GM Service Manual Online
For 1990-2009 cars only

When servicing the antilock brake system and/or the MAGNASTEER system, the following steps should be followed in order. Failure to follow these steps may result in the loss of important diagnostic data and may lead to difficult and time-consuming diagnostic procedures:

  1. Perform a vehicle preliminary diagnostic inspection. This should include:
  2. • Inspection of the MAGNASTEER actuator and electrical connections.
    • Inspection of the Electronic Brake Traction Control Module (EBTCM) electrical connectors.
  3. Perform the Diagnostic System Check. Refer to A Diagnostic System Check - ABS in Antilock Brake System. If any Diagnostic Trouble Codes (DTCs) are displayed, select DTC history to note the last malfunction that occurred. Diagnose and repair this malfunction first.
  4. If no DTCs are present, mechanical component malfunctions are present, or if the failure is intermittent and not reproducible, test drive the vehicle while using the automatic snapshot feature of the scan tool. Perform normal acceleration, stopping, and turning maneuvers. If the failure is still not reproducible, refer to Enhanced Diagnostics for more information.
  5. Once all system malfunctions have been corrected, clear the MAGNASTEER DTCs.