Circuit/System Testing
- Ignition OFF, disconnect C401.
- Ignition ON, verify that the scan tool Fuel tank Level Remaining parameter is greater than 98 percent.
- If less than 98 percent, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
- If greater than 98 percent, test the signal circuit for a short to ground between C401 and the fuel level sender. If the circuit tests normal, replace the fuel level sender.