Circuit/System Testing (Hybrid)
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition ON, attempt to establish communication with the ECM with a scan tool.
- If no communication with the ECM, refer to Control Module References for further diagnosis.
- Ignition OFF, disconnect the harness connector of the ECM.
- Ignition ON, verify that 1.5-3.4 volts is available between the CAN serial data low and the CAN serial data high circuits.
- If the voltage is not within the specified range, replace the ECM.
- Ignition OFF, test the CAN communication circuits between the ECM and the TCM for an open, short to ground, or a short to voltage.
- If the circuits/connections test OK, replace the TCM.