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
42003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...
DIAGNOSIS AND TESTING
Diagnostic Strategy
Troubleshooting an electronically controlled automatic transmission is simplified by using the proven
method of diagnosis. One of the most important things to remember is that there is a definite
procedure to follow.
NOTE:
Do not take any short cuts or assume that critical checks or adjustments have already been
made.
Follow the procedures as written to avoid missing critical components or steps.
To properly diagnose a concern have the following publications available:
zTransmission Reference Manual.
z Powertrain Control/Emissions Diagnosis (PC/ED) manual.
z TSBs and OASIS Messages.
z Wiring Diagram.
These publications provide the information required when diagnosing transmission concerns.
Use the Diagnostic Flow Chart as a guide and follow the steps as indicated.
Preliminary Inspection
zKnow and understand the customer's concern.
z Verify the concern by operating the vehicle.
z Check the fluid levels and condition.
z Check for non-factory add- on items.
z Check shift linkages for proper adjustment.
z Check TSBs and OASIS messages regarding the concern.
Diagnostics
zCarry out on- board diagnostic procedures key on engine off (KOEO) and key on engine running
(KOER).
z Record all diagnostic trouble codes (DTCs).
z Repair all non- transmission codes first.
z Repair all transmission codes second.
z Erase all continuous codes and attempt to repeat them.
z Repair all continuous codes.
z If only pass codes are obtained, refer to Diagnosis By Symptom for further information and
diagnosis.
Follow the diagnostic sequence to diagnose and repair the concern the first time. SECTION 307-
01: Automatic Transaxle/Transmission 2003 Mustang Workshop Manual Klj . 1 ba
22003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...