Ford F150 Pickup. Manual — part 1505

Repair concerns as necessary. If vehicle exhibits poor fuel economy, perform FUEL SYSTEM
PRESSURE RELEASE procedure under FUEL SYSTEM VENTING in appropriate REMOVAL &
INSTALLATION article. For a fuel smell symptom, go to step 16). For all other symptoms, go to next
step.

2) Check Fuel Tank Pressure

Turn ignition switch to OFF position. Install Filler Neck Venting Tool and Fuel Pressure Gauge from
Fuel Delivery System Special Tool Kit (134-00114) to vehicle fueling connector. Open by-pass valve,
located on fill valve. Refer to FUEL TANK VENTING procedure under COMPRESSED NATURAL
GAS FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEM VENTING in appropriate
REMOVAL & INSTALLATION article. Turn ignition switch to ON position. Record fuel tank pressure.
If fuel pressure reading is more than 500 psi (3448 kPa), turn ignition switch to OFF position. Close by-
pass valve. Remove fuel tank venting tool and go to step 7) (for no starts) or go to step 5). If fuel pressure
is 500 psi (3448 kPa) or less, turn ignition switch to OFF position. Check fuel level. Add fuel to tank if
necessary. If fuel level is okay, check for power at tank solenoid valve. Go to next step.

3) Check FSV PWR & GND Circuits To Fuel Tank Solenoid Shutoff Valve
Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool,
enter OUTPUT TEST MODE. Select ALL ON. Using a DVOM, measure voltage between FSV PWR
and GND circuits at fuel tank solenoid shutoff valve harness connector. See WIRING DIAGRAMS.
Fuel tank solenoid shutoff valve is located on fuel tank (one per tank). If voltage is 10.5 volts or less, go
to next step. If voltage is more than 10.5 volts, perform appropriate UNABLE TO VENT FUEL TANKS
OR FUEL LINES diagnostic procedures under FUEL SYSTEM (NATURAL GAS VEHICLES) in
appropriate SYSTEM & COMPONENT TESTING article to check for faulty fuel tank solenoid shutoff
valve. Replace as necessary.

4) Check For Open GND Circuit To Fuel Tank Solenoid Shutoff Valve

Using a DVOM, measure resistance between negative battery terminal and GND circuit at fuel tank
solenoid shutoff valve harness connector. If resistance is less than 5 ohms, repair open in FSV PWR
circuit to fuel tank solenoid shutoff valve. Verify symptom is no longer present. If resistance is 5 ohms or
more, repair open in GND circuit to fuel tank solenoid shutoff valve. Verify symptom is no longer
present.

5) Check Fuel Pressure
Use scan tool and access FRP PID from PID/DATA MONITOR & RECORD menu and monitor fuel
pressure. Turn ignition switch to ON position, with engine off. Record pressure reading. If the fuel
pressure reading is 80-120 psi (552-827 kPa), go to TEST DD, step 3). If the fuel pressure reading is not
80-120 psi (552-827 kPa), go to step 7).

NOTE:

When energized by scan tool, FSV PWR circuit to fuel tank solenoid
shutoff valve will remain ON for only 7 seconds.

WARNING:

Always refer to safety procedures to reduce possibility of injury. See
FUEL SYSTEM SAFETY PRECAUTIONS.

2003 Ford Pickup F150

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

7) Verify Fuel Rail Solenoid Shutoff Valve Opens
Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool,
access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM
FUNCTIONS. Select ALL ON. Start and stop tests several times by toggling START/STOP button on
scan tool. An audible click should be heard or felt from fuel rail solenoid shutoff valve when
START/STOP button is cycled on scan tool. Turn ignition switch to OFF position. If fuel rail solenoid
shutoff valve did not operate as specified, go to next step. If fuel rail solenoid shutoff valve operated
correctly, go to TEST DD, step 3).

8) Check FSV PWR & GND Circuits To Fuel Rail Solenoid Shutoff Valve
Turn ignition switch to ON position. Using scan tool, again access OUTPUT TEST MODE. See
OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Select ALL ON and press
START. Using a DVOM, measure voltage between FSV PWR and GND circuits at fuel rail solenoid
shutoff valve harness connector. See WIRING DIAGRAMS. If voltage is 10.5 volts or less, go to next
step. If voltage is more than 10.5 volts, replace fuel rail solenoid shutoff valve. Verify symptom is no
longer present.

9) Check For Open GND Circuit To Fuel Rail Solenoid Shutoff Valve

Using a DVOM, measure resistance between battery negative terminal and GND circuit at fuel rail
solenoid shutoff valve harness connector. See WIRING DIAGRAMS. If resistance is less than 5 ohms,
repair open in FSV PWR circuit to fuel rail solenoid shutoff valve. If resistance is 5 ohms or more, repair
open in GND circuit to fuel rail solenoid shutoff valve. Verify symptom is no longer present.

10) Verify Fuel Rail Solenoid Shutoff Valve Seals
Ensure fuel pressure gauge with vent hose supplied in fuel delivery system special tool kit are connected
to Schrader valve located on fuel rail. Release fuel pressure in fuel injector rail and supply lines. See
appropriate FUEL SYSTEM PRESSURE RELEASE procedure under FUEL SYSTEM VENTING in
appropriate REMOVAL & INSTALLATION article. Disconnect fuel rail solenoid shutoff valve harness
connector at fuel rail. Re-open the manual lockdown valve jackscrews that were required to be closed
while performing the fuel system pressure relief procedure. Turn ignition switch to OFF position and wait
2 minutes. Using scan tool, access FRP PID from PID/DATA MONITOR & RECORD menu. Turn
ignition switch to ON position and record FRP PID value. If FRP PID value is less than 10 psi (70 kPa),
go to next step. If FRP PID value is 10 psi (70 kPa) or more, replace fuel rail solenoid shutoff valve.
Verify symptom is no longer present.

WARNING:

Always refer to safety procedures to reduce possibility of injury. See
FUEL SYSTEM SAFETY PRECAUTIONS.

NOTE:

When energized by scan tool, FSV PWR circuit to fuel rail solenoid shutoff
valve will remain ON for only 7 seconds.

WARNING:

Always refer to safety procedures to reduce possibility of injury. See
FUEL SYSTEM SAFETY PRECAUTIONS.

2003 Ford Pickup F150

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

11) Verify Fuel Rail Solenoid Shutoff Valve Partially Opens
Turn ignition switch to OFF position. Reconnect the fuel rail solenoid shut-off valve on the fuel injection
supply manifold (fuel rail) at the harness connector. Turn ignition switch to ON position, with engine off.
Using scan tool, access FRP PID and record FRP PID value. If the fuel pressure reading is 80-120 psi
(552-827 kPa), go to next step. If the fuel pressure reading is not 80-120 psi (552-827 kPa), replace fuel
rail solenoid shutoff valve. Verify symptom is no longer present.

12) Verify Fuel Rail Solenoid Shutoff Valve Fully Opens
Turn ignition switch to OFF position. Release fuel pressure in fuel injector rail and supply lines. See
FUEL SYSTEM PRESSURE RELEASE procedure under FUEL SYSTEM VENTING in appropriate
REMOVAL & INSTALLATION article. Re-open the manual lockdown valve jackscrews that were
required to be closed while performing the fuel system pressure relief procedure. Turn ignition switch to
ON position and immediately start engine. Increase engine speed to 2500 RPM while monitoring FRP
PID value. If the fuel pressure reading is 80-120 psi (552-827 kPa), go to next step. If the fuel pressure
reading is not 80-120 psi (552-827 kPa), replace fuel rail solenoid shutoff valve. Verify symptom is no
longer present.

13) Check Fuel Pressure With Engine Running
Turn ignition switch to OFF position. Start engine and allow to idle. Using scan tool, access FRP PID
from PID/DATA MONITOR & RECORD menu. Record FRP PID value at idle speed. Increase engine
speed to 2500 RPM. Again, record FRP PID value. If FRP PID value at idle is 80-120 (552-827 kPa), and
more than 80 psi (552 kPa) at 2500 RPM, turn ignition switch to OFF position and go to next step. If FRP
PID value is not as specified, check for plugged fuel lines. Repair as necessary and retest. If fuel lines are
okay, replace fuel pressure regulator. Verify symptom is no longer present.

14) Verify Regulator Thermostat
Start engine and allow to idle. Allow engine to reach normal operating temperature. Using a thermometer
or temperature probe, measure temperature at fuel pressure regulator coolant bowl or coolant outlet. If
temperature is 59-140°F (15-60°C), turn ignition switch to OFF position and go to next step. If fuel
pressure regulator coolant bowl temperature is less than 59°F (15°C), turn ignition switch to OFF
position. Check coolant lines and coolant system for proper operation. Repair as necessary and retest. If
coolant lines and system are okay, replace fuel pressure regulator. If fuel pressure regulator coolant bowl
temperature is more than 140°F (60°C), turn ignition switch to OFF position. Replace fuel pressure

WARNING:

Always refer to safety procedures to reduce possibility of injury. See
FUEL SYSTEM SAFETY PRECAUTIONS.

WARNING:

Always refer to safety procedures to reduce possibility of injury. See
FUEL SYSTEM SAFETY PRECAUTIONS.

WARNING:

Always refer to safety procedures to reduce possibility of injury. See
FUEL SYSTEM SAFETY PRECAUTIONS.

WARNING:

Always refer to safety procedures to reduce possibility of injury. See
FUEL SYSTEM SAFETY PRECAUTIONS.

2003 Ford Pickup F150

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

regulator. Verify symptom is no longer present.

15) Verify Fuel Injector Flow
Turn ignition switch to ON position, then to OFF position. Using scan tool, access FRP PID from
PID/DATA MONITOR & RECORD menu. Record initial FRP PID value. Connect Fuel Injector Tester
from Fuel Delivery System Special Tool Kit (134-00114) to suspect fuel injector. Using scan tool, access
pulse width of 200 milliseconds and activate fuel injector tester. Record final FRP PID value. Subtract
final FRP PID value from initial FRP PID value to find fuel pressure drop. Repeat procedure for
remaining fuel injectors. Fuel pressure drop should be 35-50 psi (241-345 kPa) and all injectors should be
within 3 psi (20 kPa) of each other. If fuel injectors are not within specification, replace faulty fuel
injector(s). If fuel injectors are within specification, no concern is indicated at this time. If symptom still
exists, diagnose by symptom. See SYMPTOMS under TROUBLE SHOOTING - NO CODES - CNG,
FLEX-FUEL & GASOLINE article.

16) Check For Fuel Leak
Turn ignition switch to OFF position. Using scan tool, access FRP PID from PID/DATA MONITOR &
RECORD menu. Turn ignition switch to ON position. Verify pressure is greater than 80 psi (552 kPa). If
the fuel system does have a fuel leak, it will be necessary to repeat this step to maintain pressure. Using
Natural Gas Sniffer from fuel delivery system special tool kit, or by covering fuel system components,
lines and joints with soapy water solution. Examine the components or joints for 60 seconds for signs of
bubbles. If no bubbles develop and/or sniffer does not detect a leak, fuel leaks cannot be found and
testing is complete. If bubbles develop or sniffer senses a leak, isolate fault and repair or replace
component as necessary.

17) For Continuous Memory Only DTC P1180 & P1181: Check Fuel Pressure
The PCM receives Fuel Tank Pressure (FTP) information from the Natural Gas (NG) module, which uses
the information to infer Fuel Rail Pressure (FRP). The test fails when the inferred pressure is less than or
more than a minimum calibrated value. Possible causes are:

z

Restriction in the fuel line.

z

Plugged fuel filter.

z

Fuel pressure regulator.

Inspect fuel lines, fuel regulator and fuel filter for leaks and restrictions. Repair as necessary. If no leaks
or restrictions are found, go to next step.

18) Check Fuel Tank Pressure

WARNING:

Always refer to safety procedures to reduce possibility of injury. See
FUEL SYSTEM SAFETY PRECAUTIONS.

NOTE:

If vehicle has sat for several hours with engine off, a slight CNG smell may
be detected in and around intake manifold area. This is normal, as fuel
injectors leak down from fuel rail to intake manifold over several hours.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

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