Ford F150 Pickup. Instruction - part 1588

Disconnect A/C high pressure switch. Again, access ACP PID from PID/DATA MONITOR & RECORD 
menu. If ACP PID still indicates CLOSED, turn ignition switch to OFF position. Go to step 135) and 
check A/C high pressure switch input signal to PCM. If ACP PID indicates OPEN, turn ignition switch to 
OFF position. Reconnect A/C high pressure switch. Check A/C high pressure switch operation and check 
for overcharged A/C system. See appropriate article in AIR CONDITIONING & HEATING. 

82) Cooling Fan Always On: Disconnect CCRM & Check If Cooling Fan Still Runs 
Turn all accessories off. Turn ignition switch to ON position. Verify that cooling fan is always on. Turn 
ignition switch to OFF position. Disconnect CCRM connector. See CCRM LOCATIONS table. Turn 
ignition switch to ON position. If cooling fan is now off, go to step 84). If cooling fan is still on, locate 
and repair FAN PWR circuit for short to B+ or VPWR (Mustang 3.8L), or go to next step (all others). 

83) Check LOW & HIGH FAN PWR Circuits For Short To PWR 
 
Turn ignition switch to OFF position. Disconnect cooling fan. Turn ignition switch to ON position. Using 
a DVOM, measure voltage between chassis ground and at both LOW FAN PWR and HIGH FAN PWR 
circuits at cooling fan harness connector. If both voltage measurements are less than one volt, no fault is 
indicated. Verify previous test step results. If results were okay, concern is intermittent and cannot be 
duplicated at this time. Check engine cooling system for mechanical faults. See COOLING SYSTEM 
TROUBLE SHOOTING under ENGINE MECHANICAL in BASIC TROUBLE SHOOTING article in 
GENERAL INFORMATION. If either voltage measurement is one volt or more, locate and repair short 
to B+ or VPWR in HIGH FAN PWR or LOW FAN PWR circuit. Reconnect all components and recheck 
system operation. 

84) Check Operation Of Primary Fan Circuits 
Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Reconnect 
CCRM. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See 
OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Perform appropriate 
procedure: 

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High Speed Fan Always On (Except Mustang 3.8L) 
 
Using scan tool, access HFC and HFCF PIDs from PID/DATA MONITOR & RECORD menu. 
With HFC PID OFF (high speed cooling fan commanded OFF by PCM), HFCF PID value should 

NOTE:

Diagnostic procedures beginning with step 82) are performed when 
directed here from ELECTRIC COOLING FAN ALWAYS ON under 
SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & 
GASOLINE article.

NOTE:

A high speed or low speed fan always ON can be caused by a primary 
circuit fault, even though a DTC was not set. This step checks primary 
circuit operation.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 84) to step 98). No test procedures have been omitted.

 

2003 Ford Pickup F150 

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

  

indicate NO (no fault). If HFCF PID value indicated YES (fault present) with HIGH SPEED FAN 
commanded OFF, a primary circuit fault is detected. Go to step 15) and perform diagnostics for 
DTC P1479. If HFCF PID indicated NO with high speed cooling fan commanded OFF, primary 
circuits are okay. Replace CCRM. Recheck cooling fan operation. 

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Low Speed Cooling Fan Always On (Cooling Fan On Mustang 3.8L) 
 
Using scan tool, access LFC and LFCF PIDs from PID/DATA MONITOR & RECORD menu. 
With LFC PID OFF (low speed cooling fan commanded OFF by PCM), LFCF PID value should 
indicate NO (no fault). If LFCF PID value indicates YES (fault present) with LOW SPEED FAN 
(cooling fan on Mustang 3.8L) commanded OFF, a primary circuit fault is detected. Go to step 20) 
and perform diagnostics for DTC P1474. If LFCF PID indicated NO with low speed cooling fan 
commanded OFF, primary circuits are okay. Replace CCRM. Recheck cooling fan operation.  

98) Lack Of Cooling (A/C Not Functioning): Check For Voltage To A/C Clutch 
If A/C clutch engages, follow instructions for result: "voltage is more than 10.5 volts". If A/C clutch will 
not engage, turn ignition switch to OFF position. Disconnect A/C cycling switch. Connect a jumper wire 
between A/C cycling switch harness connector terminals. Disconnect A/C clutch. Connect a DVOM 
between power and ground terminals at A/C clutch harness connector. Start engine. Turn A/C on and wait 
15 seconds. If voltage is 10.5 volts or less, go to next step. If voltage is more than 10.5 volts, turn ignition 
switch to OFF position. Remove jumper wire. Reconnect all connectors. If symptom is "Poor A/C 
Performance In Hot Ambient Temperature" on Mustang 3.8L, check and repair A/C system as necessary. 
Ensure engine coolant temperature is not high, as this can cause PCM to disengage A/C clutch. See 
appropriate article in AIR CONDITIONING & HEATING. On all others, go to step 145) to check ACP 
switch input to PCM. 

99) Check ACCS Input To PCM With A/C ON 
 
Ensure jumper wire is still connected between A/C cycling switch harness connector terminals, engine is 
running and A/C is on. Using scan tool, access ACCS PID from PID/DATA MONITOR & RECORD 
menu. If ACCS PID value indicates ON, go to step 110). If ACCS PID value indicates OFF, PCM is not 
receiving ACCS signal. Go to next step. 

100) ACCS PID OFF With A/C ON: Check For Voltage To A/C Cycling Switch 
 
Turn ignition switch to OFF position. Disconnect A/C cycling switch. Turn ignition switch to ON 
position. Turn A/C switch on. Using a DVOM, measure voltage between chassis ground and A/C demand 
switch side of A/C cycling switch harness connector. See Fig. 372-Fig. 374 . If voltage is more than 10.5 
volts, go to next step. If voltage is 10.5 volts or less, EEC-V system is okay. Fault is in A/C system. 
Check A/C system for cause of no voltage to A/C cycling switch. See appropriate article in AIR 
CONDITIONING & HEATING. 

NOTE:

Diagnostic procedures beginning with step 98) are performed when 
directed here from CLIMATE CONTROL (LACK OF A/C COOLING, A/C 
ALWAYS ON OR A/C INOPERATIVE) 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

  

101) Check If A/C Cycling Switch Contacts Are Closed 
 
Turn ignition switch to OFF position. Using a DVOM, measure resistance between A/C cycling switch 
terminals. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, EEC-V 
system is okay. Fault is in A/C system. Check for proper refrigerant charge and A/C cycling switch 
operation. See appropriate article in AIR CONDITIONING & HEATING. 

102) Check For Voltage To Dual Function A/C High Pressure Switch 
 
Ensure ignition switch is in OFF position. Reconnect A/C cycling switch. Disconnect A/C high pressure 
switch. Turn ignition switch to ON position. Turn A/C on. Using a DVOM, measure voltage between 
chassis ground and A/C demand switch terminal at A/C high pressure switch harness connector. See Fig. 
376. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open circuit 
between A/C high pressure switch and A/C cycling switch. 

Fig. 376: Checking A/C High Pressure Switch Circuit Voltage 
Courtesy of FORD MOTOR CO. 

103) Measure Resistance Of A/C High Pressure Switch High Pressure Contacts 
 
Turn ignition switch to OFF position. Using a DVOM, measure resistance between A/C high pressure 
switch high pressure terminals. See Fig. 377. If resistance is less than 5 ohms, go to next step. If 
resistance is 5 ohms or more, check for overcharged A/C system. Service A/C system as necessary. If 
system charge is okay, replace A/C high pressure switch. See appropriate article in AIR 
CONDITIONING & HEATING. 

 

2003 Ford Pickup F150 

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

  

Fig. 377: Measuring A/C High Pressure Switch High Pressure Contact Resistance 
Courtesy of FORD MOTOR CO. 

104) Check For Voltage To PCM On ACCS Circuit 
 
Turn ignition switch to OFF position. Reconnect A/C high pressure switch. Disconnect PCM connector. 
Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to 
ON position. Turn A/C on. Using a DVOM, measure voltage between chassis ground and A/C demand 
switch input signal at PCM harness connector terminal No. 41. See PCM CONNECTOR 
IDENTIFICATION and Fig. 372-Fig. 375 . If voltage is more than 10.5 volts, replace PCM. If voltage 
is 10.5 volts or less, repair open circuit between PCM and A/C high pressure switch. 

105) For KOEO & KOER Only DTC P0645 Or P1460: Verify ACCS PID Is OFF 
DTC P0645 or P1460 indicates an excessive current draw when PCM grounds Wide Open Throttle A/C 
Cut-Off (WAC) circuit, or voltage is not detected on WAC circuit when PCM interrupts ground on WAC 
circuit. Possible causes are: 

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A/C Or Defroster On During Self-Test  

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Open Or Shorted WAC Circuit  

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Faulty WAC Relay  

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Open VPWR Circuit To WAC Relay  

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Faulty PCM  

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

If vehicle is not equipped with A/C, disregard DTC P0645 and P1460. DTC 
P0645 or P1460 can be set if A/C or defroster were on during KOEO or 
KOER self-test.

 

2003 Ford Pickup F150 

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