Ford F150 Pickup. Manual — part 1559

z

Open Or Shorted LFC, MFC Or HFC Circuit

z

Open VPWR Circuit (Or IGN START/RUN Circuit On Escape) To LFC, MFC Or HFC Relay

z

Faulty LFC, MFC Or HFC Relay

z

Faulty PCM

Turn ignition switch to OFF position. Remove appropriate fan control (LFC, MFC or HFC) relay. See
COOLING FAN RELAY LOCATIONS table. Turn ignition switch to ON position. Using a DVOM,
measure voltage between negative battery terminal and VPWR (IGN START/RUN on Escape) circuit at
appropriate fan control relay cavity. See Fig. 321-Fig. 330 . If voltage is more than 10.5 volts, go to next
step. If voltage is 10.5 volts or less, repair open in VPWR (or IGN START/RUN) circuit to appropriate
fan control relay.

2) Check For LFC, MFC Or HFC Circuit Cycling

Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition
switch to ON position. Connect a test light between VPWR (or IGN START/RUN) circuit and LFC,
MFC or HFC circuit at appropriate fan control relay cavity. See Fig. 321-Fig. 330 . Using scan tool,
access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM
FUNCTIONS. Observe test light while commanding appropriate cooling fan speed (LFC, MFC or HFC)
ON and OFF. On Escape, Sable and Taurus, commanding low speed fan ON will also command medium
fan ON. If test light illuminates and then turns off when appropriate fan control relay is commanded,
replace faulty fan control relay. If test light does not illuminate and then turn off when appropriate fan
control relay is commanded, repeat this test step. If test light still does not illuminate and then turn off
when appropriate fan control relay is commanded, turn ignition switch to OFF position, remove test light
and go to next step.

3) Check LFC, MFC Or HFC Circuit For Short To PWR In Harness

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose,
damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a
DVOM, measure voltage between negative battery terminal and LFC, MFC or HFC circuit at appropriate
fan control relay cavity. See Fig. 321-Fig. 330 . If voltage is less than one volt, go to next step. If voltage
is one volt or more, repair LFC, MFC or HFC circuit for short to PWR.

4) Check LFC, MFC Or HFC Circuit For Short To Ground In Harness

Turn ignition switch to OFF position. Disconnect scan tool from DLC. Using a DVOM, measure
resistance between negative battery terminal and LFC, MFC or HFC circuit at appropriate fan control
relay cavity. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair
LFC, MFC or HFC circuit for short to ground.

5) Check For Open LFC, MFC Or HFC Circuit

Using a DVOM, measure resistance of LFC, MFC or HFC circuit between PCM harness connector and
appropriate fan control relay cavity. See Fig. 321-Fig. 330 . If resistance is less than 5 ohms, replace
PCM. If resistance is 5 ohms or more, repair open in LFC, MFC or HFC circuit.

2003 Ford Pickup F150

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

6) For KOEO & KOER Only DTC P0481 & P1479: Check VPWR (Or IGN START/RUN On
Escape) Circuit Voltage To HFC Relay No. 1
DTC P1479 is set when HFC output is commanded ON (grounded) and PCM detects excessive current
draw on HFC circuit; or with HFC circuit commanded OFF, PCM does not detect voltage on HFC circuit.
PCM expects to detect VPWR voltage coming through HFC relay coil to HFC circuit. Possible causes
are:

z

Open Or Shorted HFC Circuit

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Open VPWR (Or IGN START/RUN) Circuit To HFC Relay

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Faulty HFC Relay No. 1 (MAIN FAN On Escape 3.0L)

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Faulty HFC Relay No. 2 (ADD FAN 2 On Escape 3.0L)

z

Faulty PCM

Turn ignition switch to OFF position. Remove HFC relay No. 1 (MAIN FAN on Escape 3.0L). See
COOLING FAN RELAY LOCATIONS table. Turn ignition switch to ON position. Using a DVOM,
measure voltage between chassis ground and VPWR (or IGN START/RUN) circuit at appropriate HFC
relay No. 1 (or MAIN FAN) cavity. See Fig. 323, Fig. 324 or Fig. 329 . If voltage is more than 10.5
volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR (or IGN START/RUN) circuit.

7) Check For HFC Circuit Cycling At HFC Relay No. 1

Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Connect test
light between VPWR (or IGN START/RUN) and HFC circuits at HFC relay No. 1 (or MAIN FAN)
cavities. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under
ADDITIONAL SYSTEM FUNCTIONS. Observe test light while commanding high speed cooling fan
ON and OFF. If test light illuminates and then turns off when high speed cooling fan is commanded,
replace HFC relay No. 1 (or MAIN FAN) and go to step 9). If test light does not illuminate and then turn
off when high speed cooling fan is commanded, leave test light connected and go to next step.

8) Check For HFC Circuit Cycling With HFC Relay No. 2 (ADD FAN 2) Removed

Ensure test light is still connected between VPWR (or IGN START/RUN) and HFC circuits at HFC relay
No. 1 (or MAIN FAN) cavities. Using scan tool, access OUTPUT TEST MODE and command cooling
fans OFF. Remove HFC relay No. 2 (ADD FAN 2 on Escape 3.0L) in battery junction box. Using scan
tool, command high speed cooling fan ON and OFF while observing test light. If test light illuminates and
then turns off when high speed cooling fan is commanded, replace HFC relay No. 2 (or ADD FAN 2). If
test light does not illuminate and then turn off when high speed cooling fan is commanded, go to step 3)
and check for open, or short to PWR or ground in HFC circuit at HFC relay No. 1 cavities.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 5) to step 7). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

High Speed Fan (HFC) relay No. 1 and 2 may also be referred to as EDF or
HEDF relay respectively.

2003 Ford Pickup F150

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

9) Verify There Is Not An Open In Circuit Specific To HFC Relay No. 2

Leave HFC relay No. 1 (or MAIN FAN) disconnected. Using scan tool, command the high speed cooling
fan on and off while viewing the HFCF PID. Repeat test, commanding the low speed cooling fan on and
off. If the HFCF PID indicates a fault (YES) when either the low or high speed cooling fan output is
commanded on and off, go to step 27). If the HFCF PID does not indicate a fault (NO) when either the
low or high speed cooling fan output is commanded on and off, install HFC relay No. 1 (or MAIN FAN).
Testing is complete.

10) For Continuous Memory Only DTC P0480 Or P1474: Check LFC Circuit For Open Or Short
To PWR
DTC P0480 or P1474 is set when PCM grounds LFC circuit and PCM detects excessive current draw is
detected on LFC circuit; or with LFC circuit not grounded by PCM and PCM does not detect voltage on
LFC circuit. PCM expects to detect VPWR voltage coming through LFC relay (or CCRM) coil to LFC
circuit. Possible causes are:

z

Open LFC Relay VPWR Circuit (IGN START/RUN Circuit On Escape)

z

Open Or Shorted LFC Circuit

z

Faulty LFC Relay

z

Faulty PCM

Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Ensure A/C and
defroster are off. Disconnect cooling fan connector (both connectors on models with 2 cooling fans).
Inspect connector(s) for loose, damaged or corroded terminals. Repair as necessary. Connect a test light
between ground and LOW FAN PWR circuits at cooling fan harness connector. For models with 2
cooling fans connect test light at the following cooling fan:

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On Escape 2.0L, Sable and Taurus, use driver's side cooling fan connector. See Fig. 322 and Fig.
329 .

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On Escape 3.0L, use passenger's side cooling fan connector. See Fig. 323 or Fig. 324 .

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On all others with 2 cooling fans, either harness connector can be used. See Fig. 325, Fig. 326 and
Fig. 330 .

Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT
TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command low speed fan ON. Test light
should illuminate. Observe test light for indication of fault (test light will turn off) while performing the
following:

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Shake, wiggle and bend LFC circuit between PCM and LFC relay.

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Shake, wiggle and bend VPWR (or IGN START/RUN) circuit to LFC relay.

z

Lightly tap on LFC relay to simulate road shock.

If fault is indicated, turn ignition switch to OFF position. Replace LFC relay or repair open or short to
PWR in LFC, IGN START/RUN or VPWR circuit as necessary. If no fault is indicated, leave test light
connected and go to next step.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

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

11) Check LFC Circuit For Short To Ground

Turn ignition switch to ON position. Ensure cooling fan connector is still disconnected and test light is
still connected. Using scan tool, command low speed fan OFF. Test light should be off. Observe test light
for indication of fault (test light will illuminate) while performing the following:

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Shake, wiggle and bend LFC circuit between PCM and LFC relay.

z

Lightly tap on LFC relay to simulate road shock.

If a fault is indicated, isolate and repair short to ground in LFC circuit or replace LFC relay as necessary.
If no fault is indicated, check for intermittent faults. Go to TEST Z, step 1).

15) For Continuous Memory Only DTCs P0482 & P1477: Check MFC Circuit For Open Or Short
To Power
DTC P1477 is set when MFC output is commanded ON (grounded) and PCM detects excessive current
draw on MFC circuit; or with MFC circuit commanded OFF, PCM does not detect voltage on MFC
circuit. PCM expects to detect IGN START/RUN voltage coming through MFC relay coil to MFC
circuit. Possible causes are:

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Open Or Shorted MFC Circuit

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Open VPWR Circuit To MFC Relay (ADD FAN 3 Relay On Escape)

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Faulty MFC (Or ADD FAN 3) Relay

z

Faulty PCM

Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Ensure A/C and
defroster are off. On Escape 2.0L, disconnect passenger's side cooling fan connector. Inspect connector
for loose, damaged or corroded terminals. Repair as necessary. Connect a test light between MEDIUM
FAN PWR and GND circuits at cooling fan harness connector. See Fig. 322. On Escape 3.0L, Sable and
Taurus, remove MFC (or ADD FAN 3) relay. See COOLING FAN RELAY LOCATIONS table.
Connect a test light between MFC and VPWR (or IGN START/RUN) circuits at MFC (or ADD FAN 3)
relay cavities. See Fig. 323, Fig. 324 or Fig. 329 . On all models, turn ignition switch to ON position.
Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL
SYSTEM FUNCTIONS. Command low speed fan ON (this also commands medium fan ON). Test light
should illuminate. Observe test light for indication of fault (test light will turn off) while performing the
following:

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On Escape 2.0L, lightly tap on MFC relay to simulate road shock.

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On all models, shake, wiggle and bend MFC circuit between PCM and MFC (or ADD FAN 3)
relay.

z

On all models, shake, wiggle and bend VPWR (or IGN START/RUN) circuit to MFC (or ADD
FAN 3) relay.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 11) to step 15). 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