Circuit/System Testing
- Ignition OFF, disconnect C401, install a 3-amp fused jumper between the signal circuit and the low reference circuit.
- Ignition ON, verify that the scan tool Fuel Tank Level Remaining parameter is less than 4 percent.
- If greater than 4 percent, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test the low reference circuit for a short to voltage or an open/high resistance.
- If all circuits test normal, replace the ECM.
- If less than 4 percent, test the signal circuit for a short to voltage or an open/high resistance between C401 and the fuel level sender. If the circuit tests normal, test the low reference circuit for a short to voltage or an open/high resistance between C401 and the fuel level sender.
- If all circuits test normal, replace the fuel level sender.