LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1691 (Hybrid Controls - DTC P181C To DTC P2792) >> DTC P1A89 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. 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.