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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls And Fuel - 2.0L (LTG) - DTC P0335 To DTC P2635 And Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC P0451-P0454: Fuel Tank Pressure Sensor >> Circuit/System Testing

Circuit/System Testing

  1. 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 B150 Fuel Tank Pressure Sensor.
  2. Test for less than 5Ω of resistance between the low reference circuit terminal 2 and ground.
    • If 5Ω 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 5Ω 
  3. Ignition ON.
  4. Test for 4.8-5.2V between the 5V reference circuit terminal 3 and ground.
    • If less than 4.8V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the 5V 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 2Ω in the 5V 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 greater than 5.2V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1V between the 5V reference circuit and ground.
    • If 1V or greater, repair the short to voltage on the circuit.
    • If less than 1V, replace the K20 Engine Control Module.
    • If between 4.8-5.2V 
  5. Verify the scan tool Fuel Tank Pressure parameter is less than 0.2V.
    • If 0.2V 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 terminal 1 and ground.
    • If 1V or greater, repair the short to voltage on the circuit.
    • If less than 1V, replace the K20 Engine Control Module.
    • If less than 0.2V 
  6. Install a 3A fused jumper wire between the signal circuit terminal 1 and the 5V reference circuit terminal 3.
  7. Verify the scan tool Fuel Tank Pressure sensor parameter is greater than 4.7V.
    • If 4.7V 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 1 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. 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 greater than 4.7V 
  8. Test or replace the B150 Fuel Tank Pressure Sensor.