Design

Design

Control module




The transmission control module (TCM) is positioned in an air cooled plastic box in the engine compartment together with the engine control module (ECM).

Shift solenoids S1, S2, S3, S4 and S5




The shift solenoids S1, S2, S3, S4 and S5 are positioned in the valve body in the transmission control system, which is mounted on the front edge of the transmission. The shift solenoids (on/off type), consist of an electrical coil which controls a hydraulic valve. The solenoids are supplied with 12 V via the transmission control module (TCM) and grounded in the control system. The shift solenoids control shifting and the transmission control module (TCM) determines which gear is to be used by activating them in different patterns.
There is a diagnostic for the shift solenoids.

Lock-up solenoid, SLU




The lock-up solenoid, SLU is in the transmission control system, which is mounted on the front edge of the transmission. The lock-up solenoid consists of an electrical coil which controls a hydraulic valve. The solenoid is controlled by pulse width modulation (PWM) voltage and is grounded via the transmission control module (TCM). The solenoid controls lock-up engagement of the torque converter. Engagement occurs through solenoid pulsing which provides a soft lock-up engagement function. The solenoid allows the torque converter to work in one of three modes:
- Open
- Controlled slipping
- Locked.
The hydraulic function of the solenoid is linear.
There is a diagnostic for the lock-up solenoid.

Line pressure solenoid, SLS




The line pressure solenoid, SLS is in the transmission control system, which is mounted on the front edge of the transmission. The line pressure solenoid, SLS consists of an electrical coil which controls a hydraulic valve. The solenoid is controlled by pulse width modulation (PWM) voltage and is grounded via the transmission control module (TCM). The hydraulic function of the solenoid is linear. The hydraulic valve is controlled by the varied current which is the result of the current pulse conditions. During high pulse conditions, (at high currents (approximately 1 A)) the line pressure is low. During low pulse conditions (at low currents) the line pressure is high. In the event of an open-circuit the line pressure reaches maximum which causes hard shifting. The hydraulic valve is then completely open.
There are diagnostics for the solenoid.

Line pressure solenoid, SLT




The line pressure solenoid, SLT is in the transmission control system, which is mounted on the front edge of the transmission. The line pressure solenoid, SLT consists of an electric coil which controls a hydraulic valve. The solenoid is controlled by pulse width modulation (PWM) voltage and is grounded via the control module. The solenoid is linear. The hydraulic valve is controlled by the varied current which is the result of the current pulse conditions. During high pulse conditions, (at high currents (approximately 1 A)) the line pressure is low. During low pulse conditions (at low currents) the line pressure is high. The solenoid also engages and disengages neutral control. In the event of an open-circuit the line pressure reaches maximum which causes hard shifting. The hydraulic valve is then completely open.
There are diagnostics for the solenoid.

Transmission input speed sensor (speed of the input shaft)




The transmission input speed sensor (speed of the input shaft) is on the top of the transmission housing. The sensor is an active sensor and is supplied with 12 V. When the pulse wheel on clutch C1 rotates, the sensor generates a pulsed current (quadratic wave) where the strength of the current depends on the position of the pulse wheel. The signals from the coils in the sensor are then affected by a magnetic resistance element, which generates a current which oscillates between 7 mA and 14 mA, and whose frequency increases with speed. Using the signal from the sensor, the transmission control module (TCM) calculates the transmission speed, unit rpm.
The transmission control module (TCM) uses information about the input shaft speed to calculate the torque reduction to be requested from the engine control module (ECM) when shifting. The value is also used to compare the engine speed (RPM) with the speed of the input shaft in order to calculate the slipping rate of the torque converter. The value is also compared with the transmission speed sensor signal in order to calculate the actual gear ratio. This is done to check whether the value corresponds to the expected gear ratio.
There are diagnostics for the transmission input speed sensor.

Transmission output speed sensor (speed of the output shaft)




The transmission output speed sensor (speed of the output shaft) is on the reverse of the transmission housing. The sensor provides signals to the transmission control module (TCM) about the vehicle speed. The output shaft speed sensor is an active sensor and is supplied with 12 V. When the pulse wheel (wheel for shift-lock) rotates the sensor generates a pulsed current (quadratic wave) where the strength of the current depends on the position of the pulse wheel. The signals from the coils in the sensor are then affected by a magnetic resistance element, which generates a current which oscillates between 7 mA and 14 mA, and whose frequency increases with speed. The control module calculates the transmission output speed using the signals from the sensor. The signal is compared with the signal from the transmission input speed sensor and is used to calculate the gear ratio and is also used for diagnostics.
There are diagnostics for the transmission output speed sensor.

Oil temperature sensor




The temperature sensor is an NTC sensor. The temperature sensor is on the transmission control system inside the side cover. It gauges the temperature of the transmission fluid in the oil pan. The temperature sensor is integrated in the cable harness. The temperature sensor is supplied with 5 V and is grounded via the transmission control module (TCM). The control module can determine the transmission fluid temperature by measuring the voltage drop above the NTC resistance of the sensor. The control module stores the time the temperature has been within a certain temperature range. If a certain temperature and time has been exceeded, a diagnostic trouble code (DTC) indicating that a oil change is necessary is stored.
There are diagnostics for the temperature sensor.

Gear-shift position sensor




The gear-shift position sensor is mounted on the top of the transmission housing, on the gear shift linkage rod. The gear selector contains a Park / Neutral position (PNP) switch and connectors which inform the transmission control module (TCM) about which gear is selected and if the back-up gear is selected so that the reversing lamps can be lit. The gear-shift position sensor is a position switch which is supplied via +15. A number of trailing contacts supply power to the sensor outputs. The combination of pins A, B, C and PA indicate the current gear selector position (see the table below). The trailing contacts can either be closed or open.
There are diagnostics for the gear-shift position sensor.





Table for the gear-shift position sensor
The value indicates the position of the gear-shift position sensor (A, B, C and PA), see the table.
• = High signal (open)
- = Low signal (grounded)

Gear selector module (GSM)




The gear selector assembly is in the tunnel console. It is mechanically connected to the transmission by a cable which moves the gear valve in the transmission control system. The gear selector module (GSM) is positioned on the top panel of the gear selector assembly. The gear selector module (GSM) uses serial communication to communicate with the transmission control module (TCM) to light the gear position indicator. The indication occurs via LEDs in the top panel.
The gear selector control module (GSM) communicates with the central electronic module (CEM) to activate the shift-lock. The shift-lock solenoid power supply and ground is directly connected to the gear selector module (GSM).
The "W" switch in the gear selector assembly top panel is positioned on the printed circuit board for the gear selector module (GSM) and activates Winter mode.
There are diagnostics for the gear selector module (GSM). Diagnostic trouble codes (DTCs) are stored in the transmission control module (TCM) in the event of a fault.

Gear selector assembly for AW55-50
There are two new types of gear selector assembly for the AW55-50. There is one gear selector assembly with seven positions and one with the Geartronic-function.

Gear selector assembly with 7 positions




The gear selector has seven positions with the following functions:
- PPark position
- RReverse position
- NNeutral position
- DAutomatic shifting between all gears. (Does not apply when the mode selector is in winter mode (W), for further information see, Function/Shifting program/Winter mode)
- 4Fifth gear is blocked in this mode
- 3Fourth and fifth gear are blocked in this mode
- LOnly first and second gear function in this mode. (Speed variation depends on which engine the transmission is working with and does not apply when the mode selector is in winter mode (W), for further information see, Function/Shifting program/Winter mode).

Gear selector assembly with Geartronic function




The gear selector assembly with Geartronic has a unique appearance and function. In addition to P/R/N/D modes it also has "manual" (MAN) shifting mode.
The gear selector for Geartronic has the following functions:
- PPark position
- RReverse position
- NNeutral position
- DAutomatic shifting between all gears. (Does not apply when the mode selector is in winter mode (W), for further information see, Function/Shifting program/Winter mode)
- MANManual shifting. There are three hall sensors on the gear selector module (GSM). A permanent magnet on the gear selector lever affects the output signals of the sensors to the gear selector module (GSM).