Circuit/System Testing

Ignition OFF, all vehicle systems OFF, this may take up to 2 min, for all vehicle systems to power down. Disconnect the harness connector at the A7 Fuel Pump and Level Sensor Assembly, ignition ON.
Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 4 and ground.
- If less than 4.8 V
1. Ignition OFF, disconnect the 5 V reference circuit at each end. Ignition ON.
2. Test for infinite resistance between the 5 V reference circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance
3. Test for less than 2 Ω on the 5 V reference circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the ECM.
- If greater than 5.2 V
1. Ignition OFF, disconnect the 5 V reference circuit at each end. Ignition ON.
2. Test for less than 1 V between the 5 V reference circuit and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V, replace the ECM.
Ignition OFF, all vehicle systems OFF, this may take up to 2 min, for all vehicle systems to power down. Disconnect the harness connector at the A7 Fuel Pump and Level Sensor Assembly.
Test for less than 5 Ω of resistance between the low reference circuit terminal 3 and ground.
- If 5 Ω or greater
1. Ignition OFF, disconnect the harness connector at the ECM.
2. Test for less than 2 Ω in the low reference circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the ECM.
- Go to next step: If less than 5 Ω
If all circuits test normal, test the B48 Fuel Temperature Sensor and B75 MAF/IAT sensor.