LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1136 (Engine Cooling System) >> Diagnostic Information and Procedures >> DTC P0480, P0481, P0691, P0692, P0693, or P0694 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect all three cooling fan relays.
    2. IMPORTANT: The following test must be performed on all three fan relay circuits.
  2. Ignition ON, verify that a test lamp illuminates between ground and the relay coil ignition circuit terminal listed below:
    • Fan 1 and Fan 3 relays terminal 85
    • Fan 2 relay terminal 86
    • If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay coil ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.
    3. IMPORTANT: The following test must be performed on all three fan relay circuits.
  3. Test for 2.6-4.6 volts between ground and the relay coil control circuit terminal listed below:
    • Fan 1 and Fan 3 relays terminal 86
    • Fan 2 relay terminal 85
    • If less than the specified range, test the relay coil control circuit for an open/high resistance or for a short to ground. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the relay coil control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
    4. IMPORTANT: The following test must be performed on all three fan relay circuits.
  4. Connect a test lamp between the relay coil control circuit and the relay coil ignition circuit, terminals 85 and 86.
  5. Command the fan relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always OFF, replace the ECM.
  6. If all circuits test normal, test or replace the relay.
scientia non olet · About LEMON Manuals