Circuit/System Testing

Primary Fuel Level Sensor Malfunction

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the A7 Fuel Pump and Level Sensor Assembly. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10Ω between the low reference circuit terminal 3 and ground.
   • If 10Ω or greater 
   1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
   2. Test for less than 2Ω in the low reference circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
   • If less than 10Ω 
3. Ignition ON.
4. Verify the scan tool Fuel Level Sensor Left Tank parameter is greater than 4.8 V.
   • If 4.8 V or less 
   1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
   2. Test for infinite resistance between the signal circuit terminal 4 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
   • If greater than 4.8 V 
5. Install a 3A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 3.
6. Verify the scan tool Fuel Level Sensor Left Tank parameter is less than 0.2 V.
   • If 0.2 V or greater 
   1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
   2. Test for less than 1V between the signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V
   3. Ignition OFF
   4. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
   • If less than 0.2 V 
7. Test or replace the B46 Fuel Level Sensor.

Secondary Fuel Level Sensor Malfunction

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B46B Fuel Level Sensor - Secondary. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10Ω between the low reference circuit terminal 3 and ground.
   • If 10Ω or greater 
   1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
   2. Test for less than 2Ω in the low reference circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
   • If less than 10Ω 
3. Ignition ON.
4. Verify the scan tool Fuel Level Sensor Right Tank parameter is greater than 4.8 V.
   • If 4.8 V or less 
   1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
   2. Test for infinite resistance between the signal circuit terminal 4 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
   • If greater than 4.8 V 
5. Install a 3A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 3.
6. Verify the scan tool Fuel Level Sensor Right Tank parameter is less than 0.2 V.
   • If 0.2 V or greater 
   1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
   2. Test for less than 1V between the signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V
   3. Ignition OFF
   4. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
   • If less than 0.2 V 
7. Test or replace the B46B Fuel Level Sensor - Secondary.