Ford F150 Pickup. Instruction — part 1507

9) Check Vacuum Supply

Turn ignition switch to OFF position. Ensure fuel pressure gauge supplied in Kit (134-00114) is
connected to Schrader valve located on fuel rail. Disconnect and plug fuel pressure regulator vacuum
hose. Install vacuum pump to fuel pressure regulator. Start engine and allow to idle. Observe fuel
pressure gauge while applying vacuum to fuel pressure regulator. If fuel pressure reading changes as
vacuum is applied, repair vacuum source to fuel pressure regulator. If fuel pressure reading does not
change as vacuum is applied, replace fuel pressure regulator.

10) Check For Restricted Fuel Return Line
Ensure fuel pressure gauge supplied in Kit (134-00114) is connected to Schrader valve located on fuel
rail. Turn ignition switch to OFF position. Leave scan tool connected to DLC. Disconnect fuel return line
at fuel rail and connect a separate hose to fuel rail and place opposite end of hose in clean, one quart
container. Turn ignition switch to ON position. Using scan tool, command fuel pump ON to obtain
maximum fuel flow. Observe fuel pressure and ensure fuel is being returned to one quart container from
hose connected to fuel rail. One command of fuel pump ON is sufficient. Compare fuel pressure to
specification. See Fig. 167. If fuel pressure is within specification and fuel flows into one quart container,
go to next step. If fuel pressure is not within specification and/or fuel does not flow into one quart
container, replace fuel pressure regulator.

11) Check Fuel Return System
Turn ignition switch to OFF position. Ensure fuel return line is disconnected at fuel rail. Disconnect fuel
return line at fuel pump. Check return line for restrictions due to blockage, kinking or pinching. Apply 3-
5 psi (21-34 kPa) compressed air to return line. If air flows freely through fuel return line, replace fuel
pump module. If air does not flow freely through fuel return line, repair or replace fuel return line.

12) Check Fuel Injector Flow & Leakage
Turn ignition switch to OFF position. Use Rotunda fuel injector tester supplied in Kit (134-00114) to
flow test and leak test fuel injectors. Follow injector tester instructions. If tests for any fuel injector are
not within specification, replace faulty fuel injector. If tests for each fuel injector are within specification
on vehicles with EFRS or MRFS, check for additional symptoms and repair as necessary. See
SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. If
tests for each fuel injector are within specification on vehicles with a returnable fuel system, check for
leaks in fuel system. Repair as necessary. If no fuel system leaks exist, replace fuel pump.

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

13) Check Fuel Supply Line For Restriction
Turn ignition switch to OFF position. Release fuel system pressure. Disconnect fuel supply line at fuel
rail and at fuel pump. Check supply line for restrictions due to blockage, kinking or pinching. Apply 3-5
psi (21-34 kPa) compressed air to fuel supply line. If air flows freely through fuel supply line, replace fuel
pump module. If air does not flow freely through fuel supply line, repair cause of restriction or replace
fuel supply line.

TEST HD: MISFIRE DETECTION MONITOR

Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. Only use this test
to diagnose:

z

Ignition System

z

Fuel Injectors

z

Fuel Pressure

z

Engine Vacuum System

z

Evaporative Emission System

z

Fuel Vapor Storage Canister

z

EVAP Canister Purge Solenoid

z

Engine Mechanical Concern

z

Crankshaft Position (CKP) Sensor

z

Crankshaft Pulse Wheel

z

Powertrain Control Module (PCM)

Testing

1) For KOER & Continuous Memory Only DTC P0300-P0310, & Continuous Memory DTC
P0316: Check For Adaptive Fuel Monitor & HO2S Continuous Memory DTCs
DTC P0300 indicates multiple cylinders are misfiring or the PCM cannot identify which cylinder is
misfiring. Possible causes are:

WARNING:

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

NOTE:

After each service or repair procedure has been completed, reconnect all
components. Perform DRIVE CYCLES. Ensure MISFIRE & FUEL MONITOR
PROCEDURES are performed. Clear DTCs and repeat QUICK TEST procedures
to ensure all EEC-V systems are working properly and DTCs are no longer
present.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

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

z

Camshaft Position Sensor.

z

Low fuel: less than 1/8 tank.

z

Stuck open EGR valve.

z

Blocked EGR passages.

DTCs P0301-P0310 are designed to monitor engine misfire and identify the specific cylinder in which the
misfire has occurred. Misfire is defined as lack of combustion in a cylinder due to absence of spark, poor
fuel metering, poor compression, or any other cause. Possible causes are:

z

Ignition system.

z

Fuel injectors.

z

Running out of fuel.

z

EVAP canister purge valve.

z

Fuel pressure.

z

Evaporative emission system.

z

Base engine.

Check for other non-misfire Continuous Memory DTCs which could cause misfire DTC. If DTC P0136,
P0156, P0171, P0172, P0175, P1130 or P1150 is present, go to step 3). If specified DTCs are not present,
go to next step.

2) Check For Other Non-Misfire Continuous Memory DTCs

Check for other non-misfire Continuous Memory DTCs which could cause misfire DTC. If any other
Continuous Memory DTCs are present, disregard misfire DTCs at this time and service other Continuous
Memory DTC as necessary. See DIAGNOSTIC TROUBLE CODE DEFINITIONS. If no other
Continuous Memory DTCs are present, go to next step.

3) Check For KOEO DTCs

Check for any KOEO DTCs which could cause misfire DTC. If any KOEO DTCs are present, service
KOEO DTCs as necessary. See DIAGNOSTIC TROUBLE CODE DEFINITIONS. If no KOEO
DTCs are present, check spark plugs and spark plug wires. Go to TEST JB, step 1). If spark plugs and
spark plug wires are okay, go to next step.

4) Check For KOER DTCs

If KOER DTC P1131, P1132, P1137, P1138, P1151, P1152, P1157 or P1158 is present, go to step 8). If
any other KOER DTCs are present, disregard misfire DTCs at this time and service DTCs as necessary.
See DIAGNOSTIC TROUBLE CODE DEFINITIONS. If no KOER DTCs are present and a misfire is
present, go to step 6) (vehicles with DPF EGR system), or go to step 7) (vehicles without DPF EGR
system). For sensor application, see SENSORS CONNECTED TO VREF CIRCUIT table. If misfire
concern is intermittent, use FREEZE FRAME DATA MODE and go to TEST Z, step 1). If no KOER
DTCs are present and no misfire is present, go to step 7).

2003 Ford Pickup F150

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

6) Check/Compare PID Values

Connect scan tool to Data Link Connector (DLC). Start engine and allow to idle. Ensure engine is
warmed to normal operating temperature. Using scan tool, access and record DPFEGR PID voltage
reading while engine is running (KOER). Turn ignition switch to OFF position. Turn ignition switch to
ON position. Select and record DPFEGR PID voltage reading while engine is off (KOEO). Compare
KOEO and KOER DPFEGR PID readings. If DPFEGR PID voltage readings are within .15 volt of each
other, go to next step. If DPFEGR PID voltage readings are not within .15 volt of each other, go to TEST
HE, step 100).

7) EGR Restriction/Flow Test
Record and clear DTCs. Disconnect and plug EGR valve vacuum hose. Perform DRIVE CYCLES.
Ensure MISFIRE & FUEL MONITOR PROCEDURES are performed. If misfire DTC is still present, go
to next step. If misfire DTC is no longer present, inspect EGR passage and intake port for blockage and
repair as necessary.

8) Check Injector Driver PIDs (INJ1F-INJ10F)

Turn ignition switch to ON position. Using scan tool, access and record appropriate injector PID (INJ1F-
INJ10F) for suspect injector. If injector PID value indicates YES, go to next step. If injector PID value
indicates NO, go to step 10).

9) Check Fuel Injector & Harness For Open

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose,
damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between
suspect fuel injector signal and VPWR circuits at PCM harness connector. See Fig. 234. See PCM FUEL
INJECTOR, PWR GND & VPWR CIRCUIT TERMINAL IDENTIFICATION table for PCM
injector terminal identification. Fuel injector resistance should be within specification. See Fig. 167. If
fuel injector resistance is within specification, replace PCM. If fuel injector resistance is not within
specification, go to TEST H, step 57).

10) Check Fuel Pressure
Turn ignition switch to OFF position. Release fuel pressure. See FUEL SYSTEM PRESSURE RELEASE
procedure in appropriate REMOVAL & INSTALLATION article. Install fuel pressure gauge to Schrader
valve on fuel rail. Start engine and allow to idle. Record initial fuel pressure gauge reading. Increase
engine speed to 2500 RPM and maintain for one minute. Record final fuel pressure gauge reading.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 4) to step 6). No test procedures have been omitted.

NOTE:

DTCs may be stored during testing and will need to be cleared following
repair.

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