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Home › Buick › 2016 › Cascada Base › Repair and Diagnosis › Electrical › Instrument Panel System Displays And Gauges › Diagnostic Information and Procedures › DTC P250A: Engine Oil Level Sensor/Switch › Circuit/System Testing

Circuit/System Testing

NOTE:
  • Circuit/System Verification must be performed before proceeding with Circuit/System Testing.
  • Verify proper engine oil level before continuing with diagnosis.
  1. Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the B35 Engine Oil Level Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 2 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    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 K20 Engine Control Module.
    • If less than 10 Ω 
  3. Ignition ON
  4. Verify the scan tool Engine Oil Level Switch parameter reads low.
    • If the Engine Oil Level Switch parameter reads OK 

      Test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

    • If the Engine Oil Level Switch parameter reads Low 
    5. NOTE:

    If a short to voltage is found on the signal circuit, the fuse in the 3A jumper wire will open.

  5. Install a 3A fused jumper wire between the signal circuit terminal 1 and the ground circuit terminal 2.
  6. Verify the scan tool Engine Oil Level Switch parameter reads OK.
    • If the Engine Oil Level Switch parameter reads Low 

      Test the signal circuit terminal A for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

    • If the Engine Oil Level Switch parameter reads OK 
  7. Test or replace the B35 Engine Oil Level Switch.
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