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Home >> Cadillac >> 2018 >> Escalade Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Engine Controls And Fuel - 6.0L (L96) - DTC P0010 To DTC P0341) >> Diagnostic Information And Procedures >> DTC P0131, P0132, P0137, P0138, P0151, P0152, P0157 Or P0158: HO2S Circuit(s) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2018 Chevrolet Suburban 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  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 - 3.0 V between the high signal circuit terminal 4 and ground.
    • If less than 1.7 V 
    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.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the high signal 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 greater than 3.0 V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Ignition ON.
    2. Test for less than 1 V between the high signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • Go to next step: If between 1.7 - 3.0 V 
  3. Verify the scan tool heated oxygen sensor Bank 1 or 2 Sensor 1 or 2 parameter is between 1.7 - 2.1 V.
    • If less than 1.7 V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the low signal circuit terminal 3 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance, replace the K20 Engine Control Module.
    • Go to next step: If between 1.7 - 2.1 V 
  4. Connect a 3 A fused jumper wire between the high signal circuit terminal 4 and the low signal circuit terminal 3.
  5. Verify the scan tool HO2S Bank 1 or 2 Sensor 1 or 2 parameter displays 0.0 V.
    NOTE: The low signal circuit is tied to a pull-up circuit within the engine control module. A voltage of 0.0 - 1.10 V on the low signal circuit is normal.
    • If greater than 0.0 V 
    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 2 Ω or greater, repair the open/high resistance in the circuit.
      • Go to next step: If less than 2 Ω
    3. Test for less than 1 V between the low signal circuit terminal 3 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • Go to next step: If 0.0 V 
  6. Verify none of the conditions listed below exist:
    • Water intrusion in the B52 heated oxygen sensor harness connector
    • Low or high fuel system pressure - Refer to Fuel System Diagnosis .
    • Fuel that is contaminated - Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Fuel saturation of the evaporative emission (EVAP) canister
    • Exhaust leaks
    • Engine vacuum leaks
    • If any of the conditions exist 

      Repair as necessary.

    • Go to next step: If none of the conditions exist 
  7. Test or replace the B52 Heated Oxygen Sensor.
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