AC system FORD MUSTANG 2003 Workshop Manual

DESCRIPTION AND OPERATION
Transmission Electronic Control System
The powertrain control module (PCM) and its input/output network control the following transmission
operations:
zShift timing
z Line pressure (shift feel)
z Torque converter clutch
The transmission control is separate from the engine control strategy in the PCM, although some of
the input signals are shared. When determining the best operating strategy for transmission operation,
the PCM uses input information from certain engine- related and driver-demand related sensors and
switches.
In addition, the PCM receives input signals from certain transmission- related sensors and switches.
The PCM also uses these signals when determining transmission operating strategy.
Using all of these input signals, the PCM can determine when the time and conditions are right for a
shift, or when to apply or release the torque converter clutch (TCC). It will also determine the best line
pressure needed to optimize shift feel. To accomplish this, the PCM uses hydraulic solenoids to control
transmission operation.
The following provides a brief description of each of the sensors and actuators used to control
transmission operation.
Powertrain Control Module (PCM)
The operation of the transmission is controlled by the powertrain control module (PCM). Many input
sensors provide information to the PCM. The PCM then controls actuators which determine
transmission operation.
Air Conditioning (A/C) Clutch
An electromagnetic clutch is energized when the clutch cycling pressure switch closes. The switch is
located on the suction accumulator/drier. The closing of the switch completes the circuit to the clutch
and draws it into engagement with the compressor driveshaft. When the A/C clutch is engaged,
electronic pressure control (EPC) is adjusted by the PCM to compensate for additional load on the
engine.
Brake Pedal Position (BPP) Switch
The brake pedal position (BPP) switch tells the PCM when the brakes are applied. The torque
converter clutch disengages when the brakes are applied. The BPP switch closes when the brakes are
applied and opens when they are released.
Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature (ECT) sensor detects temperature of engine coolant and supplies the
information to the powertrain control module. The ECT sensor is used to control torque converter
clutch (TCC) operation. The ECT is installed in the heater outlet fitting or cooling passage on the
engine. For engine control applications, the ECT signal is used to modify ignition timing, EGR flow and
air- to-fuel ratio as a function of engine coolant temperature.
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Ignition Coil —
Coil On Plug
The engine uses eight separate coil per plug units. Each coil per plug unit is controlled by the
powertrain control module (PCM).
Each coil per plug unit is mounted directly above each spark plug and activates its own spark plug in
the correct sequence as controlled by the PCM.
Refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual for additional information on the
ignition system.
Intake Air Temperature (IAT) Sensor
The intake air temperature (IAT) sensor provides the sequential fuel injection (SFI) system mixture
temperature information. The IAT sensor is used both as a density corrector for air flow calculation and
to proportion cold enrichment fuel flow. The IAT sensor is installed in the air cleaner inlet tube. The IAT
sensor is also used in determining EPC pressures.
Mass Air Flow (MAF) Sensor
The mass air flow (MAF) sensor measures the mass of air flowing into the engine. The MAF sensor
output signal is used by the powertrain control module to calculate injector pulse width. For
transmission strategies, the mass air flow sensor is used to regulate EPC, shift and torque converter
clutch scheduling.
Transmission Control Switch (TCS) and Transmission Control Indicator Lamp (TCIL)
The transmission control switch (TCS) is a momentary contact switch. When the switch is pressed, a
signal is sent to the PCM to allow automatic shifts from first through fourth gears or first through third
gears only. The PCM energizes the transmission control indicator lamp (TCIL) when the switch is off.
The TCIL indicates overdrive cancel mode activated (lamp on). When the TCIL is flashing, it indicates
electronic pressure control (EPC) circuit shorted or a monitored sensor failure.
Throttle Position (TP) Sensor
The throttle position (TP) sensor is a potentiometer mounted on the throttle body. The TP sensor
detects the position of the throttle plate and sends this information to the PCM. The TP sensor is used
for shift scheduling, electronic pressure control (EPC) and TCC control.
Digital Transmission Range (TR) Sensor
The digital transmission range (TR) sensor is located on the outside of the transmission at the manual
lever. The digital sensor completes the start circuit in PARK and NEUTRAL, and the back- up lamp
circuit in REVERSE. The digital sensor also opens/closes a set of four switches that are monitored by
the PCM to determine the position of the manual lever (P, R, N, D, 2, 1).
Output Shaft Speed (OSS) Sensor
The output shaft speed (OSS) sensor is a magnetic pickup, located at the output shaft ring gear, that
sends a signal to the powertrain control module (PCM) to indicate transmission output shaft speed.
The OSS sensor is used for torque converter clutch (TCC) control, shift scheduling and to determine
electronic pressure control (EPC).
Electronic Pressure Control (EPC) Solenoid
The EPC solenoid regulates transmission pressure. EPC valve pressure is used to control line
pressure.
Torque Converter Clutch (TCC) Solenoid Klj . 2 ba
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The TCC solenoid is used to control the apply and release of the TCC.
Shift Solenoid —
SSA, SSB
Two on/off shift solenoids provide gear selection of first through fourth gears by controlling the
pressure to the three shift valves. One unit containing the two shift solenoids is located in the main
control valve body. The shift solenoids are two- way, normally open style.
a When a manual pull- in occurs above a calibrated speed, the transmission will not downshift from the
higher gear until the vehicle speed drops below this calibrated speed.
EC = Electronically Controlled
HD = Hydraulically Disabled
Transmission Fluid Temperature (TFT) Sensor
The transmission fluid temperature (TFT) sensor is located on the lead frame assembly near the shift
solenoids on the main control valve body. It is a temperature- sensitive device called a thermistor. It
sends a voltage signal to the PCM. The voltage signal varies with transmission fluid temperature. The
PCM uses this signal to determine whether a cold start shift schedule is necessary. The shift schedule
is compensated when the transmission fluid temperature is cold. The PCM also inhibits (TCC)
operation at low transmission fluid temperatures and corrects electronic pressure control.
Vehicle Speed (VSS) Sensor
The source of vehicle speed (VSS) is model dependent. Possible sources of vehicle speed input are
anti- lock brake sensor (ABS), a gear- driven vehicle speed sensor (VSS), or an output shaft speed
sensor (OSS). The VSS signal is either an A/C signal whose frequency changes with speed, or an
SCP data message depending on the source. Some applications will have both. The vehicle speed
signal is an input to various vehicle subsystems such as the powertrain control module (PCM),
instrument cluster (speedometer and odometer), speed control system, etc. The vehicle speed source
must be operational to enter output state control (OSC) mode for diagnostics.
Regardless of the type of vehicle speed system, the PCM always uses the OSS for transmission and Solenoid Operation Chart Selector Lever Position PCM Commanded Gear Solenoids
SSA SSB TCC
P/R/N 1 ON OFF HD
(D) 1 ON OFF HD
(D) 2 OFF OFF EC
(D) 3 OFF ON EC
(D) 4 ON ON EC
w/OD OFF
1 1 ON OFF HD
2 2 OFF OFF EC
3 3 OFF ON EC
Manual 2 2 OFF OFF EC
Manual 1 1 ON OFF HD
1
a 2 OFF OFF EC Klj . 3 ba
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CAUTION: The use of any other type of transmission fluid than specified could result in
transmission failure.
If fluid needs to be added, add fluid in 0.25L (1/2 pint) increments through the filler tube. Do not overfill
the fluid. For fluid type, refer to the specification chart.
Fluid Condition Check
1. Check the fluid level.
2. Observe the color and the odor. The color under normal circumstances should be dark reddish, not brown or black or have a burnt odor.
3. Hold the fluid level indicator over a white facial tissue and allow the fluid to drip onto the facial tissue and examine the stain.
4. If evidence of solid material is found, the transmission fluid pan should be removed for further inspection.
5. If the stain is a foamy pink color this may indicate coolant in the transmission. The engine cooling system should also be inspected at this time.
6. If fluid contamination or transmission failure is confirmed by the sediment in the bottom of the fluid pan, the transmission must be disassembled and completely cleaned. This includes the
torque converter and cooler tubes. The oil- to-air cooler will need to be installed.
7. Carry out diagnostic checks and adjustments. Refer to Diagnosis By Symptom in this section. Klj . 3 ba
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DIAGNOSIS AND TESTING
Shift Point Road Test
This test verifies that the shift control system is operating correctly.
1. Bring engine and transmission up to normal operating temperature.
2. Operate vehicle with transmission range selector lever in (D) position.
3. NOTE: Shift speed ranges are approximate for all applications. For specific applications
(engine, axle ratio and application) refer to the Automatic Transmission Specification Issue,
available from Ford Customer Service Division.
Apply minimum throttle and observe speeds at which upshift occurs and torque converter
engages; refer to the 4R70W Shift Speeds chart in this section.
4. With the transmission in Overdrive (fourth gear), press the transmission control switch. The transmission should downshift to third gear. Release the accelerator pedal; engine braking
should occur.
5. Press accelerator pedal to floor, wide open throttle (WOT). Transmission should shift from third to second gear, or third to first, depending on vehicle speed. Torque converter clutch should
disengage and then reapply.
6. With the transmission in (D) position and speed above 80 km/h (50 mph) and less than half throttle, move the transmission range selector lever from (D) position to manual 2 position and
remove pressure from the accelerator pedal. Transmission should immediately downshift into
second gear. With vehicle remaining in manual 2 position, move the transmission range selector
lever into manual 1 position, and release accelerator pedal. Transmission should downshift into
first gear at speeds approximately below 45- 56 km/h (28-35 mph).
7. If transmission fails to upshift/downshift or torque converter clutch does not apply and release, refer to Diagnosis By Symptom in this section.
SECTION 307-
01: Automatic Transaxle/Transmission 2003 Mustang Workshop Manual Shift Speeds 4.6L 4V MACH 1 (3.55:1
Axle Ratio)
Throttle Position Shift MPH Km/H
Light throttle 1-
2 10-14 16-23
TP voltage 2-
3 18-22 29-35
1.25 volts 3-
4 34-37 55-60
Closed throttle 4-
3 22-25 35-40
3-2 12-16 19-26
2-1 11-7 18-11
Wide open throttle 1-
2 36-44 58-71
2-3 75-83 121-134
3-2 70 113
2-1 33 53
Shift Speeds 4.6L 2V HO (3:27:1 Axle Klj . 1 ba
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DIAGNOSIS AND TESTING
Torque Converter Diagnosis
Prior to the installation of a new or remanufactured torque converter, all diagnostic procedures must be
followed. This is to prevent the unnecessary installation of torque converters. Only after a complete
diagnostic evaluation can the decision be made to install a new or remanufactured torque converter.
Begin with the normal diagnostic procedures as follows:
1. Preliminary inspection.
2. Know and understand the customer's concern.
3. Verify the condition — carry out the torque converter operation test.
4. Carry out diagnostic procedures.
z Carry out on- board diagnostics; refer to Diagnostics.
„ Repair all non- transmission related DTCs first.
„ Repair all transmission DTCs.
„ Rerun on- board diagnostic to verify repair.
z Carry out Line Pressure Test. For additional information, refer to Special Testing Procedures in
this section.
z Carry out Stall Speed Test. For additional information, refer to Special Testing Procedures in
this section.
z Carry out Diagnostic Routines. For additional information, refer to Diagnosis By Symptom in this
section.
„Use the Diagnosis by Symptom Index to locate the appropriate routine that best
describes the symptom(s). The routine will list all possible components that may cause or
contribute to the symptom. Check each component listed; diagnose and repair as
required before changing the torque converter.
Torque Converter Operation Test
This test verifies that the torque converter clutch control system and the torque converter are operating
correctly. 5. Carry out Quick Test with scan tool. For additional information, refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual. Check for DTCs.
6. Connect a tachometer to the engine.
7. Bring the engine to normal operating temperature by driving the vehicle at highway speeds for approximately 15 minutes in (D) position.
8. After normal operating temperature is reached, maintain a constant vehicle speed of about 80 km/h (50 mph) and tap brake pedal with the left foot.
9. Engine rpm should increase when brake pedal is tapped, and decrease about five seconds after pedal is released. If this does not occur, see torque converter operation concerns. For additional
information, refer to Diagnosis By Symptom in this section.
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DIAGNOSIS AND TESTING
Visual Inspection
This inspection will identify modifications or additions to the vehicle operating system that may affect
diagnosis. Inspect the vehicle for non-
Ford factory add-on devices such as:
z electronic add- on items:
„ air conditioning
„ generator (alternator)
„ engine turbo
„ cellular telephone
„ cruise control
„ CB radio
„ linear booster
„ backup alarm signal
„ computer
z Vehicle modification:
These items, if not installed correctly, will affect the powertrain control module (PCM), or transmission
function. Pay particular attention to add- on wiring splices in the PCM harness or transmission wiring
harness, abnormal tire size, or axle ratio changes.
zLeaks; refer to Leak Inspection.
z Correct linkage adjustments; refer to Section 307 - 05 .
Shift Linkage Check
Check for a misadjustment in shift linkage by matching the detents in the transmission range selector
lever with those of the manual lever in the transmission. If they match, the misadjustment is in the
indicator. Do not adjust the shift linkage.
Hydraulic leakage at the manual control valve can cause delay in engagements and/or slipping while
operating if the linkage is not correctly adjusted. Refer to Section 307 - 05 for shift linkage adjustment.
Check TSBs and OASIS
Refer to all technical service bulletins (TSB) and OASIS messages which pertain to the transmission
concern and follow the procedure as described.
Carry Out On- Board Diagnostics (KOEO, KOER)
After a road test, with the vehicle warm and before disconnecting any connectors, carry out the Quick
Test using the scan tool. Refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual. SECTION 307-
01: Automatic Transaxle/Transmission 2003 Mustang Workshop Manual Klj . 1 ba
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DIAGNOSIS AND TESTING
Diagnostics
SECTION 307-
01: Automatic Transaxle/Transmission 2003 Mustang Workshop Manual Special Tool(s)
Transmission Fluid Pressure
Gauge
307-
004 (T57L-77820- A) Air Test Plate, Transmission
307-
246 (T92P-7006- A) Alignment Gauge, TR Sensor
307-
351 (T97L-70010- A) Breakout Box, EEC-V Control
System
418- 049 (T94L-50- EEC-V) or
equivalent MLP-
TR Cable
418- F107 (007- 00111) or
equivalent Worldwide Diagnostic System
(WDS)
418-
F224
New Generation STAR (NGS)
Tester
418- F052 or equivalent scan
tool Transmission Tester
307-
F016 (007- 00130) or
equivalent Trans Tester TR/MLP Overlay Klj . 1 ba
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DIAGNOSIS AND TESTING
Output State Control (OSC) Mode
Output State Control (OSC) allows the technician to take control of certain parameters to function the
transmission. For example, OSC allows the technician to shift the transmission only when he/she
commands a gear change. If the technician commands 1st gear in OSC, the transmission will remain
in 1st gear until the technician commands the next gear. Another example, the technician can
command a shift solenoid to turn on or off when carrying out an electrical circuit check. OSC has two
modes of operation for transmission, the BENCH MODE and the DRIVE MODE. Each
mode/parameter has a unique set of vehicle operating requirements that the technician is required to
meet before being allowed to operate OSC.
NOTE:
To operate OSC the digital transmission range (TR) sensor must be operational. No Diagnostic
Trouble Codes (DTCs) related to the digital TR sensor can be present.
To operate OSC the vehicle speed source must be operational. No diagnostic codes (DTCs) related to
this source can be present. The vehicle speed source can vary depending on vehicle configuration.
Technicians should verify which input source is applicable for their vehicle application. The following
are potential vehicle speed sources:
„anti- lock braking system (ABS)
„ output shaft speed (OSS) sensor
„ vehicle speed sensor
z The vehicle requirements MUST BE MET when SENDING the OSC value. Refer to individual
test modes for vehicle requirements.
z If the vehicle requirements are NOT MET when SENDING the OSC value, an ERROR
MESSAGE will appear. When the ERROR MESSAGE is received, OSC is aborted and must be
restarted.
z If AFTER SENDING an OSC value, and the vehicle requirements are no longer met, the PCM
will cancel the OSC value and NO ERROR message will appear. Once the vehicle requirements
are met again, the PCM will automatically SEND the previous OSC value without any additional
actions required by the service technician.
z The OSC value XXX may be sent anytime to cancel OSC.
Output State Control (OSC) Procedures
zCarry out visual inspection and vehicle preparation as required.
z Select "Vehicle and Engine Selection" menu.
z Select appropriate vehicle and engine.
z Select "Diagnostic Data Link."
z Select "Powertrain Control Module."
z Select "Output Test Mode."
z Select "KOEO On- Demand Self Test and KOER On- Demand Self Tests."
z Carry out test and record DTCs.
z Repair all NON- Transmission DTCs.
z Repair all digital TR Sensor DTCs.
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DIAGNOSIS AND TESTING
Diagnostic Trouble Code Charts
SECTION 307-
01: Automatic Transaxle/Transmission 2003 Mustang Workshop Manual Diagnostic Trouble Code Chart
Five
Digit
DTC Component Description Condition Symptom Action
P0102
P0103
P1100
P1101 MAF MAF concerns MAF system has a
malfunction which
may cause a
transmission
concern. High or low EPC
pressure, incorrect
shift schedule.
Incorrect torque
converter clutch
engagement
scheduling.
Symptoms similar
to a throttle position
(TP) failure. REFER to the
Powertrain
Control/Emissions
Diagnosis (PC/ED)
manual.
P0112 IAT IAT indicates
125°C (257°F)
(grounded) Voltage drop
across IAT
exceeds scale set
for temperature
125°C (257°F). Incorrect EPC
pressure, either
high or low, results
in harsh or soft
shifts. REFER to
thePowertrain
Control/Emissions
Diagnosis (PC/ED)
manual.
P0113 IAT IAT indicates -
40°C (-
40°F)
(open circuit) Voltage drop
across IAT
exceeds scale set
for temperature -
40°C (-
40°F). Incorrect EPC
pressure, either
high or low, results
in harsh or soft
shifts. REFER to the
Powertrain
Control/Emissions
Diagnosis (PC/ED)
manual.
P0114 IAT IAT out of on-
board
diagnostic
range IAT temperature
higher or lower
than expected
during KOEO and
KOER. Rerun on-
board
diagnostic at
normal operating
temperature. REFER to the
Powertrain
Control/Emissions
Diagnosis (PC/ED)
manual.
P0117 ECT ECT indicates
125°C (257°F) Voltage drop
across ECT
exceeds scale set
for temperature
125°C (257°F)
(grounded). Torque converter
clutch will always
be off, resulting in
reduced fuel
economy. REFER to the
Powertrain
Control/Emissions
Diagnosis (PC/ED)
manual.
P0118 ECT ECT indicates
-
40°C (- 40°F) Voltage drop
across ECT
exceeds scale set
for temperature -
40°C (-
40°F)
(open circuit). Torque converter
clutch will always
be off, resulting in
reduced fuel
economy. REFER to the
Powertrain
Control/Emissions
Diagnosis (PC/ED)
manual.
P0122
P0123
P1120 TP TP concern PCM has detected
an error that may
cause a
transmission
concern. Harsh
engagements, firm
shift feel, abnormal
shift schedule,
torque converter
clutch does not
engage, torque
converter clutch
cycling. REFER to the
Powertrain
Control/Emissions
Diagnosis (PC/ED)
manual.
P0300- Electronic EI systems EI system has a Harsh REFER to the Klj . 1 ba
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