Ford F150 Pickup. Instruction - part 1563

MFC primary circuits are okay. Replace MFC relay. Ensure FAN PWR circuit is not shorted to ground. 
Recheck cooling fan operation. If test light does not illuminate and then turn off, an MFC primary circuit 
fault is detected. Turn ignition switch to OFF position, go to step 1) and perform diagnosis for DTC 
P1477. 

79) Check Operation Of High Speed Cooling Fan Primary Circuits 
 
Reconnect cooling fan connector(s), as necessary. Turn ignition switch to ON position. Connect a test 
light between VPWR and HFC circuits at HFC relay cavities. See Fig. 322-Fig. 326, Fig. 329 or Fig. 
330 . Using scan tool, access OUTPUT TEST MODE. Observe test light while commanding high speed 
fan ON (wait 15 seconds) then OFF. If test light illuminates and then turns off, HFC primary circuits are 
okay. Replace HFC relay. Ensure FAN PWR circuit is not shorted to ground. Recheck cooling fan 
operation. If test light does not illuminate and then turn off, an HFC primary circuit fault is detected. Turn 
ignition switch to OFF position, go to step 1) and perform diagnosis for DTC P0481. 

80) Check Operation Of Low Or High Speed Cooling Fan Primary Circuits 
Turn ignition switch to OFF position. Reinstall all cooling fan relays (if removed). Turn ignition switch to 
ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under 
ADDITIONAL SYSTEM FUNCTIONS. Proceed as follows: 

z

If Directed Here For Fan Stops Running With LFC Relay Disconnected 
 
Using scan tool, access LFC and LFCF PIDs from PID/DATA MONITOR & RECORD menu. 
With LFC PID OFF (low speed fan commanded OFF by PCM), LFCF PID should read NO (no 
fault). 

z

If Directed Here For Fan Stops Running With HFC Relay Disconnected 
 
Using scan tool, access HFC and HFCF PIDs from PID/DATA MONITOR & RECORD menu. 
With HFC PID OFF (high speed fan commanded OFF by PCM, HFCF PID should read NO (no 
fault).  

If LFCF, MFCF and HFCF PIDs indicated YES with fan commanded OFF, an LFC or HFC primary 
circuit fault is detected. If PID value was YES, go to step 1) and perform diagnosis for DTC P0481 (for 
LFCF PID) or DTC P0480 (for HFCF PID). If LFCF or HFCF PIDs indicated NO with fan commanded 
OFF, LFC or HFC primary circuits are okay. Replace appropriate LFC relay (if fan stopped running with 
the low speed FC relay disconnected) or HFC relay (if fan stopped running with the high speed FC relay 
disconnected). 

NOTE:

A cooling fan that always runs, can be caused by a primary circuit fault, 
even though a DTC was not set. This step will check the primary circuit 
operation.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 80) to step 85). No test procedures have been omitted.

 

2003 Ford Pickup F150 

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

  

85) Electric Cooling Fan Concern - Escape (No DTCs): Check Fan Operation 
 
Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. Observe cooling 
fan operation while commanding low speed cooling fan ON. Both cooling fans should be operating at low 
speed (medium speed for Escape 3.0L). Using scan tool, command high speed cooling fan ON. Both 
cooling fans should be operating at high speed. If cooling fans operate as specified, return to 
SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. If 
cooling fans do not operate as specified, go to step 86) for Escape 2.0L. For Escape 3.0L, perform 
appropriate test procedure as follows: 

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If both cooling fans are inoperative when low speed fan is commanded ON, but both cooling fans 
operate when high speed fan is commanded ON, go to step 95).  

z

If both cooling fans are inoperative when low speed fan is commanded ON and only one cooling 
fan operates when high speed fan is commanded ON, leave scan tool connected and go to step 
105).  

z

If both cooling fans operate when low speed fan is commanded ON, but only one cooling fan 
operates when high speed fan is commanded ON, go to step 115).  

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If only one cooling fan operates when low speed fan is commanded ON, but both cooling fans 
operate when high speed fan is commanded ON, go to step 124).  

86) Check B+ Voltage To LFC, MFC &/Or HFC Relays (Escape 2.0L) 
 
Refer to cooling fan diagnosis table to determine cooling fan and/or fan speeds to diagnose. See 
COOLING FAN DIAGNOSIS (ESCAPE 2.0L) table. Remove appropriate LFC, MFC and/or HFC 
relays. See COOLING FAN RELAY LOCATIONS table. Using a DVOM, measure B+ circuit voltage 
between chassis ground and appropriate LFC, MFC and/or HFC relay cavity. See Fig. 322. If voltage is 
more than 10 volts, go to next step. If voltage is 10 volts or less, check for open in B+ circuit. Check 
appropriate B+ circuit fuse(s). 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. 

COOLING FAN DIAGNOSIS (ESCAPE 2.0L) 

Inoperative Cooling 
Fan

Inoperative Output Test 

Mode

Component(s) To Check

Both

Low & High

LFC, MFC & HFC Relays; Both Cooling Fans

Both

Low Only

LFC & MFC Relays; Both Cooling Fans

Both

High Only

HFC Relay; Both Cooling Fans

Driver's Side

Low & High

LFC & HFC Relays; Driver's Side Cooling Fan

Driver's Side

Low Only

LFC Relay; Driver's Side Cooling Fan

Driver's Side

High Only

HFC Relay; Driver's Side Cooling Fan

Passenger's Side

Low & High

MFC & HFC Relays; Passenger's Side Cooling

Fan

Passenger's Side

Low Only

MFC Relay; Passenger's Side Cooling Fan

Passenger's Side

High Only

HFC Relay; Passenger's Side Cooling Fan

 

2003 Ford Pickup F150 

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

  

87) Check Continuity Of Appropriate FAN PWR Circuits 
 
Disconnect appropriate cooling fan harness connectors. Refer to COOLING FAN DIAGNOSIS 
(ESCAPE 2.0L) table. Using a DVOM, measure resistance of LOW, MEDIUM and/or HIGH FAN PWR 
circuit(s) between appropriate cooling fan harness connector(s) and appropriate fan control relay harness 
cavity. If resistance(s) is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in 
affected circuits. Recheck cooling fan operation. 

88) Check For Power To Cooling Fans 
 
Reinstall LFC, MFC and/or HFC relays, as applicable. Disconnect both cooling fans, if not already 
disconnected. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. 
Perform appropriate test procedure as follows: 

z

Low &/Or Medium Speed Cooling Fan Inoperative 
 
Command low speed fan ON. Using a DVOM, measure LOW FAN PWR and/or MEDIUM FAN 
PWR circuit voltage between chassis ground and appropriate cooling fan harness connector. 

z

High Speed Cooling Fan Inoperative 
 
Command high speed fan ON. Using a DVOM, measure HIGH FAN PWR circuit voltage between 
chassis ground and appropriate cooling fan harness connector. 

If voltage measurement(s) is more than 10 volts, go to next step. If either voltage measurement is 
10 volts or less, go to step 75) to check appropriate cooling fan(s) primary circuit. 

89) Check Cooling Fan(s) GND Circuit 
 
Turn ignition switch to OFF position. Disconnect scan tool from DLC. Using a DVOM, measure 
resistance of GND circuit between chassis ground and appropriate cooling fan harness connector. If 
resistance is 5 ohms or more, repair open in GND circuit. Recheck cooling fan(s) operation. If resistance 
is less than 5 ohms, replace cooling fan(s) that were inoperative in step 85). Recheck cooling fan(s) 
operation. 

95) Measure Resistance Of Low Fan GND Circuit Between Passenger's Side Cooling Fan & MFC 
Relay (Escape 3.0L) 
 
Ensure ignition switch is turned to OFF position. Remove MFC relay (ADD FAN 3). See COOLING 
FAN RELAY LOCATIONS table. Disconnect passenger's side cooling fan harness connector. Using a 
DVOM, measure resistance of LOW FAN GND circuit between MFC relay and passenger's side cooling 
fan harness connectors. See Fig. 323 or Fig. 324 . If resistance is less than 5 ohms, go to next step. If 
resistance is 5 ohms or more, repair open in LOW FAN GND circuit between MFC relay and splice to 
HFC No. 2. Recheck cooling fan(s) operation. 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 89) to step 95). No test procedures have been omitted.

 

2003 Ford Pickup F150 

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

  

96) Measure Resistance Of Black Wire Between MFC Relay & HFC Relay No. 1 
 
Ensure ignition switch is turned to OFF position. Reconnect passenger's side cooling fan harness 
connector. Remove HFC relay No. 1 (MAIN FAN). See COOLING FAN RELAY LOCATIONS table. 
Using a DVOM, measure resistance of Black wire between MFC relay cavity No. 87 and HFC relay No. 
1 harness connector terminal No. 87A. DO NOT test resistance of Black wire that has in-line LOW 
SPEED RESISTOR. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, 
repair open in Black wire between MFC and HFC relays. Recheck cooling fan(s) operation. 

97) By-Pass MFC Relay & Check Cooling Fan Operation 
 
Ensure ignition switch is turned to OFF position. Connect scan tool to DLC. Reinstall HFC relay No. 1 
(MAIN FAN). Connect a jumper wire between MFC relay cavities No. 30 (LOW FAN GND circuit to 
passenger's side cooling fan) and No. 87 (medium speed fan control output circuit to HFC relay No. 1). 
See Fig. 323 or Fig. 324 . Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST 
MODE. Command low speed fan ON. If both fans operate, turn ignition switch to OFF position and 
replace MFC relay. Recheck cooling fan(s) operation. If both fans still do not operate, turn ignition switch 
to OFF position and go to next step. 

98) Check Normally Closed Contacts Of HFC Relay No. 1 (MAIN FAN) 
 
Ensure ignition switch is turned to OFF position. Remove HFC relay No. 1 (MAIN FAN). See 
COOLING FAN RELAY LOCATIONS table. Using a DVOM, measure resistance between HFC relay 
terminals No. 30 and 87A. If resistance is less than 5 ohms, no fault is indicated, concern may be 
intermittent. Repeat steps 95)-98) . If results are the same, return to SYMPTOMS in TROUBLE 
SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. If resistance is 5 ohms or more, 
replace HFC relay. 

105) Check Cooling Fans For Proper Operation 
 
If driver's side cooling fan did not operate in step 85), go to next step. If passenger's side cooling fan did 
not operate in step 85), go to step 110). 

106) Command High Speed Fan ON & Check For B+ To Driver's Side Cooling Fan 
 
Turn ignition switch to OFF position. Disconnect driver's side cooling fan. Turn ignition switch to ON 
position. Using scan tool, access OUTPUT TEST MODE. Command high speed fan ON. Using a 
DVOM, measure voltage between chassis ground and HIGH FAN PWR circuit at driver's side cooling 
fan harness connector. See Fig. 323 or Fig. 324 . If voltage is more than 10.5 volts turn ignition switch to 
OFF position and go to next step. If voltage is 10.5 volts or less, turn ignition switch to OFF position and 
go to step 108). 

107) Check Driver's Side Cooling Fan GND Circuit 
 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 98) to step 105). No test procedures have been omitted.

 

2003 Ford Pickup F150 

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