Design

Design

control module




The transmission control module (TCM) is integrated with the gear position sensor as one unit. The unit is fitted in the top side of the gearcase on the gear selector shaft. The control module's connector is directly connected to the transmission.

Gear position sensor
The gear position sensor is integrated with the transmission control module (TCM) as one unit.
The gear position sensor informs the transmission control module (TCM) on the gear selected, and whether reverse gear is engaged to light the reversing light. The gear position sensor contains a permanent magnet and two linear Hall sensors. The gear position sensor creates a signal voltage of between 0 and 5 V which equates to current gear selector lever position.
The gear position sensor can be diagnosed.
Voltage level for the different gear positions.
P approximately 0.65 V
R approximately 1.64 V
N approximately 2.12 V
D approximately 2.62 V

Solenoid S1 and S2




The solenoids S1 and S2 are located in the transmission control system, which is fitted on the front edge of the gearbox. The solenoids are the on/off type, and consist of an electrical coil which controls a hydraulic valve. The solenoids are supplied with 12 V power via the transmission control module (TCM) and are grounded in the control system. Solenoid S1 controls certain shifting and the transmission control module (TCM) activates solenoid S2 at engine braking for 1st gear.
The solenoids can be diagnosed.

Lock-up-solenoid, SLU




The lock-up solenoid, SLU is located in the transmission control system, which is fitted on the front edge of the gearbox. The lock-up solenoid, SLU consists of an electrical coil which controls a hydraulic valve. The solenoid is controlled with a pulsed (PWM) voltage and is grounded via the Transmission Control Module (TCM). The solenoid controls torque converter lock-up engagement. The engagement takes place by means of the solenoid being pulsed in, which enables a gentle engagement of the lock-up function. The solenoid permits the torque converter to work in one of three positions: "Open", "Controlled slipping" and "Locked". The hydraulic function of the solenoid is linear.
The solenoid can be diagnosed.

Linear pressure solenoid, SLT




The linear pressure solenoid, SLT is located in the transmission control system, which is fitted on the front edge of the gearbox. The linear pressure solenoid, SLT consists of an electrical coil which controls a hydraulic valve. The solenoid is controlled with a pulsed (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 varying current resulting from the current pulse ratio. With a high pulse ratio, i.e. high current strength (approx. 1 A), the system pressure is low, and with a low pulse ratio, i.e. low current strength, the system pressure is high. In the event of an open circuit the system pressure is at a maximum which results in hard gearshifts. Here the hydraulic valve is fully open.
The solenoid can be diagnosed.

Linear pressure solenoid SLC1, SLC2, SLC3 and SLB1




The linear pressure solenoids, SLC1, SLC2, SLC3 and SLB1 are located in the transmission control system, which is fitted on the front edge of the gearbox. The designation of the solenoid is linked to the component (clutch/brake band) that the solenoid controls. The linear pressure solenoids consist of an electrical coil which controls a hydraulic valve. The solenoids are controlled with a pulsed (PWM) voltage and are grounded via the transmission control module (TCM). The hydraulic function of the solenoids is linear. The hydraulic valves are controlled by the varying current resulting from the current pulse ratio. With a high pulse ratio, i.e. high current strength (approx. 1 A), the system pressure is low, and with a low pulse ratio, i.e. low current strength, the system pressure is high. In the event of an open circuit the system pressure is at a maximum which results in hard gearshifts. Here the hydraulic valve is fully open.
The solenoids can be diagnosed.

Speed sensor, input shaft




The speed sensor for the input shaft is located inside the gearbox. The sensor is a so-called "active sensor" (Hall sensor) and is supplied with 12 V power. When the pulse wheel on clutch C2 rotates the sensor generates a pulsed current (square wave), where the strength of the current depends on the position of the pulse wheel. The signals from the coil in the sensor are then acted on by magnetic-sensitive resistance, which means that the output signal is a current which fluctuates between 6 mA and 14 mA, and whose frequency increases with speed. The transmission control module (TCM) calculates transmission speed using the signal from the sensor.
The transmission control module (TCM) uses information on input shaft speed for:
- calculating how much torque reduction shall be requested from the engine control module (ECM) with gearshifting
- comparing engine speed with input shaft speed to calculate the slipping speed of the torque converter
- calculating gearshift timing
- calculating engagement and disengagement of the lock-up function
- comparing the signal with the signal from the transmission speed sensor for the output shaft, for calculating the current gear ratio. This is performed to identify whether the value corresponds with the expected gear ratio.
The speed sensor for the input shaft can be diagnosed.

Speed sensor, output shaft




The speed sensor for the output shaft is located inside the gearbox. The sensor provides a signal to the transmission control module (TCM) on vehicle speed. The sensor is a so-called "active sensor" (Hall sensor) and is supplied with 12 V power. When the pulse wheel rotates (the wheel for shift-lock), the sensor generates a pulsed current (square wave), where the strength of the current depends on the position of the pulse wheel. The signals from the coil in the sensor are then acted on by magnetic-sensitive resistance, which means that the output signal is a current which fluctuates between 7 mA and 14 mA, and whose frequency increases with speed. The transmission control module (TCM) uses information on output shaft speed for:
- calculating how much torque reduction shall be requested from the engine control module (ECM) with gearshifting
- comparing engine speed with output shaft speed to calculate the slipping speed of the torque converter
- calculating gearshift timing
- calculating engagement and disengagement of the lock-up function
- comparing the signal with the signal from the transmission speed sensor for the input shaft, for calculating the current gear ratio. This is performed to identify whether the value corresponds with the expected gear ratio.
The speed sensor for the output shaft can be diagnosed.

Oil temperature sensor




The temperature sensor is the NTC type. The temperature sensor is located on the transmission control system inside the side cover and measures the temperature of the transmission oil in the pan. The temperature sensor is an integrated part of the cable harness. The temperature sensor is supplied with 5 V and is grounded via the transmission control module (TCM). By measuring the voltage drop over the sensor's NTC resistor the control module can determine the temperature of the transmission oil. The transmission control module (TCM) uses the information on transmission oil temperature for:
- calculating transmission gearshift timing
- calculating engagement and disengagement of the lock-up function.
The transmission control module (TCM) stores the time for which the temperature has been within a certain temperature range and if a certain temperature and time has been exceeded, then a diagnostic trouble codes (DTC) is generated to indicated that an oil change is necessary.
The temperature sensor can be diagnosed.

Gear selector module (GSM)




The gear selector assembly is located in the tunnel console and is mechanically connected to the transmission via a cable that moves the shift valve in the transmission control system. The gear selector module (GSM) is located on the left side of the gear selector assembly. The control module is powered by and communicates via serial communication with the transmission control module (TCM). The gear position is indicated by a number of LEDs in the top panel of the gear selector assembly.
There is a directly connected cable from the transmission control module (TCM) to the gear selector module (GSM) which controls the shift-lock solenoid. The power supply and ground for the shift-lock solenoid are directly connected to the gear selector module (GSM).
The Gear Selector Module (GSM) can be diagnosed. In the event of a fault a signal on fault status is sent to the transmission control module (TCM) which then stores any diagnostic trouble codes (DTC).

Gear selector assembly

Gear selector assembly with Geartronic function




All gear selector assemblies are the Geartronic version. In addition to the selector positions P/R/N/D, there is also a position for "manual" shifting (Geartronic).
The gear selector has the following functions:
- P : Park
- R : Reverse
- N : Neutral
- D : Automatic shifting between all gears.
- +/- : Manual shift function. The indicators for both + and - are illuminated when manual mode is active.
- Three Hall sensors are mounted on the gear selector module (GSM). A permanent magnet on the gear selector actuates the sensors' output signals on the gear selector module (GSM).