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Home >> Chevrolet >> 2017 >> City Express LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 2.0L >> Diagnostic Information And Procedures >> DTC P0137-P0139 >> Circuit/System Testing

Circuit/System Testing

NOTE:

You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the B52 Heated Oxygen Sensor 2. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal 1 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.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON.
  4. Verify the scan tool HO2S parameter is approximately 450 mV.
    • If less than 450 mV 
    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 450 mV 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Ignition OFF
    4. Test for less than 2 Ω in the 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.
    • Go to next step: If 450 mV 
  5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 1.
  6. Verify the scan tool HO2S is at 0 mV.
    • If greater than 0 mV 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Ignition OFF
    4. Test for less than 2 Ω in the 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.
    • Go to next step: If at 0 mV 
  7. Replace the B52 Heated Oxygen Sensor.
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