For 1990-2009 cars

### 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 Descriptor

DTC C0201 04: 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 ABS/dynamic rear proportion (DRP) for the duration of the ignition cycle.

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

### 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

#### Connector End View Reference

Component Connector End Views

#### Description and Operation Reference

ABS Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for EBCM

### Circuit/System Verification

With scan tool installed ignition ON clear the DTCs, command the ABS solenoids ON and OFF with a scan tool. Monitor the operation of ABS solenoids turn on and off. Also, drive the vehicle in a straight line at a speed greater than 20 km/h (13 mph). If the DTC did not set as a current DTC see diagnostic aids.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Test for less than 1.0 ohm of resistance from ground circuit terminal 16 and ground.

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

3. Test for less than 1.0 ohm of resistance from ground circuit terminal 16 and ground.

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

4. 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.

5. Verify that a test lamp illuminates between the B+ circuit terminal 32 and ground.

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

6. If all circuits test normal, test or replace the EBCM assembly.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup, and programming