LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 2004 >> Focus LX, 2.0 P, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Pinpoint Test DX: Engine Coolant Temperature (ECT) Sensor Through Pinpoint Test HC: Fuel Delivery System - CNG, Flex-Fuel & Gasoline >> Pinpoint Test H: Fuel Control >> Test Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Procedure

  1. H1 PERFORM THE KOER SELF-TEST 
    NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION  table of fault code setting condition.
    FAULT CODE SETTING CONDITION

    Fault Code KOEO KOER Continuous Memory
    P0040 1     H69  
    P0041 1     H69  
    P0053  H12  H12  H12
    P0054  H12  H12  H12
    P0055  H12  H12  H12
    P0059  H12  H12  H12
    P0060  H12  H12  H12
    P0061  H12  H12  H12
    P0131    H7  H7
    P0132      H60
    P0133      H2
    P0135 1   H10  H10  H10
    P0136      H58
    P0138  H60  H60  H60
    P0141 1   H10  H10  H10
    P0144  H60  H60  H60
    P0147  H10  H10  H10
    P0151      H7
    P0152    H70  H70
    P0153      H2
    P0155 1   H10  H10  H10
    P0156      H58
    P0158    H70  H70
    P0161 1   H10  H10  H10
    P0167  H10  H10  H10
    P0171 1       H17
    P0172 1       H22
    P0174 1       H17
    P0175 1       H22
    P0201 1   H41  H41  H41
    P0202 1   H41  H41  H41
    P0203 1   H41  H41  H41
    P0204 1   H41  H41  H41
    P0205 1   H41  H41  H41
    P0206 1   H41  H41  H41
    P0207 1   H41  H41  H41
    P0208 1   H41  H41  H41
    P0209 1   H41  H41  H41
    P0210 1   H41  H41  H41
    P0211 1   H41  H41  H41
    P0212 1   H41  H41  H41
    P1127 1     H68  
    P1128 1     H69  
    P1129 1     H69  
    P1130 1       H17
    P1131 1     H17  H17
    P1132 1   H22  H22  H22
    P1137    H58  
    P1138    H58  
    P1150 1       H17
    P1151 1     H17  H17
    P1152 1   H22  H22  H22
    P1157 1     H58  
    P2195 1     H17  H17
    P2196 1   H22  H22  H22
    P2197 1     H17  H17
    P2198 1   H22  H22  H22
    P2270    H58  H58
    P2271    H58  H58
    P2272    H58  H58
    P2273    H58  H58
    P2274    H58  H58
    P2275    H58  H58
    P2278 1     H69  
    (1)
    For Natural Gas Engines see FAULT CODE SETTING CONDITION 
    • Engine at normal operating temperature.
    • Check for self-test DTCs.

    Are DTCs P0040, P0041, P1127, P1128, P1129 or P2278 present? 

    Yes No
    Key in OFF position.
    DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS .    		 GO to  H2.
  2. H2 CONTINUOUS MEMORY DTCS P0133 AND P2190: HO2S RESPONSE TEST 
    • Key ON, engine OFF.
    • Select 'Generic OBD II Function'.
    • Press CONTINUE.
    • Select 'Diagnostic Monitoring Test Results'.
    • Scroll to Test ID: 01.
    • Key in OFF position.

    Is the indicated value greater than the minimum threshold? 

    Yes No
    Key in OFF position. CLEAR the DTCs.
    Carry out the HO2S monitor drive cycle.
    GO to  H1.    		 GO to  H3.
  3. H3 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 MAF sensor assembly.
      • Hoses connecting to the throttle body.
      • Intake manifold gasket leaks.
      • PCV disconnected.
      • The vacuum lines are disconnected.
      • Improperly seated engine oil dipstick, tube or oil fill cap.
      • Exhaust leaks at flanges and gaskets.

    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) .    		 GO to  H4.
  4. H4 CHECK HO2S CIRCUIT CONTINUITY 
    • HO2S connector disconnected.
    • Check the connector (both halves) for any water contamination.
    • 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
    • Key ON, engine running.
      NOTE: HO2S is displayed as O2S on the diagnostic tool.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage greater than 1 V? 

    Yes No
    Key in OFF position. INSTALL a new HO2S.
    CHANGE the engine oil filter.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .    		 Key in OFF position.
    GO to  H5.
  5. H5 CHECK THE HO2S CIRCUIT(S) FOR AN OPEN IN THE HARNESS 
    • Remove the jumper wire(s).
      NOTE: A vehicle hoist may be required to access the HO2S harness.
    • Visually inspect the HO2S harness for exposed wiring, water contamination, corrosion, and proper assembly.
    • 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  H6. REPAIR the open circuit.
    Carry out the HO2S monitor drive cycle.
  6. H6 CHECK THE HO2S CIRCUIT FOR A SHORT TO VPWR IN THE HARNESS 
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      HO2S Signal VPWR

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  H7. GO to  H9.
  7. H7 DTC P0131: 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 burning. (rings, valve seals, oil overfill).
      • Glycol leaking internally in the engine.
      • Lead-contaminated fuel.
      • Short drive cycles in cold weather.
      • Use of unapproved cleaning agents.

    Were any of the above conditions or concerns found during inspection? 

    Yes No
    Repair the source of contamination.
    CHANGE the engine oil filter.
    RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .    		 GO to  H8.
  8. H8 DETERMINE THE DTC BEING DIAGNOSED 

    Are you diagnosing DTC P0141 or P0161? 

    Yes No
    GO to  H10. GO to  H9.
  9. H9 VERIFY THE HARNESS PINS ARE IN THE PROPER LOCATION 
    • 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
      INSTALL a new HO2S. REPAIR as necessary.
  10. H10 DTCS P0135, P0141, P0147, P0155, P0161 OR P0167: VISUALLY INSPECT THE HO2S HARNESS 
    • PCM connector connected.
    • Visually inspect the HO2S harness for exposed wiring, water contamination, corrosion, and proper assembly.

    Were any exposed wiring, contamination, corrosion and correct assembly concerns present? 

    Yes No
    REPAIR as necessary. GO to  H11.
  11. H11 PERFORM KOEO THE ON-DEMAND SELF-TEST 
    • Key ON, engine OFF.

    Are any of the following DTCs present: P0135, P0141, P0147, P0155, P0161 or P0167  .

    Yes No
    Key in OFF position.
    GO to  H12.    		 Key in OFF position.
    GO to  H13.
  12. H12 DTCS P0053, P0054, P0055, P0059, P0060 AND P0061: CHECK FOR VPWR IN THE HARNESS 
    NOTE: If DTCs are present, test their related circuits individually.
    • HO2S connector disconnected.
    • Key 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
    Key in OFF position
    GO to  H13.    		 REPAIR the open circuit.
    Check fuses.
  13. H13 CHECK THE HO2S HEATER FOR SHORTS IN THE HARNESS 
    • HO2S connector disconnected.
    • PCM connector disconnected.
      NOTE: If DTCs P0053, P0054, P0055, P0059, P0060 or P0061 are present, test their related circuits individually.
    • Measure the resistance between:
      ( + ) HO2S Connector, Harness Side ( - ) Vehicle Battery
      HO2S Heater Negative terminal
    • Measure the resistance between:
      ( + ) HO2S Connector, Harness Side ( - ) HO2S Connector, Harness Side
      HO2S Heater VPWR
      HO2S Heater SIGRTN
      HO2S Heater HO2S Signal

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  H14. REPAIR the short circuit.
  14. H14 CHECK THE HO2S CIRCUIT FOR AN OPEN IN THE HARNESS 
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) HO2S Connector, Harness Side
      HO2S Heater HO2S Heater

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  H15. REPAIR the open circuit.
  15. H15 CHECK THE INTERNAL RESISTANCE OF HO2SHTR 
    • Measure the resistance between:
      ( + ) HO2S Connector, Component Side ( - ) HO2S Connector, Component Side
      HO2S Heater VPWR

    Is the resistance between 3 ohms - 30 ohms? 

    Yes No
    GO to  H16. INSTALL a new HO2S.
  16. H16 CHECK THE HO2S CASE FOR A SHORT TO VPWR, HTR AND SIGRTN 
    • Measure the resistance between:
      ( + ) HO2S Connector, Component Side ( - ) HO2S Connector, Component Side
      HO2S Heater SIGRTN
    • Measure the resistance between:
      ( + ) HO2S Connector, Component Side ( - ) Vehicle Battery
      HO2S Heater Negative terminal

    Is the resistance greater than 10K ohms? 

    Yes No
    INSTALL a new PCM. INSTALL a new HO2S.
  17. H17 DTCS P0171, P0174, P1130, P1131, P1150, P1151, P2195 OR P2197: LEAN SYSTEM DTCS 
    NOTE: Do not clear the DTCs or reset the keep alive memory (KAM).
    • Access the PCM and record the ECT PID from the freeze frame data. The freeze frame data is used to recreate the concern.
    • Retrieve and record the self-test DTCs.

    Are any DTCs present other than the following: P0171, P0174, P1130, P1131, P1150, P1151, P2195 or P2197? 

    Yes No
    DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS . GO to  H18.
  18. H18 CARRY OUT A VISUAL INSPECTION ON THE INTAKE AIR SYSTEM AND ALL VACUUM HOSES 
    • Check the intake air system for leaks, obstructions, and damage.
    • Inspect the entire length of all the vacuum hoses for:
      • proper connections.
      • damage or cracks.
      • damaged or cracked vacuum tees.
    • Verify the integrity of the positive crankcase ventilation (PCV) system.
    • Verify the proper PCV valve part number.

    Is a concern present? 

    Yes No
    GO to  H21. GO to  H19.
  19. H19 CHECK FOR THE PRESENCE OF A VACUUM LEAK 
    NOTE: Fuel trim values at idle are more sensitive to a vacuum leak. The vacuum leak (unmetered air) represents a larger portion of the total air flow at idle than at part throttle.
    NOTE: The barometric pressure (BARO) PID is not a recommended PID to monitor when diagnosing a vacuum leak. Barometric pressure is calculated ring high engine load, when the vacuum leak represents a small
    portion of the total air flow.
    NOTE: When calculating the total fuel correction in the following steps, if LONGFT1 equals +13% and SHRTFT1 equals +23%, the total fuel correction for bank 1 equals +36%. If LONGFT2 equals +24% and SHRTFT2 equals -3% the total fuel correction for bank 2 equals +21%.
    NOTE: If the freeze frame ECT PID is available, stabilize the engine at the temperature recorded by the freeze frame ECT PID. If the freeze frame ECT PID is not available, maintain the engine coolant temperature between 82°C - 101°C (180°F - 215°F) and the intake air temperature less than 46°C (115°F).
    • Key ON, engine running.
    • Access the PCM and monitor the ECT, CHT and IAT PIDs.
    • Access the PCM and monitor the LONGFT1, SHRTFT1, LONGFT2 and SHRTFT2 PIDs.
    • Allow the engine to stabilize at the temperature necessary to recreate the concern.
    • Mathematically add and record the LONGFT PID value to the SHRTFT PID value for each bank, for a total fuel correction at idle.
    • Increase the engine speed to 2,500 RPM for 10 seconds.
    • Record the LONGFT1, SHRTFT1, LONGFT2, and SHRTFT2 PID values.
    • Mathematically add and record the LONGFT PID value to the SHRTFT PID value for each bank, for a total fuel correction at 2,500 RPM.

    Is the total fuel correction value difference, between idle and 2,500 RPM, less than 15 percent? 

    Yes No
    No vacuum leak is present
    GO to  H23.    		 GO to  H20.
  20. H20 LOCATE THE VACUUM LEAK 
    CAUTION: Do not clamp or pinch a hard plastic hose. Use a vacuum cap or equivalent to restrict the hose.
    NOTE: Restricting the EVAP vapor hose while the EVAP emission canister is purging may shift the SHRTFT. Carry out a visual inspection as necessary.
    NOTE: When monitoring for a decrease in the SHRTFT PIDs in the following steps, if SHRTFT1 equals +15% and the hose is restricted, SHRTFT1 decreases to -7%. The total decrease in the SHRTFT PIDs equals 22%.
    • Locate the vacuum tees for the intake air and PCV systems.
    • Access the PCM and monitor the SHRTFT1 and SHRTFT2 PIDs.
    • Restrict the vacuum lines one at a time for 30 seconds. If a vacuum leak is present, the SHRTFT PID values will decrease as the hose is restricted.

    Is the decrease in the SHRTFT PIDs greater than 15 percent when one of the vacuum hoses is restricted? 

    Yes No
    GO to  H21. INSPECT the intake air system for a vacuum leak in the intake manifold or intake gaskets. REPAIR as necessary. For repair verification,
    GO to  H21.
  21. H21 VACUUM LEAK REPAIR VERIFICATION 
    NOTE: If the freeze frame ECT PID is available, stabilize the engine at the temperature recorded by the freeze frame ECT PID. If the freeze frame ECT PID is not available, maintain the engine coolant temperature between 82°C - 101°C (180°F - 215°F) and the intake air temperature less than 46°C (115°F).
    • Access the PCM and monitor the SHRTFT1 and SHRTFT2 PIDs.
    • Allow the engine to stabilize at the temperature necessary to recreate the concern.
    • Record the SHRTFT1 and SHRTFT2 PID values.
    • Key in OFF position.
    • Repair the vacuum leak.
    • Key ON, engine running.
    • Allow the engine to stabilize at the temperature necessary to recreate the concern.
    • Access the PCM and monitor the SHRTFT1 and SHRTFT2 PIDs.
    • Compare the recorded SHRTFT PID values, prior to the vacuum leak repair, to the current SHRTFT PID values.

    Is the decrease in the SHRTFT PIDs greater than 15 percent? 

    Yes No
    Fault found. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) . A vacuum leak is still present,
    GO to  H20.
  22. H22 DTCS P0172, P0175, P1132, P1152, P2196 OR P2198: HO2S PERFORMANCE 
    NOTE: Address all continuous memory ignition and misfire DTCs before any KOER HO2S DTCs.
    • CHECK the intake air system for leaks, obstructions and damage.
      • CHECK the air filter element and housing for blockage.
      • Verify the integrity of the PCV system.
      • Check for vacuum leaks.

    Were there any concerns found during the visual inspection? 

    Yes No
    REPAIR as necessary. GO to  H23.
  23. H23 PERFORM THE KOER SELF-TEST 
    • Disconnect the fuel vapor hose from the intake manifold and the plug fitting at the intake manifold.
    • Start the engine and run at 2,000 RPM for 5 minutes and return to idle.
    • Key ON, engine running.
    • Perform the KOER self-test.
    • Check for self-test DTCs.

    Are DTCs P0040, P1128, P0041, P1129, P1127 or P0402 present? 

    Yes No
    Key in OFF position. DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS . Key in OFF position
    GO to  H24.
  24. H24 DETERMINE THE DTC BEING DIAGNOSED 
    • HO2S11, HO2S21 STUCK LEAN.
    • Check for self-test DTCs.

    Are DTCs P1131, P2195, P1151 or P2197 present? 

    Yes No
    Key in OFF position
    GO to  H26.    		 GO to  H25.
  25. H25 DETERMINE THE DTC BEING DIAGNOSED 
    • HO2S11, HO2S21 STUCK RICH.
    • Check for self-test DTCs.

    Are DTCs P1132, P2196, P1152 or P2198 present? 

    Yes No
    GO to  H34. Reconnect the fuel vapor line. For DTCs P0171, P0172, P0174, P0175, P1130 or P1150, GO to  H36. For all others, Unable to identify the fault at this time
    GO to PINPOINT TEST Z step 1 .
  26. H26 HO2S CIRCUIT TEST (WITH LEAN DTCS) 
    • Disconnect the HO2S related to the current DTC.
    • 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
    • Key ON, engine running.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage greater than 1.3 V? 

    Yes No
    Key in OFF position
    GO to  H27.    		 Key in OFF position
    GO to  H29.
  27. H27 CHECK THE SIGRTN CIRCUIT FOR AN OPEN IN HARNESS 
    • Disconnect the HO2S related to the current DTC.
    • Measure the resistance between:
      ( + ) HO2S Connector, Harness Side ( - ) Vehicle Battery
      SIGRTN Negative terminal

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  H36. GO to  H28.
  28. H28 CHECK THE SIGRTN CIRCUIT FOR AN OPEN IN THE HARNESS 
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) HO2S Connector, Harness Side ( - ) PCM Connector, Harness Side
      SIGRTN SIGRTN

    Is the resistance less than 5 ohms? 

    Yes No
    INSTALL a new PCM. REPAIR the open circuit.
  29. H29 CHECK THE HO2S CIRCUIT(S) FOR AN OPEN IN THE HARNESS 
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) HO2S Connector, Harness Side ( - ) PCM Connector, Harness Side
      HO2S Signal HO2S Signal

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  H30. REPAIR the open circuit.
  30. H30 CHECK THE HO2S CIRCUIT FOR A SHORT TO GND IN THE HARNESS 
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      HO2S Signal SIGRTN

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  H31. REPAIR the short circuit.
  31. H31 CHECK THE HO2S CIRCUIT FOR A SHORT TO GND IN THE HARNESS 
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) Vehicle Battery
      HO2S Signal Negative terminal

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  H32. REPAIR the short circuit.
  32. H32 CHECK THE HO2S SENSOR CIRCUIT FOR A SHORT TO GROUND 
    • HO2S connector connected. Related DTC
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      HO2S Signal SIGRTN

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  H33. INSTALL a new HO2S.
  33. H33 CHECK THE HO2S SENSOR CIRCUIT FOR A SHORT TO GROUND 
    • HO2S connector connected. Related DTC
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) Vehicle Battery
      HO2S Signal Negative terminal

    Is the resistance greater than 10K ohms? 

    Yes No
    INSTALL a new PCM. INSTALL a new HO2S.
  34. H34 HO2S CIRCUIT TEST (WITH RICH DTCS) 
    • HO2S connector disconnected. Related DTC
    • Key ON, engine running.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage less than 0.2 V? 

    Yes No
    GO to  H36. Key in OFF position
    GO to  H35.
  35. H35 CHECK THE HO2S CIRCUIT FOR A SHORT TO THE VPWR OR HEATER IN THE HARNESS 
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      HO2S Signal HO2S Heater
      HO2S Signal VPWR

    Are the resistances greater than 10K ohms? 

    Yes No
    INSTALL a new PCM. REPAIR the short circuit.
  36. H36 CHECK THE FUEL PRESSURE 
    WARNING: WHEN CHECKING THE FUEL SYSTEM REMEMBER THAT THE FUEL SYSTEM MAY STILL BE PRESSURIZED WHEN THE ENGINE IS SWITCHED OFF. ALWAYS FOLLOW THE INSTRUCTIONS RELATED TO FUEL SYSTEM PRESSURE RELIEF. ALL FUEL HANDLING SAFETY PRECAUTIONS MUST BE OBSERVED.
    • HO2S connector connected.
    • Connect the battery charger to the vehicle.
    • Mechanical fuel pressure gauge connected.
    • Key ON, engine OFF.
    • Access the PCM and control the FP PID.
    • Run the fuel pump to obtain maximum fuel pressure.

    Is the fuel pressure within range for the vehicle being diagnosed? 

    Yes No
    Key in OFF position
    GO to  H37.    		 GO to  HC1.
  37. H37 CHECK THE FUEL SYSTEM FOR PRESSURE STABILITY - FAST LEAKDOWN 
    • Key ON, engine OFF.
    • Cycle the key several times to charge the fuel system.

    Does the fuel pressure remain within 34 kPa (5 psi) of the highest reading after 10 seconds? 

    Yes No
    GO to  H39. GO to  H38.
  38. H38 VERIFY AN EXTERNAL FUEL LEAK 

    Is an external fuel leak present? 

    Yes No
    GO to  HC1. GO to  H41.
  39. H39 CHECK THE FUEL SYSTEM FOR PRESSURE STABILITY - SLOW LEAKDOWN 
    • Key ON, engine OFF.
    • Cycle the key several times to charge the fuel system.

    Does the fuel pressure remain within 34 kPa (5 psi) of the highest reading after 1 minute? 

    Yes No
    GO to  H40. GO to  HC12.
  40. H40 DETERMINE THE DTC BEING DIAGNOSED 

    Are any misfire DTCs displayed with the HO2S DTCs? 

    Yes No
    GO to  H43. GO to  H48.
  41. H41 CHECK THE INJECTOR FAULT PIDS AND ASSOCIATED DTCS 
    NOTE: Access the all INJF PIDs using a diagnostic tool.

    Are DTCs P0201 through P0210 or an associated injector fault flag PID present? 

    Yes No
    GO to  H43. GO to  H42.
  42. H42 DETERMINE THE DTC BEING DIAGNOSED 

    Are any misfire DTCs present? 

    Yes No
    GO to PINPOINT TEST HD step 12 . GO to  H48.
  43. H43 CHECK THE FUEL INJECTOR(S) AND HARNESS RESISTANCE 
    NOTE: Continuous memory DTCs are erased during this test.
    NOTE: Test all Fuel Injectors identified by DTC or PID interpretation.
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      VPWR Suspect INJ

    Is the resistance between 11 ohms - 18 ohms? 

    Yes No
    GO to  H44. GO to  H45.
  44. H44 PERFORM A THOROUGH WIGGLE TEST ON THE INJECTOR HARNESS 
    • Fuel Injector connector connected.
    • Key ON, engine running.
    • Engine at normal operating temperature.
    • Access the PCM and monitor the INJ PID.
    • Wiggle, shake, and bend small sections of the wiring harness while working from the Injector to the PCM.

    Are any injector values fluctuating in and out of range? 

    Yes No
    Key in OFF position. REPAIR the open circuit. Key in OFF position
    GO to  H45.
  45. H45 DETERMINE THE DTC BEING DIAGNOSED 

    Are DTCs P0201 through P0210 or an associated injector fault flag PID present? 

    Yes No
    GO to  H46. GO to PINPOINT TEST Z step 1 .
  46. H46 CHECK THE FUEL INJECTOR HARNESS RESISTANCE 
    NOTE: Disconnect the suspect fuel injector harness connector. Only the suspect injector needs to be diagnosed.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) INJ Connector, Harness Side
      Suspect INJ INJ
      VPWR VPWR

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  H47. REPAIR the open circuit.
  47. H47 CHECK FOR SHORTS BETWEEN CIRCUITS IN THE FUEL INJECTOR HARNESS 
    • PCM connector disconnected.
    • Suspect fuel injector disconnected.
    • Measure the resistance between:
      ( + ) INJ Connector, Harness Side ( - ) Vehicle Battery
      INJ Negative terminal
    • Measure the resistance between:
      ( + ) INJ Connector, Harness Side ( - ) Vehicle Battery
      INJ Positive terminal

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  H48. REPAIR the short circuit.
  48. H48 FLOW TEST 
    • Flow test the injector using the Fuel Injector Tester/Cleaner. For injector flow rate specification, refer to tester's instruction manual.

    Is the flow rate for each injector within specification? 

    Yes No
    For misfire related DTCs:
    GO to PINPOINT TEST HD step 8 . For Other DTCs GO to  H49. For DTCs P0201 through P0210, INSTALL a new PCM.    		 INSTALL a new Fuel Injector.
  49. H49 DETERMINE VEHICLE EQUIPMENT 

    Is a Secondary Air Pump equipped to this vehicle? 

    Yes No
    GO to  H50. GO to  H51.
  50. H50 CHECK FOR SECONDARY AIR LEAKS 
    NOTE: An HO2S always lean condition can be caused by:
    • Leaks in the hoses from the secondary air injection pump to the engine.
    • Secondary air diverted upstream of the HO2S.
    • Disconnect the secondary air injection hose(s) from the engine and the plug side of the secondary air injection system.
    • Key ON, engine running.
    • Perform the KOER self-test.

    Are DTCs P1131, P2195, P1151 or P2197 present? 

    Yes No
    GO to  H51. GO to PINPOINT TEST HM step 17 .
  51. H51 INSPECT THE INDUCTION SYSTEM FOR LEAKS 
    • Carefully inspect the following areas for potential air leaks:
      • Inlet tube(s) from the air cleaner to the throttle body.
      • Gaskets sealing the upper to lower intake manifold.
      • Vacuum hoses and lines for cracks, breaks, and proper connections.

    Are any of these conditions present? 

    Yes No
    REPAIR as necessary. For Misfire DTCs
    GO to PINPOINT TEST HD step 11 . For Other DTCs
    GO to  H52. For DTCs P0171 or P0174, GO to PINPOINT TEST DC step 26 .
  52. H52 CYLINDER COMPRESSION CHECK 
    NOTE: Use the Misfire DTC(s) displayed or prior retrieval to determine which cylinder's compression to check.
    • Perform cylinder compression checks. Refer to the appropriate ENGINE article.

    Is the suspect cylinder's compression within specification? 

    Yes No
    For P1131, P1151, P2195, P2197
    GO to  H53. For P1132, P1152, P2196, P2198 GO to  H54. For Misfire DTCs GO to PINPOINT TEST HD step 11 . For all others, GO to PINPOINT TEST DC step 26 .    		 REPAIR as necessary.
  53. H53 CHECK HO2S OUTPUT VOLTAGE 
    NOTE: Fuel calculations can be affected by unmetered air leaks. DTC P2195 may result.
    • Check the following:
      • Water contamination in the connector.
      • Leaking vacuum actuators.
      • Engine sealing (intake manifold and IAC).
      • EGR system.
      • PCV system.
      • Unmetered air leaks between the throttle body and mass air flow (MAF) sensor assembly.
    • Visually inspect the HO2S circuit for exposed wiring, contamination, corrosion and correct assembly. Repair as necessary.
    • HO2S connector disconnected.
    • Measure the voltage between:
      ( + ) HO2S Connector, Component Side ( - ) HO2S Connector, Component Side
      HO2S Signal SIGRTN
    • Run the engine at approximately 2,000 RPM.
    • Maintain engine speed for three minutes.
    • Monitor the HO2S voltage.

    Is the voltage greater than 0.4 V? 

    Yes No
    Key in OFF position
    GO to  H56.    		 Key in OFF position. INSTALL a new HO2S.
  54. H54 ATTEMPT TO GENERATE DTC P1131 OR P2195 OR P1151 OR P2197 
    • HO2S connector disconnected.
    • Connect a 5 amp fused jumper wire between the following:
      Point A HO2S Connector, Harness Side Point B Vehicle Battery
      HO2S Signal Negative terminal
    • Perform the KOER self-test.

    Did DTC P1131 or P2195 or P1151 or P2197 appear? 

    Yes No
    Key in OFF position. Remove the jumper wire(s)
    GO to  H55.    		 Key in OFF position. INSTALL a new PCM. Remove the jumper wire(s).
  55. H55 HO2S VOLTAGE CHECK 
    • HO2S connector disconnected.
    • Disconnect vacuum line to vacuum tree.
    • Run the engine at approximately 2,000 RPM.
    • Run the engine for approximately 30 seconds.
    • Measure the voltage between:
      ( + ) HO2S Connector, Component Side ( - ) HO2S Connector, Component Side
      HO2S Signal SIGRTN

      Is the voltage less than 0.4 V? 

      Yes No
      Key in OFF position. Reconnect all hoses
      GO to  H56.      		 Key in OFF position. INSTALL a new HO2S and retest vehicle.
  56. H56 PERFORM A THOROUGH WIGGLE TEST ON THE HO2S HARNESS 
    • HO2S connector connected.
    • Key ON, engine running.
    • Engine at normal operating temperature.
    • Access the PCM and monitor the HO2S Signal PID.
    • Wiggle, shake, and bend small sections of the wiring harness while working from the sensor to the PCM.

    While monitoring the HO2S PID, did the HO2S stop switching? 

    Yes No
    Key in OFF position. ISOLATE the fault and REPAIR as necessary. Key in OFF position
    GO to  H57.
  57. H57 TEST DRIVE WHILE MONITORING HO2S PID SWITCHING 
    CAUTION: This test requires an observer to monitor the HO2S PID.
    • Access the PCM and monitor the HO2S Signal and OL PIDs.
    • Start engine and let idle until vehicle goes into the closed loop fuel condition.
    • While an observer monitors the PIDs, test drive the vehicle in a manner consistent with the freeze frame data in an attempt to simulate the original fault.

    Does the HO2S PID switch? 

    Yes No
    Key in OFF position
    GO to PINPOINT TEST DC step 26 .    		 Key in OFF position. INSTALL a new HO2S.
  58. H58 KOER DTCS P1137, P2270, P1157, P2272, P1138, P2271, P1158, P2273, P2274 OR P2275: HO2S LACK OF SWITCHES STUCK LEAN OR RICH 
    NOTE: Address all continuous memory ignition and misfire DTCs before any KOER HO2S DTCs.
    • Visually inspect for:
      • Pinched, shorted, and corroded wiring and pins.
      • Oil or water contamination.
      • Crossed sensor wires.
      • Contaminated or damaged sensor.

    Were any of the above conditions or concerns found during inspection? 

    Yes No
    REPAIR as necessary. GO to  H59.
  59. H59 KOER DTCS P1137, P2270, P1157, P2272, P1138, P2271, P1158, P2273, P2274 OR P2275: CHECK FOR KOER DTCS 
    • Key ON, engine running.
    • Run the engine at approximately 2,000 RPM. Maintain engine speed for three minutes.
    • Perform the KOER self-test.

    Are any of the above listed DTCs present? 

    Yes No
    Key in OFF position
    GO to  H60.    		 Key in OFF position. Unable to duplicate or identify the fault at this time.
  60. H60 DTCS P0132, P0138 AND P0144: CHECK THE HO2S SIGNAL LEVEL TOO HIGH 
    NOTE: Fuel calculations can be affected by unmetered air leaks.
    • Carefully inspect the following areas for potential air leaks:
      • Hoses connecting to the MAF sensor assembly.
      • Hoses connecting to the throttle body.
      • Intake manifold gasket leaks.
      • PCV disconnected.
      • The vacuum lines are disconnected.
      • Improperly seated engine oil dipstick, tube or oil fill cap.
      • Exhaust leaks at flanges and gaskets.
      NOTE: Any exhaust leaks between the engine and the output of the catalyst can cause DTCs P0136 or P0156.
    • Raise the vehicle on a hoist and make sure the vehicle is level.
    • Visually inspect for:
    • Exhaust leaks at flanges and gaskets.
    • HO2S not tightened to specification.
    • Physical exhaust system concerns.
    • Aftermarket exhaust.
    • Punctures or cracks in the catalyst.

    Were any of the above conditions or concerns found during inspection? 

    Yes No
    REPAIR as necessary. GO to  H61.
  61. H61 CHECK FOR SHORTS BETWEEN CIRCUITS IN THE HO2S HARNESS 
    • PCM connector disconnected.
    • Disconnect the HO2S harness connector.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) Vehicle Battery
      HO2S Signal Negative terminal
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      HO2S Signal SIGRTN
      HO2S Signal VPWR
      HO2S Signal HO2S Heater

    Are the resistances greater than 10K ohms? 

    Yes No
    GO to  H62. REPAIR the short circuit.
  62. H62 CHECK THE HO2S CIRCUIT FOR AN OPEN IN THE HARNESS 
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) HO2S Connector, Harness Side
      HO2S Heater HO2S Heater
      VPWR VPWR
      HO2S Signal HO2S Signal
      SIGRTN SIGRTN

    Are the resistances less than 5 ohms? 

    Yes No
    GO to  H63. REPAIR the open circuit.
  63. H63 CHECK THE HO2S CIRCUIT VOLTAGE 
    • PCM connector connected.
    • HO2S connector connected.
    • Key ON, engine running.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage greater than 1.5 volts? 

    Yes No
    Key in OFF position. For PZEV GO to  H66. For All Others: GO to  H65. Key in OFF position
    GO to  H64.
  64. H64 CHECK THE HO2S CIRCUIT VOLTAGE 
    • PCM connector connected.
    • HO2S connector disconnected.
    • 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
    • Key ON, engine running.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage greater than 1.5 V? 

    Yes No
    INSTALL a new HO2S. INSTALL a new PCM.
  65. H65 CHECK FOR OVER VOLTAGE IN THE PCM 
    • Key ON, engine running.
    • HO2S connector disconnected.
    • Measure the voltage between:
      ( + ) HO2S Connector, Harness Side ( - ) Vehicle Battery
      SIGRTN Negative terminal
      HO2S Signal Negative terminal

    Are the voltages less than 1.5 V? 

    Yes No
    INSTALL a new HO2S. INSTALL a new PCM.
  66. H66 CHECK THE HO2S CIRCUIT FOR A SHORT TO VREF AND VPWR IN THE HARNESS 
    • PCM connector disconnected.
    • HO2S connector disconnected.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) HO2S Connector, Harness Side
      HO2S Signal VPWR

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  H67. REPAIR the short circuit.
  67. H67 CHECK THE HO2S CIRCUIT VOLTAGE 
    • PCM connector connected.
    • HO2S connector disconnected.
    • 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
    • Key ON, engine running.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage greater than 1.5 V? 

    Yes No
    INSTALL a new HO2S and retest vehicle. INSTALL a new PCM.
  68. H68 KOER DTC P1127: EXHAUST TEMPERATURE OUT OF RANGE 
    NOTE: Address all other DTCs before proceeding.

    Engine at normal operating temperature.

    • Key ON, engine running.
    • Access the PCM and monitor the HO2S Heater PID.

    Is the PID state ON? 

    Yes No
    Perform the KOER self-test. Run the engine until the PID indicates ON. Perform the KOER self-test.
  69. H69 KOER DTCS P0040, P0041, P1128, P1129 AND P2278: CROSSED SENSOR WIRES 
    • Key in OFF position.
      NOTE: Sensor wiring swapped bank to bank.
    • WARNING: Use caution near hot components.
    • Confirm the wiring is connected to the opposite bank.

    Are there any crossed connections or wires? 

    Yes No
    Swap the connectors on the HO2S sensors CLEAR the DTCs. REPEAT the self-test. Key in OFF position. Unable to duplicate or identify the fault at this time
    GO to PINPOINT TEST Z step 1 .
  70. H70 KOER DTCS P0132, P0138, P0152 AND P0158: CHECK THE HO2S CIRCUIT FOR HIGH AND INTERMITTENT FAULTS 
    • HO2S connector disconnected.
    • Visually inspect the HO2S harness.
    • Check the connector (both halves) for any water contamination.
    • A vehicle hoist may be required to access the HO2S harness.
    • Be sure the connectors are fully seated.
    • HO2S connector connected.
    • Key ON, engine running.
      NOTE: If DTCs are present, test their related circuits individually.
    • Access the PCM and monitor the O2S11, O2S12 and O2S13 PIDs.

    Is the suspect PID voltage above 1.5 volts? 

    Yes No
    GO to  H72. GO to  H71.
  71. H71 PERFORM A THOROUGH WIGGLE TEST ON THE HO2S HARNESS 
    • Perform a thorough wiggle test on the HO2S harness.

    Did the voltage change while performing the wiggle test? 

    Yes No
    REPAIR as necessary. GO to PINPOINT TEST Z step 1 .
  72. H72 CHECK THE SIGRTN CIRCUIT FOR AN OPEN IN THE HARNESS 
    • Key in OFF position.
    • HO2S connector disconnected. Related DTC
    • Measure the resistance between:
      ( + ) HO2S Connector, Harness Side ( - ) Vehicle Battery
      SIGRTN Negative terminal

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  H74. GO to  H73.
  73. H73 CHECK THE SIGRTN CIRCUIT FOR AN OPEN IN THE HARNESS 
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) HO2S Connector, Harness Side ( - ) PCM Connector, Harness Side
      SIGRTN SIGRTN

    Is the resistance less than 5 ohms? 

    Yes No
    INSTALL a new PCM. REPAIR the open circuit.
  74. H74 CHECK THE HO2S SIGNAL FOR A SHORT TO POWER INSIDE THE SENSOR 
    • HO2S connector disconnected.
    • Key ON, engine running.
    • Access the PCM and monitor the HO2S Signal PID.

    Is the voltage greater than 0.4 V? 

    Yes No
    GO to  H75. INSTALL a new HO2S.
  75. H75 CHECK THE HO2S CIRCUIT FOR A SHORT TO POWER IN THE HARNESS 
    • Key in OFF position.
    • HO2S connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side
      HO2S Signal VPWR
      HO2S Signal VREF

    Are the resistances greater than 10K ohms? 

    Yes No
    INSTALL a new PCM. REPAIR the short circuit.
scientia non olet · About LEMON Manuals