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Ford F150 Pickup. Instruction - part 1528

18) For Continuous Memory Only DTC P1450: Check For Visual Causes Of Excessive Fuel Tank
Vacuum
DTC P1450 is set when PCM EVAP running loss monitor detects excessive fuel tank vacuum with
engine running (not at idle). Possible causes are:

Blocked Or Kinked EVAP Canister Tube Or EVAP Canister Purge Outlet Tube (Between Fuel
Tank, EVAP Canister Purge Valve & EVAP Canister

Fuel Filler Cap Stuck Closed (No Vacuum Relief)

Contaminated Fuel Vapor Elbow On EVAP Canister

Restricted EVAP Canister

Canister Vent (CV) Solenoid Stuck Open

Plugged CV Solenoid Filter

EVAP Canister Purge Valve Stuck Open

Open In VREF Circuit (In Harness Near FTP Sensor, FTP Sensor Or PCM)

Faulty Fuel Tank Pressure (FTP) Sensor

Check for kinks or bends in fuel vapor hoses/tubes. Visually inspect EVAP canister inlet port, CV
solenoid filter and canister vent hose for contamination or debris. Check CV solenoid filter for blockage
or contamination. Repair as necessary. Perform EVAPORATIVE EMISSIONS SYSTEM LEAK
TEST under SYSTEM TESTS (EVAPORATIVE EMISSION) to verify repair. If DTC P1450 is still
present, go to next step. If no faults are found, go to next step.

19) Check FTP Voltage

Turn ignition switch to OFF position. Ensure scan tool is connected to Data Link Connector (DLC). Turn
ignition switch to ON position. Using scan tool, access FTP V PID from PID/DATA MONITOR &
RECORD menu. If FTP V PID voltage is not 2.4-2.8 volts with fuel filler cap installed, turn ignition
switch to OFF position and go to next step. If FTP V PID voltage is 2.4-2.8 volts with fuel filler cap
installed, check for possible intermittent condition causing DTC P1450. Go to TEST Z, step 1). If circuit
is okay, check for blocked or plugged EVAP system. Perform TEST C: DTC P1450: EXCESSIVE
VACUUM DETECTED IN FUEL TANK in SYSTEM TESTS (EVAPORATIVE EMISSION) to
check for blocked EVAP system condition. Repair as necessary.

20) Check Fuel Tank Pressure Sensor FTP V PID (Fuel Filler Cap Removed)

Remove fuel filler cap. Turn ignition switch to ON position. Using scan tool, access FTP V PID from
PID/DATA MONITOR & RECORD menu. If FTP V PID voltage is not 2.4-2.8 volts, turn ignition
switch to OFF position and go to next step. If FTP V PID voltage is 2.4-2.8 volts with fuel filler cap
removed, check for blocked or plugged EVAP system. Perform appropriate testing for DTC P1450. See

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

Some components may need to be removed to gain access and diagnose
EVAP components. For removal and installation procedures, see
appropriate REMOVAL & INSTALLATION article.

2003 Ford Pickup F150

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

EVAPORATIVE EMISSIONS DIAGNOSTIC TROUBLE CODE DEFINITIONS. Repair as
necessary.

21) Check For Other DTCs

Check for other 3-wire sensor KOEO, KOER or Continuous Memory DTCs that may be present with
DTC P1450. Perform

KOEO ON-DEMAND SELF-TEST

, KOER ON-DEMAND SELF-TEST and

CONTINUOUS MEMORY SELF-TEST . If any other DTCs are present along with DTC P1450,
perform appropriate system test, see DIAGNOSTIC TROUBLE CODE DEFINITIONS, and repair as
necessary. If no other DTCs are present, turn ignition switch to OFF position and go to next step.

22) Check VREF From PCM To FTP Sensor

Turn ignition switch to OFF position. Disconnect FTP sensor connector. Turn ignition switch to ON
position. Using a DVOM, measure voltage between VREF and SIG RTN circuits at FTP sensor harness
connector. See Fig. 268 or Fig. 269 . If voltage is not 4-6 volts, go to next step. If voltage is 4-6 volts,
turn ignition switch to OFF position and replace FTP sensor. See FUEL TANK PRESSURE SENSOR
under FUEL SYSTEMS in appropriate REMOVAL & INSTALLATION article. Clear DTCs and
perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST under SYSTEM TESTS
(EVAPORATIVE EMISSION) to verify repair. After test is complete, repeat QUICK TEST. If
Continuous Memory DTC P1450 is still present, perform TEST C: DTC P1450: EXCESSIVE
VACUUM DETECTED IN FUEL TANK in SYSTEM TESTS (EVAPORATIVE EMISSION). Repair
as necessary.

Fig. 268: Identifying FTP Sensor Circuits & Connector Terminals (ZX2)
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

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

Fig. 269: Identifying FTP Sensor Circuits & Connector Terminals (All Others)
Courtesy of FORD MOTOR CO.

23) Check For Open VREF & SIG RTN Circuits Between PCM & FTP Sensor

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose,
damaged or corroded terminals. Using a DVOM, measure resistance of VREF and SIG RTN circuits
between PCM harness connector and FTP sensor harness connector. See Fig. 268 and Fig. 269 . If both
resistance measurements are less than 5 ohms, replace PCM. If either resistance measurement is 5 ohms

2003 Ford Pickup F150

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

or more, repair open in VREF or SIG RTN circuit.

26) For KOEO, KOER & Continuous Memory DTC P0452: Check For FTP Sensor Connector
Contamination
DTC P0452 is set when PCM detects Fuel Tank Pressure (FTP) sensor input signal drops below
minimum allowable parameter of less than .22 volt. Possible causes are:

Contaminated FTP Sensor Connector

Faulty Powertrain Control Module (PCM)

FTP Circuit Shorted To GND Or SIG RTN

Faulty FTP Sensor

Turn ignition switch to OFF position. Visually inspect FTP sensor connector for liquid fuel
contamination. Check for submerged FTP sensor in liquid fuel (tank mounted type only). Repair as
necessary and adjust fuel tank overfill. If FTP sensor connector is okay, go to next step.

27) Check For Low FTP Sensor Voltage
Turn ignition switch to OFF position. Ensure scan tool is connected to Data Link Connector (DLC). Turn
ignition switch to ON position. Using scan tool, access FTP V PID from PID/DATA MONITOR &
RECORD menu. If FTP V PID is not available on scan tool, measure voltage by backprobing between
FTP and SIG RTN circuits at PCM harness connector. See PCM CONNECTOR IDENTIFICATION
and Fig. 268 or Fig. 269 . If voltage measurement on DVOM or FTP V PID value is less than .22 volt, go
to next step. If voltage is .22 volt or more, DTC P0452 is intermittent. Check for intermittent faults. Go to
TEST Z, step 1).

28) Check Opposite Induced High FTP Signal

Turn ignition switch to OFF position. Disconnect FTP sensor connector. Connect a jumper wire between
VREF and FTP circuits at FTP sensor harness connector. Turn ignition switch to ON position.

Using scan tool, access FTP V PID from PID/DATA MONITOR & RECORD menu. If FTP V PID is not
available on scan tool, measure voltage by backprobing between FTP and SIG RTN circuits at PCM
harness connector. If voltage measurement on DVOM or FTP V PID value is 4-6 volts, replace FTP
sensor. See FUEL TANK PRESSURE SENSOR under FUEL SYSTEMS in appropriate REMOVAL &
INSTALLATION article. Perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST under
SYSTEM TESTS (EVAPORATIVE EMISSION) to verify repair. If voltage measurement on DVOM or
FTP V PID value is not 4-6 volts, remove jumper wire and go to next step.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 23) to step 26). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

FTP sensor input with no pressure/vacuum on fuel tank (filler cap open or
not open) should be 2.37-2.97 volts.

2003 Ford Pickup F150

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

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