FORD MUSTANG 2003 Workshop Manual

z
Does the vacuum drop? system for normal
operation.
No
REPAIR or INSTALL a
new function selector
switch. TEST the
system for normal
operation.
A13 REVIEW THE VEHICLE'S HISTORY
z
Key in OFF position.
z Review the vehicles history.
z Did the climate control system function correctly prior to
this concern? Yes
GO to
A16 .
No
GO to A14 .
A14 CHECK THE VACUUM HOSES TO DAMPER DOORS
z
Connect a vacuum pump to each hose and try to pull a vacuum.
If the vacuum pump can pull a vacuum, the hose is plugged. If
the vacuum pump pulls a partial vacuum, the hose is restricted.
z Is a hose plugged or restricted? Yes
INSTALL a new
vacuum hose. TEST
the system for normal
operation.
No
GO to
A15 .
A15 CHECK THE VACUUM HARNESS
z
Compare the vacuum hose color in each vacuum harness to the
vacuum diagram.
z Does the hose color agree with the schematics? Yes
GO to
A16 .
No
INSTALL a new
vacuum harness. TEST
the system for normal
operation. A16 CHECK A/C VACUUM CIRCUIT
z
Check the A/C vacuum circuit for pinched or kinked vacuum
hose. Yes
REPAIR or INSTALL a
new vacuum hose.
TEST the system for
normal operation.
No
GO to
A17 . Klj . 12 ba
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z
Is the hose pinched or kinked? A17 CHECK VACUUM CIRCUIT CONNECTIONS
z
Check each vacuum hose connection to determine if it is partially
connected or disconnected.
z Is a vacuum hose disconnected or partially connected? Yes
RECONNECT the
hose. TEST the system
for normal operation.
No
GO to
A18 .
A18 CHECK THE VACUUM HOSE
z
Disconnect the suspect hose.
z Plug one end of the hose and attach a vacuum pump to the other
end. Check for a leak in the hose.
z Does the vacuum hose leak? Yes
REPAIR or INSTALL a
new hose. TEST the
system for normal
operation.
No
GO to
A19 .
A19 CHECK THE VACUUM CONTROL MOTOR
z
Disconnect: Vacuum Control Motor.
z Check the vacuum control motor for leaks with a vacuum pump. Yes
GO to
A20 .
No
INSTALL a new
vacuum control motor.
TEST the system for
normal operation. Klj . 13 ba
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PINPOINT TEST B: INSUFFICIENT, ERRATIC, OR NO HEAT z
Does the vacuum control motor hold a vacuum? A20 CHECK THE VACUUM CONTROL MOTOR INSTALLATION
z
Key in OFF position.
z Check the attachment of the vacuum control motor arm to
damper door.
z Is the vacuum control motor arm attached to the door or
door crank arm? Yes
REPAIR or INSTALL a
new damper door.
TEST the system for
normal operation.
No
CONNECT the vacuum
control motor arm to
the door and check
operation. TEST the
system for normal
operation.
Test Step Result / Action to Take
B1 CHECK FOR CORRECT ENGINE COOLANT LEVEL
z
Key in OFF position.
z Check the engine coolant level when hot and cold.
z Is the engine coolant at the correct level (hot/cold) as
indicated on the engine coolant recovery reservoir? Yes
GO to
B2 .
No
GO to B3 .
B2 CHECK FOR HOT WATER TO THE HEATER CORE INLET
HOSE WARNING: The heater core inlet hose will become
too hot to handle and may cause serious burns if the
system is working correctly.
z Key in START position.
z Allow the engine to reach normal operating temperature.
z Feel the heater core inlet hose. Yes
GO to
B4 .
No
TEST the engine cooling
system for correct
operation. REFER to
Section 303 - 03A or
Section 303 - 03B . Klj . 14 ba
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PINPOINT TEST C: THE A/C DOES NOT OPERATE/DOES NOT
OPERATE CORRECTLY z
Is the heater core inlet hose too hot to handle? B3 CHECK THE ENGINE COOLING SYSTEM INCLUDING
RADIATOR CAP FOR LEAKS z
Fill the engine cooling system to specified level.
z NOTE: It is not necessary to check the components
separately at this time.
z Pressure check the engine cooling system. Refer to Section 303 - 03A or
Section 303 - 03B .
z Does the engine cooling system, including the radiator
cap, hold pressure? Yes
GO to
B4 .
No
Pressure test the heater
core. REFER to
Component Tests, Heater
Core — Pressure Test. B4 CHECK THE HEATER CORE OUTLET HOSE FOR HOT
WATER z
Feel the heater core outlet hose.
z Is the heater core outlet hose cool or cold? Yes
TEST the heater core for a
plugged or partially
plugged condition. REFER
to
Section 303 - 03A or
Section 303 - 03B .
No
GO to Pinpoint Test E .
Test Step Result / Action to Take
C1 CHECK THE PCM PID WACF
z
Connect the diagnostic tool.
z Turn the function selector to the OFF position.
z Key in ON position.
z Enter the following diagnostic mode on the diagnostic
tool:
z Monitor the PCM PID WACF while turning the function
selector.
z Does the PCM PID WACF read YES? Yes
REFER to the Powertrain
Control/Emissions Diagnosis
(PC/ED) manual.
No
GO to
C2 .
C2 CHECK THE PCM PID WACF WITH THE A/C ON
z
Turn the function selector switch to the A/C position.
z Enter the following diagnostic mode on the diagnostic Yes
REFER to the Powertrain Klj . 15 ba
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tool:
z Monitor the PCM PID WACF while turning the function
selector.
z Does the PCM PID WACF read YES? Control/Emissions Diagnosis
(PC/ED) manual.
No
GO to
C3 .
C3 CHECK THE PCM PID ACCS WITH THE A/C ON
z
Key in START position.
z Make sure the engine is at idle.
z Enter the following diagnostic mode on the diagnostic
tool: PCM PID ACCS.
z Monitor the PCM PID ACCS while turning the function
selector.
z Does the PCM PID ACCS read ON? Yes
GO to
C4 .
No
GO to C6 .
C4 CHECK PCM PID WAC WITH THE A/C ON
NOTE:
When PCM PID WACF is YES, this is the same
fault as DTC P1460.
z Enter the following diagnostic mode on the diagnostic
tool: PCM PID WAC.
z Monitor the PCM PID WAC while turning the function
selector.
z Does the PCM PID WAC read ON? Yes
GO to
C20 .
No
GO to C5 .
C5 CHECK THE INPUT SIGNAL TO THE PCM
z
Key in OFF position.
z Disconnect: PCM C175.
z Key in ON position.
z Measure the voltage at PCM C175- 41, circuit 198
(DG/OG), harness side and ground.
z Is the voltage reading greater than 10 volts? Yes
INSTALL a new powertrain
control module. TEST the
system for normal operation.
No
GO to
C6 .
C6 CHECK THE REFRIGERANT PRESSURE
z
Key in OFF position.
z Connect the manifold gauge set. Refer to Refrigerant System Tests in this section.
z Is the system pressure 345- 1,724kPa (50-250psi)? Yes
GO to
C7 .
No
REPAIR the leaks and
RETEST the system for normal
operation. REFER to Section 412 - 03 .
C7 CHECK THE SUPPLY TO THE FUNCTION SELECTOR
SWITCH z
Key in OFF position.
z Disconnect: Function Selector Switch C294c.
z Key in ON position.
z Measure the voltage at the function selector switch
C294c- 2, circuit 883 (PK/LB), harness side and ground. Yes
GO to
C17 .
No
GO to C8 . Klj . 16 ba
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z
Is the voltage reading greater than 10 volts? C8 CHECK CIRCUIT 883 (PK/LB) FOR A SHORT TO
GROUND z
Key in OFF position.
z Measure the resistance between the function selector
switch C294c- 2, circuit 883 (PK/ LB) harness side and
ground.
z Is the resistance less than 5 ohms? Yes
GO to
C9 .
No
GO to C11 .
C9 CHECK CIRCUIT 348 (VT) FOR SHORT TO GROUND
z
Disconnect: A/C Cycling Switch C130.
z Measure the resistance between the function selector
switch C294c- 4, circuit 348 (VT) harness side and
ground.
z Is the resistance reading less than 10,000 ohms? Yes
REPAIR circuit 348 (VT). TEST
the system for normal
operation.
No
GO to
C10 .
C10 CHECK FOR A SHORTED FUNCTION SELECTOR
SWITCH z
Connect: Function Selector Switch C294c.
z Measure the resistance between the A/C cycling switch
C130- 4, circuit 348 (VT) harness side and ground. Yes
INSTALL a new function
selector switch. REFER to
Section 412
- 04 . TEST the
system for normal operation.
No
GO to C13 . Klj . 17 ba
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z
Turn the function selector switch to each of the following
positions and note the resistance reading:
zMAX A/C
z A/C
z VENT
z FLOOR
z MIX
z DEFROST
z Are any of the readings less than 10,000 ohms? C11 CHECK CIRCUIT C198 (DG/OG) FOR A SHORT TO
GROUND z
Connect: A/C Cycling Switch C130.
z Disconnect: A/C Pressure Cut-off Switch C1078.
z NOTE: The A/C pressure cut- off switch C1078 for the
3.8L engine is shown, C1078 for the 4.6L engines is
similar. The pin locations and the circuits are identical.
z Measure the resistance between the A/C pressure cut-
off switch C1078- 3, circuit 198 (DG/OG), harness side
and ground.
z Is the resistance reading less than 10,000 ohms? Yes
GO to
C14 .
No
GO to C12 .
C12 CHECK THE A/C CYCLING SWITCH FOR A SHORT
TO GROUND z
Disconnect: A/C Cycling Switch C130.
z NOTE: The A/C pressure cut- off switch C1078 for the
3.8L engine is shown, C1078 for the 4.6L engines is
similar. The pin locations and the circuits are identical.
z Measure the resistance between the A/C pressure cut-
off switch C1078- 2, circuit 420 (DB/YE), harness side
and ground. Yes
REPAIR circuit C420 (DB/YE)
for a short to ground. TEST for
normal operation.
No
INSTALL a new A/C cycling
switch. REFER to
Section 412 -
03 . TEST system for normal
operation. Klj . 18 ba
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z
Is the resistance reading less than 10,000 ohms? C13 CHECK CIRCUIT 198 (DG/OG) FOR A SHORT TO
GROUND z
Connect: A/C Pressure Cut- off Switch C1078.
z Measure the resistance between PCM C175- 41, circuit
198 (DG/OG), harness side and ground.
z Is the resistance less than 10,000 ohms? Yes
GO to
C15 .
No
INSTALL a new A/C fuse (15A).
TEST the system for normal
operation. If the fuse opens,
install a new PCM. REFER to
the Powertrain
Control/Emissions Diagnosis
(PC/ED) manual. C14 CHECK THE A/C PRESSURE CUT-
OFF SWITCH z
Disconnect: A/C Pressure Cut-off Switch C1078.
z Measure the resistance between the Rotunda EEC- V
Breakout Box pin 41, circuit 198 (DG/OG), and ground.
z Is the resistance less than 10,000 ohms? Yes
REPAIR circuit 198 (DG/OG)
for a short to ground. TEST the
system for normal operation.
No
INSTALL a new A/C pressure
cut-
off switch. REFER to
Section 412 - 03 .
C15 CHECK THE FUNCTION SELECTOR SWITCH
z
Key in OFF position.
z Connect: Function Selector Switch C294c.
z Disconnect: A/C Cycling Switch C130.
z Key in ON position.
z Turn the function selector switch to the A/C position.
z Measure the voltage between C130- 4, circuit 348 (VT),
harness side and ground. Yes
GO to
C17 .
No
GO to C16 . Klj . 19 ba
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z
Is the voltage reading greater than 10 volts? C16 MEASURE THE RESISTANCE OF CIRCUIT 348 (VT)
z
Key in OFF position.
z Disconnect: Function Selector Switch C294c.
z Measure the resistance between the A/C function
selector switch C294c- 1, circuit 348 (VT), harness side
and A/C cycling switch C130- 4, circuit 348 (VT), harness
side.
z Is the resistance reading less than 5 ohms? Yes
INSTALL a new function
selector switch. REFER to
Section 412
- 04 . TEST the
system for normal operation.
No
REPAIR circuit 348 (VT) for an
open. TEST the system for
normal operation. C17 MEASURE THE VOLTAGE TO THE A/C PRESSURE
CUT- OFF SWITCH z
Key in OFF position.
z Connect: A/C Cycling Switch C130.
z Disconnect: A/C Pressure Cut-off Switch C1078.
z Turn the function selector switch to the A/C position.
z NOTE: The A/C pressure cut- off switch C1078 for the
3.8L engine is shown, C1078 for the 4.6L engines is
similar. The pin locations and the circuits are identical.
z Measure the voltage at the A/C high pressure cut- off
switch C1078- 2 circuit 420 (DB/YE), harness side and
ground. Yes
GO to
C19 .
No
GO to C18 . Klj . 20 ba
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z
Is the voltage reading greater than 10 volts? C18 CHECK THE A/C CYCLING SWITCH
z
Key in OFF position.
z Disconnect: A/C Cycling Switch C130.
z NOTE: The A/C pressure cut- off switch C1078 for the
3.8L engine is shown, C1078 for the 4.6L engines is
similar. The pin locations and the circuits are identical.
z Measure the resistance between A/C cycling switch
C130- 2, circuit 420 (DB/YE), harness side and the A/C
high pressure cut- off switch C1078-2, circuit 420
(DB/YE), harness side.
z Is the resistance less than 5 ohms? Yes
INSTALL a new A/C cycling
switch. REFER to
Section 412 -
03 . TEST the system for
normal operation.
No
REPAIR circuit 420 (DB/YE) for
an open. TEST the system for
normal operation. C19 CHECK THE A/C PRESSURE CUT-
OFF SWITCH z
Key in OFF position.
z NOTE: The A/C pressure cut- off switch C1078 for the
3.8L engine is shown, C1078 for the 4.6L engines is
similar. The pin locations and the circuits are identical.
z Measure the resistance between Rotunda Breakout Box
pin 41 and A/C high pressure cut- off switch C1078-3,
circuit 198 (DG/OG), harness side.
z Is the resistance less than 5 ohms? Yes
INSTALL a new A/C pressure
cut-
off switch. REFER to
Section 412 - 03 . TEST the
system for normal operation.
No
REPAIR circuit 198 (DG/OG)
for an open. TEST the system
for normal operation. C20 CHECK THE GROUND CIRCUIT AT THE CONSTANT
CONTROL RELAY MODULE z
Key in OFF position. Yes Klj . 21 ba
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