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Engine Controls - Trouble Shooting - No Codes - Eec-V: Diagnosis Ford Expedition I

Testing & Diagnostics ~3589 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 appropriate BASIC DIAGNOSTIC PROCEDURES article and SELF-DIAGNOSTICS - EEC-V 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. Rough Idle, Stalls, Misses, Hesitation Or Surge
  2. Hard Start/Long Crank Or Erratic Start/Erratic Crank
  3. No Start/Normal Crank
  4. Slow Return To Idle
  5. High Idle (Diesels/Runs On)
  6. Low Idle (Stalls On Deceleration)
  7. Backfires
  8. Loss Of Power
  9. Spark Knock
  10. Poor Fuel Economy
  11. Emissions Compliance
  12. Warning Indicator Lights
  13. Improper Automatic Transmission Shift
  14. Tachometer Inoperative
  15. High Oil Consumption
  16. Electric Cooling Fan Does Not Run At Low/& Or High Speed
  17. Electric Cooling Fan Always On
  18. Exhaust Smoke
  19. Fuel Smell
  20. Engine Noise
  21. Climate Control (Lack Of Cooling)
  22. Climate Control (A/C Always On)
  23. A/C Does Not Turn Off During WOT
  24. Sulfur Smell

Symptom Checks

Check the following items

  1. Check the following Parameter Identification (PID) values: DPFEGR, LONGFT 1, LONGFT 2 and VPWR. See PIN VOLTAGE/PID VALUE CHARTS article. On some models, DPFEGR PID may not be applicable. If DPFEGR PID voltage is not .2-1.3 volt with Key On Engine Off (KOEO), go to TEST HE, step 100) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If LONGFT 1 or LONGFT 2 PID value is low (-20 percent), concentrate checks in areas that would cause engine to run rich. If LONGFT 1 or LONGFT 2 PID value is high (+20 percent), concentrate checks in areas that would cause engine to lean. If VPWR PID voltage is not 10.5-17.0 volts check charging system. If VPWR PID voltage is 10.5-17.0 volts but not within .5 volt of battery voltage, check VPWR circuit and PWR GND circuits. See WIRING DIAGRAMS article.
  2. If engine idles rough at idle, turn ignition off. Turn ignition on. Using scan tool, select INJxF PIDs from PID/DATA monitor menu. There is one INJxF PID available for each engine cylinder and the "x" indicates the appropriate injector number (1-10). If any PID value indicates YES, an injector fault exists. Turn ignition off and disregard any DTCs that are present at this time. On Natural Gas models, go to TEST HA, step 60) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. On all other models, go to TEST H, step 56) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. With transmission in Park or Neutral, if engine stalls, check Idle Air Control (IAC) system. See TEST KE, step 2) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  5. Check fuel delivery system. On TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  6. Check exhaust system for restriction. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  7. Check PCV system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  8. On natural gas vehicles, check injector circuits between Natural Gas (NG) module and injectors. See TEST HA, step 57) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  9. On A/T models, ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. See appropriate article in AUTOMATIC TRANSMISSIONS.
  10. Check EVAP system. On Taurus Flex Fuel, if engine stalls, go to TEST HX, step 95) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. For all other symptoms, go to TEST HX, step 92) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. On all other models, if engine stalls, go to TEXT HX, step 19) in SELF-DIAGNOSTICS - EEC-V article. For all other symptoms, go to TEST HX, step 44) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  11. Check engine mechanical condition. Check compression, camshaft, valve train components, etc.
  12. 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 TEST HU under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  13. On Continental and Windstar, with A/C on, if there is any idle concerns, go to TEST DS, step 22) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  14. Check for driveline faults. On M/T models, check clutch operation. On all models, check charging system. Check for engine surge with A/C on. Check for engine surge with cruise control on. On models 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»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

Perform the following

  1. Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  2. Check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. Check for restricted exhaust system. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. Check Positive Crankcase Ventilation (PCV) system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  5. Check Fuel Evaporation (EVAP) system.
  6. Check intake air system. See TEST HU under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  7. Check starting system.
  8. On F150 Lightning Pickup and Super-Duty Pickup models, check secondary circuits used for high speed fuel pump operation. See TEST KA, step 70) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  9. Check for contaminated Mass Airflow (MAF) sensor. If MAF sensor is okay, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

Perform the following

  1. Check ignition and fuel system. On Contour, Cougar and Mystique, go to TEST KA, step 75) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. On all others, go to TEST A under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  2. Check if engine will start at part throttle. If engine starts, Idle Air Control (IAC) system may be defective. Go to TEST KE, step 2) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. Check for restricted exhaust system. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. Check engine mechanical condition. Check compression, camshaft, valve train components, etc. If no problems are indicated, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

Check the following items

  1. Check PCV system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  2. Check air intake air system. See TEST HU under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If air intake system is okay, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

Check the following items

  1. Check air intake system. See TEST HU under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If air intake system is okay, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

Check the following items

  1. On A/T models, torque converter may not be functioning properly. See appropriate article in AUTOMATIC TRANSMISSIONS.
  2. If idle is low (with A/C on) on F250 (less than 8500 lbs. GVW), F350 (less than 8500 lbs. GVW), Econoline 5.4L and Econoline 6.8L, check ACCS Parameter Identification (PID) value. See PIN VOLTAGE/PID VALUE CHARTS article. With A/C clutch engaged, ACCS PID value should indicate ON. If PID value indicates OFF, go to TEST KM, step 10) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. Check fuel delivery fuel system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. Check air intake system. See TEST HU under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  5. Check engine mechanical condition. Check compression, camshaft, valve train components, etc. If mechanical condition is okay, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

Check the following items

  1. Check secondary ignition system. See TEST JB under SYSTEM TESTS n SELF-DIAGNOSTICS - EEC-V article.
  2. Check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. Check exhaust system for restriction. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. Check engine mechanical condition. Check compression, camshaft, valve train components, etc. If mechanical condition is okay, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

Check the following items

  1. Check the following Parameter Identification (PID) values: DPFEGR, LONGFT 1 and LONGFT 2. See PIN VOLTAGE/PID VALUE CHARTS article. On some models DPFEGR PID may not be applicable. If DPFEGR PID voltage is not .2-1.3 volt with Key On Engine Off (KOEO), go to TEST HE, step 100) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If LONGFT 1 or LONGFT 2 PID value is low (-20 percent), concentrate checks in areas that would cause engine to run rich. If LONGFT 1 or LONGFT 2 PID value is high (+20 percent), concentrate checks in areas that would cause engine to lean.
  2. On Econoline 4.6L, Explorer 4.0L SOHC, Mountaineer 4.0L SOHC, Pickup 4.6L and all models with a 5.4L engine, also check IMTVF PID. Using scan tool, select IMTVF PID. Turn ignition on and note PID value. Start engine and raise engine speed to 3000 RPM. Again, note PID value. If either PID value indicates YES, go to TEST HU, step 65) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. Check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  5. Check exhaust system. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  6. Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  7. On A/T models, ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. See appropriate article in AUTOMATIC TRANSMISSIONS.
  8. Check for binding/dragging brakes.
  9. On Contour, Cougar, Econoline 4.2L, Mustang and Mystique, check if A/C turns off under Wide Open Throttle (WOT) conditions. See «A/C DOES NOT TURN OFF DURING WOT»(ref-596-S26281875262000030800000) symptom.
  10. On F150 Lightning Pickup and Super-Duty Pickup models, check secondary circuits used for high speed fuel pump operation. See TEST KA, step 70) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  11. On M/T models, check clutch operation. On all models, check charging system. Check customer driving habits (i.e., driving with excessive loads). If no problems are indicated, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - 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 TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  5. Check PCV system. See TEST HB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  6. On models with Knock Sensor (KS), check KS input to PCM. See TEST DG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  7. Check intake air system. Check engine oil quality. If no problems are indicated, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

Check the following items

  1. Check the following Parameter Identification (PID) values: DPFEGR, LONGFT 1, LONGFT 2 and VPWR. See PIN VOLTAGE/PID VALUE CHARTS article. On some models, DPFEGR PID may not be applicable. If DPFEGR PID voltage is not .2-1.3 volt with Key On Engine Off (KOEO), go to TEST HE, step 100) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If LONGFT 1 or LONGFT 2 PID value is low (-20 percent), concentrate checks in areas that would cause engine to run rich. If LONGFT 1 or LONGFT 2 PID value is high (+20 percent), concentrate checks in areas that would cause engine to lean. If VPWR PID voltage is not 10.5-17.0 volts check charging system. If VPWR PID voltage is 10.5-17.0 volts but not within .5 volt of battery voltage, check VPWR circuit and PWR GND circuits. See WIRING DIAGRAMS article.
  2. Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. Check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. Check exhaust system. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  5. Check PCV system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - 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.
  11. If no problems are indicated, return to «SYMPTOM DIAGNOSIS»(ref-596-S26873152162000030800000) to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.

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 TEST HX, step 44) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  2. Check engine emissions. If HC emissions are excessive, check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If fuel delivery system is okay, check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If ignition system is okay, check PCV system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If PCV system is okay, check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  3. If NOx emissions are excessive, check engine mechanical condition (excessive cylinder carbon build-up). If engine mechanical condition is okay, on A/T models, check transmission torque converter operation. On all models, 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 appropriate SYSTEMS & COMPONENT TESTING article.
  4. If CO emissions are excessive, check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If ignition system is okay, check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If fuel system is okay, check PCV system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If PCV system is okay, check exhaust system for restriction. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - 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. On Pickups with Power Takeoff (PTO) and Malfunction Indicator Light (MIL) concern, check PTO input to PCM. See TEST FB, step 3) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  2. If MIL is always on when engine is running and no DTCs are present, check MIL circuits. On Continental, Expedition, F150, F250 Light Duty, Mustang, Navigator, Town Car and Windstar, go to appropriate INSTRUMENT PANELS article in ACCESSORIES. On all other models, go to TEST NB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. If Malfunction Indicator Light (MIL) does not come on at all, check MIL circuits. On Continental, Expedition, F150 and F250 Light-Duty Picups, Mustang, Navigator, Town Car and Windstar, go to appropriate INSTRUMENT PANELS article in ACCESSORIES. On all other models, go to TEST NB, step 2) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. If Transmission Control Indicator (TCIL) does not come on when engine is running and no DTCs are present, check TCIL circuits. See TEST TB, step 6) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  5. If Transmission Control Indicator (TCIL) does not come at all, check TCIL circuits. On Continental, Mustang and Windstar, go to appropriate INSTRUMENT PANELS article in ACCESSORIES. On all other models, go to TEST TB, step 8) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  6. On Escort and Tracer, if Shift Indicator Light (SIL) is always on or always off, go to TEST KL under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  7. If temperature warning indicator light does not function properly, check cooling system. If engine overheats, check and repair cooling system as necessary. If cooling system operates at normal operating temperature, go to TEST DL, step 40) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Check the following items

  1. Check transmission mechanical components. See appropriate article in AUTOMATIC TRANSMISSIONS.

Check the following items

  1. On models with CTO circuit at PCM pin No. 48, go to TEST JH under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. To determine if CTO circuit is used, go to appropriate PIN VOLTAGE/PID VALUE CHART under PIN VOLTAGE/PID VALUE CHARTS article. Check pin No. 48 under OUTPUTS.
  2. Check instrumentation. See appropriate INSTRUMENT PANELS article in ACCESSORIES for diagnosis and testing.

Check the following items

  1. Check PCV system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - 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.

Check the following items

  1. On Escort, Mustang and Tracer, if cooling fan(s) does not operate at all speeds, go to TEST X, step 40) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  2. On all other models, if cooling fan(s) do not operate at all speeds, go to TEST KF, step 30) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

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, proceed as follows.
  2. On Escort, Mustang 4.6L and Tracer, go to TEST X, step 80) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. On Mustang 3.8L, go to TEST X, step 82) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  4. On Continental and Windstar, go to TEST KF, step 63) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  5. On all other models, go to TEST KF, step 60) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Perform the following

  1. On Natural Gas vehicles, check fuel delivery system for leaks. See TEST HB, step 16) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  2. Check EVAP system. On Taurus Flex Fuel, go to TEST HX, step 92) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. On all other models, go to TEST HX, step 44) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Perform the following

On Mustang, go to TEST X, step 98) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. On Contour, Cougar, Econoline 4.2L, and Mystique, go to TEST KM, step 8) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. On all other models, go to appropriate article in HVACl for diagnosis and repair.

On Mustang, go to TEST X, step 40) under SYSTEM TESTS n SELF-DIAGNOSTICS - EEC-V article. On Contour, Cougar, Econoline 4.2L and Mystique, go to TEST KM, step 20) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. On all other models, go to appropriate article in AIR CONDITIONING & HEATING for diagnosis and repair.

Check the following items

  1. On all models except Contour, Cougar, Econoline 4.2L, Mustang and Mystique, this symptom cannot be present without another A/C symptom also being present. See appropriate article in HVAC for diagnosis of other A/C symptoms.
  2. If vehicle is a Contour, Cougar, Econoline 4.2L, Mustang or Mystique, perform QUICK TEST. See SELF-DIAGNOSTICS - EEC-V article. If any Diagnostic Trouble Codes (DTCs) are present, perform appropriate system test. If no DTCs are present, on Mustang, go to TEST X, step 130) under SYSTEM TESTS in SELF DIAGNOSTICS - EEC-V article. On Contour, Cougar, Econoline 4.2L and Mystique, go to TEST KM, step 25) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Check the following items

  1. Check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  2. Check Evaporative Emission (EVAP) system. See TEST HX, step 44) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
  3. Sulfur content can vary in different fuels. Try a different fuel source.

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 TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

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