Ford 2003 Mustang Workshop Manual page 2158

Pressurize the EVAP system to 3.48 kPa (14
inches H O).
2
Does the pressure drop immediately?
C3 CHECK FOR BLOCKAGE BETWEEN THE FUEL
FILLER PIPE AND THE FUEL VAPOR TEE
Connect the Evaporative Emission System Leak
Tester to the fuel filler pipe.
Pressurize the EVAP system to 3.48 kPa (14
inches H O).
2
Does the pressure drop immediately?
C4 CHECK FOR FUEL TANK PRESSURE SENSOR
PID WITHOUT PRESSURE APPLIED
Disconnect the EVAP canister outlet tube at the
EVAP canister.
Key in ON position.
Access PCM PID FTP V.
Record the reading.
Is PID FTP V reading between 2.40 and 2.80
volts?
C5 CHECK FOR STUCK OPEN EVAP CANISTER
PURGE VALVE CONDITION AT IDLE
Connect the EVAP canister outlet tube.
Remove the plug from the EVAP return tube and
reconnect the tube to the intake manifold.
Verify that the fuel filler cap is correctly installed.
Key in ON position.
Access PCM PIDs FTP V and EVAPPDC.
Start the engine and allow to idle.
Monitor the FTP V and EVAPPDC PIDs.
When PID EVAPPDC is zero, is PID FTP V
reading below 2.40 volts?
PINPOINT TEST D: HISSING SOUND WHEN REMOVING FUEL CAP
GO to Pinpoint Test D
Yes
GO to C4 .
No
GO to Pinpoint Test D
Yes
GO to C5 .
No
REFER to Powertrain
Control/Emissions Diagnosis (PC/ED)
manual to continue diagnosis.
Yes
INSTALL a new EVAP canister purge
valve. REFER to Evaporative Emission
Canister Purge Valve
CARRY OUT an EVAP system leak
test. REFER to Evaporative Emission
System Leak Test in this section. If the
system passes the leak test, CARRY
OUT an evaporative emissions repair
verification drive cycle. REFER to
Evaporative Emission Repair
Verification Drive Cycle
No
CARRY OUT the EVAP system leak
test. REFER to Evaporative Emission
System Leak Test in this section. If the
system passes the leak test, CARRY
OUT the evaporative emissions repair
verification drive cycle. REFER to
Evaporative Emission Repair
Verification Drive Cycle
.
.
in this section.
in this section.
in this section.