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Home >> Lincoln >> 2004 >> Town Car Protection Series >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Pinpoint Test Hd: Misfire Detection Monitor Through Pinpoint Test HY: Generator/Regulator System - CNG, Flex-Fuel & Gasoline >> Pinpoint Test HF: Catalyst Efficiency Monitor and Exhaust Systems >> Test Procedure
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Test Procedure

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
P0420      HF1
P0430      HF1
  1. HF1 DTCS P0420 OR P0430: CHECK FOR MISFIRE DETECTION MONITOR DTCS 
    NOTE: Be sure the customer has not:
    • Refueled the vehicle with leaded gasoline.
    • Noticed a high vehicle oil consumption. (An engine that consumes oil at a high rate deposits high levels of phosphorus on the catalyst and reduces the catalyst efficiency).
    NOTE: Internal deterioration of a catalytic converter is usually caused by abnormal engine operation upstream of the catalyst. Events that can produce higher than normal temperatures in the catalyst are particularly suspect. For example, misfiring can cause higher than normal catalyst operating temperatures.
    • Check for continuous memory DTCs.

    Are DTCs P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0309, P0310, P0315, P0316 or P1309 present? 

    Yes No
    GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS for pinpoint test direction and REPAIR misfire DTCs. GO to  HF2.
  2. HF2 CHECK FOR HO2S DTCS 
    NOTE: Incorrect HO2S signal input can cause an abnormal temperature in the catalyst.

    Are there any HO2S DTCs? 

    Yes No
    GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS for pinpoint test direction and REPAIR HO2S DTCs. GO to  HF3.
  3. HF3 CHECK FOR CHT OR ECT SENSOR DTCS 
    NOTE: Temperature sensor DTCs can indicate the thermostat is not operating correctly or the engine coolant level is not filled to specification, producing above normal operation temperatures.
    • Check for self-test DTCs.

    Are DTCs P0117, P0118, P0125, P0128, P1117, P1285, P1288, P1289, P1290 or P1299 present? 

    Yes No
    GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS for pinpoint test direction and REPAIR CHT or ECT DTCs. GO to  HF4.
  4. HF4 CHECK FOR ANY OTHER DTCS 

    Were there any other DTCs recorded in HF1 (not including the initial P0420 or P0430)? 

    Yes No
    GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS for pinpoint test direction. REPAIR the other DTCs first. GO to  HF5.
  5. HF5 CHECK THE ELECTRONIC ENGINE CONTROL (EEC) WIRING HARNESS/PCM 
    NOTE: Check the HO2S sensor electrical connectors to ensure the correct HO2S sensor is connected to the correct electrical connector. The electrical connectors are color coded to ensure the correct connection is made.

    If the electrical connection of the rear HO2S are interchanged/crossed, the catalyst efficiency monitor test will fail.

    • Visually inspect the vehicle's HO2S harness connectors for any indication of crossed wiring.
    • Visually inspect the harness for exposed wiring, corrosion and correct routing.
    • Disconnect the PCM, and inspect for damaged, or pushed out pins, corrosion and loose wires.

    Are there any concerns with the wiring or the PCM connection? 

    Yes No
    REPAIR/REPLACE as necessary.
    Carry out the catalyst monitor drive cycle to verify the repairs.    		 GO to  HF6.
  6. HF6 CHECK THE FUEL PRESSURE 
    WARNING: THE FUEL SYSTEM REMAINS PRESSURIZED WHEN THE ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHEN WORKING ON THE FUEL SYSTEM.
    WARNING: BEFORE SERVICING OR REPLACING ANY COMPONENTS IN THE FUEL SYSTEM, REDUCE THE POSSIBILITY OF INJURY OR FIRE BY FOLLOWING THE WARNING, CAUTION, AND HANDLING DIRECTIONS IN SAFE FUEL HANDLING PRACTICES: GASOLINE, METHANOL, AND METHANOL BLENDS AT BEGINNING OF PINPOINT TEST HC.
    NOTE: Fuel pressure above specification can produce an abnormally rich air/fuel mixture. This rich air/fuel mixture can cause higher than normal catalyst operating temperatures.
    • Return Fuel Systems RFS:
      • INSPECT the vacuum hose going to the fuel pressure regulator for proper installation and cracks. Repair as necessary.
      • Verify the vacuum source to the fuel pressure regulator.
    • Mechanical Returnless Fuel Systems MRFS:
      • If applicable, inspect the vacuum hose going to the fuel rail pulse damper for proper installation and cracks. Repair as necessary.
    • Connect a Rotunda fuel pressure gauge or equivalent.
      NOTE: On Electronic Returnless Fuel System (ERFS), the fuel pressure can be monitored by the diagnostic tool using the Fuel Rail Pressure (FRP) sensor PID.
    • Start the engine. Record the fuel pressure.
    • GO to PINPOINT TEST HC . Compare the recorded fuel pressure reading to the Fuel System Specification Chart found at the beginning of Pinpoint Test HC.
    • Key in OFF position.

    Is the fuel pressure within specifications.

    Yes No
    Fuel pressure is OK. If applicable, remove the fuel pressure gauge.
    GO to  HF7.    		 Fuel pressure is out of specification.
    GO to PINPOINT TEST HC step 3 .
  7. HF7 CHECK FOR LEAKS IN THE EXHAUST SYSTEM 
    NOTE: If a catalyst is in series with a leaking exhaust system, it can fail the Catalyst Efficiency Monitor test.
    • INSPECT the exhaust system for: leaks, cracks, loose connections, punctures or non-factory modifications.

    Were any problems found? 

    Yes No
    Repair as necessary.
    Carry out the catalyst monitor drive cycle to verify the repairs.    		 GO to  HF12.
  8. HF8 CHECK FOR RESTRICTIONS IN THE EXHAUST SYSTEM 
    NOTE: A slight pressure in the exhaust system is normal, but excessive exhaust back pressure seriously affects engine operation.
    • INSPECT the following for damage or restrictions:
      • Front and rear exhaust pipes.
      • Catalytic Converter.
      • Muffler and tailpipe assembly.

    Were any problems found? 

    Yes No
    Repair as necessary.
    CLEAR continuous memory DTCs.
    Carry out the catalyst monitor drive cycle to verify the repairs.    		 GO to  HF9.
  9. HF9 CHECK FOR EXCESSIVE EXHAUST BACK PRESSURE 
    • The internal condition of exhaust system's ability to flow can be checked with an Exhaust Back Pressure tool.

    Is an Exhaust Back Pressure tester available? 

    Yes No
    GO to  HF10. GO to  HF11.
  10. HF10 CHECK FOR EXCESSIVE EXHAUST BACK PRESSURE WITH EXHAUST BACK PRESSURE TOOL 
    • INSTALL an exhaust back pressure tester and follow the tool manufacturer installation and testing instructions.
    NOTE: Typical exhaust back pressure (when measured near the exhaust manifold and at normal engine operating temperature) should not exceed 20.7 kPa (3 psi) at idle and 55.2 kPa (8 psi) at WOT under load.

    Did the exhaust back pressure test indicate a restriction? 

    Yes No
    REPAIR as necessary.
    Carry out the catalyst monitor drive cycle to verify the repairs.
    For further diagnosis of the symptoms (lack of power, loss of power, or no start) GO to SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE .    		 No indication of restrictions or leaks have been detected in the exhaust system.
    For further diagnosis of the symptoms (lack of power, loss of power, or no start) GO to SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE .
    If your here because of DTCs P0420 or P0430, the catalytic converter could be chemically inactive.
    GO to  HF12.
  11. HF11 CHECK MANIFOLD VACUUM FOR AN INDICATION OF EXCESSIVE EXHAUST SYSTEM RESTRICTION 
    • Attach a vacuum gauge to the intake manifold vacuum source.
      NOTE: When the engine is first started and is idled, the reading may be normal 51-74 kPa (15-22 in. Hg), but as the engine RPM is increased, the back pressure caused by a clogged exhaust system causes the needle to slowly drop to 0 kPa (0 in. Hg). The needle then may slowly rise. Excessive exhaust restriction causes the needle to drop to a low point even if the engine is only idling.
    • Observe the vacuum gauge while increasing the engine RPM.

    Did vacuum gauge indicate a exhaust restriction concern? 

    Yes No
    REPAIR as necessary.
    Carry out the catalyst monitor drive cycle to verify the repairs.
    For further diagnosis of the symptoms (lack of power, loss of power, or no start) GO to SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE .    		 No indication of restrictions or leaks have been detected in the exhaust system.
    For further diagnosis of the symptoms (lack of power, loss of power, or no start) GO to SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE .
    If your here because of DTCs P0420 or P0430, the catalytic converter could be chemically inactive.
    GO to  HF12.
  12. HF12 COMPLETE CATALYST MONITOR DRIVE CYCLE 
    • Complete Catalyst Monitor Drive Cycle. Refer to DRIVE CYCLES .
    • Retrieve the continuous memory DTCs.

    Are DTCs P0420 or P0430 present? 

    Yes No
    REPLACE the catalyst located between the monitored HO2S sensors, only for the bank referenced (P0420 Bank1, P0430 Bank 2). Do not replace any unmonitored catalyst unless it is replaced as an assembly. Test is complete and no faults were found.
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