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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 277 (Engine Controls And Fuel - 3.6L (LGX LF4) - DTC P0010 To DTC P0119 (LF4)) >> Diagnostic Information and Procedures >> DTC P0030-P0032, P0036-P0038, P0050-P0054, P0056-P0060, P0135, P0141, P0155, P0161, P103B, or P103C: HO2S Heater Control (LGX) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the appropriate B52 Heated Oxygen Sensor, ignition ON.
  2. Verify that a test lamp illuminates between the ignition voltage circuit terminal 2 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition/Vehicle » Off & Remove » Test lamp
    2. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition/Vehicle » Off & Remove » Test lamp
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test all components connected to the fuse and replace as necessary.
    • If the test lamp illuminates 
  3. Verify DTC P103B, P103C is not set.
    • If a related DTC is set 
    1. Ignition/Vehicle OFF
    2. Disconnect the electrical connector:X2@K20 Engine Control Module
    3. Disconnect the electrical connector: B52A Heated Oxygen Sensor-Bank 1 Sensor 1or B52B Heated Oxygen Sensor - Bank 1 Sensor 2
    4. Test for less than 2 Ω between the test points:Ignition circuit terminal 2 @B52D Heated Oxygen Sensor-Bank 1 Sensor 2 or B52F Heated Oxygen Sensor - Bank 2 Sensor 2.(harness side) & Terminal 28 X2 @Control module harness
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Test or replace the component:K20 Engine Control Module
    • If a related DTC is not set 
  4. Verify that a test lamp does not illuminate between the ignition voltage circuit terminal 2 and the control circuit terminal 1.
    • If the test lamp illuminates 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the control circuit 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 the test lamp does not illuminate 
  5. Remove the test lamp.
  6. Verify the scan tool HO2S 1 or 2 Heater Control Circuit High Voltage Test Status parameter is OK when commanding the HO2S Heater Sensor 1 or 2 ON with a scan tool.
    • If OK is not displayed 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the control 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.
    • If OK is displayed 
    7. NOTE:
    • Less than 10 Ω of additional resistance on the ignition voltage circuit, or control circuit may set a DTC. If there is a resistance on a circuit, the driver will remain ON and the scan tool HO2S High Voltage Test Status parameter will display OK.
    • Performing this test may set additional DTCs.
  7. Install a 10 A fused jumper wire between the control circuit terminal 1 and the ignition voltage circuit terminal 2.
    8. NOTE:

    This test may only be performed once per key cycle. If test is repeated, ignition OFF, allow the engine control module to shut down completely, then ignition ON.

  8. Verify the scan tool HO2S 1 or 2 Heater Control Circuit High Voltage Test Status parameter is Malfunction when commanding the HO2S Heater Sensor 1 or 2 ON with a scan tool.
    • If Malfunction is not displayed 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2 Ω in the control 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 Malfunction is displayed 
  9. Test or replace the B52 Heated Oxygen Sensor.
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