Ford F150 Pickup. Instruction - part 1543

 
Turn ignition switch to OFF position. Remove fuel pump relay from instrument panel relay block (F250-
F550 Pickup), or battery junction box in engine compartment (all others). Using a DVOM, measure 
voltage between chassis ground and B+ circuit cavity at fuel pump relay. See Fig. 299-Fig. 304 . If 
voltage is more than 10.5 volts, go to step 23) (F150 Lightning 5.4L SC), or go to next step (all others). If 
voltage is 10.5 volts or less, check condition of related fuse/fuse links. If fuse/fuse links are blown, check 
for short to ground in B+ and FP PWR circuit. Repair as necessary. If fuse/fuse links are okay, repair 
open in B+ circuit. 

22) Check For Open FP PWR Circuit Between Fuel Pump Relay & FPM Splice 
 
Using a DVOM, measure resistance between negative battery terminal and FP PWR circuit cavity at fuel 
pump relay. If resistance is less than 10 ohms, replace fuel pump relay. If resistance is 10 ohms or more, 
repair open in FP PWR circuit between fuel pump relay and FPM splice (Some applications may have the 
IFS switch in this part of the circuit. First verify that the IFS switch is set). See WIRING DIAGRAMS. 

23) Check VPWR & IFS Circuits To IFS Switch Relay (F150 Lightning 5.4L SC) 
Remove IFS switch relay from battery junction relay box in engine compartment. Turn ignition switch to 
ON position. Using a DVOM, measure voltage between VPWR and IFS circuit cavities at IFS switch 
relay. See Fig. 304. If voltage is more than 10.5 volts, go to step 28). If voltage is 10.5 volts or less, go to 
next step. 

24) Check For VPWR To IFS Switch Relay 
 
Using a DVOM, measure voltage between chassis ground and VPWR circuit cavity at IFS switch relay. If 
voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, check for blown battery 
junction box fuse No. 10 (15-amp). If fuse is blown, check for short to ground in VPWR circuit. If fuse is 
okay, check for open in VPWR circuit between battery junction box and IFS switch relay. See WIRING 
DIAGRAMS. 

25) Check Ground Circuit To IFS Switch 
 
Turn ignition switch to OFF position. Disconnect Inertia Fuel Shutoff (IFS) switch connector. Ensure IFS 
switch is set. Using a DVOM, measure resistance of ground circuit between chassis ground and IFS 
switch harness connector. See Fig. 304. If resistance is less than 5 ohms, go to next step. If resistance is 5 
ohms or more, repair open in ground circuit. 

26) Check IFS Switch 
 
Using a DVOM, measure resistance between IFS switch terminals. See Fig. 305. If resistance is less than 
5 ohms between terminals, go to next step. If resistance is 5 ohms or more between terminals, reset or 
replace IFS switch as necessary. 

27) Check For Open IFS Circuit 

NOTE:

On F150 Lightning 5.4L SC, Inertia Fuel Shutoff (IFS) switch relay may also 
be referred to as crash fuel shutoff relay.

 

2003 Ford Pickup F150 

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

  

 
Using a DVOM, measure resistance of IFS circuit between IFS switch harness connector and IFS switch 
relay cavity. If resistance is 5 ohms or more, repair open in IFS circuit. If resistance is less than 5 ohms, 
no fault is indicated. Disregard DTC P0232 at this time. Repeat QUICK TEST. 

28) Check FP PWR Circuit Continuity Between Fuel Pump Relay & IFS Switch Relay 
 
Turn ignition switch to OFF position. Using a DVOM, measure resistance of FP PWR circuit between 
fuel pump relay cavity and IFS switch relay cavity. If resistance is less than 5 ohms, go to next step. If 
resistance is 5 ohms or more, repair open in FP PWR circuit. 

29) Check Operation Of IFS Switch Relay & Fuel Pump Relay 
 
With IFS relay removed, energize IFS relay by connecting a jumper wire between positive battery 
terminal and IFS switch relay terminal No. 86 and another jumper wire between negative battery terminal 
and IFS switch relay terminal No. 85. See Fig. 306. Using a DVOM, measure resistance between IFS 
switch relay terminals No. 30 and 87. Resistance should be less than 5 ohms. Repeat test for fuel pump 
relay. Replace appropriate relay as necessary. If relays are okay, repair open in FP PWR circuit between 
FPM splice and IFS switch relay. See WIRING DIAGRAMS. 

30) For Continuous Memory Only DTC P0232: Check Fuel Pump Secondary Circuits 
If Continuous Memory DTC P0230 is also present, go directly to step 40). DTC P0232 indicates that 
PCM detected high FPM circuit voltage when fuel pump was commanded OFF. Possible causes are: 

z

Inertia Fuel Shutoff (IFS) switch open or not reset.  

z

Open circuit between fuel pump and FPM connection to FP PWR circuit.  

z

Poor fuel pump ground.  

z

Fuel pump internally open.  

z

Fuel pump secondary circuits shorted to PWR.  

z

Fuel pump relay contacts always closed.  

z

Open FPM circuit between PCM and connection to FP PWR circuit.  

z

Faulty low speed fuel pump relay or related circuits (F150 Lightning 5.4L SC).  

z

Faulty PCM (Engine will start).  

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 wiggling and bending FP PWR 
circuit between fuel pump relay and fuel pump. A fault (an open or short to VPWR) will be indicated by 

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

DTC P0232 can be set if IFS switch is tripped then reset, or if PWR was 
supplied to FP PWR circuit when PCM expected fuel pump to be OFF.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 30) to step 35). No test procedures have been omitted.

 

2003 Ford Pickup F150 

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

  

FPM PID value changing to ON. Wiggle and bend FPM circuit between PCM and FP PWR circuit splice. 
Wiggle and bend fuel pump ground circuit from fuel pump to ground. Lightly tap on fuel pump, IFS 
switch and fuel pump relay to simulate road shock. On F150 Lightning 5.4L SC, remove low speed fuel 
pump relay and note FPM PID. On all models, check connectors for clean tight connection. If no faults 
are found (FPM PID value remains OFF), fault cannot be duplicated at this time. Go to TEST Z, step 1). 
If any fault is found, proceed as follows:  

z

On F150 Lightning 5.4L SC, if FPM PID consistently indicates ON with low speed fuel pump relay 
disconnected, check fuel pump relay ground circuit resistor. See Fig. 304. Replace resistor as 
necessary. If resistor is okay, repair open circuit between low speed fuel pump relay and wiring 
harness splice. If FPM PID still indicates ON, isolate fault found while performing wiggle test and 
repair as necessary.  

z

On all others, isolate fault and repair as necessary.  

35) For Continuous Memory Only DTC P0231: Check Harness Circuits 
 
DTC P0231 indicates PCM commanded fuel pump ON and B+ voltage is not detected on Fuel Pump 
Monitor (FPM) circuit. Possible causes are: 

z

Open B+ circuit to fuel pump relay.  

z

Open FP PWR circuit between fuel pump relay and connection to FPM circuit.  

z

Faulty fuel pump relay.  

z

Faulty PCM (Engine will start).  

z

On Mustang 4.6L, open FP PWR circuit from low speed fuel pump relay through resistor to FPM 
splice (Engine will start).  

z

On F150 Lightning 5.4L SC, faulty Inertia Fuel Shutoff (IFS) Switch, IFS switch relay, or concern 
with related wiring.  

Turn ignition switch to OFF position. Disconnect PCM connector. Inspect connector for loose, damaged 
or corroded terminals. Repair as necessary. Connect a jumper wire between chassis ground and FP circuit 
at PCM harness connector. See PCM CONNECTOR IDENTIFICATION and Fig. 299-Fig. 304 . 
Connect DVOM between chassis ground and FPM circuit at PCM harness connector. Turn ignition 
switch to ON position. Fuel pump should turn on and voltage reading on DVOM should be more than 10 
volts. Observe DVOM for indication of fault while performing the following:  

z

Wiggle and bend B+ circuit to fuel pump relay.  

z

Wiggle and bend FP PWR circuit between fuel pump relay and FPM circuit splice.  

z

Lightly tap on fuel pump relay to simulate road shock.  

z

Check all connectors for clean, tight connection.  

z

Lightly tap on IFS switch and IFS switch relay.  

z

On F150 Lightning 5.4L SC, shake, wiggle and bend circuits connected to Inertia Fuel Shutoff 
(IFS) switch relay.  

NOTE:

Some applications have the FPM splice to the FP PWR circuit between the 
inertia IFS switch and the fuel pump. On those applications, be aware that 
P0231 could be set if the IFS switch was tripped then reset.

 

2003 Ford Pickup F150 

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

  

A fault will be indicated by a sudden change in DVOM voltage. Turn ignition switch to OFF position. 
Inspect the fuel pump relay connector for corrosion and damaged pins. If any faults are found, isolate 
fault and repair as necessary. If no faults are found, fault cannot be duplicated at this time. Go to TEST Z, 
step 1). 

40) For Continuous Memory Only DTC P0230: Check Fuel Pump Primary Circuits 
DTC P0230 is set when FP output is commanded ON (grounded) and excessive current draw is detected 
on FP circuit; or when FP output is commanded OFF, voltage is not detected on FP circuit (PCM expects 
VPWR voltage on FP circuit to fuel pump relay coil). Possible causes are: 

z

Open or shorted Fuel Pump (FP) circuit.  

z

Open VPWR circuit to fuel pump relay.  

z

Faulty fuel pump relay.  

z

Faulty PCM.  

Turn ignition switch to ON position and wait 5 seconds. Using scan tool, access FPF PID from 
PID/DATA MONITOR & RECORD menu. FPF PID value should indicate no fault (NO), indicating 
PCM detects VPWR voltage through fuel pump relay coil and FP circuit. Observe FPF PID value for 
indication of fault while performing the following:  

z

Wiggle and bend FP circuit between fuel pump relay and PCM.  

z

Wiggle and bend VPWR circuit between fuel pump relay and PCM power relay.  

z

Check connectors for clean, tight connection.  

z

Lightly tap on fuel pump relay to simulate road shock.  

FPF PID will read indicate a fault (YES), when an open or short is indicated. If a fault is indicated, isolate 
and repair open or short in affected circuit. If no fault is indicated, check for intermittent faults. Go to 
TEST Z, step 1). 

45) For KOEO & KOER Only DTC P1232: Check VPWR Voltage To Low Speed Fuel Pump Relay
DTC P1232 is set when LFP circuit is commanded ON (grounded), excessive current draw is detected on 
LFP circuit; or when LFP circuit is commanded OFF, voltage is not detected on LFP circuit. PCM 
expects to detect VPWR voltage through low speed fuel pump relay coil to LFP circuit. Possible causes 
are: 

z

Open or shorted Low Speed Fuel Pump (LFP) circuit. 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 35) to step 40). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 40) to step 45). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

 

2003 Ford Pickup F150 

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