FixVault

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 the CRNK relay.
  2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the relay ground circuit terminal 85 and ground.
    • If not within the specified range, test the ground circuit for an open/high resistance.
  3. Ignition OFF, connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85. Turn the ignition to the start position. The test lamp should illuminate for a maximum of 10 seconds when the ignition is held in the start position.
    • If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the ECM.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. If all circuits test normal, test or replace the CRNK relay.