Ford F150 Pickup. Instruction - part 1560

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

16) Check MFC Circuit For Short To Ground 
 
Turn ignition switch to ON position. Ensure cooling fan connector is 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: 

z

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

z

On Escape 3.0L, Sable and Taurus, check MFC (or ADD FAN 3) relay for intermittent concerns.  

z

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

If fault is indicated, replace MFC (or ADD FAN 3) relay or repair short to ground in MFC circuit as 
necessary. If fault is not indicated, check for intermittent faults. Go to TEST Z, step 1). 

20) For Continuous Memory Only DTCs P0481 & P1479: Check HFC Circuit For Open Or Short 
To PWR 
DTC P0481 or 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 VPWR Circuit (Or IGN START/RUN Circuit On Escape)  

z

Open Or Shorted HFC Circuit  

z

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

z

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

Turn ignition switch to OFF position. 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 circuit and HIGH FAN PWR circuit 
at cooling fan harness connector. For models with 2 cooling fans connect test light at the following 
cooling fan:  

z

On Escape 2.0L, use passenger's side cooling fan connector. See Fig. 322.  

z

On all others with 2 cooling fans, either harness connector can be used. See Fig. 323, Fig. 324, Fig. 
325, Fig. 326, Fig. 329 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 high speed fan ON. Test light 
should illuminate. Observe test light for indication of fault (test light will turn off) while performing the 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 16) 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

  

following:  

z

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

z

Shake, wiggle and bend VPWR circuit (IGN START/RUN circuit on Escape) to HFC relay (ADD 
FAN 2 and MAIN FAN relay on Escape 3.0L).  

z

Lightly tap on HFC relay to simulate road shock.  

If fault is indicated, turn ignition switch to OFF position. Replace HFC relay or repair open or short to 
VPWR (or IGN START/RUN) circuit as necessary. If fault is not indicated, go to next step. 

21) Check HFC Circuit For Short To Ground 
 
Turn ignition switch to ON position. Ensure cooling fan connector(s) are disconnected and test light is 
still connected. Using scan tool, command high speed fan OFF. Test light should be off. Observe test 
light for indication of fault (test light will illuminate) while performing the following: 

z

Shake, wiggle and bend HFC circuit between PCM and HFC relay (ADD FAN 2 and MAIN FAN 
relay on Escape 3.0L).  

z

Lightly tap on HFC (or ADD FAN 2 and MAIN FAN) relay to simulate road shock.  

If fault is indicated, turn ignition switch to OFF position. Replace relay or repair short to ground in HFC 
circuit as necessary. If fault is not indicated, check for intermittent faults. Go to TEST Z, step 1). 

23) For Continuous Memory Only DTC P0481 Or P1479: Check HFC Circuit For Open Or Short 
To PWR 
DTC P0481 or 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 VPWR Circuit  

z

Open Or Shorted HFC Circuit  

z

Faulty HFC Relay No. 1  

z

Faulty HFC Relay No. 2  

Turn ignition switch to OFF position. Ensure A/C and defroster are off. Disconnect both cooling fan 
connectors. Disconnect one high speed FC relay (either one). Connect a test light between HFC and 
VPWR circuits at HFC relay cavity. See Fig. 323, Fig. 324, Fig. 325, Fig. 327 or Fig. 329 . 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 (if test light does not turn 
on, command high speed fan on). Test light should illuminate. Observe test light for indication of fault 
(test light will turn off) while performing the following:  

z

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

z

Shake, wiggle and bend VPWR circuit to HFC relay.  

z

Lightly tap on HFC relay to simulate road shock. 

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

 

2003 Ford Pickup F150 

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

  

If fault is indicated, turn ignition switch to OFF position. Replace HFC relay or repair open or short to 
VPWR circuit as necessary. If fault is not indicated, go to next step. 

24) Check HFC Circuit For Short To Ground 
 
Turn ignition switch to ON position. Ensure cooling fan connectors are 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: 

z

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

z

Check HFC relay that is disconnected for intermittent concerns.  

If fault is indicated, turn ignition switch to OFF position. Replace HFC relay or repair short to ground in 
HFC circuit as necessary. If fault is not indicated, check for intermittent faults. Go to TEST Z, step 1). 

25) One Or All Fans Inoperative: Check Fan Control Fault PIDs To Verify Fan Control Primary 
Circuits 
Connect scan tool to Data Link Connector (DLC). Ensure A/C is off and engine temperature is below the 
temperature where the cooling fan would come on. Turn ignition switch to ON position. Using scan tool, 
access LFCF, MFCF or HFCF PIDs (as appropriate, according to which circuits the vehicle has) from 
PID/DATA MONITOR & RECORD menu. For Escape 3.0L, Focus 2.0L, Sable and Taurus with fan 
operates, but not at all speeds, while viewing HFCF PID, disconnect one high speed FC relay, then 
reconnect relay and disconnect other high speed FC relay. If LFCF, MFCF or HFCF PIDs indicate YES, 
a primary circuit fault is present in that specific circuit. Go to next step (Escape 3.0L, Focus 2.0L, Sable 
and Taurus), or go to step 1) (all others). If LFCF, MFCF or HFCF PIDs indicate NO, go to step 162) 
(Aviator), go to step 85) (Escape), step 132) (Sable and Taurus), or go to step 30) (all others). 

26) Did HFCF PID Indicate Fault With Both Relays Connected? 
 
If the HFCF PID indicates a fault with both high speed FC relays connected, turn ignition switch to OFF 
position. Go to step 7). If the HFCF PID indicates a fault with only one high speed FC relay connected, 
turn ignition switch to OFF position. Go to next step. 

27) Check VPWR To Relay That Was Connected 
 
Ensure that the relay was CONNECTED when HFCF indicated a fault. Disconnect applicable high speed 
FC relay. Turn ignition switch to ON position. Check VPWR (IGN START/RUN for Escape) circuit 
voltage at the applicable high speed FC relay harness connector. If voltage is greater than 10.5 volts, turn 
ignition switch to OFF position. Go to next step. If voltage is not greater than 10.5 volts, repair open 
circuit. 

28) Check HFC Circuit Between High Speed FC Relays? 

NOTE:

Perform test step 25) when directed from ELECTRIC COOLING FANS 
INOPERATIVE AT LOW, MEDIUM &/OR HIGH SPEED symptom under 
SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & 
GASOLINE article.

 

2003 Ford Pickup F150 

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

  

 
Measure resistance of the HFC circuit between the high speed FC relay No. 1 and 2 harness connectors. If 
resistance is less than 5.0 ohms, replace high speed FC relay that was connected when HFCF PID 
indicated a fault. If resistance is 5.0 ohms or more, repair open circuit. 

30) Electric Cooling Fan Concern (With No DTCs): Check Fan Operation 
 
Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT 
TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command cooling fan ON and check fan 
operation. On models with 2-speed fan, check both fan speeds. Wait 20 seconds after commanding high 
fan speed ON. Ensure cooling fan speed changes. If cooling fan(s) operate at all speeds, cooling fan 
circuits are okay. Return to symptom that directed you here. See SYMPTOMS in TROUBLE 
SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. If cooling fan(s) does not 
operate at all speeds, command cooling fan OFF. Leave ignition switch in ON position and remain in 
OUTPUT TEST MODE. Go to step 50) (Windstar), step 41) (Ranger), or next step (all others). 

31) Check Fan(s) For Operation At Any Speed 
During operational check of both fan speeds, if cooling fan(s) operate at one speed only, go to step 40). If 
cooling fan(s) are inoperative at any speed, go to next step. 

32) Cooling Fan Will Not Operate At Any Speed: Command High Speed Fan ON & Check For 
Voltage To Cooling Fan 
 
Turn ignition switch to ON position. Ensure scan tool is connected, in OUTPUT TEST MODE and 
cooling fan commanded OFF. Disconnect cooling fan connector (both connectors on models with 2 
cooling fans). Using scan tool, command high speed cooling fan ON. Using a DVOM, measure voltage 
between chassis ground and HIGH FAN PWR circuit at appropriate cooling fan cavity. See Fig. 325-Fig. 
327, Fig. 329 or Fig. 321 . If voltage is 10 volts or less, power is not being supplied to cooling fan. Go to 
next step. If voltage is more than 10 volts, power is being supplied to cooling fan. Go to step 37) to check 
cooling fan ground circuit. 

33) Check B+ To HFC & LFC Relays 
 
Turn ignition switch to OFF position. Ensure cooling fan connector(s) are disconnected. Remove HFC 
and LFC relays. See COOLING FAN RELAY LOCATIONS table. Using a DVOM, measure voltage 
between negative battery terminal and B+ circuit at HFC and LFC relay cavities. See Fig. 321-Fig. 327 or 
Fig. 329 . If both voltage measurements are more than 10 volts, go to next step. If either voltage 
measurement is 10 volts or less, check for B+ circuit fault. Check appropriate B+ circuit fuse(s). See 
WIRING DIAGRAMS. If fuse(s) is okay, check for open in B+ circuit. Repair as necessary. If fuse(s) is 
blown, check B+ and FAN PWR circuits for short to ground before replacing fuse. Repair as necessary. 
Recheck cooling fan operation. 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 28) to step 30). No test procedures have been omitted.

NOTE:

On models with 2 cooling fans, if one cooling fan is inoperative and the 
other cooling fan operates normally, go to step 70).

 

2003 Ford Pickup F150 

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