Ford F150 Pickup. Instruction - part 1508

Compare fuel pressure gauge readings to specification. See Fig. 167. If fuel pressure gauge readings are 
within specification, go to next step. If fuel pressure gauge readings are not within specification, check 
and repair fuel system as necessary. 

11) Check Ability Of Fuel System To Hold Fuel Pressure 
 
Start engine and allow to idle. Record fuel pressure gauge reading. Increase engine speed to 2500 RPM 
and maintain for one minute. Check for fuel leaking from around fuel injectors, fuel pressure regulator 
and fuel lines. Repair as necessary. If fuel pressure gauge reading remains within 5 psi (34 kPa) of 
specification for one minute, go to step 12). If fuel pressure gauge reading does not remain within 5 psi 
(34 kPa) of specification for one minute, check fuel system for faults and repair as necessary. 

12) Check Fuel Injector Flow & Leakage 
Turn ignition switch to OFF position. Use Rotunda fuel injector tester from Kit (113-00114) to flow test 
fuel injectors. Follow injector tester instructions. Fuel injector flow rate should be within specification. If 
flow rate for each fuel injector is within specification, fuel delivery system is not the likely cause of 
misfire DTC. Go to step 20). If flow rate for any fuel injector is not within specification, clean or replace 
defective fuel injector(s). 

20) Check Vacuum System 
 
Inspect all vacuum hoses for kinks or damage. Ensure all vacuum connections are clean and tight. Repair 
as necessary and perform DRIVE CYCLES. Ensure MISFIRE & FUEL MONITOR PROCEDURES are 
performed to verify repair. If vacuum system is okay, go to next step. 

21) Check Crankshaft Damper & Pulley Assembly 
 
On models equipped with crankshaft pulley-mounted pulse ring, check crank pulley and pulse ring for 
damage or looseness. On models not equipped with crankshaft pulley-mounted pulse ring, remove front 
cover if necessary. Check crank pulley and pulse ring for damage or looseness. On all models, repair as 
necessary and disconnect battery for 5 minutes to allow PCM to learn new data. If no faults are found, go 
to next step. 

22) Check Evaporative Emission System 
Inspect carbon (EVAP) canister for fuel saturation. Replace carbon (EVAP) canister if liquid fuel is 
present. Perform DRIVE CYCLES. Ensure MISFIRE & FUEL MONITOR PROCEDURES are 
performed to verify repair. If carbon (EVAP) canister is okay, go to next step. 

WARNING:

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

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 12) to step 20). No test procedures have been omitted.

NOTE:

The MISFIRE MONITOR can be affected by evaporative emission system.

 

2003 Ford Pickup F150 

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

  

23) Pressure Test Evaporative Emission System 
 
Using Rotunda Evaporative Emission System Tester (134-00056), pressure test evaporative system 
starting at EVAP service port (if equipped), then at fuel filler cap. Follow evaporative emission system 
tester instructions. If evaporative emission system holds pressure, go to next step. If system does not hold 
pressure, isolate fault and repair as necessary. 

24) Check Vacuum In Evaporative Emission System 
 
Inspect vacuum hoses between engine and carbon canister for restrictions or damage. Ensure all vacuum 
connections are clean and tight. Check for fuel tank vent system blockage. Repair as necessary. If no 
faults are found, go to step 26). 

26) Check EVAP Canister Purge Valve Housing For Leaks 
 
Turn ignition switch to OFF position. Ensure EVAP CPV is connected. Connect hand-held vacuum pump 
to fuel vapor port from EVAP canister at EVAP CPV and apply 16 in. Hg (53 kPa). If EVAP CPV holds 
vacuum at room temperature, go to next step. If EVAP CPV does not hold vacuum at room temperature, 
replace EVAP CPV. 

27) Check For Filter Contamination 
 
Disconnect hose from vacuum input port of EVAP CPV. Connect vacuum pump to EVAP CPV vacuum 
input port and apply 10-15 in. Hg (48-52 kPa). If EVAP CPV holds vacuum or EVAP CPV is very slow 
to release vacuum, service EVAP CPV filter. If unable to clean or remove blockage to filter, replace 
EVAP CPV. If vacuum is not held as specified, remove vacuum pump, reconnect all components and go 
to step 29). 

29) Check Engine Mechanical Condition 
This test step will determine if there are any base engine concerns that may have caused Misfire DTC or 
drive concern. Perform the following in order to evaluate base engine integrity: 

z

Engine compression and leakdown tests.  

z

Valve train analysis.  

z

Check positive crankcase ventilation system.  

z

Check for possible leaks.  

Repair as necessary. If no faults can be found, misfire DTC is intermittent. Go to TEST Z, step 1) to 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 24) to step 26). No test procedures have been omitted.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 27) to step 29). No test procedures have been omitted.

NOTE:

Engine temperature may affect results of this test.

 

2003 Ford Pickup F150 

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

  

check intermittent ignition system concern. If ignition system is okay, go to next step. 

30) Check For Additional Misfire DTCs 
 
DTC P0300 indicates multiple cylinders are misfiring or PCM cannot identify which cylinder is 
misfiring. If any other misfire DTCs are present, return to step 1). If no other misfire DTCs are present, 
go to next step. 

31) Check For Other Continuous Memory DTCs 
 
If any other Continuous Memory DTCs are present, service DTCs as necessary. See DIAGNOSTIC 
TROUBLE CODE DEFINITIONS. If no other Continuous Memory DTCs are present, go to next step. 

32) 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. Turn ignition switch to OFF position. Turn ignition switch to ON 
position, with engine off. Select and record DPFEGR PID voltage reading while engine is off. Compare 
KOEO and KOER DPFEGR PID voltage readings. If DPFEGR PID voltage readings are within .15 volt 
of each other, go to step 40) (vehicles with Hall Effect CMP sensor), or go to step 41) (vehicles with 
variable reluctance CMP sensor). If DPFEGR PID voltage is not as specified, go to TEST HE, step 100). 

40) For Continuous Memory Only DTC P1336: Check Hall Effect CMP Sensor Output, PCM 
Disconnected 
This fault indicates CKP or CMP sensor input signal to PCM was erratic. Possible causes for this fault 
are: 

z

Faulty Powertrain Control Module (PCM)  

z

Faulty Camshaft Position (CMP) Or Crankshaft Position (CKP) Sensor  

z

Engine Mechanical Concern  

z

Harness Concerns  

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 voltage between CMP and 
PWR GND circuits at PCM harness connector. See WIRING DIAGRAMS. See PCM CONNECTOR 
IDENTIFICATION. Use remote starter switch and bump engine in short bursts for at least 10 
revolutions. If voltage switches between less than 2 volts and more than 8 volts, check CMP sensor for 
correct installation and synchronization (if necessary). See IGNITION SYSTEMS in appropriate 

NOTE:

Hall Effect type Camshaft Position (CMP) sensor has a 3-pin connector. 
Variable reluctance type CMP sensor has a 2-pin connector.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 32) to step 40). 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

  

REMOVAL & INSTALLATION article. If CMP sensor is correctly installed and synchronized, replace 
PCM. If voltage does not switch between less than 2 volts and more than 8 volts, replace CMP sensor. 

41) For Continuous Memory Only DTC P1309: Check Variable Reluctance CMP Sensor Output, 
PCM Connected 
This fault indicates MISFIRE MONITOR was disabled due to CMP sensor input signal to PCM 
malfunction. Possible causes for this fault are: 

z

Faulty Camshaft Position (CMP) Sensor  

z

Faulty Powertrain Control Module (PCM)  

z

Faulty Crankshaft Position (CKP), Engine Coolant Temperature (ECT) Or Mass Air Flow (MAF) 
Sensor  

Turn ignition and all accessories off. Ensure PCM is connected. Using a DVOM, backprobe and measure 
AC voltage between CMP and PWR GND circuits at PCM harness connector. See WIRING 
DIAGRAMS. See PCM CONNECTOR IDENTIFICATION. Start engine and vary engine speed. If 
AC voltage varies more than .1 volt, check CMP sensor for correct installation. If CMP sensor is 
correctly installed, replace PCM. If AC voltage does not vary more than .1 volt, replace CMP sensor. 

42) For Continuous Memory Only DTC P0315: Check Physical Condition Of Crankshaft Pulse 
Wheel 
DTC P0315 is set when PCM is unable to learn and correct for mechanical variations in Crankshaft Pulse 
Wheel tooth spacing (allowable correction tolerances have been exceeded). Possible causes for this fault 
are: 

z

Faulty Crankshaft Position Pulse Wheel Teeth  

z

Faulty Crankshaft Position (CKP) Sensor  

Inspect crankshaft pulse wheel for damaged teeth or for excessive wobble. Inspect for a loose crankshaft 
pulse wheel or damaged CKP sensor. Repair as necessary. If CKP sensor and crankshaft pulse wheel are 
okay, inspect crankshaft for damage. See appropriate article in ENGINES. Disconnect battery for 5 
minutes to allow PCM to learn new data. 

TEST HE: EGR SYSTEM 

Diagnostic Aids 

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

DTC P1309 indicates Misfire Detection Monitor is not enabled.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

After each service or repair procedure has been completed, reconnect all 
components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-
V systems are working properly and DTCs are no longer present.

 

2003 Ford Pickup F150 

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