Circuit/System Testing
WARNING: This page is about a different car, the 2012 GMC Yukon, 2012 Chevrolet Tahoe, and 2012 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description .
- Ignition ON, verify the scan tool hood position parameter displays Open.
- If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F.
- Ignition OFF for 1 minute, disconnect the harness connector at the ignition coil.
- Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes, test for less than 5 Ω between the ground circuit terminal B and ground.
- If greater than the specified range, repair the ground circuit for an open/high resistance.
- Test for less than 5 Ω between the low reference circuit terminal C and ground.
- If greater than the specified range, test the circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Test for less than 2 between the ignition voltage circuit terminal A and the fuse.
- If greater than the specified range, repair the ignition voltage circuit for high resistance.
- Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal A and ground.
- If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition voltage circuit fuse is open, test all components connected to the ignition voltage circuit and replace as necessary.
- If all circuits test normal, test or replace the ignition coil assembly.