Ford F150 Pickup. Instruction — part 1547

Courtesy of FORD MOTOR CO.

Fig. 310: Identifying Fuel Pump Driver Module Circuits & Connector Terminals (Mustang)
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

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

Fig. 311: Identifying Fuel Pump Driver Module Circuits & Connector Terminals (ZX2)
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

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

Fig. 312: Identifying Fuel Pump & Rear Electronics Module Circuits & Connector Terminals (LS &
Thunderbird)
Courtesy of FORD MOTOR CO.

Testing

1) For KOEO, KOER & Continuous Memory DTCs P1233 & P1234: Check For KOEO DTC
P1233 Or P1234
These DTCs indicate PCM has stopped receiving duty cycle signal from Fuel Pump Driver Module
(FPDM). Possible causes are:

z

Inertia Fuel Shutoff (IFS) Switch Needs To Be Reset

z

Open FPDM Ground Circuit

z

Open Or Shorted FPM Circuit

z

Faulty IFS Switch

z

Faulty FPDM

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

DTC P1233 and P1234 are identical, except DTC P1234 will not illuminate
Malfunction Indicator Lamp (MIL). On LS models, these DTCs indicate PCM
is not receiving fuel level information on SCP network from Rear
Electronics Module (REM). See MODULE COMMUNICATIONS NETWORK -
LS article in ACCESSORIES & EQUIPMENT for complete DTC listing and
test procedures.

2003 Ford Pickup F150

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

z

Faulty PCM

z

Open FPDM PWR Circuit; Or Open B+ Circuit To Constant Control Relay Module (CCRM) (ZX2
& Mustang)

z

Faulty CCRM (ZX2 & Mustang)

z

Open Ground Circuit To CCRM (Mustang)

If DTC P1233 or P1234 is present in KOEO ON-DEMAND SELF-TEST, go to next step. If DTC P1233
or P1234 is not present in KOEO ON-DEMAND SELF-TEST, PCM is now receiving a signal from
FPDM. DTC P1233 or P1234 may have been set due to Inertia Fuel Shutoff (IFS) switch being tripped,
then reset. If engine starts, go to step 25). If engine is now a no-start, disregard DTCs P1233 and P1234 at
this time and repeat QUICK TEST. If any other DTCs are present, perform appropriate system test and
repair as necessary. After repairing the engine no-start condition, go to step 25) to diagnose intermittent
causes of DTC P1233 or P1234.

2) Attempt To Start Engine

Attempt to start engine. If engine starts, go to step 15). If engine does not start, verify IFS switch is set
(button depressed) and go to next step.

3) Check Power & Ground Circuits To FPDM

Turn ignition switch to OFF position. Disconnect FPDM connector. Turn ignition switch to ON position.
Using a DVOM, measure voltage between FPDM PWR circuit and GND circuit at FPDM harness
connector. See Fig. 308-Fig. 310, and Fig. 311 . If voltage is more than 10.5 volts, replace FPDM. If
voltage is 10.5 volts or less, go to next step.

4) Check Power To FPDM

Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and
FPDM PWR circuit at FPDM harness connector. If voltage is more than 10.5 volts, repair open ground
circuit to FPDM. If voltage is 10.5 volts or less, go to next step (Mustang and ZX2), or go to step 8) (all
others).

5) Check B+ Voltage To CCRM (Mustang & ZX2)

Turn ignition switch to OFF position. Disconnect CCRM connector. On Mustang, CCRM is mounted on
a bracket behind engine coolant reservoir. On ZX2, CCRM is located in left front of engine compartment.
On all models, measure voltage between CCRM harness connector terminal No. 11 (B+ circuit) and
chassis ground. See Fig. 310, Fig. 311 and Fig. 313 . If voltage is more than 10.5 volts, go to next step
(Mustang), or step 7) (ZX2). If voltage is 10.5 volts or less, check condition of related fuse. If fuse is
blown, check for short to ground in B+ or FPDM PWR circuits to FPDM. Repair as necessary. If fuse is
okay, repair open in B+ circuit.

2003 Ford Pickup F150

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