2003 FORD MUSTANG air condition

Principles of Operation
Evaporative Emission (EVAP) Canister Purge Valve
The EVAP canister purge valve is controlled by the powertrain control module (PCM). The EVAP
canister purge valve controls the flow of fuel vapors from the EVAP canister to the engine intake
manifold during various engine operating modes. The EVAP canister purge valve is normally closed.
Evaporative Emission (EVAP) Canister
Fuel vapors from the fuel tank are stored in the EVAP canister. When the engine is running, the vapors
are purged from the EVAP canister for combustion.
Canister Vent Solenoid
During the Evaporative Emission (EVAP) System Test Monitor, Evaporative Emissions Repair
Verification Drive Cycle, and the Evaporative Emission System Leak Test, the canister vent solenoid is
closed to allow a vacuum to be drawn on the fuel tank at a specific level. The canister vent solenoid is
normally open.
Fuel Tank Pressure (FTP) Sensor
The fuel tank pressure sensor is used to measure the fuel tank pressure during the Evaporative
Emissions Monitor Test. The fuel tank pressure sensor is mounted in the fuel vapor control valve tube
as it crosses over the fuel tank.
Fuel Vapor Control Valve
The fuel vapor control valve is normally between the EVAP canister and the fuel vapor vent valve. Its
function is to prevent the flow of liquid fuel into the EVAP canister or up to the canister purge valve
during refueling, and to prevent the collection of liquid fuel in the fuel vapor hoses by overfilling the fuel
tank.
Fuel Vapor Vent Valve (FVV) Assembly
The fuel vapor vent valve (FVV) assembly is mounted on the top of the fuel tank. It is used to control
the flow of fuel vapors entering the EVAP system. The head portion of the assembly prevents the fuel
tank from overfilling during refueling. The assembly also has a spring float, which prevents liquid fuel
from entering the vapor delivery system under severe handling or vehicle rollover conditions. In the
upright position, the open bottom of the float will lift and shut off the orifice. Under severe handling
conditions, the spring will push the float closed when angles allow liquid fuel to reach the orifice. In a
rollover condition, the weight of the open bottom float and spring pressure will close the orifice.
Fuel Filler Pipe Check Valve
The fuel filler pipe check valve is an intricate part of the fuel filler pipe. It is intended to prevent liquid
fuel from re-entering the fuel filler pipe from the fuel tank on refueling or roll over conditions.
Fuel Filler Cap
The fuel filler cap is used to prevent fuel spill and to close the EVAP system to the atmosphere.
Evaporative Emission System Monitor
When a fault occurs, the EVAP system monitor is reset to NO and a diagnostic trouble code (DTC) is
set in the PCM memory. After the DTC is repaired, the vehicle drive cycle must be completed to reset
the monitor in preparation for inspection and maintenance testing. EVAP Emission System Leak Test Klj . 2 ba
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To start the testing, conditions of stable purging and vehicle speed must be satisfied. During the first
stage, the canister vent solenoid is closed, while the EVAP canister purge valve remains open,
applying and building vacuum in the system as indicated by the FTP sensor. This phase checks for
major leaks in the EVAP system.
In the second stage, the EVAP canister purge valve closes and the system looks for minimal decay
rate in the EVAP vacuum, indicating the absence of any small EVAP system leaks.
The last stage is entered only if stage two of the leak test has failed and checks whether the failed test
was due to excess vapor generation. It monitors fuel vapor generation rate. Initially, the canister vent
solenoid is opened to equalize EVAP system pressure to atmosphere. Then the canister vent solenoid
is closed, allowing pressure to build if vapor generation is present in sufficient quantity. If the rate of
generation is found to be too high, the EVAP running loss system leak test is aborted. If not, then a
small leak is diagnosed.
On-
Board Refueling Vapor Recovery (ORVR) Evaporative Emission (EVAP) System
The basic elements forming the ORVR system are as follows:
zThe fuel filler pipe forms a seal to prevent vapors from escaping the fuel tank while liquid is
entering the fuel tank. Liquid in the one inch diameter tube blocks vapors from rushing back up
the fuel filler pipe.
z A fuel vapor control valve controls the flow of vapors out of the fuel tank. The valve closes when
the liquid level reaches a height associated with fuel tank usable capacity. The valve
accomplishes the following:
„limits the total amount of fuel that can be dispensed into the fuel tank
„ prevents liquid gasoline from exiting the fuel tank when submerged (as well as when
tipped well beyond a horizontal plane as part of the vehicle rollover protection in road
accidents)
„ minimizes vapor flow resistance during anticipated refueling conditions
z Fuel vapor tubing connects the fuel vapor control valve to the EVAP canister. This routes the
fuel tank vapors, displaced by the incoming liquid, to the EVAP canister.
z A check valve in the fuel filling system prevents liquid from rushing back up the fuel filler pipe
during the liquid flow variations associated with the filler nozzle shut- off.
Between refueling events, the EVAP canister is purged with fresh air so that it may be used again to
store vapors accumulated during engine soaks or subsequent refueling events. The vapors drawn off
of the carbon in the EVAP canister are consumed by the engine.
Inspection and Verification 1. Verify the customer concern is with the evaporative emission (EVAP) system.
2. Visually inspect for the following obvious signs of mechanical damage.
Visual Inspection Chart Mechanical
z
Fuel filler cap
z EVAP test port
z EVAP canister or canister vent solenoid Klj . 3 ba
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Pinpoint Tests
NOTE:
Reinstall or install new evaporative emission hose clamps removed or damaged during testing
procedures.
PINPOINT TEST A: DTC P0442 SMALL LEAK IN EVAP SYSTEM tube assembly.
z EVAP canister tube.
z EVAP canister purge
outlet tube.
z Excessive fuel odor zCanister vent solenoid.
z Evaporative emissions
canister.
z Fuel vapor control valve
tube assembly.
z Evaporative emissions
test port.
z EVAP canister purge
outlet tube. z
Go To Pinpoint Test E .
z Unable to refuel vehicle zFuel filler pipe.
z Canister vent solenoid.
z Fuel vapor control valve
tube assembly. z
Go To Pinpoint Test D .
Test Step Result / Action to Take
NOTE:
Condition P0442 DTC set: less than 0.625 kPa (2.5 inches H
2 O) bleed-
up over 15
seconds at 75% fuel fill. Vapor generation limit: more than 0.625 kPa (2.5 inches H 2 O) over 120
seconds. A1 VISUALLY INSPECT THE
COMPONENTS FOR SMALL LEAKS z
Check for the presence of a fuel filler
cap. Do not tighten or check for correct
installation at this time.
z Verify the canister vent solenoid is
correctly seated on the EVAP canister.
z Check for cut or loose connections to
fuel vapor hoses, tubes and
connections in the following locations:
„EVAP canister to EVAP canister
purge valve
„ EVAP canister to fuel vapor vent
valve assembly
„ fuel vapor control valve tube
assembly to fuel tank
z Check the fuel filler pipe for damage.
z Is a concern with a hose, tube,
connection or valve visually
evident? Yes
REPAIR or INSTALL new components as
necessary.GO to
A2 .
No
GO to A2 .
A2 CHECK AT THE EVAP TEST PORT
FOR SMALL SYSTEM LEAKS z
Disconnect and plug the evaporative
emission return tube at the intake Yes
GO to
A3 . Klj . 5 ba
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PINPOINT TEST B: DTC P0455 MAJOR LEAK OR NO FLOW
DETECTED OR DTC P1443 VERY SMALL OR NO PURGE FLOW
DETECTED IN SYSTEM Procedure in this section.
z Pressurize the EVAP system to 3.48
kPa (14 inches H
2 O).
z Using the ultrasonic leak detector,
check the fuel vapor control valve tube
to the fuel tank for leaks. Check the
fuel tank pressure sensor, fuel vapor
control valve tube and the fuel filler
pipe. Check fuel tank to EVAP canister
-canister vent solenoid.
z Is a leak detected? A10 CHECK EVAP SYSTEM AT FUEL
FILLER PIPE z
Reconnect the EVAP canister purge
outlet tube to the fuel vapor tee.
z Complete the evaporative emission
system leak test. Refer to Evaporative Emission System Leak Test in this
section.
z Does the EVAP system pass the
leak test? Yes
RESTORE the system to normal operation.
CARRY OUT the evaporative emission 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.
No
GO to A6 .
Test Step Result / Action to Take
NOTE:
Condition DTC P0455 set: – 1.74 kPa (-7.0 inches H
2 O) over 30 seconds. NOTE:
Condition DTC P1443 set: – 1.74 kPa (-7.0 inches H
2 O) over 30 seconds with more than
0.02 lb/min vapor flow. B1 CHECK FOR DIAGNOSTIC
TROUBLE CODE P0455 OR
P1443 z
Use the recorded results
from the PCM DTCs.
z Is DTC P0455 present? Yes
GO to
B2 .
No
GO to B3 .
B2 VISUALLY CHECK FOR
GROSS EVAP SYSTEM LEAKS z
Check for the presence of a
fuel filler cap. Do not tighten
or check for correct
installation at this time.
z Check the input port
vacuum and EVAP return
tube are connected to the
EVAP canister purge valve.
z Check that the canister vent
solenoid is correctly
attached to the EVAP Yes
REPAIR or INSTALL new EVAP components as necessary.
GO to
B3 .
No
GO to B3 . Klj . 8 ba
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PINPOINT TEST C: DTC P1450 EXCESSIVE VACUUM DETECTED IN
THE FUEL TANK Tester to the fuel filler pipe.
z Pressurize the EVAP
system to 6.47 to 6.97 kPa
(26 to 28 inches H
2 O).
z Does the pressure drop
immediately? No
INSTALL new fuel tank vapor line(s). REPEAT pinpoint test
Step B5 to verify the repair. CARRY OUT the evaporative
emission system leak test. REFER to
Evaporative Emission System Leak Test in this section. If the system passes the
leak test, CARRY OUT the evaporative emission repair
verification drive cycle. REFER to Evaporative Emission Repair Verification Drive Cycle in this section.
B6 CHECK FOR FAILED EVAP
CANISTER PURGE VALVE OR
FUEL TANK PRESSURE
SENSOR z
Use the recorded results
from the PCM DTCs.
z Are DTC codes P0455 and
P1443 present? Yes
INSTALL a new EVAP canister purge valve. REFER to
Evaporative Emission Canister Purge Valve
in this section.
CARRY OUT the evaporative emission system leak test.
REFER to Evaporative Emission System Leak Test in this
section. If no leak is detected, CARRY OUT the evaporative
emissions repair verification drive cycle. REFER to
Evaporative Emission Repair Verification Drive Cycle in this
section.
No
INSTALL a new fuel tank pressure sensor. REFER to Fuel Tank Pressure Sensor in this section. CARRY OUT the
evaporative emission system leak test. REFER to
Evaporative Emission System Leak Test in this section. If
the system passes the leak test, CARRY out the
evaporative emission repair verification drive cycle. REFER
to Evaporative Emission Repair Verification Drive Cycle in
this section. Test Step Result / Action to Take
NOTE:
Condition P1450 DTC set: more than - 1.79 kPa (-7.2 inches H
2 O) over 30 seconds. C1 CHECK FOR VISUAL CAUSES OF EXCESSIVE
FUEL TANK VACUUM z
Check for kinks or bends in the fuel vapor hoses
and tubes.
z Visually check the EVAP canister inlet port,
canister vent solenoid filter or outlet hose for
contamination or foreign material.
z Check the canister vent solenoid for blockage or
contamination.
z Is a concern with a hose, tube, connection or
component visually evident? Yes
REMOVE any contamination or foreign
material around fuel vapor hoses and
tubes. REPAIR the hoses, tubes or
components as necessary. After all
visual concerns are repaired, GO to
C2
.
No
GO to C2 .
C2 CHECK FOR BLOCKAGE BETWEEN EVAP
TEST PORT AND CANISTER VENT SOLENOID z
Disconnect and plug the EVAP return tube at the
intake manifold.
z Connect the Evaporative Emissions System Leak
Tester to the EVAP test port. Yes
GO to
C3 .
No Klj . 10 ba
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PINPOINT TEST D: HISSING SOUND WHEN REMOVING FUEL CAP z
Pressurize the EVAP system to 3.48 kPa (14
inches H
2 O).
z Does the pressure drop immediately? GO to
Pinpoint Test D .
C3 CHECK FOR BLOCKAGE BETWEEN THE FUEL
FILLER PIPE AND THE FUEL VAPOR TEE z
Connect the Evaporative Emission System Leak
Tester to the fuel filler pipe.
z Pressurize the EVAP system to 3.48 kPa (14
inches H
2 O).
z Does the pressure drop immediately? Yes
GO to
C4 .
No
GO to Pinpoint Test D .
C4 CHECK FOR FUEL TANK PRESSURE SENSOR
PID WITHOUT PRESSURE APPLIED z
Disconnect the EVAP canister outlet tube at the
EVAP canister.
z Key in ON position.
z Access PCM PID FTP V.
z Record the reading.
z Is PID FTP V reading between 2.40 and 2.80
volts? Yes
GO to
C5 .
No
REFER to Powertrain
Control/Emissions Diagnosis (PC/ED)
manual to continue diagnosis. C5 CHECK FOR STUCK OPEN EVAP CANISTER
PURGE VALVE CONDITION AT IDLE z
Connect the EVAP canister outlet tube.
z Remove the plug from the EVAP return tube and
reconnect the tube to the intake manifold.
z Verify that the fuel filler cap is correctly installed.
z Key in ON position.
z Access PCM PIDs FTP V and EVAPPDC.
z Start the engine and allow to idle.
z Monitor the FTP V and EVAPPDC PIDs.
z When PID EVAPPDC is zero, is PID FTP V
reading below 2.40 volts? Yes
INSTALL a new EVAP canister purge
valve. REFER to
Evaporative Emission Canister Purge Valve in this section.
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 in this section.
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. Klj . 11 ba
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GENERAL PROCEDURES
Evaporative Emission Repair Verification Drive Cycle
Drive Cycle Recommendations
NOTE:
The following procedure is designed to execute and complete the evaporative emission repair
verification drive cycle and to clear the Ford P1000, inspection and maintenance (I/M) readiness code.
When the ambient air temperature is below 4.4°C (40°F) or above 37.8°C (100°F), or the altitude is
above 2,438 meters (8,000 feet), the EVAP monitor will not run. If the P1000 must be cleared in these
conditions, the powertrain control module (PCM) must detect them once (twice on some applications)
before the EVAP monitor can be bypassed and the P1000 cleared. The EVAP bypassing procedure is
described in the following drive cycle.
1. Most OBD II monitors will complete more readily using a steady foot driving style during cruise or acceleration modes. Operating the throttle in a smooth fashion will minimize the time
necessary for monitor completion.
2. Fuel tank level should be between one- half and three-quarters full with three- quarters full being
the most desirable.
3. The evaporative monitor can only operate during the first 30 minutes of engine operation. When executing the procedure for this monitor, stay in part throttle mode and drive in a smooth
fashion to minimize fuel slosh.
Drive Cycle Preparation
NOTE: For best results, follow each of the following steps as accurately as possible.
4. NOTE: This step bypasses the engine soak timer and resets OBD II monitor status.
Install the scan tool. Turn the key ON with the engine OFF. Cycle the key off, then on. Select
the appropriate vehicle and engine qualifier. Clear all diagnostic trouble codes (DTCs) and carry
out a PCM reset.
5. Begin to monitor the following PIDs: ECT, EVAPDC, FLI (if available) and TP MODE. Press Diagnostic Data Link, PCM, PID/Data monitor and record, press trigger to select each PID, then
start.
6. Start the engine without returning the key to the OFF position.
Preparation for Monitor Entry
WARNING: Strict observance of posted speed limits and attention to driving conditions
SECTION 303-
13: Evaporative Emissions 2003 Mustang Workshop Manual Special Tool(s)
Worldwide Diagnostic System
(WDS)
418-
F224,
New Generation STAR (NGS)
Tester
418- F052, or equivalent scan
tool Klj . 1 ba
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DESCRIPTION AND OPERATION
Electronic Engine Controls —
Cobra
Most of the Cobra engine electronic controls are similar to that of the non- supercharged 4.6L (2V)
engine. These components are as follows:
zCrankshaft position (CKP) sensor
z Throttle position (TP) sensor
z Idle air control (IAC) valve
z Mass air flow (MAF) sensor
z Heated oxygen sensors (HO2S)
z Engine coolant temperature (ECT) sensor
There are also three controls that are unique to the Cobra engine. These are as follows:
zIntegrated temperature and manifold absolute pressure (T- MAP) sensor
z Supercharger bypass vacuum solenoid
z Supercharger bypass vacuum solenoid — actuator
Supercharger Bypass Vacuum Solenoid and Actuator
The Supercharger bypass vacuum solenoid will bleed off boost under the following conditions:
zheavy engine misfire
z engine coolant over- temperature
z loss of intercooler fluid
z pump failure
This prevents damage that can occur if boost were allowed under these conditions. The solenoid is
located on the upper LH side of the engine. The solenoid uses engine vacuum to operate a actuator
and linkage that connects to the pressure bleed off valve. The actuator is located near the solenoid
and is connected to it by a vacuum line.
Integrated Temperature and Manifold Absolute Pressure (TMAP) Sensor
The TMAP sensor is located on the upper LH side of the engine and is used to measure current
manifold absolute pressure and manifold air charge temperature. SECTION 303-
14: Electronic Engine Controls 2003 Mustang Workshop Manual Klj . 1 ba
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