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Test Procedure

  1. DW1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) 

    Are DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0041, P0053, P0054, P0060, P00D2, P0130, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0139, P013A, P013B, P013C, P013E, P0140, P0141, P014A, P0157, P0158, P0159, P0161, P016A, P1127, P2297, P2A01, or P2A04 present? 

    Yes No
    GO to DW2  . For all others, GO to Section 4, DTC List DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .
  2. DW2 VISUALLY INSPECT THE HO2S HARNESS 
    • Ignition OFF.
    • Verify the HO2S connectors are connected to the correct engine bank.
    • Visually inspect for:
      • crossed sensor wires
      • pinched, shorted, and corroded wiring and pins
      • oil or water contamination
      • damaged HO2S

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For DTCs P0133, P0140 or P2297, GO to DW3  .
    For DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0053, P0054, P0060, P0135, P0141 or P0161, GO to  DW14.
    For DTC P1127, GO to  DW19.
    For all others, GO to  DW5.
  3. DW3 CHECK THE HO2S RESPONSE TEST RESULTS 

    Is the indicated value greater than the minimum threshold? 

    Yes No
    The system is operating correctly at this time.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to DW4  .
  4. DW4 CARRY OUT THE KOER SELF-TEST 
    • Engine at normal operating temperature.
    • Carry out the PCM KOER self-test.

    Are DTCs P0040, P0041 or P1127 present? 

    Yes No
    For DTC P1127, GO to  DW19.
    For all others, GO to  DW8.    		 GO to DW5  .
  5. DW5 CHECK FOR A SOURCE OF POTENTIAL HO2S CONTAMINATION 
    • Investigate the following items as potential sources of HO2S contamination:
      • use of unapproved silicon sealers
      • fuel contaminated by silicon additives
      • excessive oil consumption
      • glycol leaking internally in the engine
      • contaminated fuel
      • short drive cycles in cold weather
      • use of unapproved cleaning agents

    Is a concern present? 

    Yes No
    REPAIR the source of the contamination.
    CHANGE the engine oil and oil filter.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.    		 GO to DW6  .
  6. DW6 CHECK FOR UNMETERED AIR LEAKS 
    NOTE: Fuel calculations can be affected by unmetered air leaks.
    • Carefully inspect the following areas for potential air leaks:
      • hoses connecting to the mass air flow (MAF) sensor assembly
      • hoses connecting to the throttle body
      • intake manifold gasket leaks
      • positive crankcase ventilation (PCV) system
      • the vacuum lines are disconnected
      • incorrectly seated engine oil dipstick, tube or oil fill cap

    Are any air leaks present? 

    Yes No
    REPAIR the source of the air leak. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.    		 GO to DW7  .
  7. DW7 CHECK FOR EXHAUST SYSTEM AND FUEL SELECTION CONCERNS 
    • Inspect the exhaust system for the following:
      • exhaust leaks at flanges and gaskets
      • exhaust leaks at the HO2S
      • aftermarket accessories and performance modifications
    • Verify with the customer that flex fuel is not being used on a non-flex fuel vehicle.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to DW8  .
  8. DW8 CHECK THE HO2S SIGNAL 
    NOTE: Diagnose the suspect sensor indicated by the DTC.
    NOTE: Verify the harness pins are in the correct location.
    NOTE: HO2S is displayed as O2S on the scan tool.
    • Ignition OFF.
    • HO2S connector disconnected.
    • Ignition ON, engine running.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage less than 1.1 V? 

    Yes No
    GO to DW9  . GO to  DW10.
  9. DW9 CHECK THE HO2S CIRCUIT CONTINUITY 
    • Ignition OFF.
    • Connect a 5 amp fused jumper wire between the following:
      Point A HO2S Connector, Harness Side Point B HO2S Connector, Harness Side
      HO2S Signal VPWR
    • Ignition ON, engine running.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage greater than 1 V? 

    Yes No
    INSTALL a new HO2S. REFER to the appropriate Electronic Engine Controls article.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to DW10  .
  10. DW10 CHECK THE HO2S CIRCUITS FOR AN OPEN 
    • Ignition OFF.
    • Remove the jumper wires, if connected.
    • Check the connector (both halves) for any water contamination.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) PCM Connector, Harness Side (-) HO2S Connector, Harness Side
      HO2S Signal HO2S Signal
      SIGRTN SIGRTN

    Are the resistances less than 5 ohms? 

    Yes No
    GO to DW11  . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  11. DW11 CHECK THE HO2S CIRCUIT FOR A SHORT 
    • Measure the resistance between:
      (+) HO2S Connector, Harness Side (-) HO2S Connector, Harness Side
      HO2S Signal SIGRTN
      HO2S Signal VPWR
    • Measure the resistance between:
      (+) HO2S Connector, Harness Side (-)
      HO2S Signal Ground

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to DW12  . REPAIR the short circuit. Clear the PCM DTCs.
    REPEAT the self-test.
  12. DW12 CHECK THE HO2S CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) HO2S Connector, Harness Side (-)
      HO2S Signal Ground

    Is any voltage present? 

    Yes No
    REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to DW13  .
  13. DW13 CARRY OUT A THOROUGH WIGGLE TEST ON THE HO2S HARNESS 
    • Ignition OFF.
    • PCM connector connected.
    • HO2S connector connected.
    • Ignition ON, engine OFF.
    • Access the PCM and monitor the HO2S Signal PID.
    • Carry out a thorough wiggle test on the HO2S harness.

    Does the voltage change during the wiggle test? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For DTC P00D2, GO to DW14  .
    For all others, GO to  DW20.
  14. DW14 CHECK FOR VPWR 
    NOTE: Diagnose the suspect sensor indicated by the DTC.
    • Ignition OFF.
    • HO2S connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) HO2S Connector, Harness Side (-) HO2S Connector, Harness Side
      VPWR SIGRTN

    Is the voltage greater than 10.5 V? 

    Yes No
    GO to DW15  . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  15. DW15 CHECK THE HO2S HEATER FOR SHORT CIRCUITS 
    • Ignition OFF.
    • PCM connector disconnected.
    • Measure the resistance between:
      (+) HO2S Connector, Harness Side (-)
      HO2SHTR Ground
    • Measure the resistance between:
      (+) HO2S Connector, Harness Side (-) HO2S Connector, Harness Side
      HO2SHTR VPWR
      HO2SHTR SIGRTN
      HO2SHTR HO2S Signal

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to DW16  . REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.
  16. DW16 CHECK THE HO2S HEATER CIRCUIT FOR AN OPEN 
    • Measure the resistance between:
      (+) PCM Connector, Harness Side (-) HO2S Connector, Harness Side
      HO2SHTR HO2SHTR

    Is the resistance less than 5 ohms? 

    Yes No
    GO to DW17  . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.
  17. DW17 CHECK THE INTERNAL RESISTANCE OF THE HO2S HEATER 
    • Measure the resistance between:
      (+) HO2S Connector, Component Side (-) HO2S Connector, Component Side
      HO2SHTR VPWR

    Is the resistance between 3 - 30 ohms? 

    Yes No
    GO to DW18  . INSTALL a new HO2S. REFER to the appropriate Electronic Engine Controls article. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  18. DW18 CHECK THE HO2S HEATER CIRCUIT A SHORT 
    • Measure the resistance between:
      (+) HO2S Connector, Component Side (-) HO2S Connector, Component Side
      HO2SHTR SIGRTN
    • Measure the resistance between:
      (+) HO2S Connector, Component Side (-)
      HO2SHTR Ground

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  DW20. INSTALL a new HO2S. REFER to the appropriate Electronic Engine Controls article. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .
    REPEAT the self-test.
  19. DW19 EXHAUST TEMPERATURE OUT OF RANGE 
    NOTE: Address all other DTCs before proceeding.
    • Ignition ON, engine running.
    • Engine at normal operating temperature.
    • Access the PCM and monitor the HTR11 (MODE) PID.

    Is the PID state ON? 

    Yes No
    CARRY OUT the KOER self-test. RUN the engine until the PID indicates ON. CARRY OUT the KOER self-test.
  20. DW20 CHECK FOR CORRECT PCM OPERATION 
    • Ignition OFF.
    • Disconnect all the PCM connectors.
    • Visually inspect for:
      • pushed out pins
      • corrosion
    • Connect all the PCM connectors and make sure they seat correctly.
    • Carry out the PCM self-test.
    • Verify the concern is still present.

    Is the concern still present? 

    Yes No
    INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) , Programming the VID Block for a Replacement PCM. The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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