Ford F150 Pickup. Instruction — part 1576

z

Open Or Shorted Thermostat Assembly

z

Faulty PCM

Turn ignition switch to OFF position. Disconnect THTRC connector. Turn ignition switch to ON
position. Using a DVOM, measure voltage between chassis ground and VPWR circuit (Light
Blue/Orange wire) at THTRC harness connector. If voltage is more than 10.5 volts, go to next step. If
voltage is 10.5 volts or less, repair open in Light Blue/Orange wire between THTRC and splice No. 153
at engine.

11) Check THTRC Resistance

Turn ignition switch to OFF position. Using a DVOM, measure resistance between THTRC connector
terminals. Resistance should be 14-16 ohms. If resistance is within specification, go to next step. If
resistance is not within specification, replace THTRC.

12) Check THTRC Circuit For Open In Harness

Ensure ignition switch is turned to OFF position. Disconnect PCM connector. Inspect connector for loose,
damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of THTRC
circuit (Dark Blue wire) between THTRC harness connector and PCM harness connector. See PCM
CONNECTOR IDENTIFICATION and Fig. 354. If resistance is less than 5 ohms, go to next step. If
resistance is 5 ohms or more, repair open in THTRC circuit.

13) Check THTRC Circuit For Short To GND Or VPWR In Harness

Using a DVOM, measure resistance between THTRC circuit, and SIG RTN, PWR GND and VPWR
circuits at PCM harness connector. If all resistance measurements are more than 10 k/ohms, go to TEST
Z, step 1) (for Continuous Memory DTC P1432), or replace PCM (for KOEO or KOER DTC P1432). If
any resistance measurement is 10 k/ohms or less, repair THTRC circuit for short to GND, SIG RTN or
VPWR circuit.

TEST NB: MALFUNCTION INDICATOR LIGHT

Diagnostic Aids

This test is used to diagnose the following:

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Malfunction Indicator Light (MIL) Bulb Or Socket

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Wiring Harness Circuit; (MIL)

z

Faulty Powertrain Control Module (PCM)

Testing

NOTE:

Diagnostic procedures beginning with step 1) are performed when
directed here from an MIL concern under WARNING INDICATOR LIGHTS
under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-

2003 Ford Pickup F150

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

1) MIL Always On: Check MIL Circuit For Shorts To GND In Harness
If vehicle will not start, go to TEST A, step 1). Service all KOEO or Continuous Memory DTCs before
continuing. If no DTCs are present, turn ignition switch to OFF position. Disconnect PCM connector.
Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM,
measure resistance between PCM harness connector terminals No. 2 (MIL), and PWR GND and SIG
RTN circuit terminals. See PCM PWR GND, SIG RTN & VREF TERMINAL IDENTIFICATION
table. See PCM CONNECTOR IDENTIFICATION. If resistance is 10 k/ohms or less, repair MIL
circuit between PCM and MIL for short to PWR GND or SIG RTN circuit. If resistance is 10 k/ohms or
more, replace PCM.

2) MIL Never On

If vehicle will not start, go to TEST A, step 1). Turn ignition switch to ON position. Connect jumper wire
between PCM pin 2 at the PCM harness connector to battery negative terminal. If the MIL lamp
illuminates, turn ignition switch to OFF position and replace PCM. If the MIL lamp does not illuminate,
turn ignition switch to ON position and go to step

4)

.

4) Check Voltage On B+ Circuit

Turn ignition switch to OFF position. Disconnect instrument cluster connector. Refer to appropriate
INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Turn ignition switch to ON
position. Using a DVOM, measure voltage between negative battery terminal and B+ circuit at instrument
cluster harness connector. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or
less, repair open in instrument cluster fuse or B+ circuit to instrument cluster. See appropriate
INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Recheck MIL operation.

5) Check For Open MIL Circuit Between PCM & Instrument Cluster

Turn ignition switch to OFF position. Disconnect PCM connector. Inspect connector for loose, damaged
or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of MIL circuit between
PCM harness connector terminal No. 2 and MIL circuit at instrument cluster harness connector. See
PCM CONNECTOR IDENTIFICATION. If resistance is 5 ohms or more, repair open in MIL circuit.
Recheck MIL operation. If resistance is less than 5 ohms, check MIL bulb and instrument cluster. See
appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Repair as necessary.
If no concerns are found, replace PCM. Recheck MIL operation.

TEST NC: IGNITION ENGINE SPEED INPUT CIRCUIT

FUEL & GASOLINE article. For Escape, Expedition, Focus, F150 Pickup,
LS, Mustang, Navigator, Thunderbird, Town Car or Windstar, see
appropriate INSTRUMENT PANELS article in ACCESSORIES &
EQUIPMENT for MIL diagnosis.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 2) to step 4). No test procedures have been omitted.

2003 Ford Pickup F150

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

Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used
to diagnose a faulty Powertrain Control Module (PCM). DTC P0320 indicates that (2) successive erratic Profile
Ignition Pulses (PIP) signals have occurred. Possible causes are:

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Loose Wires &/Or Connectors

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Short Circuit To Ground In Ignition Secondary System (Coil, Wires Or Plugs)

z

Incorrect 2-Way Radio Installation

Testing

1) For KOEO & Continuous Memory Only DTC P0320: Erratic Ignition
The ignition engine speed sensor input signal to PCM is continuously monitored. The test fails when the
signal indicates that two successive erratic Profile Ignition Pickup (PIP) pulses have occurred. Possible
causes are:

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Loose wires/connectors.

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Arcing secondary ignition components (coil, wires and plugs).

z

On board transmitter (2-way radio).

Ensure 2-way radio antenna and all harness connections are properly installed and routed. If any faults
were present, repair as necessary. If vehicle will not start, go to TEST A, step 1). If fault is intermittent,
go to TEST Z, step 1). If vehicle will start and no faults were present, check for missing PIP signal. Go to
TEST JD, step 1).

TEST ND: ENGINE RPM/VEHICLE SPEED LIMITER

Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. DTC P0219
(engine overspeed), P0297 (vehicle overspeed) and P1270 indicate that vehicle was operated in a manner which
caused engine or vehicle speed to exceed a calibrated limit. Possible causes are:

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Wheel Slippage Caused By Mud, Ice, Water, Snow, Etc.

NOTE:

After each service or repair procedure has been completed, reconnect all
components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-
V systems are working properly and DTCs are no longer present.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

After each service or repair procedure has been completed, reconnect all
components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-
V systems are working properly and DTCs are no longer present.

2003 Ford Pickup F150

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

z

Excessive Engine RPM In Neutral

z

Vehicle Driven At Excessive Rate Of Speed

Testing

1) For Continuous Memory Only DTC P0219, P0297 and P1270: Excessive Engine RPM/Vehicle
Speed
These DTCs indicate the vehicle has been operated in a manner, which caused the engine or vehicle to
exceed a calibration limit. The engine RPM and vehicle speed are continuously monitored and evaluated
by the PCM. The DTC is set when the RPM or vehicle speed falls out of a calibrated range. Possible
causes are:

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Wheel slippage (water, ice, mud and snow).

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Excessive engine RPM in Neutral or operated in the wrong transmission gear.

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Vehicle driven at a high rate of speed.

If any of the specified causes have occurred, system is okay. Clear PCM memory. Ensure vehicle owner
has an understanding of what causes DTC to set. If none of specified causes have occurred, clear PCM
memory. Check for other driveability concerns. See SYMPTOMS under TROUBLE SHOOTING - NO
CODES - CNG, FLEX-FUEL & GASOLINE article. Repair as necessary. If no other concerns are
present, return vehicle to customer.

TEST QA: UNABLE TO ACTIVATE SELF-TEST/SCP COMMUNICATION ERROR/DTC NOT
LISTED

Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used
to diagnose the following:

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Standard Corporate Protocol (SCP) Communication Bus Circuits BUS(+) & BUS(-), Between DLC &
PCM

z

Data Link Connector (DLC) Harness Circuits; (CHASSIS GND, PWR GND & B+). See Fig. 355 or Fig.
356

z

High Speed-Controller Area Network (HS-CAN) 500 kB/sec (kilobytes per second) communication bus
harness circuits: HS-CAN(+) High, HS-CAN(-) Low, between DLC and PCM

z

Open VPWR Circuit To Powertrain Control Module (PCM)

z

Faulty PCM

NOTE:

On vehicles with 4WD, ensure 4WD system is operating properly. Improper use
or operation of 4WD system may cause DTC P1270 to be stored in PCM. See
appropriate DIAGNOSIS article in TRANSFER CASES for diagnosis and testing.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

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