Ford F150 Pickup. Instruction — part 1602

EXHAUST SYSTEMS under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article.

z

Check EVAP emission system for blockages (engine stalls) or leaks (excessive fuel odor). See SYSTEM
TESTS (EVAPORATIVE EMISSION) in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE
article.

z

Check PCV system. See TEST HG: PCV SYSTEM under SYSTEM TESTS in SELF-DIAGNOSTICS -
CNG, FLEX-FUEL & GASOLINE article.

z

Check starting system. See appropriate STARTERS article in ENGINES.

z

Visually inspect Mass Air Flow (MAF) sensor for contamination.

z

If no concern is found, check for intermittent faults. See TEST Z: INTERMITTENT under SYSTEM
TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

NO START/NORMAL CRANK - ALT FUEL MODE

z

If ALT fuel switch indicator is on then goes off, see TEST AC: NO START/HARD START IN ALT
FUEL - ALT FUEL SWITCH INDICATOR IS ON, THEN OFF under SYSTEM TESTS in SELF-
DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

z

If ALT fuel switch indicator is always on, see TEST AD: NO START - ALT FUEL SWITCH
INDICATOR IS ON STEADY under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/CNG article.

z

If ALT fuel switch indicator is always off, see TEST AE: NO START - ALT FUEL SWITCH
INDICATOR IS OFF under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/CNG article.

z

If engine is still a no-start after completing previous tests, see TEST KE: IDLE AIR CONTROL
VALVE under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check engine mechanical condition. Check compression, camshaft, valve train components, etc. and
repair as necessary. See appropriate article in ENGINES. If no concern is found, check for intermittent
faults. See TEST Z: INTERMITTENT under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG,
FLEX-FUEL & GASOLINE article.

NO START/NORMAL CRANK - GASOLINE MODE

z

Check fuel system. See TEST AB: NO START - GASOLINE under SYSTEM TESTS in SELF-

CAUTION: Extended cranking due to a no-start condition, can load exhaust system

with raw fuel, which may ruin catalytic converter after engine is started.

NOTE:

If ALT fuel switch indicator illuminates and then goes off, vehicle may switch
automatically to gasoline mode. Check vehicle for add-on anti-theft devices that
may disable ignition system. If equipped, disable system before continuing.

CAUTION: Extended cranking, due to a no-start condition, can load exhaust system

with raw fuel, which may ruin catalytic converter after engine is started.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/CNG

DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

z

If engine is still a no-start after completing previous test, see TEST KE: IDLE AIR CONTROL
VALVE under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check engine mechanical condition. Check compression, camshaft, valve train components, etc. and
repair as necessary. See appropriate article in ENGINES. If no problem is found, check for intermittent
faults. See TEST Z: INTERMITTENT under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG,
FLEX-FUEL & GASOLINE article.

NO START/NORMAL CRANK - GASOLINE & ALT FUEL MODES

z

Check add-on anti-theft devices. Visually inspect system and check with customer.

z

Check fuel system. See TEST AA: NO START - GASOLINE & ALTERNATE FUEL under
SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

z

Check secondary ignition system. See TEST JB: SECONDARY IGNITION under SYSTEM TESTS in
SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check idle air control system, see TEST KE: IDLE AIR CONTROL VALVE under SYSTEM TESTS
in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check exhaust system for restriction. See TEST HF: CATALYST EFFICIENCY MONITOR &
EXHAUST SYSTEMS under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article.

z

Check engine mechanical condition. Check compression, camshaft, valve train components, etc. and
repair as necessary. See appropriate article in ENGINES. If no problem is found, check for intermittent
faults. See TEST Z: INTERMITTENT under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG,
FLEX-FUEL & GASOLINE article.

SLOW RETURN TO IDLE

z

Check vacuum hoses, lines and throttle body for vacuum leaks.

z

Check air intake system. See TEST HU: AIR INTAKE SYSTEM under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check PCV system. See TEST HG: PCV SYSTEM under SYSTEM TESTS in SELF-DIAGNOSTICS -
CNG, FLEX-FUEL & GASOLINE article.

z

Check fuel delivery system. See TEST HC: FUEL DELIVERY SYSTEM under SYSTEM TESTS in
SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

z

If no concern is found, check for intermittent faults. See TEST Z: INTERMITTENT under SYSTEM
TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

CAUTION: Extended cranking due to a no-start condition, can load exhaust system

with raw fuel, which may ruin catalytic converter after engine is started.

NOTE:

Add-on anti-theft devices may disable the starting system. If equipped, ensure
unit is disabled.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/CNG

FAST IDLE (DIESELS/RUNS ON)

z

Check base engine for air leaks, including proper sealing of intake manifold and components attached to
intake air; such as EGR valve or IAC valve.

z

Check air intake system. See TEST HU: AIR INTAKE SYSTEM under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check cooling system for overheating. If cooling system is overheating, repair as necessary. See
appropriate ELECTRIC COOLING FANS article in ENGINE COOLING.

z

Check A/C system. See appropriate AUTOMATIC or MANUAL A/C-HEATER SYSTEMS article in
HVAC.

z

For a fast idle concern, turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition
on. Using scan tool, access PCM and select TP MODE PID from PID/DATA MONITOR & RECORD
menu. Monitor TP MODE PID while wiggling TP sensor circuits. With throttle closed, TP MODE PID
should read C/T (closed throttle). If TP MODE PID is not C/T with throttle closed, select and monitor TP
V and TPREL PIDs for sudden changes while wiggling TP sensor circuits. At vehicle start, TPREL PID
reading will begin at about 1.25 volts and count down to lowest TP V value since engine start-up. If TP V
value goes below normal range, then increases again, TPREL will set to lower voltage. If TP V is
about .04 volt more than TPREL value at closed throttle, PCM will go into part throttle mode. Also check
for loose or worn throttle plates. If no problem is found, check for intermittent faults. Go to TEST Z:
INTERMITTENT under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article.

LOW IDLE (STALLS ON DECELERATION)

z

Check air intake system. See TEST HU: AIR INTAKE SYSTEM under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check fuel delivery system. See TEST HC: FUEL DELIVERY SYSTEM under SYSTEM TESTS in
SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

z

Check A/T Torque Converter Clutch (TCC) system. See appropriate DIAGNOSIS article in
AUTOMATIC TRANSMISSIONS.

BACKFIRES

z

Check secondary ignition system. See TEST JB: SECONDARY IGNITION under SYSTEM TESTS in
SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check fuel delivery system. See TEST HC: FUEL DELIVERY SYSTEM under SYSTEM TESTS in
SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

z

Check engine mechanical condition. Check compression, camshaft, valve train components, etc., and
repair as necessary. See appropriate article in ENGINES.

NOTE:

If vehicle runs normally after ignition is off, check for damaged ignition switch,
IGN RUN circuit shorted to power and/or VPWR circuit shorted to power. See
ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in
ELECTRICAL.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/CNG

z

Check exhaust system for restriction. See TEST HF: CATALYST EFFICIENCY MONITOR &
EXHAUST SYSTEMS under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article.

LACK/LOSS OF POWER

z

Check air intake system. See TEST HU: AIR INTAKE SYSTEM under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check secondary ignition system. See TEST JB: SECONDARY IGNITION under SYSTEM TESTS in
SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check fuel delivery system. See TEST HC: FUEL DELIVERY SYSTEM under SYSTEM TESTS in
SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

z

Check exhaust system for restriction. See TEST HF: CATALYST EFFICIENCY MONITOR &
EXHAUST SYSTEMS under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article.

z

Check EGR system. See TEST HE: EGR SYSTEM under SYSTEM TESTS in SELF-DIAGNOSTICS
- CNG, FLEX-FUEL & GASOLINE article.

z

Check engine mechanical condition. Check compression, camshaft, valve train components, etc., and
repair as necessary. See appropriate article in ENGINES.

z

On A/T models, check ATF level, throttle linkage and A/T Torque Converter Clutch (TCC) solenoid or
circuits. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

z

Check for dragging brakes and repair as necessary. See appropriate DISC & DRUM article in BRAKES.

z

Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, access PCM and
select DPFEGR (if equipped), LONGFT1 and LONGFT2 PIDs from PID/DATA MONITOR &
RECORD menu. See appropriate PIN VOLTAGE/PID VALUE CHARTS article. DPFEGR PID value
should be within .15 volt of Key On Engine Off (KOEO) value. If LONGFT1 or LONGFT2 PID value is
low (-20 percent), concentrate checks in areas that would cause engine to run rich. If LONGFT1 or
LONGFT2 PID value is high (+20 percent), concentrate checks in areas that would cause engine to run
lean.

z

Check Mass Air Flow (MAF) sensor and related circuits. See TEST DC: MASS AIRFLOW SENSOR
under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Additional Checks

Check customer driving habits. Check for correct PCM Vehicle Identification (VID) block information.
See FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY
(FLASH EEPROM) under PROGRAMMING PCM in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article. Check charging system. See appropriate GENERATORS & REGULATORS article
in ELECTRICAL. Ensure engine RPM/speed limiting functions of PCM are operating properly. Check

NOTE:

The PCM is equipped with an over RPM/speed limit function. If programmed
speed is exceeded, fuel delivery will shut off and DTC P1270 will be set in PCM
memory. Verify the symptom reported is under normal driving conditions
without excessive engine/vehicle load.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/CNG