FixVault
Home › Cadillac › 2012 › Escalade EXT › Repair and Diagnosis › External Pages › Different car › Section 1220 (Hybrid Engine Control System) › Diagnostic Information and Procedures › DTC P1A89 › Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
  1. Disconnect the 42 Volt harness connector at the APM.
  2. Turn the ignition to ON.
  3. Use the APM Intermediate Voltage Control on the scan tool to turn on the 42 volt circuit.
    • If the voltage is greater than 40 volts, replace the power steering control module (PSCM).
    • If the voltage is less than 40 volts, replace the APM.
About FixVault