Circuit/System Testing
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- 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, disconnect the FAN CNTRL relay.
- Connect a 30A fused jumper between the normally-open switch contacts terminal 30 and terminal 87 at the FAN CNTRL relay connector in order to complete the left fan ground circuit. Leave this jumper in place for the remainder of this procedure.
- Ignition OFF, disconnect the affected relays.
- For DTC P0480 - FAN LO relay
- For DTC P0481 - FAN HI relay
- For DTC P0482
- FAN Mid 1 relay
- FAN CNTRL relay
- FAN Mid 2 relay
- Verify that a test lamp does not illuminate between B+ and the affected relay control circuit terminal.
- FAN LO relay - Terminal 86
- FAN Mid 1 relay - Terminal 86
- FAN CNTRL relay - Terminal 85
- FAN Mid 2 relay - Terminal 86
- FAN HI relay - Terminal 86
- If the test lamp illuminates, test the relay control circuit for a short to ground. If the circuit tests normal, replace the ECM.
- Install a 3A fused jumper wire between the affected relay control circuit terminal and ground.
- FAN LO relay - Terminal 86
- FAN Mid 1 relay - Terminal 86
- FAN CNTRL relay - Terminal 85
- FAN Mid 2 relay - Terminal 86
- FAN HI relay - Terminal 86
- Command the affected relay ON with a scan tool. Verify the scan tool affected relay control circuit Short Grnd Test Status Parameter is Fault.
- If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Connect a 30A fused jumper between the positive voltage terminal at the battery and the fan voltage supply circuit terminal at the affected relay connector and verify fan activation.
- FAN LO relay - Terminal 30
- FAN Mid 1 relay - Terminal 30
- FAN CNTRL relay - Terminal 87A
- FAN Mid 2 relay - Terminal 87
- FAN HI relay - Terminal 87
- If the fan does not activate, test the engine coolant fan resistor for an open, if the resistor tests normal, test the fan voltage supply circuit for a short to ground or open/high resistance. If the circuit tests normal, test the fan ground circuit for an open/high resistance. If the circuits test normal, replace the fan.
- Ignition ON, connect a 30A fused jumper between the relay switch voltage supply circuit terminal and the fan voltage supply circuit terminal at the affected relay connector and verify fan activation.
- FAN LO relay - Terminal 87 to Terminal 30
- FAN Mid 1 relay - Terminal 87 to Terminal 30
- FAN Mid 2 relay - Terminal 30 to Terminal 87
- FAN HI relay - Terminal 30 to Terminal 87
- If the fan does not activate, test the affected relay switch voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, test all connected components and replace as necessary.
- Ignition ON, verify that a test lamp illuminates between the affected relay coil voltage supply circuit terminal and ground.
- FAN LO relay - Terminal 85
- FAN Mid 1 relay - Terminal 85
- FAN CNTRL relay - Terminal 86
- FAN Mid 2 relay - Terminal 85
- FAN HI relay - Terminal 85
- If the test lamp does not illuminate, test the affected relay coil voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, test all connected components and replace as necessary.
- If all circuits and the ECM test normal, replace the affected relay.