Tailgate drive control units J605 and J756

Introduction

For increased user convenience, an automatic tailgate is optional in the new Audi A6 Avant  ́05. The automatic opening and closing function is implemented by two electric motors mounted on the tailgate hinges. Each electric motor has a step- up gear, a magnetic coupling, measuring sensors and an electronic control unit. The tailgate drive on the driver side (left-hand side) is the system master; it is connected to the convenience CAN bus. The tailgate drive on the front passenger side is the slave.

Automatic opening

Opening of the automatic tailgate can be initiated by pressing the centre button on the remote control key, or by pulling the release button on the driver's door, or by pressing the handle on the tailgate. The opening cycle can be interrupted by repeating the initiating operation. Pressing again the centre button on the remote control key or the tailgate release button in the driver's door continues the interrupted opening cycle.

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Tailgate control unit -master- J605

Tailgate control unit -slave- J756

Tailgate release button in the driver door

32Saving the limit position of the tailgate

If the tailgate was stopped in an intermediate position, this position can be saved as a future end position. To do this, the "close" button on the tailgate must be pressed for at least 5 s. Please note that this function is only available as of a minimum opening angle of 45 degrees.

Automatic closing

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"Close" button in the tailgate

For safety reasons, automatic closing can only be initiated with the tailgate "close" button or with the tailgate handle. Automatic closing can also be interrupted by repeating either operation.

Pressing the "close" button or the tailgate handle again would, however, not continue the closing cycle, but would initiate an opening cycle.

The magnetic coupling

The torque generated by the electric motor to open and close the tailgate is transmitted via a magnetic coupling. The magnetic coupling consists of a permanent magnet and a solenoid. When the tailgate is opening, the magnetic effect of the permanent magnet is intensified by the solenoid so that a sufficiently high torque can be transmitted from the electric motor.

The permanent magnet alone can hold the tailgate in an open position against its weight and against the pressure of the gas-filled spring. When the tailgate is opened or closed manually, the solenoid produces a magnetic field which neutralises the magnetic effect of the permanent magnet.

The magnetic coupling is open and the tailgate can move freely.

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Convenience electronics

Manual tailgate operation

When the tailgate is moved manually from a stopped intermediate position, the deenergised holding torque is overcome and the "Manual" mode is activated. This manual movement is detected by means of Hall sensors, whereupon the control units energise the couplings in the "freewheel" direction. When movement stops, the couplings is deenergised after approximately one second and the tailgate holds its position automatically.

Torque bar

Speed control

The torque needed to open and close the tailgate is dependent upon several factors, such as the momentary vehicle position, ambient temperature and momentary tailgate position. For this reason, a speed regulator was implemented in the control unit; it adjusts the momentary motor speed to a default speed characteristic. Motor speed is controlled via a high-frequency PWM signal which controls the motor current.

A second possible way to operate the tailgate manually is to open the closed tailgate by means of the tailgate handle button. The couplings will then also be energised in the "freewheel" direction. This state is maintained for approximately 0.5 seconds after releasing the handle button. If no manual operation is detected during this phase, the couplings will again be energised in the "open" direction and the tailgate will open automatically.

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Control unit

Magnetic coupling

Drive lever

Electric motor

2nd gear

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Sensors

Road speed is monitored by a Hall sensor on the left tailgate drive. The right tailgate drive also has a Hall sensor which detects when "manual" mode is required. An additional three small Hall sensors on the left-hand side monitor the direction of movement of the tailgate and the current tailgate position. The Hall sensors are also used for anti- pinch protection.

This is implemented by a speed/distance detection system. If an obstruction detected, the drive will stop. If an obstruction is detected during a closing cycle, the tailgate is reopened approx. 4 degrees.

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Hall sensor PCB for the detecting the direction of movement of the tailgate and the tailgate position

Transport mode and standby current management

When transport mode is activated, the tailgate control unit is activated, too. In this condition, the tailgate must be operated manually. The electric motors are deactivated and only manual operation is possible. The same applies to standby current management from power-off stage 2.

Deactivating the electrical tailgate drive

The following system faults will cause the electric tailgate drive to be deactivated:·

–No CAN communication with driver door control unit J386

–No CAN communication with convenience system central control unit J393

–No CAN communication with entry and start authorisation control unit J518

–Components protection in convenience system central control unit J393 active

–The tailgate power latching system does not start up when the tailgate is open or the started- up power latching system provides no feedback to the convenience system central control unit J393

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Convenience electronics

System overview - Tailgate control unit

Tailgate closing button in tailgate

Driver door control unit J386

Data bus diagnostic interface J533

Power management system J644

Tailgate control unit,

driver side J605

Discrete communication wire

Wake-up line

Convenience system central control unit J393

Entry and start authorisation control unit J518

Trailer detector control unit J345

Tailgate control unit,

front passenger side J756

Rear right power latching motor

Softtouch handle in tailgate

CLS antenna

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Tailgate release button in driver door

ABS with EDL J104

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The tailgate control unit J605 receives the vehicle speed signal from the ABS with EDL control unit J104. For safety reasons, automatic tailgate opening and closing are deactivated at a vehicle speed of 3 kph.

If the tailgate control unit J605 receives from the trailer detector control unit the information "trailer detected", the automatic tailgate operation will also be deactivated for safety reasons.

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Powertrain CAN bus

Convenience CAN bus

Softtouch in the tailgate

Convenience system central control unit J393

Terminal 30

Tailgate control unit - master - J605

Sensors

Magnetic coupling

Terminal 30

Tailgate control unit - slave - J756

Power latching system

Tailgate lock

Interior tailgate release

Sensors

Magnetic coupling

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●The tailgate control unit master J605 communicates with the tailgate control unit slave J756 via a single- wire bus specified by systems supplier Valeo (no LIN bus).

●Via the wake-up line, the tailgate control unit master J605 can wake up the tailgate control unit slave J756. This is the case if the convenience CAN bus is reactivated in Sleep Mode, or if the interior tailgate release is operated while the convenience CAN bus is in Sleep Mode. The slave tailgate control unit wakes up the master control unit J605 if manual operation of the tailgate is detected .

●The function block of the rear right power latching motor shows two sensors. They have the task of monitoring the two end positions of the power latching system and informing the convenience system central control unit when they are reached.

General description

 

The tailgate control unit -J605 comprises the following scope of functions:

 

1. General introduction

1.1 Transport mode

1.2 No-load current management

2. Initiate automatic opening

3. Initiate automatic closing

4. Opening movement

5. Closing movement

6. Obstacle detection

7. Stop at interim position

8. Open tailgate by emergency release

9. Deactivation of electric tailgate drive

 

1. General introduction

The tailgate is activated by two control units: the master tailgate control unit -J605 and the slave tailgate control unit 2 -J756. The master control unit (tailgate control unit -J605) is always located on the left when looking into the boot. Consequently, the slave control unit (tailgate control unit 2 -J756) is always located on the right. The tailgate drives and the tailgate control unit form a single unit. They have one part number.

 

1.1 Transport mode

Transport mode is set to minimise the power consumption during transportation. Transport mode is deactivated in adaption channel 1 of the battery energy manager, or is deactivated automatically after a distance of 50 km has been driven. The transport mode can be activated/deactivated at any time. If transport mode is set, the functionality of the tailgate control unit is inactive and the tailgate can only be operated manually.

 

1.2 No-load current management

To improve the starting performance of the vehicle, convenience and infotainment components functions are to be restricted/disabled dependent on state of charge.

To that end, the battery energy manager (BEM) transmits the relevant shut-off stage to the control units via CAN dependent on the state of charge in the battery and the no-load current. In shut-off stage 2, the functionality of the tailgate control unit is inactive and the tailgate can only be operated manually.

 

2. Initiate automatic opening

- Open via handle button (Softtouch);

- Open via remote control ;

- Open via remote release button (interior button);

- Open via tailgate interior button (tailgate button);

 

3. Initiate automatic closing

- Close via tailgate interior button (tailgate button);

- Close via remote control (optional);

- Close via handle button (Softtouch);

- Close via remote release button (interior button);

 

4. Opening movement

The opening movement is initiated by a command from the bus (handle button - Softtouch,  remote opening (inside button). The opening movement can only be started when:

- the lock is open or is opened within a time window of 500ms (programmable) after the bus command;

- no relevant shut-off stage is active - 3 stages: automatic open, automatic close and manual operation are shut off separately;

- the vehicle speed is below 3 km/h;

- the voltage is above 8.5 V;

- optionally: no obstacle is detected;

- component protection is not active.

 

If the command was accepted, the clutch is first engaged. Then the motor is activated. This is done with a speed control (dependent on the position of the tailgate, the vehicle position and the ambient temperature). The opening movement may be interrupted by an obstacle. The tailgate then stops at the position at which the obstacle was detected.

 

The "selectable opening stop" is defined by:

- the factory setting (this is not the maximum mechanical opening angle);

- the driver's programming input;

 

Maximum opening of the tailgate is initiated by pressing the remote control again within a

fixed time window (500ms - programmable) after the "selectable opening stop" point has been reached.

 

 

5. Closing movement

The closing movement is initiated by a command from the tailgate interior button (tailgate button).

The closing movement can only be started when:

- the lock is open;

- the control unit detects the current position;

- no relevant shut-off stage is active - 3 stages: automatic open, automatic close and manual operation are shut off separately;

- the vehicle speed is below 3 km/h;

- optionally: no obstacle is detected;

- component protection is not active;

- the power latch is raised.

 

If the command was accepted, the clutch is first engaged. Then the motor is activated. This is done with a speed control (dependent on the position of the tailgate, the vehicle position and the ambient temperature).

The closing movement is stopped if:

- the lock is closed;

- an obstacle is detected;

- the movement is stopped by a button press.

 

6. Obstacle detection

Response to an obstacle being detected:

When an external force is detected and the closing movement stopped, the movement is reversed 4° (programmable. Then the tailgate interior button is switched to "open". When an external force is detected and the opening movement stopped,

the tailgate is held in position.

 

7. Stop at interim position

The automatic closing movement of the tailgate is stopped when:

- an obstacle is detected;

- a new signal is transmitted from the remote control;

- the tailgate interior button (tailgate button) is pressed - Important note: in contrast to release on initiation of closing movement;

- the remote release button (interior button) is pressed;

- the handle button (Softtouch) is pressed;

 

The automatic opening movement of the tailgate is stopped when:

- an obstacle is detected;

- a new signal is transmitted from the remote control;

- the tailgate interior button (tailgate button) is pressed - Important note: in contrast to release on initiation of closing movement;

- the remote release button (interior button) is pressed;

- the handle button (Softtouch) is pressed;

 

After a stop the drive can only be reactivated once all control elements have been inactive for at least 100 ms (programmable). No current is applied to the clutch when in stopped mode. In this state the clutch transmits a currentless torque that is sufficient to hold the tailgate in position in any state against the weight of gravity and the force of the gas-filled springs.

 

8. Open tailgate by emergency release

Please refer to the owner's manual.

 

9. Deactivation of electric tailgate drive

The following factors lead to deactivation of the electric tailgate drive:

- Vehicle speed above 3 km/h;

- "Trailer detected" signal from trailer recognition control unit -J345;

- No CAN communication with driver's door control unit -J386;

- No CAN communication with convenience system central control unit J393;

- No CAN communication with entry and start authorisation control unit -J518;

- Component protection in convenience system central control unit -J393;

- Power latch in tailgate lock does not rise when tailgate is open/power latch up feedback is sent to the convenience system central control unit -J393;

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