performance
DTC C12D5: : ECU Hardware Performance
DTC C12D6: : ECU Hardware Performance
DTC C12D7: : ECU Hardware Performance
DTC C12D8: : ECU Hardware Performance
DTC C12D9: : ECU Hardware Performance
DTC C12DA: : ECU Hardware Performance
DTC C12DB: : ECU Hardware Performance
DTC C12DC: : ECU Hardware Performance
DTC C12DD: : ECU Hardware Performance
DTC C12DE: : ECU Hardware Performance
DTC C12DF: : ECU Hardware Performance
DTC C12E0: : ECU Hardware Performance
DTC C12F2: : ECU Hardware Performance
DTC C12F3: : ECU Hardware Performance
DTC C12F4: : ECU Hardware Performance
DTC C12F5: : ECU Hardware Performance
DTC C12F6: : ECU Hardware Performance
DTC C12FE: : ECU Hardware Performance
DTC C056D 3C: ECU Hardware Performance Internal Communication Failure
DTC C056D 59: ECU Hardware Performance Circuit/Component Protection Time-out
DTC C12E9: ECU Hardware Performance Circuit/Component Protection Time-out
Circuit/System Description
The electronic brake control module (EBCM) detects an internal malfunction.
Conditions for Running the DTC
• | Ignition voltage is greater than 10 volts. |
Conditions for Setting the DTC
The EBCM detects an internal malfunction.
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
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Verify DTC C056D is not set.
⇒ | If DTC is set, replace the EBCM. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ABS replacement, setup, and programming