Antilock Brake System - Greater than/Equal to 3900 kg (8600 lb) GVW

DTC C0201

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (with HP2) (Initial Inspection and Diagnostic Overview)Diagnostic System Check - Vehicle (without HP2) (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptor
DTC C0201
- Antilock Brake System (ABS) Enable Relay Contact Circuit

Circuit/System Description

The solenoid relay, located within the electronic brake control module (EBCM), supplies battery voltage to all of the valve solenoids.

Conditions for Running the DTC

* Ignition voltage is greater than 9.5 volts.
* The solenoid relay is commanded ON.

Conditions for Setting the DTC

One or more of the following conditions exists:

* The EBCM detects an open in the battery positive voltage circuit to the solenoid valve relay.
* The EBCM detects a stuck open solenoid valve relay or an open circuit between the solenoid valve relay and solenoid valves.

Action Taken When the DTC Sets

* The EBCM disables the antilock brake system (ABS)/traction control system (TCS)/dynamic rear proportion (DRP) for the duration of the ignition cycle.
* The ABS indicator turns ON.
* The Traction Control indicator turns ON.
* The red Brake Warning indicator turns ON.
* The driver information center (DIC) displays the SERVICE BRAKE SYSTEM/TRACTION SYSTEM message.

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.

Reference Information
Schematic Reference

Antilock Brake System Schematics (Greater than/Equal to 3900 kg (8600 lb) GVW)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

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

Circuit/System Verification

Ignition ON, observe the scan tool EBCM Battery Voltage Signal parameter. The reading should be battery voltage.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Test for less than 1 ohm between the ground terminals 13 and 38 and ground.

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

3. Verify that a test lamp illuminates between the B+ terminals 25 and 1 and ground.

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

4. If all circuits test normal, 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