C0552

DTC C0552 or C121D

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provide an overview of each diagnostic category.

DTC Descriptors
DTC C0552 00
- Improper Shutdown

DTC C121D
- Improper Shutdown

Circuit/System Description

The electronic brake control module(EBCM) monitors the number of Key On and Key Off cycles. When it detects that a Key Off cycle was incomplete or non-existent this fault will set. This means the fault reports a problem that occurred at the end of the previous ignition cycle. If this occurs during an EBCM service operation, any calibrations or offsets learned during that service operation may not be properly stored in memory.

Conditions for Running the DTC

* Ignition ON.
* The ignition voltage is greater than 10 volts.
* The EBCM is initializing.

Conditions for Setting the DTC

A Key Off cycle was interrupted before completion, or power was removed from the module with the key in the ON position, vehicle moving and brake is applied.

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.

Diagnostic Aids

This DTC can set if battery voltage drops below 8 volts with ignition ON.

Reference Information
Schematic Reference

Antilock Brake System Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

ABS Description and Operation (ABS Hybrid (HP2))
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the electronic brake control module.
2. Ignition OFF, test for less than 1 ohm between the ground circuits listed below and ground.

* Terminal 13
* Terminal 38

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the B+ circuit Terminal 1 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Cycle ignition, verify DTC C0552 or C121D is not set.

• If DTCs are set, replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming