Workshop

HYDRA – MATIC 4L40 – E / 5L40 – E

Figure 8
A. THROTTLE POSITION SENSOR (TPS)
B. MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
C. ENGINE SPEED SENSOR
D. MANIFOLD AIR TEMPERATURE (MAT) SENSOR
E. ENGINE COOLANT TEMPERATURE (ECT) SENSOR
F. INPUT SPEED SENSOR (ISS)
G. OUTPUT SPEED SENSOR (OSS)
H. TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR
I. INTERNAL MODE SWITCH (IMS)
J. ACCELERATOR PEDAL POSITION (APP) SENSOR
K. TCC BRAKE SWITCH
1. PRESSURE CONTROL
SOLENOID
2. TCC/PWM SOLENOID
3. 1-2 SHIFT SOLENOID
4. 2-3 SHIFT SOLENOID
5. 4-5 SHIFT SOLENOID
* TRANSMISSION CONTROL
MODULE (TCM) SOME MODELS
* POWERTRAIN CONTROL
MODULE (PCM)
* ENGINE CONTROL
MODULE (ECM) SOME MODELS
* BODY CONTROL
MODULE (BCM)
* DIAGNOSTIC LINK
CONNECTOR (DLC)
TRANSMISSION COMPONENTSTRANSMISSION COMPONENTSELECTRONIC CONTROLLERSELECTRONIC CONTROLLERSINFORMATION SENSORSINFORMATION SENSORS
ELECTRICAL COMPONENTS
Electrical signals from various sensors provide information to the TCM or PCM, about vehicle speed,
throttle position, engine coolant temp, range selector position, engine speed and converter turbine speed.
The TCM or PCM uses this information to determine upshift and downshift speeds, apply or release of the
TCC and what fluid pressure is needed to apply the clutch packs. This type of control provides consistent
shift points and shift quality based on the operating conditions of the vehicle.
If for any reason the entire electronic control system of the transmission becomes disabled, all three shift
solenoids will be turned off. This "Safety Mode" operating state forces the transmission to operate in 5th
gear when the range selector is in any forward range. Also, the pressure control solenoid is turned off which
will increase line pressure to the maximum.
Note: Some models use an Engine Control Module (ECM) and a Transmission Control Module (TCM)
and some models use a Powertrain Control Module (PCM) for both engine and transmission
management.
AUTOMATIC TRANSMISSION SERVICE GROUP
Technical Service Information
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