ROUGH OR ROLLING IDLE, STALLS, MISSES, HESITATION OR SURGE
| WARNING | On some models, vehicle may stall if engine is left running during refueling. Advise customer to always turn engine off during refueling to avoid contamination or damage to EVAP system. |
Note. The Powertrain Control Module (PCM) is equipped with an over RPM/speed limiting function that will shut off fuel delivery when predetermined engine speed is exceeded.
Preliminary Checks
Check for vacuum leaks. Check air intake duct and air filter. Check ignition wiring. Check fuel quality (octane, winter/summer grade fuel, methanol, etc.). Check wiring harness connector for poor connections.
Engine Runs Rough At Idle
Turn ignition switch to ON position. Using scan tool, select INJxF PIDs from PID/DATA MONITOR & RECORD menu. There is one INJxF PID available for each engine cylinder, and the "x" indicates the appropriate injector number (1-10). AllINJxF PIDs should indicate NO (no fault). If any INJxF PID value indicates YES, an injector fault exists. Go to TEST HA, step 60) (Natural Gas models), or go to TEST H, step 56) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Engine Now Starts, But Stalls In Park Or Neutral
If engine will start and run normally at part throttle, check Idle Air Control (IAC) system. Go to TEST KE, step 2) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Miscellaneous Component Or System Checks
Check the following
- Check Mass Air Flow (MAF) sensor. Go to TEST DC, step 25) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check secondary ignition system. Go to TEST JB, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check fuel delivery system. Go to TEST HB, step 1) (Natural Gas models), or go to TEST HC, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check exhaust system for restriction. Go to TEST HF, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check PCV system. Go to TEST HG, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check EVAP emission system for blockages (engine stalls) or leaks (excessive fuel odor). Service appropriate symptom under SYSTEM TESTS (EVAPORATIVE EMISSIONS) in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On A/T models, ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
- Check engine mechanical condition. Check compression, camshaft, valve train components, etc. and repair as necessary. See appropriate article in ENGINES.
- Check air intake system. Go to TEST HU, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Natural Gas Vehicles With Rough Idle
Check injector circuits between Natural Gas (NG) module and injectors. Go to TEST HA, step 57) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Idle Concerns With A/C On (Continental, LS, Thunderbird & Windstar)
Check A/C Pressure (ACP) sensor input to PCM. Go to TEST DS, step 22) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Additional Checks
Note. Some models use a PID that will indicate whether PCM is reducing torque (095E b0), and if so, why torque is being reduced (095Eb1-13). Refer to scan tool manufacturer's operating instructions.
Ensure Powertrain Control Module (PCM) Vehicle Identification (VID) block is correct. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE under PROGRAMMING PCM in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. Check engine RPM/speed limiting functions of PCM. Check for incorrect high vehicle speed signal from ABS, VSS or OSS. Check driveline(s), manual transmission or clutch assembly. Check charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. Check traction control system, if equipped. If engine surges with A/C on, or has a rolling idle and/or engine stumble when A/C cycles on, check A/C system and A/C compressor diode. See appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. Check cruise control system if engine surges with cruise control on. See appropriate CRUISE CONTROL SYSTEMS article in ACCESSORIES & EQUIPMENT.
Check battery condition and starter current draw.
Check the following
- Check secondary ignition system. Go to TEST JB, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check fuel delivery system. Go to TEST HB, step 1) (Natural Gas models), or go to TEST HC, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check exhaust system for restriction. Go to TEST HF, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check PCV system. Go to TEST HG, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check EVAP emission system for blockages (engine stalls) or leaks (excessive fuel odor). Service appropriate symptom under SYSTEM TESTS (EVAPORATIVE EMISSIONS) in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check air intake system. Go to TEST HU, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check starting system. See appropriate STARTERS article in STARTING & CHARGING SYSTEMS.
- Check Mass Airflow (MAF) sensor for contamination.
- Check high speed fuel pump secondary circuits (Lightning 5.4L SC models only). Go to TEST KA, step 70) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
NO-START/NORMAL CRANK
| CAUTION | Extended cranking, due to a no-start condition, can load exhaust system with raw fuel, which can damage catalytic converter after engine is started. |
After repairing a no-start condition on models with electric Secondary Air Injection (AIR) system, disconnect AIR solid state relay. Start and run engine until surplus fuel is used, and then reconnect relay. Disconnecting AIR solid state relay may set a Continuous Memory DTC. After repairs are completed, clear DTCs. See CLEARING CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Check Inertia Fuel Shutoff (IFS) switch. Check fuel pressure and quality (octane, winter/summer grade fuel, methanol, etc.). Check add-on alarm/anti-theft devices. Check wiring harness connectors. Check for disconnected or restricted air intake duct. Check fuses and relays.
Check the following
- Check fuel and ignition systems. Go to TEST KB, step 85) (LS and Thunderbird), or go to TEST A, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check exhaust system for restriction. Go to TEST HF, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check engine mechanical condition. Check compression, camshaft, valve train components, etc. See appropriate article in ENGINES.
Engine Will Now Start & Run Normally At Part Throttle
If engine starts and runs only at part throttle, check Idle Air Control (IAC) system. Go to TEST KE, step 2) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Check for vacuum leaks. Check throttle linkage operation. Check throttle body.
Check the following
- Check PCV system. Go to TEST HG, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check air intake system. Go to TEST HU, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Note. If engine runs normally after ignition switch is turned to OFF position, check for damaged ignition switch or IGN RUN or VPWR circuit for short to power. See WIRING DIAGRAMS article.
Check for vacuum leaks. Check for deposits on throttle plate. Check throttle linkage operation. Check for binding/sticking cruise control linkage. Check for air intake duct leaks. Check for leaking intake manifold gasket. Check Idle Air Control (IAC) or Exhaust Gas Recirculation (EGR) valves. Ensure vehicle is at normal operating temperature.
Engine Idles Fast
Turn ignition switch to OFF, then back to ON position. Using scan tool, select TP V and TPREL PIDs from PID/DATA MONITOR & RECORD menu. Observe TP V and TPREL PIDs while wiggling TP sensor circuits. At vehicle start, TPREL PID value will begin at about 1.25 volts and count down to the lowest TP V value read since engine start-up. If TP V value goes below normal range, then increases again, TPREL will set to the lower voltage. If TP V is about .04 volt more than TPREL value at closed throttle, PCM will go into part throttle mode. Check for loose or worn throttle plates. If no concern is found, go to TEST Z, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article and check for intermittent faults.
Check air intake system. Go to TEST HU, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Check Idle Air Control (IAC) wiring harness connector. Check for vacuum leaks. Ensure vacuum hoses are routed properly. Check air intake duct.
Stall Or Quit On Deceleration (A/T Models)
Check Torque Converter Clutch (TCC), TCC solenoid or TCC circuit may not be functioning properly. See appropriate OVERHAUL or DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
Low Idle With A/C On (Econoline 4.6L, 5.4L & 6.8L)
Check ACCS PID. Connect scan tool to Data Link Connector (DLC). Start engine and allow to idle. Using scan tool, access ACCS PID from PID/DATA MONITOR & RECORD menu. With A/C clutch engaged, ACCS PID value should indicate ON. On models where PCM cannot control A/C clutch on and off, PCM uses ACCS circuit to determine additional load on engine. If ACCS PID does not indicates ON, go to TEST KM, step 10) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Check the following
- Check fuel delivery system. Go to TEST HB, step 1) (Natural Gas models), or go to TEST HC, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check air intake system. Go to TEST HU, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check fuel filler cap for damage or improper installation. Repair as necessary.
- Check engine mechanical condition. Check compression, camshaft, valve train components, etc. and repair as necessary. See appropriate article in ENGINES.
Check vacuum hose routing. Check spark plug wiring (if equipped) for incorrect firing order.
Check the following
- Check secondary ignition system. Go to TEST JB, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check fuel delivery system. Go to TEST HB, step 1) (Natural Gas models), or go to TEST HC, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check engine mechanical condition. Check compression, camshaft, valve train components, etc. and repair as necessary. See appropriate article in ENGINES.
- Check exhaust system for restriction. Go to TEST HF, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
LACK/LOSS OF POWER
Note. Ensure symptom is reported under normal driving conditions without excessive engine/vehicle load. PCM is equipped with an engine RPM/speed limit function. If programmed speed is exceeded, fuel delivery will shut off and DTC P1270 will be set in PCM memory. If vehicle is equipped with a Knock Sensor (KS), a lack of power may result when vehicle is operated with a breakout box installed at PCM. KS circuits are not shielded in the breakout box, and KS signal noise may be noticed by PCM. If this happens, spark timing will be retarded and a lack of power may result.
Check vacuum hose routing. Check for restricted air filter. Check wiring harness connectors. Check throttle linkage. Check for obstructed radiator. Check Automatic Transmission Fluid (ATF) level.
Check the following
- Check fuel delivery system. Go to TEST HB, step 1) (Natural Gas models), or go to TEST HC, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check secondary ignition system. Go to TEST JB, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check Mass Air Flow (MAF) sensor. Go to TEST DC, step 25) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check exhaust system for restriction. Go to TEST HF, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check engine compression. Check engine mechanical condition and repair as necessary. Check intake manifold gasket, camshaft and valves. See appropriate article in ENGINES.
- On A/T models, diagnose by symptom (POOR PERFORMANCE). See appropriate OVERHAUL or DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
- Check for binding or dragging brakes. See appropriate article in BRAKES.
- Ensure Powertrain Control Module (PCM) Vehicle Identification (VID) block is correct. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE under PROGRAMMING PCM in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. Check engine RPM/speed limiting functions of PCM (proper high vehicle speed signal from ABS, VSS or OSS). On M/T models, check clutch operation. On all models, check charging system. Check operation of Intake Manifold Runner Control (IMRC) or Intake Manifold Tuning Valve (IMTV), if equipped. Check customer driving habits (i.e., driving with excessive loads).
Lack/Loss Of Power (Mustang Only)
Ensure A/C clutch disengages under Wide Open Throttle (WOT) conditions and engages a few seconds after returning to idle. If A/C does not cut off, see A/C DOES NOT TURN OFF DURING WOT (MUSTANG) symptom under CLIMATE CONTROL (LACK OF A/C COOLING, A/C ALWAYS ON OR A/C INOPERATIVE).
Lack/Loss Of Power (F150 Lightning 5.4L SC Only)
Check supercharger bypass system operation. Go to TEST KJ, step 13) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. Also check high speed fuel pump secondary circuits. Go to TEST KA, step 70) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Note. Some models use a PID that will indicate whether PCM is reducing torque (095E b0), and if so, why torque is being reduced (095Eb1-13). Refer to scan tool manufacturer's operating instructions.
Check customer driving habits. Ensure Powertrain Control Module (PCM) Vehicle Identification (VID) block is correct. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE under PROGRAMMING PCM in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. Check Intake Manifold Runner Control (IMRC) linkage, if equipped. Check manual transmission or clutch assembly. Check charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. Check engine RPM/speed limiting functions of PCM. Check for incorrect high vehicle speed signal from ABS, VSS or OSS.
Ensure engine is not exceeding normal operating temperature. Check cooling system for overheating, correct coolant level and coolant concentration. If cooling system is overheating, repair as necessary. See appropriate article in ENGINE COOLING.
Check the following
- Check Mass Air Flow (MAF) sensor input to PCM. Go to TEST DC, step 25) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check engine mechanical condition. Check compression, camshaft, valve train components, etc. and repair as necessary. Check engine oil quality. See appropriate article in ENGINES.
- Check fuel delivery system. Go to TEST HB, step 1) (Natural Gas models), or go to TEST HC, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check secondary ignition system. Go to TEST JB, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check PCV system. Go to TEST HG, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
POOR FUEL ECONOMY
Note. Fuel consumption can be increased during stop-and-go driving, trailer towing, short-run operation, extended winter warm-up periods, improper tire inflation or size, high speed driving, improper axle ratio, road and weather conditions, and aftermarket add-ons. Determine if any of these factors are the cause of poor fuel mileage before proceeding with diagnostic procedure.
Check for restricted air filter/air intake duct. Check Automatic Transmission Fluid (ATF) level. Check fuel quality and coolant level. Ensure engine is operating at normal operating temperature. Check cooling system for stuck open or closed thermostat, correct coolant level or coolant concentration. Repair as necessary. See appropriate article in ENGINE COOLING.
Check the following
- Check secondary ignition system. Go to TEST JB, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check fuel delivery system. Go to TEST HB, step 1) (Natural Gas models), or go to TEST HC, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check exhaust system for restriction. Go to TEST HF, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On A/T models, diagnose by symptom (POOR PERFORMANCE). See appropriate OVERHAUL or DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
- Check PCV system. Go to TEST HG, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Note. Some models use a PID that will indicate whether PCM is reducing torque (095E b0), and if so, why torque is being reduced (095Eb1-13). Refer to scan tool manufacturer's operating instructions.
Ensure Powertrain Control Module (PCM) Vehicle Identification (VID) block is correct. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE under PROGRAMMING PCM in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. Check for binding or dragging brakes. See appropriate article in BRAKES. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves and repair as necessary. See appropriate article in ENGINES. Check for contaminated Mass Airflow (MAF) sensor. Check air intake system.
VEHICLE FAILS EMISSIONS/EMISSIONS COMPLIANCE
For emissions compliance procedures, see EMISSIONS COMPLIANCE under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - EEC-V - GASOLINE article.
HISSING SOUND WHEN REMOVING FUEL CAP
For diagnostic procedures, see HISSING SOUND WHEN REMOVING FUEL CAP symptom under SYSTEM TESTS (EVAPORATIVE EMISSION) in SYSTEM & COMPONENT TESTING - EEC-V - GASOLINE article.
EXCESSIVE FUEL ODOR
For diagnostic procedures, see EXCESSIVE FUEL ODOR symptom under SYSTEM TESTS (EVAPORATIVE EMISSION) in SYSTEM & COMPONENT TESTING - EEC-V - GASOLINE article.
UNABLE TO REFUEL VEHICLE
For diagnostic procedures, see UNABLE TO REFUEL VEHICLE symptom under SYSTEM TESTS (EVAPORATIVE EMISSION) in SYSTEM & COMPONENT TESTING - EEC-V - GASOLINE article.
WARNING INDICATOR LIGHTS
Note. If exhaust emission test fails and Malfunction Indicator Light (MIL) is on, perform EMISSIONS COMPLIANCE procedures under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - EEC-V - GASOLINE article. If MIL is illuminated and engine is a no-start, perform NO START/NORMAL CRANK symptom diagnosis first. If MIL is illuminated and engine runs rough at idle, perform ROUGH OR ROLLING IDLE, STALLS, MISSES, HESITATION OR SURGE symptom diagnosis first.
The following warning indicators may illuminate
- Malfunction Indicator Light (MIL)
- Transmission Control Indicator Light (TCIL)
- Shift Indicator Light (SIL)
- Temperature Warning Indicator Light Or Gauge - Models With Cylinder Head Temperature (CHT) Sensor
- Check Fuel Cap Indicator Light
Preliminary Check
Check wiring harness connectors. Ensure fuel filler cap is installed and tightened properly.
Pickups With Power Takeoff (PTO) & MIL Concern
Check PTO input to PCM. Go to TEST FB, step 3) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
MIL Always On When Engine Is Running, No DTCs Are Present
Check MIL circuits. On Blackwood, Continental, Escape, Expedition, Focus, F150 Pickup, LS, Mustang, Navigator, Thunderbird, Town Car or Windstar, see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. On all other models, go to TEST NB, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
TCIL Always On When Engine Is Running, No DTCs Are Present
Check TCIL circuits. On Continental, Focus, LS, Mustang, Thunderbird, Town Car or Windstar, see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. On all other models, go to TEST TB, step 6) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
MIL Inoperative (Including Bulb Check When Engine Is First Started)
Check MIL circuits. On Continental, Escape, Expedition, Focus, F150 Pickup, LS, Mustang, Navigator, Thunderbird, Town Car or Windstar, see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. On all other models, go to TEST NB, step 2) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Transmission Control Indicator (TCIL) Inoperative
Check TCIL circuits. On Continental, Focus, LS, Mustang, Thunderbird, Town Car or Windstar, see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. On all other models, go to TEST TB, step 8) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Temperature Warning Indicator Light Or Temperature Gauge Inoperative (Models With CHT Sensor Only)
Check cooling system or indicator light circuits. If engine is overheating, note that since a PCM DTC was not retrieved, PCM has not attempted to illuminate light. Check and repair cooling system as necessary. If cooling system is operating at normal operating temperature, go to TEST DL, step 40) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
SIL Always On Or Inoperative
Check SIL circuits. Go to TEST KL, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Fuel Cap Indicator Light Always On Or Inoperative
Check fuel indicator light circuits. On Blackwood, Continental, Escape, Explorer and Mountaineer (150-pin PCM), F250 Pickup, LS, Mustang, Thunderbird, Town Car or Windstar, see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. On all other models, if check fuel indicator light is always ON, go to TEST HX, step 88) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. For check fuel indicator light is always OFF, go to TEST HX, step 89) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Check Automatic Transmission Fluid (ATF) level and condition. Check wiring harness connectors. Check for vehicle modifications. Check for electronic add-on items. Check for misadjusted shift linkage.
Check A/T mechanical components and A/T shift solenoids and Torque Converter Clutch (TCC) solenoid operation. See appropriate OVERHAUL or DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
Check wiring harness connectors for loose, damaged or corroded terminals.
Tachometer Inoperative On Models With Clean Tach Output (CTO) Only
Check CTO circuit from PCM terminal No. 48. Go to TEST JH, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. To determine if CTO circuit is used, see appropriate PIN VOLTAGE/PID VALUE CHARTS article. Check terminal No. 48 under OUTPUTS.
Speedometer/Odometer Inoperative On Models With Manual Shift On-The-Fly (MSOF) Only
Check Transfer Case Speed Sensor (TCSS) circuits. Go to TEST DP, step 30) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Check instrumentation. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.
Check for external engine oil leaks. Check for correct oil dipstick. Check for proper oil viscosity.
Check the following
- Check PCV system. Go to TEST HG, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check engine mechanical condition. Check valves, valve guides, valve stem oil seals, intake manifold gaskets, cylinder head oil drain passages and piston rings. See appropriate article in ENGINES.
Perform the following checks
- Engine coolant level.
- Cooling fan wiring harness connections.
- Coolant leaks.
- Water/anti-freeze mixture.
- Radiator condition.
- Collapsed/restricted radiator hoses.
- Radiator pressure cap.
- Overflow system.
Check the following
- On Escort and Mustang, if cooling fan(s) do not operate at any speed, go to TEST X, step 40) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On LS and Thunderbird, if hydraulic cooling fan(s) do not operate at any speed, go to step TEST KH, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On Pickups with Visctronic cooling fan clutch, if cooling fan does not operate, go to TEST KG, step 4) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On all others, if cooling fan(s) do not operate at all speeds, go to TEST KF, step 25) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
If directed back here from another article for further cooling fan diagnosis, check engine cooling system for mechanical faults. See COOLING SYSTEM in TROUBLE SHOOTING article in GENERAL INFORMATION.
ELECTRIC, HYDRAULIC OR VISCTRONIC COOLING FAN(S) ALWAYS ON
Note. This is intended to diagnose an electric, hydraulic or Visctronic cooling fan that is always on with a "cool" engine, and A/C and defroster off.
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 or hydraulic cooling fan. If cooling fan runs continuously, check cooling fan ACPSW or ACP circuits. Perform the following
- On Escort, and Mustang 4.6L, go to TEST X, step 80) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On Mustang 3.8L, go to TEST X, step 82) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On Continental and Windstar, go to TEST KF, step 63) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On LS and Thunderbird, go to TEST KH, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On Pickups with Visctronic cooling fan clutch, go to TEST KG, step 10) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- On all other models, go to TEST KF, step 60) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
If directed back here from another article for further cooling fan diagnosis, check engine cooling system for mechanical faults. Check engine cooling system for mechanical faults. See COOLING SYSTEM in TROUBLE SHOOTING article in GENERAL INFORMATION.
EXHAUST SMOKE
Note. Black smoke may indicate a rich fuel mixture, blue smoke may indicate engine burning oil, and white smoke may indicate water in combustion chamber.
Black Smoke (Rich Mixture)
Check the following
- Check fuel delivery system. Go to TEST HB, step 1) (Natural Gas models), or go to TEST HC, step 1) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check secondary ignition system. Go to TEST JB, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
Blue Smoke (Burning Oil)
Check the following
- Check PCV system. Go to TEST HG, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
- Check engine mechanical condition. Check valve guides, valve stems, valve seals, oil drain passages in cylinder heads (Blue smoke on start-up), piston rings and cylinder bores, and repair as necessary. See appropriate article in ENGINES.
White Smoke (Water In Combustion)
Check for cylinder head gasket leaks, intake manifold gasket leaks, cracked engine block or cylinder head(s) and repair as necessary. See appropriate article in ENGINES.
Check fuel tank(s), hoses, connectors and lines for leaks.
CLIMATE CONTROL (LACK OF A/C COOLING, A/C ALWAYS ON OR A/C INOPERATIVE)
Note. For additional A/C system information, see appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
Lack Of A/C Cooling Or A/C Inoperative (Mustang)
Go to TEST X, step 98) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
A/C Always On (Mustang)
Go to TEST X, step 140) under SYSTEM TESTS in SELF DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
A/C Does Not Turn Off During WOT (Mustang)
Go to TEST X, step 130) under SYSTEM TESTS in SELF DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
A/C System Concerns (All Others)
Check A/C system. See appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING for diagnosis and repair.
WACF PID Displays YES
If directed here from a MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article with Parameter Identification (PID) WACF displaying YES (fault present), perform diagnostics for KOEO DTC P1460 in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
EXHAUST ODOR (SULFUR SMELL)
Note. On vehicles with a NEW catalytic converter or vehicles with 5,000-10,000 miles, sulfur smell may be normal due to the highly active state of catalytic converter. Replacing catalytic converter on these vehicles may worsen symptom.
Ensure odor is from exhaust and not from an under hood odor, such as battery acid. Ensure that there are no other driveability or exhaust smoke symptoms. See appropriate symptom under SYMPTOM DIAGNOSIS under SYMPTOMS.