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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 15 (Engine Controls And Fuel - 2.4L - DTC P0114 To DTC P0604) >> Diagnostic Information and Procedures >> DTC P0131, P0132, P0134, P0137, P0138, P0140, or P2A00: HO2S Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition OFF and all vehicle systems OFF, disconnect the appropriate B52 Heated Oxygen Sensor harness connector. It may take up to 2 minutes for all vehicle systems to power down. Ignition ON.
  2. Test for 1.7-3.0V between the high signal circuit terminal B and ground.
    • If less than 1.7V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the high signal 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 high 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 3.0V 
    1. Ignition OFF, disconnect the harness connector at the K20 engine Control Module. Ignition ON.
    2. Test for less than 1V between the high signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • If between 1.7-3.0V 
  3. Verify the scan tool HO2S1 or 2 parameter is between 1.7-2.1V.
    • If less than 1.7V 
    1. Ignition OFF, disconnect the harness connector at the K20 engine Control Module.
    2. Test for infinite resistance between the low signal circuit terminal A 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 between 1.7-2.1V 
  4. Connect a 3A fused jumper wire between the high signal circuit terminal B and the low signal circuit terminal A.
    5. NOTE:

    The low signal circuit is tied to a pull-up circuit within the engine control module. A voltage of 0.0-1.10V on the low signal circuit is normal.

  5. Verify the scan tool HO2S1 or 2 parameter displays 0.0V.
    • If greater than 0.0V 
    1. Ignition OFF, disconnect the harness connector at the K20 engine Control Module. Ignition ON.
    2. Test for less than 2 Ω in the low signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω
    3. Test for less than 1 V between the low signal circuit terminal A 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 0.0V 
  6. Verify none of the following conditions exist:
    • If any of the conditions exist 

      Repair as necessary.

    • If none of the conditions exist 
  7. Test or replace the B52 Heated Oxygen Sensor.
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