Test Procedure
- DW1 CHECK FOR DTCS
Are DTCs P0054, P0137, P0138, P013A, P013E or P0141 present?
Yes No For DTC P013A, GO to DW5.
For all others, GO to DW2.RETURN to Symptom Charts , for further direction. - 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 DTC P013E, GO to DW5.
For all others, GO to DW3. - DW3 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 DW4. - Investigate the following items as potential sources of HO2S contamination:
- DW4 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 airflow (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 DW5. - Carefully inspect the following areas for potential air leaks:
- DW5 CHECK FOR EXHAUST SYSTEM CONCERNS NOTE: Pressure above 241 kPa (35 psi) can cause damage to system components. Regulate the shop air to 34.4 - 68.9 kPa (5 - 10 psi) before connecting to the system.NOTE: Remember to remove the plastic bag from the air filter at the completion of this step.
- Place the air filter in a plastic bag to prevent air flow out of the intake port and reinstall it in the vehicle.
- Pressurize the exhaust system at the exhaust pipe outlet with 34.4 - 68.9 kPa (5 - 10 psi) regulated shop air.
- Check the exhaust system for leaks using a soap and water solution.
- Apply the soap and water solution to the following areas:
- exhaust welds, flex pipe, flanges and gaskets
- universal HO2S and mounting surface
- downstream HO2S and mounting surface
- exhaust system in between the exhaust manifold and rear HO2S
- Check the exhaust flange bolts for correct torque.
- Check the rear HO2S for correct torque.
Is a concern present?
Yes No For DTCs P013A or P013E, REPAIR as necessary.
CARRY OUT the HO2S and Catalyst OBD Monitor Drive Cycle Procedures. REFER to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE .
Clear the PCM DTCs. REPEAT the self-test.
For all others, REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.For DTCs P013A or P013E, INSTALL a new HO2S. REFER to the Service Information, Electronic Engine Controls.
CARRY OUT the HO2S and Catalyst OBD Monitor Drive Cycle Procedures. REFER to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE .
Clear the PCM DTCs. REPEAT the self-test.
For all others, GO to DW6. - DW6 CHECK FOR VPWR
- HO2S connector disconnected.
- Check the connector (both halves) for any water contamination.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) HO2S Connector, Harness Side (-) VPWR - Pin 1 Ground
Is the voltage greater than 10.5 V?
Yes No GO to DW7. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test. - DW7 CHECK THE HO2S CIRCUITS FOR AN OPEN
- Ignition OFF.
- PCM connector disconnected.
- Measure the resistance between:
(+) HO2S Connector, Harness Side (-) PCM Connector, Harness Side HO2S12 - Pin 4 HO2S12 - Pin E21 HTR12 - Pin 2 HTR12 - Pin E35 SIGRTN - Pin 3 SIGRTN - Pin E9
Are the resistances less than 5 ohms?
Yes No GO to DW8. REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test. - DW8 CHECK THE HO2S CIRCUITS FOR A SHORT
- Measure the resistance between:
(+) HO2S Connector, Harness Side (-) HO2S Connector, Harness Side HO2S12 - Pin 4 SIGRTN - Pin 3 HO2S12 - Pin 4 HTR12 - Pin 2 HTR12 - Pin 2 SIGRTN - Pin 3 - Measure the resistance between:
(+) HO2S Connector, Harness Side (-) HO2S12 - Pin 4 Ground HTR12 - Pin 2 Ground
Are the resistances greater than 10K ohms?
Yes No GO to DW9. REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. - Measure the resistance between:
- DW9 CHECK THE HO2S CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) HO2S Connector, Harness Side (-) HO2S12 - Pin 4 Ground HTR12 - Pin 2 Ground SIGRTN - Pin 3 Ground
Is any voltage present?
Yes No REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to DW10. - DW10 CHECK THE INTERNAL RESISTANCE OF THE HO2S HEATER
- Ignition OFF.
- Measure the resistance between:
(+) HO2S Connector, Component Side (-) HO2S Connector, Component Side HTR12 - Pin 2 VPWR - Pin 1
Is the resistance between 3 - 30 ohms?
Yes No GO to DW11. INSTALL a new HO2S. REFER to the Service Information, Electronic Engine Controls. RESET the keep alive memory (KAM). REFER to Diagnostic Methods .
REPEAT the self-test. - DW11 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 O2S12 (VOLT) 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.GO to DW12. - DW12 CHECK THE HO2S SIGNAL
- Ignition OFF.
- HO2S connector disconnected.
- Ignition ON, engine running.
- Access the PCM and monitor the O2S12 (VOLT) PID.
Is the voltage less than 1 V?
Yes No GO to DW13. GO to DW14. - DW13 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 HO2S12 - Pin 4 VPWR - Pin 1 - Ignition ON, engine running.
- Access the PCM and monitor the O2S12 (VOLT) PID.
Is the voltage greater than 1 V?
Yes No INSTALL a new HO2S. REFER to the Service Information, Electronic Engine Controls.
Clear the PCM DTCs. REPEAT the self-test.GO to DW14. - DW14 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 RESETTING THE KEEP ALIVE MEMORY (KAM) The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.