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 C0245 00: Wheel Speed Sensor Frequency Malfunction

### Circuit/System Description

The wheel speeds are detected by active wheel speed sensors. Each wheel speed sensor receives 12 V reference voltage from the electronic brake control module (EBCM) and provides an alternating current square wave signal to the EBCM. As the wheel spins, the EBCM uses the frequency of the square wave signal to calculate the wheel speed.

### Conditions for Running the DTC

• | DTC C0035, C0040, C0045, or C0050 is not present.

• | Vehicle speed is greater than 14 km/h (9 MPH).

• | Brake is not applied.

• | Vehicle is not cornering.

### Conditions for Setting the DTC

Wheel speed differences between one wheel and the others is greater than 20%

### Action Taken When the DTC Sets

• | The EBCM disables the ABS, traction control, stability control and hill start assist for the duration of the ignition cycle.

• | The ABS indicator turns ON.

• | The traction control/stability control-active indicator turns ON.

• | The brake warning indicator turns ON.

### Conditions for Clearing the DTC

• | A current DTC clears when the diagnostic runs and passes.

• | The EBCM will turn OFF the indicator in the next ignition cycle.

### 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 Verification

Ignition ON, observe the scan tool Wheel Speed Sensor parameters. The reading should be the same speed on all sensors when driving in a straight line at a speed greater than 20 km/h (13 MPH).

### Circuit/System Testing

1. Inspect for one tire that has improper air pressure or improper size.

⇒ | If not all the same pressure, adjust all tire pressures to specification. If not all the same size, replace the incorrect tire and verify the DTC does not reset.

2. If the DTC resets, replace the K17 Electronic Brake Control Module (EBCM).

### Repair Instructions

• | Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Control Module References for EBCM replacement, setup and programming