Ford F150 Pickup. Manual - part 1531

Fig. 274: Identifying Fuel Pump Module Circuits & Connector Terminals (ZX2) 
Courtesy of FORD MOTOR CO. 

81) Check FLI Circuit For Short To VPWR In Harness 
 
Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. 
Using a DVOM, measure voltage between negative battery terminal and FLI circuit at fuel pump module 
harness connector. If voltage is more than 10.5 volts, repair short to VPWR in FLI circuit. If voltage is 
10.5 volts or less, replace PCM. 

82) Check FLI Circuit For Short To PWR GND In Harness 
 
Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance 
between negative battery terminal and FLI circuit at PCM harness connector. If resistance is more than 10 
k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to PWR GND in FLI circuit. 

83) Check FLI Circuit For Short To CASE GND In Harness 
 
Using a DVOM, measure resistance between CASE GND and FLI circuits at PCM harness connector. If 
resistance is more than 10 k/ohms, go to step 85). If resistance is 10 k/ohms or less, repair short between 
FLI and CASE GND circuits. 

85) Check FLI Circuit For Open In Harness 
 
Using a DVOM, measure resistance of FLI circuit between PCM harness connector, fuel pump module 
connector (pigtail), and instrument cluster connector. See Fig. 271-Fig. 274 . For instrument cluster 
connector and terminal identification, see appropriate INSTRUMENT PANELS article in 
ACCESSORIES & EQUIPMENT. If both resistance measurements are less than 10 ohms, go to next 

 

2003 Ford Pickup F150 

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

  

step. If either resistance measurement is 10 ohms or more, repair open in FLI circuit. 

86) Check CASE GND Circuit For Open In Harness 
 
Turn ignition switch to OFF position. Ensure PCM is disconnected. Using a DVOM, measure resistance 
of CASE GND circuit between PCM harness connector, fuel pump module connector (pigtail), and 
instrument cluster harness connector fuel gauge ground terminal. See Fig. 271-Fig. 274 . If either 
resistance measurement is 10 ohms or more, repair open in CASE GND circuit. If both resistance 
measurements are less than 10 ohms, perform fuel gauge symptom diagnosis. See appropriate 
INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Repair or replace fuel gauge as 
necessary. Clear DTCs and repeat QUICK TEST. If DTC P0460, P0462 or P0463 is still present, replace 
PCM. 

88) CHECK FUEL CAP Indicator Always ON (No DTCs) 
Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. 
If CHECK FUEL CAP indicator light is off, replace PCM. If CHECK FUEL CAP indicator is still 
illuminated, PCM is not grounding the CHECK FUEL CAP indicator circuit and causing CHECK FUEL 
CAP indicator to illuminate. Check for short to ground in CHECK FUEL CAP indicator circuit between 
instrument cluster and PCM. See PCM CHECK FUEL CAP INDICATOR CIRCUIT TERMINAL 
IDENTIFICATION table. See WIRING DIAGRAMS. Repair as necessary. 

PCM CHECK FUEL CAP INDICATOR CIRCUIT TERMINAL IDENTIFICATION 

89) CHECK FUEL CAP Indicator Always OFF (No DTCs) 
Turn ignition switch to OFF position. Disconnect CHECK FUEL CAP indicator circuit harness connector 
at instrument cluster. See WIRING DIAGRAMS. Disconnect PCM connector(s). Using a DVOM, 
measure resistance of CHECK FUEL CAP indicator circuit between CHECK FUEL CAP indicator 
circuit at instrument cluster harness connector and PCM harness connector. See PCM CHECK FUEL 
CAP INDICATOR CIRCUIT TERMINAL IDENTIFICATION table. See PCM CONNECTOR 
IDENTIFICATION. If resistance is 5 ohms or more, repair open circuit. If resistance is less than 5 
ohms, check fuel cap indicator bulb. If bulb is okay, replace PCM.  

TEST HY: GENERATOR/REGULATOR SYSTEM 

NOTE:

Perform test step 88) when directed from WARNING INDICATOR LIGHTS 
symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, 
FLEX-FUEL & GASOLINE article.

Application

PCM Terminal No.

ZX2

79

Pickup F150 (Except Lightning and NGV)

70

Sable, Taurus, Explorer Sport, Explorer Sport Trac & Ranger

82

NOTE:

Perform test step 89) when directed here from WARNING INDICATOR 
LIGHTS 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

  

Diagnostic Aids 

Perform this test when directed by QUICK TEST. This test is intended to diagnose the following:  

z

Generator/Regulator  

z

Wiring Harness Circuits (GEN-MON, GEN-COM & BATT-SENSE)  

z

Powertrain Control Module (PCM)  

DTC P1244 is set when PCM detects voltage regulator temperature (calculated generator load frequency) falls 
above 97 percent. DTC P1245 is set when PCM detects voltage regulator temperature (calculated generator load 
frequency) falls below 6 percent. DTC P1246 is set when PCM detects voltage regulator temperature 
(calculated generator load frequency) has failed. Possible causes are:  

z

Generator Circuit Open, Or Shorted To GND Or PWR  

z

Faulty Generator Drive Mechanism  

z

Faulty Generator/Regulator Assembly  

z

Faulty PCM  

Fig. 275: Identifying Generator Wiring Harness Connector Terminals (Aviator, Explorer & 
Mountaineer) 

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

  

Courtesy of FORD MOTOR CO. 

Fig. 276: Identifying Generator Wiring Harness Connector Terminals (Escape 2.0L & Focus) 
Courtesy of FORD MOTOR CO. 

Fig. 277: Identifying Generator Wiring Harness Connector Terminals (LS & Thunderbird) 
Courtesy of FORD MOTOR CO. 

 

2003 Ford Pickup F150 

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