GM Service Manual Online
For 1990-2009 cars only

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 P0501: Electronic Brake Control Module - Left Front Wheel Speed Signal

Circuit/System Description

The wheel speeds are detected by active wheel speed sensors. Each wheel speed sensor receives a 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. The EBCM sends the wheel speed information as a high speed Controller Area Network (CAN) serial data message. Modules connected to the high speed CAN circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules.

Conditions for Running the DTC

Ignition ON

Conditions for Setting the DTC

A supervised periodic message that includes the wheel speed serial data has not been received.

Action Taken When the DTC Sets

DTC P0501 is a Type C DTC.

Conditions for Clearing the DTC

DTC P0501 is a Type C DTC.

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 EBCM 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. Ignition ON, verify that DTC C0035, C0040, C0045, C0050 or U0121 is not present.
  2. If any listed DTC is present, diagnose that first.
  3. Replace the K17 Electronic Brake Control Module (EBCM) and verify the DTC does not reset.
  4. If the DTC resets, replace the K71 Transmission Control Module.

Repair Instructions

    • Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
    •  Control Module References for module replacement, setup and programming.
    • Transmission control module (TCM), refer to Control Module References for replacement, setup and programming.