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Brief description FA 57

Brief description FA 57


Automatic transmission FA 57 is an electronically controlled 5 stage automatic transmission with lock-up function and facility to shift manually.

The FA 57 is principally constructed around 4 planetary gear units, disc clutches, torque converter with lock-up coupling, hydraulic control system and an electronic control system.

The gearbox is controlled by a control module (TCM), which continuously processes information from its own sensors as well as from other control modules. On the basis of this processed information, it controls the transmission hydraulic system.

The FA 57 has the following advantages over conventional hydraulic transmission:


• Improved shifting performance and smoother shifting as torque is reduced when shifting takes place.

• Reduced mechanical stresses on the entire drive train due to torque limitation.

• Improved fuel economy thanks to driving programmes optimizing fuel consumption as well as lock-up in 3rd, 4th and 5th gears. To improve fuel economy further, the lock-up clutch is allowed to slip. This means that a difference of 50 and 200 rpm is permitted between the engine speed and the input shaft speed. This is only permitted at low engine loads. The engine then pulls for longer with slipping lock-up and the transmission does not need to disengage lock-up (transfer power through the torque converter). Slipping lock-up is the primary reason for a high-grade transmission fluid. If the temperature of the transmission fluid rises, a temperature-dependent program is automatically selected, protecting the gearbox from heat damage. See Temperature sensor, transmission fluid .

• Possibility to choose between driving programs: Normal, Sport, Winter and Manual.

• Self-diagnosis and storage of diagnostic trouble codes.



• TCM sends and receives information from other control modules in the car via analogue signals and bus communication, see Bus communication


User recommendations

The selector lever has six positions for petrol-engined cars: P, R, N, D, M and L

and seven positions for cars with 2.2 l diesel engine: P, R, N, D, 4, 3,

Selector lever position P

Position P must only be selected when the car is stationary. The selector lever and the transmission are both locked. The engine can be started.

Selector lever position R

Position R must only be selected when the car is stationary. This position cannot be selected without lifting the selector lever detent.

Wait a moment before depressing the accelerator to give the reverse gear time to engage properly.

In order to protect the transmission against damage reverse gear cannot be engaged if the car is being driven forward at a speed exceeding 7 km/h. This is achieved by the release of brake B3 that is normally applied when reversing.

Selector lever position N

The transmission is in neutral when N is selected. The engine can be started. The handbrake must be applied to prevent the car from moving.

To avoid excessively high engine and transmission temperatures, N should be selected when the car is at a standstill for lengthier periods.

NOTE! Never select the N position when the car is being driven. This can result in damage to the transmission.

Selector lever position D

Position D is the normal driving position. When engaging a gear wait for a moment before accelerating so that the gear position has time to engage. The transmission will change gear automatically between gears 1-5.

Selector lever position 4 (diesel)

In this position, 5th gear is blocked. The car starts in 1st gear and then shifts automatically between gears 1-4.

If the lever is moved from position D to position 4, downshifting to 4th gear takes place and engine braking is improved. The selector lever should not be moved to this position at speeds above 150 km/h.

Selector lever position 3 (diesel)

This position is preferable when driving in mountainous areas with a heavily laden car. Engine power is utilised more efficiently and engine braking is improved. The transmission shifts automatically between 1st and 3rd gears. Gears 4 and 5 are blocked. The selector lever should not be moved to position 3 at speeds above 125 km/h.

Selector lever position M

Gear shifting up and down is possible manually in position M via two buttons located on the left and right sides of the airbag module in the steering wheel in the same switch panel which controls the radio. One press on the left button (-) produces a downshift and one press on the right button (+) produces an upshift from the gear position, on condition that TCM allows shifting for the current speed.

TCM sends a bus message concerning the selected gear that MIU uses and indicates which gear is currently engaged on its display with a number (1-5). This is shown immediately to the left of the ordinary gear position display (P,R,N,D,M,L). The gear change must be completed before the next up or downshifting can take place. When position M is selected a more sporty feeling is obtained. Note however that if the SPORT button is pressed in when the selector lever is in the D position, the text "Sport" fades out in the MIU when the selector lever is moved to position M.

The following limitations and conditions have been introduced to increase road safety and to protect the engine and transmission:

If the driver forgets or fails to change up during full acceleration and the speed exceeds certain criteria for the selected gear, TCM will change up automatically to the next gear.

If the driver forgets or fails to change down even though the speed is far below the lower speed limit for the selected gear, TCM will automatically select a lower gear to avoid dangerous situations such as the driver attempting to pull away in fifth gear.

If the driver requests full torque in e.g. 4th or 5th gear and the engine speed is below 2,000 rpm, TCM will respectively change down to 3rd or 4th gear to ensure safe overtaking for example. Shifting from 3rd to 4th gear and from 4th to 5th gear can take place when the engine speed rises above 2,000 rpm. The driver can choose to pull away in first, second or third gear but not in fourth or fifth gear. The gears can be shifted up or down manually even when cruise control is activated.

Selector lever position L

Position L should be selected when a powerful engine braking effect on very steep hills is required or when starting with a heavy load on a steep incline. The transmission shifts down to 1st gear at 35 km/h. Following which 1st gear is maintained.

If the selector lever is moved from position D to position L an immediate downshift to 4th gear takes place if speed is 175 km/h or less. If the lever is moved from position D or M at higher speeds downshifting takes place automatically. This takes place in steps via gears 4, 3 and 2 to gear 1 depending on the speed of the car. This position should be used with heavy loads downwards on steep hills to save the brakes and protect the power train.

Towing

The following rules must be observed when towing a car that has automatic transmission:


1. The car must only be towed in a forward direction (front wheels leading). Towing backwards causes transmission failure!

2. The selector lever must be in position N.

3. National regulations governing towing speeds must be complied with.

If laws permit the highest towing speed allowed is 50 km/h. The longest towing distance allowed is 50 km. If the car needs to be towed further than this, its front wheels must be raised off the ground.

4. The engine cannot be started by pushing or towing the car.