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Engine Controls - Tests W/o Codes 4.6L: Diagnosis Lincoln Continental IX

Testing & Diagnostics ~2774 words

SYMPTOMS

CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in the GENERAL INFORMATION section before disconnecting battery.

SYMPTOM DIAGNOSIS

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in «BASIC TESTING» article and «TESTS W/CODES» article were performed before diagnosing a symptom. Symptom checks are listed in order of probability, ease of accomplishment, and accessibility. Symptoms available for diagnosis are as follows

  1. No Crank
  2. Hard Start/Long Crank
  3. No Start/Normal Crank
  4. Slow Return To Idle
  5. High Idle (Diesels/Runs On)
  6. Low Idle (Stalls On Deceleration)
  7. Rough Idle, Stalls, Misses, Hesitation Or Surge
  8. Backfires
  9. Loss Of Power
  10. Spark Knock
  11. Poor Fuel Economy
  12. Emissions Compliance
  13. Warning Indicator Lights
  14. Improper Automatic Transmission Shift
  15. Tachometer, Speedometer Or Fuel Gauge Inoperative
  16. High Oil Consumption
  17. Electric Cooling Fan Does Not Run At Low/& Or High Speed
  18. Electric Cooling Fan Always On
  19. Exhaust Smoke
  20. Fuel Smell
  21. Engine Noise
  22. Climate Control (Lack Of Cooling)
  23. Climate Control (A/C Always On)
  24. A/C Does Not Turn Off During WOT
  25. Brakelights Always On Or Off
  26. Sulfur Smell
  27. Fuel Pump Always Runs

Symptom Checks

Check the following items

  1. Check starter relay.
  2. Check starter circuit.
  3. Check charging circuit.
  4. Check for defective flywheel.
  5. Check ignition switch.
  6. Check for seized/hydro-locked engine.
  7. Check transmission linkage adjustment or Transmission Range (TR) sensor adjustment. See ADJUSTMENTS in AUTOMATIC TRANSMISSION article in the TRANSMISSION SERVICING section. If no problems are indicated, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Perform the following

  1. Check secondary ignition system. See CIRCUIT TEST JB in «TESTS W/CODES» - EEC-V article.
  2. Check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article.
  3. Check for restricted exhaust system. See CIRCUIT TEST HF in «TESTS W/CODES» - EEC-V article.
  4. Check cooling system for overheating (hard hot start symptom only).
  5. Check Positive Crankcase Ventilation (PCV) system. See CIRCUIT TEST HG in «TESTS W/CODES» - EEC-V article.
  6. Check Fuel Evaporation (EVAP) system.
  7. Check intake air system. See CIRCUIT TEST HU in «TESTS W/CODES» - EEC-V article.
  8. Check starting system.
  9. Check for contaminated Mass Airflow (MAF) sensor. If MAF sensor is okay, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Perform the following

  1. Check if engine will start with throttle closed. If engine starts, go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent causes of no-start condition.
  2. Check if engine will start at part throttle. If engine starts, Idle Air Control (IAC) system may be defective. Go to CIRCUIT TEST KE, step 2) in «TESTS W/CODES» - EEC-V article.
  3. Check ignition and fuel system. See CIRCUIT TEST A in «TESTS W/CODES» - EEC-V article.
  4. Check for restricted exhaust system. See CIRCUIT TEST HF in «TESTS W/CODES» - EEC-V article.
  5. Check engine mechanical condition. Check compression, camshaft, valve train components, etc. If no problems are indicated, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Check the following items

  1. Check PCV system. See CIRCUIT TEST HG in «TESTS W/CODES» - EEC-V article.
  2. Check intake air system. See CIRCUIT TEST HU in «TESTS W/CODES» - EEC-V article. If air intake system is okay, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Check the following items

  1. Check air intake system. See CIRCUIT TEST HU in «TESTS W/CODES» - EEC-V article. If air intake system is okay, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Check the following items

  1. With engine running, check if idle speed decreases or engine stalls when IAC valve is disconnected. If idle speed does not decrease or if engine does not stall, check for IAC system fault. See CIRCUIT TEST KE in «TESTS W/CODES» - EEC-V article.
  2. Torque converter may not be functioning properly. See TRANSMISSION SERVICE & REPAIR article for symptom diagnosis.
  3. Check fuel delivery fuel system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article.
  4. Check air intake system. See CIRCUIT TEST HU in «TESTS W/CODES» - EEC-V article.
  5. Check engine mechanical condition. Check compression, camshaft, valve train components, etc. If mechanical condition is okay, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Check the following items

  1. With transmission in Park or Neutral, if engine stalls, check Idle Air Control (IAC) system. See CIRCUIT TEST KE, step 2) in «TESTS W/CODES» - EEC-V article.
  2. With transmission in Park or Neutral, if engine idles rough, check if idle speed decreases or engine stalls when IAC valve is disconnected. If idle speed does not decrease or if engine does not stall, check for IAC system fault. See CIRCUIT TEST KE in «TESTS W/CODES» - EEC-V article.
  3. Check the following Parameter Identification (PID) values: DPFEGR, ECT, IAC, LONGFT 1, LONGFT 2, VPWR and VREF. See «PIN VOLTAGE CHARTS» article. On some vehicles, all PIDs may not be applicable.
  4. Check secondary ignition system. See CIRCUIT TEST JB in «TESTS W/CODES» - EEC-V article.
  5. Check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article.
  6. Check exhaust system for restriction. See CIRCUIT TEST HF in «TESTS W/CODES» - EEC-V article.
  7. Check PCV system. See CIRCUIT TEST HG in «TESTS W/CODES» - EEC-V article.
  8. Ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. See TRANSMISSION SERVICE & REPAIR article.
  9. Check EVAP system. If engine stalls, go to CIRCUIT TEST HX, step 19) in «TESTS W/CODES» - EEC-V article. For all other symptoms, go to CIRCUIT TEST HX, step 44) in «TESTS W/CODES» - EEC-V article.
  10. Check engine mechanical condition. Check compression, camshaft, valve train components, etc.
  11. If engine stalls at idle, runs rough at idle, has a rolling idle or has any symptoms associated with a sticking throttle body, go to CIRCUIT TEST HU in «TESTS W/CODES» - EEC-V article.
  12. With A/C on, if there is any idle concerns, go to CIRCUIT TEST DS, step 22) in «TESTS W/CODES» - EEC-V article.
  13. Check for driveline faults. Check charging system. Check for engine surge with A/C on. Check for engine surge with cruise control on. On vehicles with rolling idle and/or engine stumbles when A/C cycles on, check A/C compressor diode. If no problems are indicated, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Check the following items

  1. Check secondary ignition system. See CIRCUIT TEST JB in «TESTS W/CODES» - EEC-V article.
  2. Check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article.
  3. Check exhaust system for restriction. See CIRCUIT TEST HF in «TESTS W/CODES» - EEC-V article. If no problems are indicated, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Check the following items

  1. Check the following Parameter Identification (PID) values: DPFEGR, ECT, IAC, LONGFT 1, LONGFT 2, VPWR and VREF. See «PIN VOLTAGE CHARTS» article. On some vehicles, all PIDs may not be applicable.
  2. Check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article.
  3. Check secondary ignition system. See CIRCUIT TEST JB in «TESTS W/CODES» - EEC-V article.
  4. Check exhaust system. See CIRCUIT TEST HF in «TESTS W/CODES» - EEC-V article.
  5. Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  6. Ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. See TRANSMISSION SERVICE & REPAIR article.
  7. Check for binding/dragging brakes.
  8. Check charging system. Check customer driving habits (i.e., driving with excessive loads). If no problems are indicated, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Check the following items

  1. Check cooling system for overheating. If cooling system is overheating, go to ENGINE RUNS HOT symptom.
  2. Check engine mechanical condition. Check compression, camshaft, valve train components, etc.
  3. Check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article.
  4. Check secondary ignition system. See CIRCUIT TEST JB in «TESTS W/CODES» - EEC-V article.
  5. Check PCV system. See CIRCUIT TEST HB in «TESTS W/CODES» - EEC-V article.
  6. On vehicles with OCT ADJ circuit (PCM terminal No. 30), check octane adjust input to PCM. See CIRCUIT TEST FG, step 5) in «TESTS W/CODES» - EEC-V article.
  7. On vehicles with Knock Sensor (KS), check KS input to PCM. See CIRCUIT TEST DG in «TESTS W/CODES» - EEC-V article.
  8. Check intake air system. Check engine oil quality. If available, check Technical Service Bulletins (TSBs) for octane adjust information. If no problems are indicated, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms or go to CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article and check for intermittent faults.

Check the following items

  1. Check the following Parameter Identification (PID) values: DPFEGR, ECT, IAC, LONGFT 1, LONGFT 2, VPWR and VREF. See «PIN VOLTAGE CHARTS» article. On some vehicles, all PIDs may not be applicable.
  2. Check secondary ignition system. See CIRCUIT TEST JB in «TESTS W/CODES» - EEC-V article.
  3. Check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article.
  4. Check exhaust system. See CIRCUIT TEST HF in «TESTS W/CODES» - EEC-V article.
  5. Check PCV system. See CIRCUIT TEST HG in «TESTS W/CODES» - EEC-V article.
  6. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  7. Check for contaminated Mass Airflow (MAF) sensor.
  8. Ensure engine operates at normal operating temperature.
  9. Ensure transmission operates properly.
  10. Check for dragging brakes.

Check the following items

  1. If vehicle failed an EVAP Leak Test or a Purge Flow Test only, check for damaged fuel filler cap. Visually check all EVAP lines/hoses for proper connections, damage or blockage. Check EVAP canister for damage. If no problems are indicated, go to CIRCUIT TEST HX, step 44) in «TESTS W/CODES» - EEC-V article.
  2. Check the following Parameter Identification (PID) values: DPFEGR, ECT, IAC, LONGFT 1, LONGFT 2, VPWR and VREF. See «PIN VOLTAGE CHARTS» article. On some vehicles, all PIDs may not be applicable.
  3. Check engine emissions. If HC emissions are excessive, check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article. If fuel delivery system is okay, check secondary ignition system. See CIRCUIT TEST JB in «TESTS W/CODES» - EEC-V article. If ignition system is okay, check PCV system. See CIRCUIT TEST HG in «TESTS W/CODES» - EEC-V article. If PCV system is okay, check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  4. If NOx emissions are excessive, check engine mechanical condition (excessive cylinder carbon build-up). If engine mechanical condition is okay, check transmission torque converter operation. Check cooling system. If cooling system is okay, check for causes for engine running lean (vacuum leaks, low fuel pressure, etc.). If no problems are found, check catalytic converter efficiency. See «SYSTEM/COMPONENT TESTS» article.
  5. If CO emissions are excessive, check secondary ignition system. See CIRCUIT TEST JB in «TESTS W/CODES» - EEC-V article. If ignition system is okay, check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article. If fuel system is okay, check PCV system. See CIRCUIT TEST HG in «TESTS W/CODES» - EEC-V article. If PCV system is okay, check exhaust system for restriction. See CIRCUIT TEST HF in «TESTS W/CODES» - EEC-V article. If exhaust system is okay, check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.

Check the following items

  1. If Malfunction Indicator Light (MIL) is always on, go to CIRCUIT TEST NB, step 1) in «TESTS W/CODES» - EEC-V article.
  2. If Malfunction Indicator Light (MIL) does not come on, go to CIRCUIT TEST NB, step 2) in «TESTS W/CODES» - EEC-V article.
  3. If Transmission Control Indicator (TCIL) does not come on, go to CIRCUIT TEST TB, step 8) in «TESTS W/CODES» - EEC-V article.
  4. If engine does not start, go to CIRCUIT TEST A in «TESTS W/CODES» - EEC-V article.

Check the following items

  1. Check transmission mechanical components. See TRANSMISSION SERVICE & REPAIR article.

Check the following items

  1. If tachometer is inoperative, go to CIRCUIT TEST JH in «TESTS W/CODES» - EEC-V article.
  2. If fuel gauge is inoperative, check instrument cluster and fuel gauge circuits. See INSTRUMENT PANELS article in the ACCESSORIES & EQUIPMENT section for diagnosis and testing.
  3. If speedometer is inoperative, go to INSTRUMENT PANELS article in the ACCESSORIES & EQUIPMENT section for diagnosis and testing.

Check the following items

  1. Check PCV system. See CIRCUIT TEST HG in «TESTS W/CODES» - EEC-V article.
  2. Check engine mechanical condition. Check valves, valve guides, valve stem oil seals, intake manifold gaskets, cylinder head oil drain passages and piston rings. If no problems are indicated, return to «SYMPTOM DIAGNOSIS» to identify any additional symptoms.

Check the following items

  1. If cooling fan(s) does not operate at all speeds, go to CIRCUIT TEST KF, step 30) in «TESTS W/CODES» - EEC-V article.
  2. If cooling fan(s) operates at all speeds, check for other causes of overheating symptom (internal engine problems, excessive vehicle load, transmission overheating, brake drag or faulty gauge/sender). Repair as necessary.

Check the following items

  1. Ensure all accessories, A/C and defroster are off, and engine is cooled (so cooling fan would not normally come on). Start engine. Check electric cooling fan. If cooling fan runs continuously, check wiring harness to cooling fan. Check wiring harness to A/C high pressure switch (on 2-speed cooling fan applications) or A/C pressure sensor.
  2. If cooling fan still runs continuously, turn A/C off. Start engine. Using scan tool, select ACP V PID. If PID voltage is more than 3 volts, check for high A/C system pressure. If PID voltage is 3 volts or less, go to CIRCUIT TEST KF, step 65) in «TESTS W/CODES» - EEC-V article.
  3. If cooling fan still runs continuously, start engine and allow to idle. Using scan tool, select ACP PID. If PID value indicates OPEN, go to CIRCUIT TEST KF, step 65) in «TESTS W/CODES» - EEC-V article. If PID value indicates CLOSED, with engine running at idle, disconnect A/C high pressure switch. Again, using scan tool, view ACP PID. If PID value still indicates CLOSED, check for short to ground in ACPSW circuit. See appropriate wiring diagram in «WIRING DIAGRAMS»(/lincoln/continental/ix-1995-2002/remont/wiring-diagrams-engine-performance/#wiring-diagrams) article. If circuit is not shorted to ground, check A/C high pressure switch operation. Also, check for overcharged A/C system.

Perform the following

  1. When ignition is turned on, fuel pump should run for about 5 seconds then shut off. If fuel pump does not shut off, go to «FUEL PUMP ALWAYS ON» symptom.
  2. Check EVAP system. Go to CIRCUIT TEST HX, step 44) in «TESTS W/CODES» - EEC-V article.

Perform the following

Check the following items

  1. Ensure that voltage at A/C clutch is less than 2 volts with A/C switch off. If voltage is 2 volts or more, go to CIRCUIT TEST X, step 125) in «TESTS W/CODES» - EEC-V article.

Check the following items

  1. This symptom cannot be present without another A/C symptom also being present. See «A/C-HEATER SYSTEM» article for diagnosis of other A/C symptoms.

Check the following items

  1. Check brakelight circuits for open and short circuits. See appropriate wiring diagram in EXTERIOR LIGHTS article in the ACCESSORIES & EQUIPMENT section.
  2. If vehicle has a PCM controlled electronic transmission, perform QUICK TEST. See «TESTS W/CODES» - EEC-V article. If any Diagnostic Trouble Codes (DTCs) are present, perform appropriate CIRCUIT TEST.

Check the following items

  1. Check fuel delivery system. See CIRCUIT TEST HC in «TESTS W/CODES» - EEC-V article.
  2. Check Evaporative Emission (EVAP) system. See CIRCUIT TEST HX, step 44) in «TESTS W/CODES» - EEC-V article.

Check the following items

  1. If engine cannot be turned off, check for damaged ignition switch or short to power in IGN RUN circuit or VPWR circuit. See appropriate wiring diagram in «WIRING DIAGRAMS»(/lincoln/continental/ix-1995-2002/remont/wiring-diagrams-engine-performance/#wiring-diagrams) article.
  2. Perform QUICK TEST. See «TESTS W/CODES» - EEC-V article. If any DTCs are present, perform appropriate CIRCUIT TEST.

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the PCM setting a fault code, which may help in diagnosis. If fault code is not present, check for intermittents. See CIRCUIT TEST Z in «TESTS W/CODES» - EEC-V article.

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