Vauxhall Workshop Service and Repair Manuals

Additional Functions of Easytronic (M20 MTA)

Reducing System Pressure in the MTA Hydraulic System. TECH 2 main menu: "Programming", submenu: "Drain accumulator

When carrying out some jobs on the MTA system, it is essential for safety reasons to release the system pressure. The system pressure can only be released using TECH 2. It is essential that the instructions in Tech 2 are followed. If the exact sequence of the individual steps in Tech 2 is not followed, the system pressure may, in some circumstances, build up again.

If there are communication problems between TECH 2 and the TCU of the MTA system or the pressure sensor of the MTA system is defective, it is not possible to relieve the system pressure in the MTA system. In such cases, the entire MTA system must be replaced (with the transmission removed). It is absolutely forbidden to open the pressure lines of the MTA system and repair or replace individual components. The safety guidelines for the M20 MTA transmission must be followed .

Generating System Pressure - MTA Hydraulic System

If the hydraulic pressure in the MTA system is below the required working pressure, there are 2 ways of generating pressure in the MTA system:

• By opening the driver's door; the system actuates the high-pressure pump in response to the information received from the door contact switch, and the pressure in the MTA system is increased to the required system pressure.
• By switching on the ignition; this action applies voltage to the MTA and the required system pressure is generated via the high-pressure pump.

Functions When the Engine is Switched Off

For safety reasons, each gear selection process performed via the selector lever when the engine is off and the ignition is switched on is only actually carried out if the brake is depressed. Only 1st gear, reverse gear and neutral can be engaged when the engine is switched off and the ignition switched on.

Emergency Start with Weak Battery

If the battery does not have sufficient power to start the engine, it is possible to perform an emergency start with a weak battery, provided the required system pressure is already present in the MTA system. The vehicle can be pushed with the ignition on and the transmission in neutral and then 1st or 2nd gear can be engaged via the selector lever once sufficient speed has been reached.

Ignition, Request to Start, Enabling of Starter

The start enable for the engine is issued by the MTA via the CAN (provided that the CIM has sent the request to start via the CAN and that the brake is depressed). When the brake is depressed, MTA automatically engages N and issues the start enable.

The Request to Start involves an input signal which transmits the driver's request to start the engine (ignition lock in position 3). The control unit does not, however, respond immediately to this engine start request by issuing a Starter Enable command. It first checks the starter conditions. If these conditions are met, the control unit closes the starter enabling relay and the engine starts. The following conditions must be met:

• Selector lever in neutral position and transmission in neutral
• Footbrake must be depressed

Starting Off with Engine Running

When the engine is running and the vehicle is stationary, 1st gear, 2nd gear and reverse gear can be selected with the brake depressed in order to start off. To select reverse gear, the vehicle must be stationary (transmission input speed = 0). After releasing the brake, the vehicle will start to creep. In this process, the clutch is operated slowly by the MTA system and vehicle speed is kept to approx. 5 km/h. Each of the 3 gears has a special curve for engaging the clutch stored in the control unit. To accelerate, the driver can use the accelerator to meter the torque transmitted via the clutch.

ABS and Number of Wheel Revolutions

Depending on the vehicle configuration the control unit receives the rpm of the right/left front wheels from the ABS control unit or from a converter box via High-Speed CAN-bus. If the vehicle has ABS, in addition, the information ABS active is sent to the control unit. If braking to a standstill when the ABS signal is active, the clutch is opened immediately by the control unit on safety grounds to interrupt the drive.

Selector Lever

The system uses an electronic selector lever which communicates with the MTA control unit via a serial interface. The driver sends his driving/gear change requests to Easytronic via the selector lever. The selector lever for the MTA transmission must always be moved to the stop in each direction. After actuation, it will return automatically to the centre position. Therefore, it is important to keep an eye on the gear or mode display in the transmission display.

The gears can be changed manually in manual mode. "M" appears in the transmission display along with the actual gear engaged. If the engine speed is too low the MTA control unit also switches to a lower gear in manual mode. This prevents the engine from stalling.

Shift selector lever "+" or "-"

• shift to higher gear
• "-" = shift to lower gear

If the driver chooses to shift down to a gear which is too low, the gear will not change. This prevents over or under-revving. Repeated short, consecutive movements of the selector lever will cause the transmission to shift through the gears. If the vehicle is in automatic mode, when selecting "+" or "-" the MTA controller changes to manual mode as the selector lever is actuated. "M" and the current gear are displayed in the transmission display.

Shift selector lever to "A"

Enables switching between automatic and manual modes.

Shift selector lever to "R"

Engage reverse gear only when the vehicle is at a standstill. Reverse gear is engaged by actuating the selector lever while depressing the foot brake. "R" appears in the transmission display. The vehicle starts to creep after the foot brake is released. It is possible to start in reverse gear without actuating the foot brake only when the gas pedal is actuated directly after actuating the selector lever. If the gas pedal is not actuated immediately no gear is engaged ("R" flashes). Shift the selector lever to "N" and repeat start by shifting the selector lever to "R" after first actuating the foot brake

Sport mode

In Sport mode the MTA uses special shift characteristics and a more sporty configuration for clutch control. A gear symbol with an "S" in the centre is displayed when Sport mode is active.

It is only possible to engage Sport mode when

• MTA is not in the emergency running program (limp-home).
• winter mode is deactivated. Sport mode is deactivated when winter mode is activated.
• the control unit reacts to the Sport mode request and switches to Sport mode.

While Sport mode is active, kickdown starts are performed as sprint starts.

Winter mode

Winter mode is activated and deactivated by a button. It is no longer possible to select 1st gear (exception: Kickdown). The vehicle starts in 2nd gear. When the winter program is selected in manual mode, automatic mode is activated. If the selector lever is shifted to "N" or "R" and back to "A" in winter mode, winter mode is retained.

When switching to manual mode, winter mode is retained. After returning to "A" it is saved. Winter mode can also be activated/deactivated using the Winter button.

Note:   Winter mode is deactivated at clutch temperatures over 260 ° Celsius.