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C0201




DTC C0201

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 provides an overview of each diagnostic category.

DTC Descriptor

DTC C0201 00
- Antilock Brake System (ABS) Enable Relay Contact Circuit

Diagnostic Fault Information






Circuit/System Description

The electronic brake control module (EBCM) controls it's internal valve relay to command the valve solenoids ON or OFF.

Conditions for Running the DTC

* Ignition voltage is greater than 10 V.

* The solenoid relay is commanded ON.

Conditions for Setting the DTC

* The EBCM detects no change when commanding the valve relay ON or OFF.

* 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 driver information center displays a message and/or a warning indicator.

* The EBCM disables the ABS, the traction control system and the vehicle stability enhancement system for the duration of the ignition cycle.

Conditions for Clearing the DTC

* When the condition for setting the DTC is no longer present.

* The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.

Note: During normal diagnostic and/or repair verification technicians may find that the ABS, Traction control and/or Stability control indicators may be ON with NO DTCs displayed by the electronic brake control module. Do not replace the electronic brake control module for this condition.

If the ABS, Traction control and/or Stability control indicators are ON with no DTCs set, perform the following steps:

1. Remove the key from the ignition, open and close the driver's door to turn off retained accessory power, and wait 60 seconds.

2. Ignition ON, if the ABS, Traction Control and/or Stability control indicators are still illuminated, operate the vehicle at speeds greater than 16 km/h (10 MPH) to complete the self test. The electronic brake control module should request all indicators to turn OFF.

3. If indicators remain ON with no DTCs set after the drive cycle, disconnect the battery for at least 60 seconds then reconnect the battery.

4. Operate the vehicle at speeds greater than 40 km/h (25 MPH), the electronic brake control module should request all the indicators to turn OFF.

Reference Information

Schematic Reference

Antilock Brake System Schematics [1][2]Antilock Brakes / Traction Control Systems

Connector End View Reference

Component Connector End Views 5 Bow Lowered Switch (CM7)

Description and Operation

ABS Description and Operation Description and Operation

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 Control Module References 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 and all vehicle systems OFF, disconnect the harness connector at the electronic brake control module. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 5 ohms between the ground circuits listed below and ground.

* Terminal 13

* Terminal 38

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

3. Ignition ON, verify that a test lamp illuminates between the B+ circuits listed below and ground.

* Terminal 1

* Terminal 25

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

4. If all circuits test normal, replace the electronic brake control module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

Control Module References Control Module References for electronic brake control module replacement, programming and setup