Transmission - Design and Function: Other Volvo S80 I

General

The on-board diagnostic (OBD) system was introduced to improve driver safety and to protect the Transmission. Furthermore, it allows for driving with reduced function (through the "Fail Safe Mode" and "Limp-home" programs).

The Transmission Control Module (TCM) has an integrated diagnostic function which checks its own function, the function of all connected components and cables and that the anticipated messages are received. In event of a fault information is stored in the form of Diagnostic trouble codes (DTCs).

If the Transmission Control Module (TCM) detects a fault a diagnostic trouble code (DTC) is stored. If the fault is serious "Limp-home" intervenes to Protect The Transmission from damage. (For information about "Limp-home" refer to the In and output signals, Illustration 2).

At the same that a diagnostic trouble code (DTC) is generated the system stores the relevant parameters with The Diagnostic Trouble code (DTC) as a "Freeze Frame".

The fault message is transmitted on the network and picked up by the affected modules. The signal for to activate the fault message travels to the Driver Information Module (DIM) via the Central Electronic Module (CEM) so that the check and warning lamps begin indication and a fault message is displayed.

Diagnostic trouble codes (DTCs) are read off via the On board diagnostic system OBD II output using VIDA. Diagnostic trouble codes (DTCs), guided fault-tracing and repair instructions are accessible via the symptom input in VIDA.

Activating components and functions

There are four components and functions which can be activated to make servicing easier

1. Shift solenoid S1
2. Shift solenoid S2
3. Line pressure solenoid STH
4. Lock-up solenoid SL

Emergency programs

The Transmission Control Module (TCM) automatically takes certain corrective steps to protect the transmission and maintain as much driveability as possible.

The Transmission Control Module (TCM) makes an evaluation of whether the discovered fault is critical for safety or not, in the same way as previously. There are different emergency programs depending on the type of fault and how serious it is

1. Emergency program 1 No lock-up function Check and warning lamps flash for certain diagnostic trouble codes (DTCs)

1. Emergency program 2 As above with no line pressure solenoid STH control (hard gearshifts). Indicator and warning lamps flash.

1. Emergency position " Limp-home" Interrupted activation of all solenoids (hard gearshifting, impossible to drive in certain gears). Indicator and warning lamps flash.

Note. Note that diagnostic trouble codes (DTCs), standard symptoms and help functions are liable to change.

Scheme 1276

Main components

The gear selector assembly is a more complicated version than previously. Partially because there are more electronics and partially because two special functions have been developed (keylock and shiftlock).

The 4T65EV gear selector assembly is available in two variants, standard and Geartronic. Many functions are common, but the Geartronic gearbox has more functions.

In Geartronic the engaged gear in MAN is displayed in a window in the combined instrument panel tachometer. In case of a fault in the transmission a diagnostic trouble code (DTC) is generated and displayed in the combined instrument Panel.

As well as the ordinary gear shift positions, the "Winter "(W) program can be selected."The "Winter" program can be used when starting and driving on slippery surfaces. The WINTER program is engaged manually using a button beside the gear selector lever (8).

Gear shift position with Geartronic

The following gear shift positions are available with Geartronic: P, R, N, D and MAN . Four gear shift positions can be selected in manual position.

MAN position is engaged from D position by moving the gear selector lever backwards. Using the spring the lever is inserted in the gear position MAN where the gear which was engaged in D position is fixed. By moving the gear selector lever forward or backwards manual up and downshifting is achieved.

"Kick-down" also functions in MAN position.

GSM

The gear selector assembly, solenoid and printed circuit board together constitute the gear selector module and it is a slave module to the Transmission Control Module (TCM).

Information between the gear selector module and the Transmission Control Module (TCM) is transferred using serial communication, which requires a micro processor located on the printed circuit board.

The Transmission Control Module (TCM) gives instructions to the gear selector module about which LEDs should be lit up and to what strength of illumination. In addition the Transmission Control Module (TCM) controls the solenoid connection at the reverse inhibitor.

The gear selector module provides the Transmission Control Module (TCM) with information about the position of the "Winter" button and controls the connection of the solenoid for the reverse inhibitor function. In Geartronic information is sent about the gear shift position in MAN and if the gear selector lever is moved backwards or forwards.

The gear selector module is connected to the transmission diagnostic system.

Cables

Gear shift cables

The cable casing and ends are fixed with snap fasteners at the gear selector assembly and on the transmission which makes it easy to install and remove the cables (10).

The cable is adjusted at the transmission using a clip.

Ignition switch interlock cable

There is a ignition switch interlock cable (9) between the ignition switch and the gear selector assembly.

Park/neutral position (PNP) switch and ignition switch lock

Park/neutral position (PNP) switch and ignition switch lock are two safety systems which operate independently of each other.

The shiftlock is an electro- mechanical system which operates with the gear selector assembly solenoid (1).

The keylock is an active, completely mechanical system which is connected to the ignition switch interlock cable (9) between the gear selector assembly and ignition switch.

To be able to move the gear selector lever from position P , the ignition key must be in the ignition position and the brake pedal must be depressed (shiftlock).

In order to be able to remove the ignition key from the lock cylinder the gear selector lever must be in the P position (ignition switch lock).

Scheme 1277

Power flow

At fourth the engine torque is reduced through the planetary trains.

Power is transferred from the turbine shaft via the driven chain wheel (1) to the input shaft (2). The shaft is connected by the 2nd clutch (C2) to the clutch housing (10) to which one end of the reverse drum is connected. The other end of the drum is connected to the front planetary train (P1) ring gear (4).

3 rd clutch (C3) is engaged but does not transfer any power because the freewheel 1 (F1) freewheels.

4th clutch (C4) is connected to the 4th clutch shaft (11) and to the transmission housing. The sun wheel (3) for the front planetary train (P1) is connected to the shaft and is therefore held stationary. The planetary gear holder (4) rotates around the fixed sun gear.

The servo (7) locks brake 3 (B3) around freewheel 3 (F3) which is held secure. F3 freewheels and does not therefore have a function but is only engaged in preparation for downshifting. The rear planetary train planetary gear carrier is therefore able to rotate.

The front planetary train (P1) planetary gear rotates and takes the ring gear (1) with it, which rotates at a higher speed. The front planetary train (P1) ring gear (5) is connected to the rear planetary train (P2) planetary gear carrier(5).

Finally the rear planetary gear carrier (5) transfers the power to the output shaft via the final drive sun gear shaft (8), the planetary gear carrier on to the differential gear.

Scheme 1278

Power is transferred from the turbine shaft to the driven chain wheel (1) to which is connected to the input shaft (2). The shaft is connected to the input clutch (C1) which grips the second freewheel (F2) outer bearing track.

The freewheel clutch in F2 transfers power to the front planetary train (P1) sun gear (3). At engine braking the freewheeling connection disengages and F2 freewheels. The car can then roll freely.

The servo (12) locks brake 1 (B1) around the 2nd clutch housing (13) so that it is fixed. This means that the reverse drum (10), which is connected to the housing, is also held in place. The other end of the drum is connected to the front planetary train (P1) planetary gear carrier (4) which is also held in position.

The front planetary train (P1) sun gear (3) drives the front ring gear (5) via the planetary gears in the held planetary gear carrier (4). The ring gear will therefore spin in the opposite direction to the sun wheel.

The front planetary train (P1) ring gear is connected to the rear planetary train (P2) planetary gear carrier(5) which will rotate. The output planetary train (P2) planetary gear holder is coupled with the final drive sun wheel shaft (8). The torque moves to the differential via the final drive planetary gear carrier.

Scheme 1279

The planetary trains operate reductively, engine torque is increased through the planetary trains.

Power is transferred from the turbine shaft to the driven chain wheel (1) to the input shaft (2). The shaft is connected to the input clutch (C1) which grips the second freewheel (F2) outer bearing track.

The freewheel clutch in F2 transfers power to the front planetary train (P1) sun gear (3). At engine braking the freewheeling connection disengages and F2 freewheels. The car can then roll freely.

The servo (7) locks brake 3 (B3) around freewheel 3 (F3) which is held secure. Freewheel 3 holds the rear planetary train (P2) sun gear drum (6) via the free wheel clutches.

From the sun gear (3) the torque is transferred, via the planetary gear, to the front planetary gear carrier (4) which is connected to the rear planetary train (4) ring gear. The planetary gears transfer the power to the rear planetary train (P2) planetary gear carrier (5). The planetary gear carrier rotates around the rear sun gear drum (6).

The rear planetary gear carrier (5) transfers power to the final drive sun gear shaft (8). The power is transferred from the sun gear (9) to the planetary gears which rotate in the final drive. The final drive ring gear is held stationary by the transmission housing. Torque is transferred from the planetary gear carrier to the large differential gears in the differential and then out to the output shaft.

Engine brake

In gear shift position 1 the power flow is as described below, with the difference that 3rd clutch (C3) and freewheel 1 (F1) are connected. When engine braking the power reverses via 2 and C3 instead of over freewheel 1 (F2) and the input clutch (C1). Connecting brake 2 (B2) occurs using a servo (17). Brake 2 allows engine braking by locking the rear sun gear drum (6) which would otherwise freewheel using freewheel 3 (F3).

If the transmission is equipped with Geartronic the power in the first manual gear will take the same route as in gear shift position 1.

Scheme 1280

As with first gear, the planetary trains function reductively, in other words torque from the engine increases.

Power is transferred from the turbine shaft to the driven chain wheel (1) to which is connected to the input shaft (2). The shaft is connected to 2nd clutch (C2). One end of the reverse drum (10) is connected to the 2nd clutch housing The other end of the drum is connected to the rear planetary train (P2) ring gear (4).

The input clutch (C1) is engaged and connected to the outer freewheel 2 (F2) bearing cap. The freewheeling clutches are in the open position and F2 freewheels.

The servo (7) locks brake 3 (B3) around freewheel 3 (F3) which is held secure. Freewheel 3 holds the rear planetary train (P2) sun gear drum (6) via the free wheel clutches.

The rear planetary train (P2) forces the its planetary gear carrier (5) to, via the planetary gear, rotate around the fixed sun gear (6).

The rear planetary gear carrier (5) transfers the power via the final drive sun gear shaft (8) via the planetary gear carrier on to the differential gear and finally to the output shaft in the same way as first gear.

In gearshift position 2 the power flow is the same as is described above with the one difference that brake 2 (B2) is locked using a servo (17). Brake 2 allows engine braking by locking the rear sun gear drum (6) which would otherwise freewheel using freewheel 3 (F3). Brake 3 (B3) is connected but has no function.

Note. If the transmission is equipped with Geartronic the power in the second manual gear will take the same route as in second gear in gear shift position 2.

Scheme 1281

When 3rd gear is engaged both planetary trains will rotate at the same speed which gives a 1:1 gear ratio to the final dive. Torque is unchanged when it has passed the planetary trains.

Power is transferred from the turbine shaft via the driven chain wheel (1) to the input shaft (2). The shaft is connected by the 2nd clutch (C2) to the clutch housing (10) to which one end of the reverse drum is connected. The other end of the drum is connected to the front planetary train (P1) ring gear (4).

The input shaft is connected to 3rd clutch (C3) which transfers power to the outer bearing cap at the freewheel 1 (F1). The power is then transferred to the front planetary gear (P1) sun wheel (3). The sun gear rotates at the same speed as the input shaft.

The servo (7) locks brake 3 (B3) around freewheel 3 (F3) which is held secure. The freewheel clutches are open which means that F3 freewheels. The rear planetary train (P2) sun gear drum (6) is permitted to rotate.

The rotation of the front planetary gear (P1) and sun wheel and planetary gear carrier (4) forces the ring gear (5) to rotate clockwise at the same speed. The ring gear is connected with the rear planetary train (P2) planetary train holder (5). The torque is transferred via the P2 planetary gears on to the rear sun gear drum (6).

The rear planetary gear carrier (5) transfers the power to the output shaft via the final drive sun gear shaft (8), the planetary gear carrier and the differential gear in the same way as first two gears.

Engine braking

In gear shift position 3 the power flow is as described below, with the difference that 3rd clutch (C3) and freewheel 3 (F1) are connected. At engine braking the power is reversed over the input clutch (C1) via freewheel 2 (F2) instead of 3rd clutch (C3) and freewheel 3 (F1).

If the transmission is equipped with Geartronic and the power in the third manual gear will take the same route as in third gear in gear shift position 3.

Scheme 1282

Power is transferred from the turbine shaft to the driven chain wheel (1). The chain wheel is connected to the input shaft (2). The shaft is connected to the input clutch (C1) which grips the second freewheel (F2) outer bearing track.

The freewheel clutch in F2 transfers power to the front planetary train (P1) sun gear (3).

From the front planetary train (P1) sun gear the power is transferred via the planetary gears to the planetary gear carrier (4).

The front planetary train planet gear holder (4) is located together with the rear planetary train (P2) ring gear (4).

The rear planetary gear carrier (5) is connected to the final drive sun gear shaft (8). The sun gear shaft is held (in P position by the shift-lock (15) and in N position by the weight of the car) and prevents the rear planetary train (P2) planetary gear carrier (5) from moving. The planetary gear will rotate, but power cannot be transferred.

The planetary gears for the rear planetary train (P2) drive the rear sun gear drum (6).

The outer section of free wheel 3 (F3) is connected to the rear planetary train (P2) sun gear drum. Freewheel 3 holds the rear sun gear drum secure (6) via the free wheel clutches.

When first gear or reverse gear are selected only brake 3 (B3) needs to engage for the car to move.

The Transmission Control Module (TCM) controls gearshifting and lock-up engagement by acting on the transmission hydraulic system. The gearshifting is managed by two shift solenoids (S1, S2). The Transmission Control Module (TCM) determines when and if the lock-up connection is engaged, which occurs using the lock-up solenoid (SL). The solenoids function in the same way as those on the AW 42.

The Transmission Control Module (TCM) governs the hydraulic control system, oil flow and oil pressure to the transmission clutches and brakes.

The interaction of components

An eccentric pump (1) with variable displacement (the flow can vary as required) is located on the pump shaft. The oil pump pumps the oil which lubricates the moving transmission components and provides the necessary system pressure for the transmission hydraulic system. Like the AW 42 the oil is cooled by an external cooler in the radiator. For certain markets there will also be an serially additional cooler serially connected to the standard cooler.

The line pressure is initially determined by a relief valve located behind the oil pump in the hydraulic system valve housing. The relief valve is in turn controlled by signals from the line pressure solenoid (STH).

Oil from the pressure regulating valve reaches a manual valve which is connected to gear shift linkage rod. The circuits in gearshift positions P, R ,N, D, 3, 2, 1 (only MAN , gear 3, with Geartronic) are supplied with oil via the manual valve. The gear shift linkage rod directly operates the valve and depending on the valve position the channels are opened or closed. This means that the oil flow is provided to the different circuits in the transmission.

The accumulator is used when connecting 2nd (4), 3rd (4) and 4th clutches, which provides softer gearshifts. The pressure in the accumulators is affected by the pressure in the three accumulator valves which are located in the valve housing.

To ensure a constant oil level in the oil pan (6) there is a thermostat (5) which reacts to the oil temperature. The oil level in the oil pan is regulated with comparison to oil level in the side cover. At low temperatures the channel to the oil pan is opened and oil can flow back down into the trough. At high temperatures the channel is shut an part of the oil remains in the side cover. The oil level in the oil pan is higher when the transmission is cold.

Scheme 1283

Electronic control system

The transmission is controlled via the Transmission Control Module (TCM). The module has a connector for all input and output signals used for controlling the transmission and when communicating with other modules.

There are two connectors for information exchange between the Transmission Control Module (TCM) and the transmission

1. the terminal for engine speed (RPM) sensor which supplies output shaft Speed
2. terminal for other transmission sensors and solenoids

The connectors are connected to the Transmission Control Module (TCM) via the engine cable harness.

The Transmission Control Module (TCM) monitors and collects information from the different sensors in the transmission. The Transmission Control Module (TCM) communicate with the cars other modules via the CAN and with the slave gear selector module using serial communication. The signals are treated by the Transmission Control Module (TCM) which determines which gear would give the best driving characteristics. As with the AW 42 transmission, the module orders gear shifts using the solenoid in the hydraulic system.

From the gear selector assembly the force is transferred, via the transmission cable, to the gear shift linkage rod which mechanically operates a hydraulic valve inside the transmission. The gear shift linkage rod also controls the shift-lock.

A display to the left of the combined instrument panel provides information on the status of the functions which are controlled by the Transmission Control Module (TCM).

Shifting points

By referring to the accelerator pedal (AP) position, the vehicle speed and the engine speed (RPM) exact shifting points are obtained.

A Driver Adaptive function replaces the previous"Sport" and "Econ"gearshifting programs. The "Winter" program remains and is engaged manually using a button beside the gear selector lever. Driver adaptive control (reactive) means that the Transmission Control Module (TCM) interprets the drivers driving behavior and adapts the shifting program continuously. The module registers factors such as whether the driver quickly depresses the accelerator pedal (AP) and then switches over to a sportier shifting program. If the driver drives more calmly the shifting points are adjusted so that driving is as economically as possible.

The Transmission Control Module (TCM) also refers to the conditions when the shifting points are selected

1. Uphill slopes; counteracts frequent gearshifting.
2. When driving at high altitudes, the gear shift points are altered in direct response to the reduced engine torque which is a result of the lower oxygen content in the air.
3. Emissions from the engine; helps engine to reduce exhaust gases.
4. Transmission temperature; prevents the transmission overheating.
5. Differential speed; minimizes the wear on the transmission in event of wheelspin, by moving the shifting.
6. Sharp bends; moves the shifting to increase the comfort

Shift quality

The shifting quality depends on the engine torque and engine speed (RPM). The Transmission Control Module (TCM) communicate via the CAN bus with the Engine Control Module (ECM) which in turn can change the engines output torque and any torque amplification in the torque converter.

The transmission has torque controlled adaptable pressure regulation. Pressure regulation involves the transmission itself regulating pressure at each shift so that harsh shifting can be avoided. Each gear shifting is judged by the Transmission Control Module (TCM) and is stored in the memory, which provides compensation for wear in the transmission and clutch. The version means that shifting quality is always of the highest level.

When replacing the transmission it must be zeroed using VIDA.

Lock up engagement is electronic. The Transmission Control Module (TCM) gives a signal to the lock up solenoid which controls torque converter lock up function. In Geartronic holds the lock up engaged for a longer time which gives a faster response and therefore a sportier feeling.

Emergency program - "Fail Safe Mode"

If any part of the transmission hard or software is out of function, the "Fail Safe Mode" intervenes automatically. The situation means a predetermined behavior in the car, despite the fact that parts of the equipment are not functioning.

The reduced function in the transmission intervenes in case of electrical fault and in case of faults in the oil temperature and engine speed (RPM) signals from the transmission. The condition means that the Automatic Shifting Function is reduced.

In case of serious electronic faults the electronics are disconnected, ("Limp home" intervenes) which means that all the shifting solenoids are inactive and automatic shifting ceases. If the gear selector lever is in the D position (or MAN in Geartronic) third gear is automatically engaged. The driver can only select from R, P or N . Lock-up function does not function because the lock-up solenoid (SL) is not functioning. Because the line pressure solenoid (STH) is inactive, oil pressure will be maximal, resulting in harsher Shifting.

Information from the network

The Transmission Control Module (TCM) receives the following information from the network

1. Specific information for the 4T65EV / EV-GT: The gear selector lever is moved forwards / backwards in Geartronic (in MAN position) Information to the Transmission Control Module (TCM) which is common to the AW 42 and the 4T65EV / EV-GT: Throttle opening angle Brake pedal activated Cruise control activated Activating via the cruise control buttons (3 x) Cruise control overloaded Checking any cruise control sequence numbers Last cruise control speed Difference in speed between left and right front wheels Prevents torque reduction sweeping Coolant temperature in the engine Engine speed >400 RPM Engine input speed to torque converter Engine torque Global signals on CAN-bus (6 x) Gear selector module fault Ignition key position "Kickdown" Requirement for choke angle in throttle Lean in right/left turns Anti-wheel spin control, request downshift Anti wheel spin control, on/off Anti wheel spin control, lock gearshift Checking CAN communication Vehicle speed (wheel speed)

Information to the network

The Transmission Control Module (TCM) receives the following information from the network

1. Specific information for the 4T65EV / EV-GT: Fast shift position in Geartronic (in MAN position) Information from the Transmission Control Module (TCM) which is common to the AW 42 and the 4T65EV / EV-GT: Actual gear Transmission fluid temperature Actual transmission (AW 42 or 4T65EV / EV-GT) Gear engaged Actual gear selector lever position Lock-up (0-100%) Increase / decrease slipping in lock up Releasing shift lock Reverse inhibitor function at high speed Next gear (planned to be automatically engaged) Diagnostic message Controlling the warning lamp Controlling the Malfunction Indicator Lamp (MIL) Reply (containing stored diagnostic trouble codes (DTCs) Message in combined instrument panel Reduced engine torque during shifting Request for torque limiting Vehicle speed Transmission Control Module (TCM) "Winter"-program engaged

Scheme 1284

General 4T65EV / EV-GT

The 4T65EV / EV-GT is a transverse, four gear, electronically controlled automatic transmission with a torque converter lock-up function. 4T65EV / EV-GT has been developed by General Motors for use with six cylinder engines.

The following engines are used with the 4T65EV / EV-GT

A short transmission is required because Volvos transverse six cylinder engine takes up a lot of the space between the side members. The new transmission has two shafts, linked together with a double chain.

The transmission has torque controlled, adaptive pressure regulation which provides high gear shift quality and low fuel consumption.

A driver adaptive function replaces the previous"Sport" and "Econ"gearshifting programs. The "Winter" program remains and is engaged manually using a button beside the gear selector lever.

As an alternative to the conventional automatic transmission, the transmission can be equipped with Geartronic, a manual position for fast shifting.

The transmission is electronically controlled using the Transmission Control Module (TCM) which controls it based on signals from the network and sensor in the transmission.

The Transmission control module has a built in diagnosis which is read off via the data link connector (DLC) using VIDA.

Scheme 1285

Clutches

1. C1: Input clutch. Connects the input shaft with freewheel 2 (F2). Transfers the flow to the front planetary train (P1) sun wheel.
2. C2: 2nd clutch. Connects the 2nd clutch (C2) housing with the input shaft. Transfers power to the rear planetary train (P2) ring gear / front planetary train (P1) planetary gear carrier.
3. C3: 3rd clutch. Connects the input shaft with freewheel 1 (F1). Transfers the flow to the front planetary train (P1) sun wheel.
4. C4: 4th clutch. Connects the transmission housing with the fourth clutch shaft. Locks the front planetary train (P1) sun gear via the fourth clutch shaft and transmission housing.

Brakes

1. B1: Brake 1. Brakes 2nd clutch (C2) housing, reverse gear and the rear planetary train (P2) ring gear / front planetary train (P1) planetary gear carrier.
2. B2: Brake 2. Brakes the rear planetary train (P2) sun gear.
3. B3: Brake 3. Brakes freewheel 3 (F3) hub.

Components with free wheel mode

1. F1: Freewheel 1. Freewheel function F1 permits overrun from the input shaft and 3rd clutch (C3) and the front planetary train (P1) sun gear.
2. F2: Freewheel 2. Freewheel function F2 permits overrun from the input shaft and 1st clutch (C1) and the front planetary train (P1) sun gear.
3. F3: Freewheel 3. Freewheel function F3 permits overrun between the rear planetary train (P2) sun gear and the transmission housing.

The transmission consists of planetary trains, clutch plates, brakes, freewheels and final drive gears.

4T65EV / EV-GT has a lock-up clutch sheathed with carbon fiber friction material. The clutch can be either engaged, slipping or disengaged. When the lock-up clutch is slipping vibration and sound is damped. Engagement of lock-up occurs electronically in the two highest gears in position D . If the transmission is equipped with Geartronic, engagement occurs in the three highest manual gears.

When engine braking the power is reversed through the transmission. In transmissions without Geartronic engine braking occurs in the highest gear in each gear shift position. With Geartronic engine braking occurs in all gears (gear shift position MAN ).

In total, four clutch driven plates, three free wheel components and three brake bands work together in the transmission.

Together the two planetary trains provide five different gears (four forward gears and one back-up (reverse). The front planetary train (P1) and the rear planetary train (P2) work in tandem in that the outer ring gear in one gear is connected to the planetary train holder on the other and vice versa. The planetary trains have separate sun gear shafts which surround the transmission output shaft.

When shifting, the two planetary trains are engaged by the clutch driven plates. The clutch plates are compressed by hydraulic pistons. The brake bands then lock parts of the planetary trains to the transmission housing. Different gear ratios and rotation directions are maintained by braking or disengaging the different components in the planetary trains.

Power is transferred from the engine flywheel to the torque converter which transfers it on to the turbine shaft. There is a driving chain wheel on the turbine shaft which transmits power via a double chain to a driven chain wheel (1) which is linked to the input shaft. From the shaft the power is divided in different ways dependent on the signals from the Transmission Control Module (TCM) and from the transmission cable.

There are three servos in the 4T65EV / EV-GT which each power one brake. The function of the servos is to allow two or three opposes a hydraulic jack until a gradually connection of the respective bands occurs. By comparison the AW 42 has only one servo.

Geartronic

The only thing which separates the Geartronic from a standard transmission is that one of the panels has a different design and some different gaskets. Other components are common in both cases. The Geartronic gear selector assembly has a different construction.

Components activated in selected gears

X = activated.

F = freewheel.

O = connected and unloaded.

* Components connected in the transmission position MAN in Geartronic

X = activated.

F = freewheel.

O = connected and unloaded.

* Components connected in the transmission position MAN in Geartronic

OBD II is a diagnostics system designed to meet statutory requirements. Fault-tracing instruments can be plugged in to the OBD II socket in order to read diagnostic trouble codes (DTCs) and system parameters. OBD II contains only emission related diagnostic trouble codes (DTCs) and parameters and cannot provide the comprehensive range of information available from the Volvo On-board diagnostics system.

Emergency programs in the event of a fault

An emergency program is activated to deal with the fault when the transmission control module (TCM) detects a transmission fault (permanent fault). The control system then implements corrective action to protect the transmission, while leaving the car in the best possible driveable condition. Minor malfunctions do not activate an emergency program.

There are different programs depending on the type of fault

1. Emergency mode I
2. Emergency mode II
3. Emergency mode III
4. Limp-home mode

Emergency mode I is activated in the event of minor faults and the Limp-home mode is activated for the most serious faults. If the malfunction is intermittent, the transmission control module (TCM) returns to normal operation the next time the ignition is switched on.

Emergency mode I

1. The warning lamp in the combined instrument panel lights (S80), flashes (S/V/C70) for certain diagnostic trouble codes (DTCs).
2. The transmission shifts in all gears but transmits no signal to the lock-up solenoid. This means that lock-up is not available.

Emergency mode II

1. Remedy as for Emergency mode I.
2. No reduction of line pressure when moving the gear selector between positions P-R, N-R and N-D. This results in harsh shifting.
3. No torque limiting request from the engine control module (ECM) during gear shifting.
4. The warning lamp in the combined instrument panel lights / flashes.

Emergency mode III

1. Remedy as for Emergency modes I and II.
2. No control of line pressure solenoid SLT. Constant maximum system pressure. This results in harsh shifting and harsher gear engagement in positions P-R, N-R and N-D.

Limp-home mode

1. The transmission control module (TCM) interrupts the activation of all solenoids. This results in the transmission not shifting at all. The transmission operates only in 3rd gear in positions 3 and L, 4th gear in position D and reverse in position R. Shifting can only be carried out manually between 3rd and 4th gear and reverse gear.
2. No control of line pressure solenoid STH. Constant maximum system pressure. This results in harsh shifting and harsher gear engagement in positions P-R, N-R and N-D.
3. The warning lamp in the combined instrument panel flashes.

Note. When starting and driving, the gear selector should first be moved to position L to minimize stress on the transmission.

See Emergency programs in the event of a fault

See DESIGN

Downloading software and replacing the control module

New software can be downloaded into the transmission control module (TCM). When ordering software, the hardware and the software in the car is compared to the data in the Volvo central database. If the comparison is OK the software is downloaded to the control module. If the comparison between the car and Volvo central database is not OK, the database is updated with the car configuration. When this is complete the software is downloaded.

See FUNCTION

See Downloading software and replacing the control module

See FUNCTION

See Downloading software and replacing the control module

See FUNCTION