CRNK Relay Circuit Malfunction
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.
- Ignition ON, observe the scan tool ECM Ignition 1 parameter. The reading should be B+ voltage.
- If not the specified value, test the ECM/TRANS ignition circuit terminal 54 X2 (LNF) or terminal 19 X1 (L61/LE5) for a short to ground or an open/high resistance.
- Ignition OFF, disconnect the CRNK relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) .
- Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the ground circuit terminal 85 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
- Connect a test lamp between the ground circuit terminal 85 and the control circuit terminal 86.
- Ignition ON, transmission in Park (MN5) or clutch pedal pressed (M86/MU3). Command the starter relay ON and OFF with a scan tool (L61/LNF), or turn the ignition switch between the start and run positions (LE5). The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always ON, test the control circuit for a 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.
- Ignition OFF, connect the CRNK relay. Disconnect the X1 harness connector at the starter solenoid.
- Ignition ON, transmission in park (MN5) or clutch pedal pressed (M86/MU3). Command the starter relay ON with a scan tool (L61/LNF), or turn the ignition switch to the START position (LE5). Verify that a test lamp illuminates between the starter terminal A X1 and ground.
- If the test lamp does not illuminate, test the starter control circuit for an open/high resistance. If the circuit tests normal, test or replace the CRNK relay.
- If all circuits test normal, test or replace the starter.