LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2012 >> Cruze Eco, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 140 (Engine Cooling System) >> Diagnostic Information and Procedures >> DTC P0480 or P0481 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect both KR20 Cooling Fan Relays.
    2. NOTE: The following tests must be performed on each fan relay.
  2. Ignition ON, verify that a test lamp illuminates between ground and the relay coil B+ circuit terminal listed below:
    • KR20C low speed COOL FAN 1 relay terminal 85
    • KR20D high speed COOL FAN 2 relay terminal 85
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the output control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the G10 engine cooling fan.
    3. NOTE: The following tests must be performed on each fan relay.
  3. Connect the red lead of the DMM to a control circuit terminal listed below. Connect the black lead to ground. Set the DMM on the diode setting. The DMM should display OL:
    • KR20C low speed COOL FAN 1 relay terminal 86
    • KR20D high speed COOL FAN 2 relay terminal 86
    • If less than the specified range, test the appropriate relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
    4. NOTE: The following tests must be performed on each fan relay.
  4. Command the KR20 cooling fan relay ON and OFF with a scan tool. The DMM should transition from OL when commanded OFF to less than 1 V when commanded ON.
    • If the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. If all circuits test normal, test or replace the appropriate KR20 cooling fan relay.
scientia non olet · About LEMON Manuals