Ford F150 Pickup. Instruction — part 1479

Turn ignition switch to ON position. Using scan tool, access CHT V PID from PID/DATA MONITOR &
RECORD menu. If CHT V PID voltage is more than 4.6 volts, replace CHT sensor. For LS and
Thunderbird, if CHT V PID voltage is 4.6 volts or less, go to step 22). For all others, go to next step.

21) Check VREF Circuit Voltage At TP Sensor

Disconnect TP sensor connector. Turn ignition switch to ON position. Using a DVOM, measure voltage
between VREF and SIG RTN circuits at TP sensor harness connector. See Fig. 163-Fig. 166 . If voltage
is 4-6 volts, VREF voltage is okay. Reconnect TP sensor and go to next step. If voltage is not 4-6 volts,
go to TEST C, step 1).

22) Check CHT Signal Circuit For Short To Ground

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose,
damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between CHT
circuit, and PWR GND and SIG RTN circuits at PCM harness connector. See PCM PWR GND, SIG
RTN & VREF TERMINAL IDENTIFICATION table. See PCM CONNECTOR
IDENTIFICATION and Fig. 193 or Fig. 194 . If all resistance measurements are more than 10 k/ohms,
replace PCM. If any resistance measurement is 10 k/ohms or less, repair short between circuits.

30) For KOEO, KOER & Continuous Memory DTC P1285: Early Warning Of Engine Overheat
Condition
This DTC indicates that PCM sensed an engine overheat condition from CHT sensor. Possible causes for
fault are:

z

Low Engine Coolant Level

z

Engine Mechanical Concern

z

Engine Cooling System Concerns

z

CHT Sensor Concern

Check cooling system for external or internal leaks and restrictions. Check coolant level and cooling fan
operation. Check for blockage in radiator. Repair as necessary. If electric cooling fan does not operate,
see appropriate symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-
FUEL & GASOLINE article. If a cooling fan DTC is retrieved, see DIAGNOSTIC TROUBLE CODE
DEFINITIONS. If cooling system is okay and no faults are found, check CHT sensor operation. Go to
step 3).

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 22) to step 30). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 30) to step 40). No test procedures have been omitted.

NOTE:

Diagnostic procedures beginning with step 40) are performed when

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

40) Engine Temperature Warning Light Always On Or Temp Gauge Reads Hot, Engine Not
Overheating
If QUICK TEST was performed and no DTCs are present, go to next step. If QUICK TEST was not
performed, perform QUICK TEST and service any DTCs that are present.

41) Engine Temperature Warning Light Always On Or Temp Gauge Reads Hot (No DTCs)

Engine Temperature Warning Indicator (gauge or lamp) is a warning system that gives driver information
during an engine overheating condition. PCM monitors CHT sensor and determines if fail-safe cooling
mode is needed. If fail-safe cooling is needed, PCM can signal driver in 2 ways:

z

Temperature Warning Indicator Hard Wired To PCM

PCM grounds engine temperature warning circuit when engine is overheating. This causes
instrument cluster indicator to illuminate and/or forces temperature gauge to "H" (Hot) zone. A
DTC P1285 will also be stored in PCM.

z

Temperature Warning Indicator Information Received Through SCP

PCM sends an SCP message to instrument cluster to signal an overheating condition. This causes
instrument cluster indicator to illuminate and/or forces temperature gauge to "H" (Hot) zone. A
DTC P1285 will also be stored in PCM. This test only diagnoses PCM hard wire systems with no
cooling system DTCs stored.

Possible causes are:

z

Faulty ECT sensor.

z

Faulty instrument cluster.

z

Faulty wiring harness between PCM and instrument cluster.

z

Faulty PCM.

Disconnect PCM connector(s). Turn ignition switch to ON position. If engine temperature warning light
is off, or temperature gauge measurement is in the normal zone, replace PCM. If engine temperature
warning light is still illuminated, or temperature gauge measurement is in still in the "H" (Hot) zone,
PCM is not the cause. Check instrument cluster and temperature warning light circuits. See appropriate
INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT for diagnosis and testing.

directed here from WARNING INDICATOR LIGHTS symptom under
SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL &
GASOLINE article.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 41) to step 80). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

80) For Continuous Memory Only DTC P0116: Check CHT Sensor Resistance With Engine Off
DTC P0116 indicates CHT sensor drifted higher than normal sensor calibration curve and could prevent
one or more OBD-II monitors from functioning. PCM will set DTC P0116 when all of the following
conditions are met:

z

Cylinder head temperature at engine start up exceeds IAT temperature by more than calibrated
value, about 30°F (-1°C).

z

Cylinder head temperature exceeds a calibrated value, about 225°F (107°C).

z

Fuel, HO2S, catalyst and misfire monitors have not completed.

z

Calibrated timer to set DTC P0116 has expired.

Possible causes for this fault are:

z

Faulty CHT Sensor

z

Coolant System Fault

Ensure engine temperature is at ambient room temperature. A soak period of 6 hours may be required.
Turn ignition switch to OFF position. Disconnect CHT sensor connector. Using a DVOM, measure
resistance between CHT sensor terminals. See CHT SENSOR SPECIFICATIONS table. If resistance is
as specified, go to next step. If resistance is not as specified, replace CHT sensor.

81) Check CHT Sensor Resistance With Engine Running

Start engine and bring to operating temperature. Run at 2000 RPM for 2 minutes. Using a DVOM,
measure resistance between CHT sensor terminals. See CHT SENSOR SPECIFICATIONS table. If
resistance is not as specified, replace CHT sensor. If resistance is as specified, fault is not present at this
time. Perform DRIVE CYCLES. Ensure OBD-II DRIVE CYCLE is performed to ensure Fuel, HO2S,
Catalyst and Misfire monitors can be activated.

90) For Continuous Memory Only DTC P0117, P0118, P1117, P1289 Or P1290: Intermittent Check
These DTCs indicate intermittent CHT sensor failure. Possible causes for these faults are:

z

Open Or Grounded Circuit

z

Faulty CHT Sensor

z

Low Coolant Level

z

Faulty PCM

Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool,
access CHT V PID from PID/DATA MONITOR & RECORD menu. While observing CHT V PID,
lightly tap on CHT sensor and wiggle sensor connector to simulate road shock. A fault is indicated by a
sudden change of CHT V PID temperature reading. If no fault is indicated, go to next step. If fault is

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 81) to step 90). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

indicated, turn ignition switch to OFF position. Disconnect and inspect connectors. If connectors are
okay, replace CHT sensor. Clear DTCs and perform DRIVE CYCLE. Ensure OBD-II DRIVE CYCLE is
performed to verify repair.

91) Check EEC-V Wiring Harness

Ensure CHT V PID is still selected. Starting at CHT sensor connector and working toward PCM, wiggle,
shake and bend small sections of wiring harness. A fault is indicated by a sudden change of CHT V PID
temperature reading. If no fault is indicated, go to next step. If fault is indicated, isolate and repair as
necessary. Clear DTCs and perform DRIVE CYCLES. Ensure OBD-II DRIVE CYCLE is performed to
verify repair.

92) Check PCM & Wiring Harness

Turn ignition switch to OFF position. Disconnect CHT sensor and PCM harness connectors. Inspect
connectors for loose, damaged or corroded terminals. Repair as necessary. Perform DRIVE CYCLES.
Ensure OBD-II DRIVE CYCLE is performed to verify repair. If connectors are okay, concern cannot be
located at this time. Perform DRIVE CYCLES. Ensure OBD-II DRIVE CYCLE is performed to verify
repair.

100) For KOEO, KOER & Continuous Memory DTC P0217, & For KOER & Continuous Memory
Only DTC P1299: Engine Overheat Condition Occurred
These DTCs indicate an engine overheat condition was detected by CHT sensor and FMEM fail-safe
cooling strategy was activated. On F150 Lightning 5.4L SC models, boost from supercharger will be by-
passed to avoid possible engine damage. Possible causes for this fault are:

z

Cooling System Fault

z

Low Coolant Level

z

Engine Mechanical Fault

Locate cooling system fault and repair as necessary.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 92) to step 100). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

WARNING:

To avoid personal injury, DO NOT loosen coolant pressure relief cap
while engine is operating or hot. Cooling system is under pressure
and steam and/or hot coolant can come out forcefully when cap is
loosened slightly.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

WARNING:

To avoid personal injury, DO NOT loosen coolant pressure relief cap

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline