Ford F150 Pickup. Instruction — part 1464

Fig. 177: IAT, ECT & EOT Sensor Specifications
Courtesy of FORD MOTOR CO.

4) Check ECT Sensor Resistance With Engine Running
Reconnect all connectors. Start engine and operate at 2000 RPM for 2 minutes. Turn ignition switch to
OFF position. Disconnect ECT sensor. Using a DVOM, measure resistance between ECT sensor SIG and
SIG RTN circuit terminals. See Fig. 171. Compare sensor resistance to appropriate temperature
specification in illustration. See Fig. 177. If resistance is not as specified for, replace faulty ECT sensor.
If resistance is as specified, replace PCM.

10) For KOEO & KOER Only DTC P0113 Or P0118: Check Voltage Between VREF & SIG RTN
DTC P0113 (IAT) or P0118 (ECT) indicates IAT or ECT sensor signal is more than self-test maximum.
Maximum measurement should be 4.6 volts at -58°F (-50°C). Check for following possible causes:

z

Open Circuit In Harness Or Connector

z

Sensor Signal Short To Power

z

Faulty Sensor

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 4) to step 10). No test procedures have been omitted.

NOTE:

For LS and Thunderbird with electronic throttle control, go to next step.
For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

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

z

Faulty PCM

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

11) Simulate Opposite Signal To PCM

Turn ignition switch to OFF position. Disconnect suspect temperature sensor. Connect a jumper wire
between suspect sensor harness connector SIG and SIG RTN circuit terminals. With scan tool installed,
turn ignition switch to ON position.

Using scan tool, access suspect sensor ECT-V or IAT-V PID from PID/DATA MONITOR & RECORD
menu. If PID value is less than .2 volt or more than 248°F (120°C), replace suspect sensor. If PID value
is .2 volt or more, or 248°F (120°C) or less, remove jumper wire and go to next step.

12) Check Temperature Sensor SIG & SIG RTN Circuits For Open In Harness

Turn ignition switch to OFF position. Ensure suspect temperature sensor is disconnected. Disconnect
PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary.
Using a DVOM, measure resistance of SIG RTN circuit between PCM harness connector and suspect
sensor harness connector. Record resistance. Using a DVOM, measure resistance of SIG circuit between
PCM harness connector and suspect sensor harness connector. See Fig. 171-Fig. 176 . See WIRING
DIAGRAMS. If both resistance measurements are less than 5 ohms, replace PCM. If either resistance
measurement is 5 ohms or more, repair open in affected circuit.

13) Check Temperature Sensor SIG Circuit For Short To VREF In Harness

Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance
between suspect sensor VREF circuit and SIG circuit (ECT or IAT) terminals at PCM harness connector.
See Fig. 171-Fig. 176 . See WIRING DIAGRAMS. If resistance is more than 10 k/ohms, replace PCM.
If resistance is 10 k/ohms or less, repair short to VREF in wiring harness.

20) For KOEO & KOER Only DTC P0112 Or P0117: Simulate Opposite Signal To PCM
DTC P0112 (IAT) or P0117 (ECT) indicates sensor signal is less than self-test minimum. Minimum
signal for IAT and ECT sensor is .2 volt or 250°F (121°C). Possible causes for these faults are:

NOTE:

If a scan tool communication concern exists, remove jumper wire and go
to step 13).

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 13) to step 20). 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

z

Circuit Grounded In Wiring Harness

z

Faulty Sensor

z

Faulty Connection

z

Faulty PCM

Turn ignition switch to OFF position. Disconnect suspect temperature sensor connector. Inspect
connector for loose, damaged or corroded terminals. Repair as necessary. Connect scan tool to Data Link
Connector (DLC). Turn ignition switch to ON position. Using scan tool, access ECT-V or IAT-V PID
from PID/DATA MONITOR & RECORD menu. For LS and Thunderbird with electronic throttle
control, if PID value is 4.2 volts or less, or -40°F (-40°C) or more, go to step 22). All others, go to next
step. If PID value is more than 4.2 volts, or less than -40°F (-40°C), replace faulty temperature sensor.

21) Check VREF Voltage To TP Sensor

Turn ignition switch to OFF position. Disconnect TP sensor connector. Turn ignition switch to ON
position. Using a DVOM, measure voltage between VREF and SIG RTN terminals at TP sensor harness
connector. 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, see TEST C, step 1).

22) Check Temperature Sensor SIG Circuit For Short To Ground

Turn ignition switch to OFF position. Ensure suspect sensor is disconnected. Disconnect PCM connector
(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM,
measure resistance between suspect sensor SIG, SIG RTN and PWR GND circuits at PCM harness
connector. See PCM PWR GND, SIG RTN & VREF TERMINAL IDENTIFICATION table. See
Fig. 171-Fig. 176 . See WIRING DIAGRAMS. If any resistance measurement is 10 k/ohms or less,
repair short to ground in affected circuit. If all resistance measurements are more than 10 k/ohms, replace
PCM.

80) For Continuous Memory Only DTC P0116: Check Temperature Sensor Resistance With
Engine Off
DTC P0116 indicates ECT 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

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

z

Engine coolant 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.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 22) 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

Possible causes for this fault are:

z

Faulty CHT Or ECT Sensor

z

Coolant System Fault

Ensure engine temperature is at ambient room temperature before performing this test step. A soak period
of 6 hours may be required. Soak period allows IAT and CHT or ECT to stabilize and not differ by more
than a calibrated value. Turn ignition switch to OFF position. Disconnect ECT sensor. Using a DVOM,
measure resistance between SIG and SIG RTN circuit terminals at suspect sensor harness connector. See
Fig. 171. Compare sensor resistance to appropriate temperature specification in illustration. See Fig. 177.
If resistance is not as specified, replace faulty sensor. If resistance is as specified, go to next step.

81) DTC P0116: Check Temperature Sensor Resistance With Engine Running
Reconnect suspect sensor connector. Start engine and operate at 2000 RPM for 2 minutes. Turn ignition
switch to OFF position. Disconnect suspect sensor. Using a DVOM, measure resistance between SIG and
SIG RTN circuits at suspect sensor terminals. See Fig. 171. Compare sensor resistance to appropriate
temperature specification in illustration. See Fig. 177. If resistance is not as specified, verify thermostat
and cooling system for correct operation. If okay, replace faulty sensor. If resistance is as specified, fault
is not present at this time. Perform DRIVE CYCLES to determine if fuel, HO2S, catalyst and misfire
monitors can be executed. Repeat QUICK TEST.

90) For Continuous Memory Only DTCs P0112, P0113, P0118, P1112 & P1117: Check For
Intermittent
These DTCs indicate possible intermittent fault. Possible causes for these faults are:

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Faulty Sensor

z

Faulty Sensor Connector

z

Open Or Grounded Circuit In Harness

z

Faulty PCM

Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool,
access ECT-V and IAT-V PID from PID/DATA MONITOR & RECORD menu. While observing
appropriate PID, tap on sensor and wiggle sensor connector to simulate road shock. If no change in PID
voltage reading occurs, go to next step. If any change in PID voltage reading occurs, turn ignition switch
to OFF position. Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. If
connectors are okay, replace faulty temperature sensor. If directed here for Continuous Memory DTCs
P1112 and P1117, perform DRIVE CYCLES to verify repair. Repeat QUICK TEST.

NOTE:

Engine must be at normal operating temperature before taking
temperature sensor measurements.

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