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 Descriptors

DTC C0240: ECM Traction Control Not Allowed

### Circuit/System Description

#### C0240

The engine control module (ECM) and the electronic brake control module (EBCM) communicate on the serial data link, whenever the ignition is ON.

### Conditions for Running the DTC

#### C0240

Ignition ON.

### Conditions for Setting the DTC

#### C0240

The EBCM receives a serial data message stating that the ECM has lost the ability to reduce engine torque.

### Action Taken When the DTC Sets

#### C0240

• | The EBCM disables the traction control system (TCS) and vehicle stability enhancement system (VSES).

• | 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 50 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

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information.

### Circuit/System Testing

Important: It is recommend that the defective components be replaced, and not the complete brake master cylinder assembly.

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 23 and ground.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

3. If the circuits test normal, replace the EBCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM or ECM replacement, setup, and programming