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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (Engine Controls - Trouble Shooting - No Codes - EEC-V - Gasoline) >> Symptoms >> Emissions Compliance >> Diagnostic Routines

Diagnostic Routines

WARNING: This page is about a different variant/trim than selected.

  1. 1) Vehicle Failed EVAP Compliance

    If vehicle failed an EVAP Emissions System Leak Test or a Purge Flow Test only, go to step  35). If vehicle failed EVAP, Purge Flow and gas tests, go to next step.

  2. 2) Baseline Vehicle

    Using an exhaust gas analyzer, baseline the vehicle. If vehicle must be driven to achieve baseline, ensure baseline drive cycle is able to be repeated to verify the repairs. During baseline, check for any related symptoms that may be present (driveability, A/T shifting or exhaust smoke). If other symptoms are present, perform QUICK TEST in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. If no other symptoms are present, go to next step.

  3. 3) Preliminary Checks

    Check for vacuum leaks or blockage. Check wiring harness connectors. Ensure proper scheduled maintenance has been performed. Check intake air tube and air cleaner for obstructions, leaks or dirty element. Ensure proper emission controls and components are installed on vehicle. Repair as necessary, then go to step  40). If no repairs are necessary and all checks are okay, go to next step.

  4. 4) Perform PCM Quick Test

    Perform QUICK TEST in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article to retrieve Diagnostic Trouble Codes (DTCs). If no DTCs are present, go to next step. If DTCs are present, repair as necessary, then go to step  40).

  5. 5) Check Carbon Monoxide (CO) Levels

    Check vehicle CO levels. If vehicle did not have excessive CO levels, go to next step. If vehicle had excessive CO levels, this indicates that engine is running rich. Go to step  15).

  6. 6) Check Hydrocarbon (HC) Levels

    Check vehicle HC levels. If vehicle did not have excessive HC levels, go to next step. If vehicle had excessive HC levels with low to normal CO levels, this indicates that engine is running lean. Go to step  25).

  7. 7) Check Oxides Of Nitrogen (NOx) Levels

    Check vehicle NOx levels. If vehicle did not have excessive NOx levels, verify all previous testing. If vehicle had excessive NOx levels, go to step  30).
    8. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 7) to step 15). No test procedures have been omitted.

  8. 15) High CO Levels: Check HC Levels
    Check vehicle HC levels. If vehicle had excessive HC levels, check for incomplete combustion/running rich. Go to next step. If vehicle did not have excessive HC levels, go to step  17).

  9. 16) Check Secondary Ignition System

    See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  40). If secondary ignition system is okay, go to next step.

  10. 17) Check Fuel Delivery System For Leak-Down Or High Fuel Pressure

    See TEST HB (natural gas models) or TEST HC (except natural gas models) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  40). If fuel delivery system is okay, go to next step.

  11. 18) Check PCV System

    See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  40). If PCV system is okay, go to next step.

  12. 19) Check Exhaust System

    See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  40). If exhaust system is okay, go to next step.

  13. 20) Check Engine Mechanical Condition

    See appropriate article in ENGINES. Check compression, camshaft, valve train components, etc., repair as necessary, then go to step  40). If no engine mechanical problems are indicated and all checks are okay, go to step  45).
    14. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 20) to step 25). No test procedures have been omitted.

  14. 25) High HC With Normal To Low CO Level, Check Fuel Delivery System
    Check fuel delivery system for leak-down or low pressure. See TEST HB (natural gas models) or TEST HC (except natural gas models) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  40). If fuel delivery system is okay, go to next step.

  15. 26) Check Secondary Ignition System

    See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  40). If secondary ignition system is okay, go to next step.

  16. 27) Check PCV System

    See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  40). If PCV system is okay, go to next step.

  17. 28) Check Engine Mechanical Condition

    See appropriate article in ENGINES. Check compression, camshaft, valve train components, etc., repair as necessary, then go to step  40). If no engine mechanical problems are indicated and all checks are okay, go to step  45).
    18. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 28) to step 30). No test procedures have been omitted.

  18. 30) High NOx With Normal To Low HC & CO Levels
    Check engine for concerns such as excessive carbon build-up in combustion chamber, repair as necessary, then go to step  40). See appropriate article in ENGINES. If no engine mechanical problems are indicated, check A/T Torque Converter Clutch (TCC) operation and cooling system. Check for running lean concerns (vacuum leaks or low fuel pressure), go to step  25). Repair as necessary. If all checks are okay, go to step  45).
    19. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 30) to step 35). No test procedures have been omitted.

  19. 35) EVAP System Concern: Preliminary Checks
    Check I/M test report to determine when concern is present. Verify concern and inspect and repair the following as necessary:
    • Check fuel filler cap for proper installation, physical damage or contamination.
    • Check EVAP system hoses and lines for proper connection, damage or blockage.
    • Check fuel vapor storage canister for damage.

    If all checks are okay, go to next step. If repairs have been performed, go to step  38).

  20. 36) Perform PCM Quick Test

    Perform QUICK TEST in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article to retrieve Diagnostic Trouble Codes (DTCs). If no DTCs are present, go to next step. If DTCs are present, repair as necessary, then go to step  38).

  21. 37) Check EVAP Emissions System For Leaks

    See appropriate symptom in SYSTEM TESTS (EVAPORATIVE EMISSIONS) in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  38). If EVAP Emission system is okay, verify test results. If results are okay, go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  38).

  22. 38) EVAP Emissions System Repair Verification

    After making repairs to EVAP emissions system, reset KAM and relearn basic adaptive strategy. See RESETTING KEEP-ALIVE MEMORY (KAM) under CLEARING CODES in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Repeat PCM QUICK TEST. See QUICK TEST in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Repair any DTCs that may be retrieved and perform EVAP system leak test and flow check. See SYSTEM TESTS (EVAPORATIVE EMISSIONS) in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. If original concern has not been corrected or if another concern exists, repeat step  1).
    23. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 38) to step 40). No test procedures have been omitted.

  23. 40) Repair Verification
    After making repairs to appropriate system, reset KAM and relearn basic adaptive strategy. See RESETTING KEEP-ALIVE MEMORY (KAM) under CLEARING CODES in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Repeat PCM QUICK TEST. See QUICK TEST in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Repair any DTCs that may be retrieved and perform baseline test using gas analyzer. If vehicle requires driving for the baseline test, drive at least 5 miles to relearn some additional Adaptive Learning Strategy (trim values). If a gas level is still high or another gas level is above acceptable range, repeat step  1).
    24. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 40) to step 45). No test procedures have been omitted.

  24. 45) Catalyst Delta Temperature Test
    Disconnect connector or hoses from secondary AIR system, if equipped. Start and run engine for 2 minutes at 2500 RPM to heat exhaust system. Turn ignition switch to OFF position. Disconnect and ground one spark plug wire from each cylinder bank (for COP applications, disconnect one coil connector from each cylinder bank). Start and run engine at 1000 RPM. Disconnect Idle Air Control (IAC) valve while maintaining 1000 RPM. Using an infrared temperature probe, measure temperature at both the inlet and outlet of each catalytic converter. If the temperature difference between inlet and outlet of each catalytic converter is 50°F (28°C) or less, repeat test step to verify readings. If temperature differences are still 50°F (28°C) or less, replace affected catalytic converter. Reconnect all connectors, IAC valve and AIR system. Go to step  40). If the temperature difference between inlet and outlet of each catalytic converter is more than 50°F (28°C), the catalytic converters are operating correctly. Reconnect all connectors, IAC valve and AIR system. Repeat PCM QUICK TEST and verify test results. See QUICK TEST in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. If results are okay, go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Follow diagnostic procedures and repair as necessary, then go to step  40).
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