P0609

DTC C0055 or P0609

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (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 Descriptors
DTC C0055 01
- Rear Wheel Speed Sensor Circuit Short to Battery

DTC C0055 04
- Rear Wheel Speed Sensor Open Circuit

DTC C0055 0F
- Rear Wheel Speed Sensor Circuit Erratic

DTC C0055 26
- Rear Wheel Speed Sensor Circuit Frequency Too Low

DTC P0609
- Vehicle Speed Output Circuit

Diagnostic Fault Information





Circuit/System Description

The engine control module (ECM) converts the data from the vehicle speed sensor to a 128K pulses/mile engine speed signal. The electronic brake control module (EBCM) uses the vehicle speed signal from the ECM in order to calculate the rear wheel speed.

Conditions for Running the DTC

* Ignition ON.
* Ignition voltage is greater than 10 volts.

Conditions for Setting the DTC

The EBCM detects a short to voltage, short to ground or an open/high resistance on the rear wheel speed sensor signal circuit.

Action Taken When the DTC Sets

* The EBCM disables the Antilock Brake System (ABS) for the duration of the ignition cycle.
* A DIC message and/or a warning indicator may be displayed.

Conditions for Clearing the DTC

* The condition for setting the DTC is no longer present.
* The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

ABS Description and Operation (w/JL4) (ABS Description and Operation (With RPO JL4))ABS Description and Operation (without JL4) (ABS Description and Operation (Without RPO JL4))
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 Testing

1. Ignition OFF disconnect the harness connector at the EBCM.
2. Ignition ON, test for 9.8 - 10.2 volts between the signal circuit terminal 20 and ground.

• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the ECM.
• If greater than the specified range, test the signal circuit for a short to voltage. If all circuits test normal, replace the ECM.

3. 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/BPMV or ECM/PCM replacement, setup, and programming