Ford F150 Pickup. Instruction - part 1548

Fig. 313: Identifying Constant Control Relay Module Connector Terminals 
Courtesy of FORD MOTOR CO. 

6) Check GND Circuit To CCRM 
 
Using a DVOM, measure resistance of ground circuit between chassis ground and CCRM harness 
connector terminal No. 18. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or 
more, repair open in ground circuit. 

7) Check For Open FPDM PWR Circuit 
 
Using a DVOM, measure resistance of FPDM PWR circuit between CCRM harness connector terminal 
No. 5 and FPDM harness connector terminal No. 2 (ZX2), or No. 9 (Mustang). If resistance is less than 5 
ohms, replace CCRM. If resistance is 5 ohms or more, FPDM PWR circuit is open. Go to step 13) to 
isolate fault. 

8) Check B+ Voltage To FPDM Power Supply Relay 
 
Disconnect fuel pump relay in battery junction box. Using a DVOM, measure voltage of B+ circuit 
between chassis ground and fuel pump relay cavity No. 3. See Fig. 309. If voltage is more than 10.5 
volts, go to next step. If voltage is 10.5 volts or less, check for blown B+ circuit fuse to fuel pump relay 
located in battery junction box in engine compartment. If fuse is okay, repair open B+ circuit. If fuse is 
blown, check B+ or FPDM PWR circuit for short to ground. 

9) Check For GND To FPDM Power Supply Relay 
 
Turn ignition switch to OFF position. Disconnect scan tool from DLC. Using a DVOM, measure 
resistance of GND circuit between negative battery terminal and fuel pump relay cavity No. 2. See Fig. 
309. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in 
ground circuit. 

10) Check For Open FPDM PWR Circuit 
 
Using a DVOM, measure resistance of FPDM PWR circuit between FPDM power supply relay cavity 
No. 5 and FPDM harness connector terminal No. 9. See 

Fig. 309

 and Fig. 314 . If resistance is less than 5 

ohms, reconnect FPDM and go to next step. If resistance is 5 ohms or more, FPDM PWR circuit is open. 
Go to step 13) to isolate fault. 

 

2003 Ford Pickup F150 

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

  

Fig. 314: Identifying Fuel Pump Driver Module Connector Terminals 
Courtesy of FORD MOTOR CO. 

11) Check VPWR Circuit (IGN START/RUN Circuit On Sable & Taurus) Voltage To FPDM 
Power Supply Relay 
 
Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and 
VPWR circuit (IGN START/RUN circuit on Sable and Taurus) at FPDM power supply relay cavity No. 
1. See Fig. 309. If voltage is more than 10.5 volts, replace FPDM power supply relay. If voltage is 10.5 
volts or less, repair open in VPWR circuit (IGN START/RUN circuit on Sable and Taurus). See 
WIRING DIAGRAMS. 

13) Isolate Open In FPDM PWR Circuit 
 
Disconnect Inertia Fuel Shutoff (IFS) switch connector. Perform the following: 

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On Mustang and ZX2, use a DVOM and measure resistance of FPDM PWR circuit between IFS 
switch harness connector terminal No. 2 and CCRM harness connector terminal No. 5. See Fig. 
305 and Fig. 313 .  

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On Focus, Sable and Taurus, measure resistance of FPDM PWR circuit between IFS switch harness
connector terminal No. 2 and FPDM power supply relay cavity No. 5. See Fig. 305 and Fig. 309 .  

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On all models, measure resistance of FPDM PWR circuit between FPDM harness connector and 
IFS switch harness connector terminal No. 1. See Fig. 305, Fig. 309, Fig. 310, Fig. 311 and Fig. 
314 .  

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 11) to step 13). No test procedures have been omitted.

 

2003 Ford Pickup F150 

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

  

If all resistance measurements are less than 5 ohms, verify IFS switch is set (button depressed). If IFS 
switch is set, replace IFS switch. If any resistance measurement is 5 ohms or more, repair open in 
appropriate FPDM PWR circuit. 

15) Check For Open FPM Circuit 
 
Turn ignition switch to OFF position. Disconnect FPDM and PCM connector(s). Inspect connectors for 
loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of FPM 
circuit between PCM harness connector terminal No. 40 and FPDM harness connector terminal No. 4 
(ZX2), or No. 7 (all others). See PCM CONNECTOR IDENTIFICATION and Fig. 314. If resistance 
is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in FPM circuit. 

16) Check FPM Circuit For Short To PWR In Harness 
 
Turn ignition switch to ON position. Using a DVOM, measure voltage between PCM harness connector 
terminal No. 40 and chassis ground. If voltage is less than one volt, go to next step. If voltage is one volt 
or more, repair short to PWR in FPM circuit. 

17) Check FPM Circuit For Short To Ground In Harness 
 
Turn ignition switch to OFF position. Disconnect scan tool from Data Link Connector (DLC). Using a 
DVOM, measure resistance between PCM harness connector terminal No. 40 and chassis ground. If 
resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to 
ground in FPM circuit. 

18) Check For FPM Output From FPDM 
Reconnect FPDM connector. Turn ignition switch to ON position. Using a DVOM, measure DC voltage 
between PCM harness connector terminals No. 40 and 51. If voltage is .02-1.0 DC volt, replace PCM. If 
voltage is not .02-1.0 DC volt, replace FPDM. 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 13) to step 15). No test procedures have been omitted.

NOTE:

In the following test step, it is normal for voltage to cycle less than .02 volt 
and return to .02-1.0 volt.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 18) to step 25). No test procedures have been omitted.

NOTE:

With no fault detected, FPDM will send a 50 percent duty cycle signal on 
FPM circuit to PCM. FPM PID value should display 50 percent. Depending 
on scan tool being used, some scan tools will display a random value of 
85-115 percent.

NOTE:

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

 

2003 Ford Pickup F150 

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

  

25) Check Circuits That May Cause An Intermittent Loss Of Power Supply To FPDM; Also Check 
For Intermittent Opens Or Shorts On FPM Circuit 
Turn ignition switch to ON position. Using scan tool, access FPM PID from PID/DATA MONITOR & 
RECORD menu. Observe FPM PID value for indication of fault while performing the following: 

z

Wiggle and bend all FPDM system related circuits (FPDM PWR or VPWR, and GND).  

z

Wiggle and bend FPM circuit between PCM and FPDM.  

z

On Mustang and ZX2, wiggle and bend B+ circuit to CCRM terminal No. 11.  

z

On Mustang, wiggle and bend GND circuit to terminal No. 18 at CCRM.  

z

On Focus, Sable and Taurus wiggle and bend B+ and GND circuits to FPDM power supply relay.  

z

Lightly tap on IFS switch, CCRM, FPDM and FPDM power supply relay to simulate road shock.  

A fault will be indicated if FPM PID value changes from 50 percent, or value stops fluctuating. If any 
faults are found, isolate fault and repair as necessary. If no faults are found, concern cannot be duplicated 
at this time. Go to TEST Z, step 1). 

30) For KOEO & KOER Only DTC P1235 Or P1236: Check For These DTCs To Be Present In 
KOEO Or KOER On-Demand Self-Tests 
These DTCs indicate that FPDM has detected an invalid or missing FP circuit signal from PCM. FPDM 
will send a message to PCM through FPM circuit, indicating failure has been detected. PCM will set the 
DTC when message has been received. Possible causes are: 

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Open Or Shorted FP Circuit  

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Faulty FPDM  

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Faulty PCM  

If DTC P1235 or P1236 is present in KOEO or KOER self-test, DTC is a hard fault. Go to next step. If 
DTC P1235 or P1236 is not present in KOEO or KOER self-test, check for an intermittent fault. Go to 
step 42) (LS and Thunderbird), or go to step 45) (all others). 

31) Check For Open FP Circuit Between FPDM & PCM 
 
Turn ignition switch to OFF position. Disconnect FPDM connector. Disconnect PCM connector(s). 
Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, 
measure resistance of FP circuit between PCM harness connector and FPDM harness connector (REM on 

from step 25) to step 30). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

DTC P1235 and P1236 are identical, except DTC P1236 will not illuminate 
Malfunction Indicator Lamp (MIL). On LS and Thunderbird, FPDM functions 
are incorporated in Rear Electronics Module (REM). Also, REM does not 
use an FPM circuit. Diagnostic information will be sent through SCP 
network. In the following steps, if directed to perform an FPDM action, 
complete the action using REM. See Fig. 308-Fig. 312 .

 

2003 Ford Pickup F150 

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