Soft Top, Function - GF77.30-P-0002RR
Model 190.4
Function requirements, general
- Transport mode not activated
- No overvoltage or undervoltage
When the transport mode is activated, the closed soft top cannot be opened.
Soft top in general
The soft top is operated electro-hydraulically by actuating two hydraulic cylinders.
The soft top control hydraulic unit motor in the soft top control hydraulic unit actuates the hydraulic pump, which generates the required operating pressure.
The hydraulic cylinder is controlled by the soft top control control unit.
Eleven sensors monitor the position of soft top, the lock actuation element and the header bows. The soft top control control unit directly reads in the signals of the sensors.
Control points:
- Power soft top switch
- Transmitter key (A8/1) (Comfort opening/closing function)
Emergency actuation: The soft top can be opened and closed manually.
The soft top control comprises the following partial functions:
- Open/close soft top
- Stop mode
- Overload protection
- Control and warning messages
Additional function requirements for opening/closing soft top
- No engine start (circuit 50 Off)
- Circuit 15 ON (for control point switch for soft top actuation)
- Soft top in defined position
- Speed below 60 km/h
- Trunk lid closed
The electronic ignition lock control unit sends the circuit 15 and circuit 50 status over the interior CAN to the soft top control control unit.
The position of the soft top is sensed by evaluating the signals from all sensors. The soft top control control unit directly reads in the signals of the sensors. The instrument cluster sends the vehicle speed via user interface CAN, gateway AMG control unit and interior CAN to the soft top control control unit.
The rear SAM control unit directly reads in the status of the trunk lid lock main catch switch and sends this via the interior CAN to the soft top control control unit.
Open/close soft top
When the soft top control switch is actuated, the soft top is opened or closed manually for the time the request is present. The front SAM control unit directly reads in the status of the soft top actuation switch in the electronic overhead control unit and transmits the status to the soft top control control unit via the interior CAN.
When the "Comfort opening/closing" function is actuated using the transmitter key, the soft top is opened or closed as long as the request is pending.
Open soft top procedure:
- Completely closed side windows are lowered.
The soft top control control unit transmits the request to lower the side window to the door control units via the interior CAN. The door control units then actuate the power window motors. Hall sensors are integrated into the power window motors. Their signals indicate the position of the side windows. The door control units transmit the information for the position of side window to the soft top control control unit via the interior CAN.
- Movement of the soft top is started.
The soft top control control unit directly actuates the soft top control hydraulic unit motor. The hydraulic pump driven by the soft top control hydraulic unit motor generates the operating pressure required for the movement. The soft top control control unit then actuates the solenoid valves in the soft top hydraulic unit directly, allowing oil to flow into the individual hydraulic cylinders. First the soft top is pressed slightly toward front, so that the soft top control control unit can unlock the soft top on the left and right cowl (upper windshield frame) by actuating the lock actuation element drive electric motor. Then the soft top is opened.
- At the end of the opening procedure, the soft top is laid down on the lock mounts behind the roll bars and locked For this purpose the soft top control control unit directly actuates the lock actuation element drive electric motor.
- The soft top control control unit actuates the side flap drive electric motors to close the header bows.
The hydraulic cylinders in question remain activated for a short time even after reaching the individual end positions (defined over the signals from the limit switches) in order to compensate for tolerances in the switching points of the sensors.
Close soft top procedure:
- Completely closed side windows are lowered.
- The header bows are opened.
- The lock mounts are unlocked.
- The soft top is folded up toward front behind the roll bar.
- The soft top is locked in the upper frame of the windshield.
- The side windows are closed again (except on vehicles with code 494 (USA version)).
During the soft top operation, the message "Soft top in operation" is displayed in the instrument cluster. If the vehicle speed is above 60 km/h during opening, the soft top control control unit stops the movement. The instrument cluster's multifunction display shows the message "Completely open/close soft top". Then soft top control control unit transmits the request to display a corresponding message via the interior CAN, AMG gateway control unit and user interface CAN to the instrument cluster.
The soft top control control unit monitors the movement of the soft top. For this purpose it checks the actuation time of the solenoid valves for each movement (except in the stop mode) until the input signals from the sensors are received. If the stored time is exceeded, the actuation is interrupted and a fault is stored in the soft top control control unit.
If the soft top is not completely locked, it can be locked later by a new operation request. The side windows are not completely closed in this case.
Only when the soft top closed, all side windows are closed completely.
Additional function requirements for stop mode
- Soft top not in locked end position
Stop mode
If the opening or closing procedure of the soft top is interrupted due to erroneous or missing input factors, the soft top control control unit activates the stop mode. During the stop mode the solenoid valves in the soft top control hydraulic unit are actuated so that the motion of the soft top is stopped. The soft top is arrested. When the opening or closing procedure of the soft top is enabled and a new actuation request is present, it is restarted or continued.
As soon as stop mode is active, a warning message ("Completely open/close soft top") appears on the instrument cluster.
When the stop mode is active, the soft top is arrested when:
- Circuit 15 ON for 7 min
- Circuit 15 OFF for 15 s
If the opening and closing procedure of the soft top is not yet enabled, the stop mode is reactivated after a new request is received.
If stop mode has been aborted, the soft top control unit transmits the request to output a warning via interior CAN, AMG gateway control unit and the user interface CAN to the instrument cluster 15 s before shutting off the first solenoid valve. The message "Soft top lowers" appears in the instrument cluster. A warning gong sound in addition. The soft top control unit withdraws the request to output an acoustic warning, if all solenoid valves have been switched off after 5 s.
If a new request is recognized and the position search made by the soft top control unit is successful, all solenoid valves are switched off and the motion of the soft top is continued starting at the fixed position. The opening and closing procedure of the soft top is interrupted when a speed of 4 km/h is exceeded, so that the soft top cannot be damaged by the aerodynamic drag.
If a solenoid valve responsible for stop mode function is defective, the stop mode is not started.
Overload protection
Opening and closing the soft top is possible even when a hydraulic oil temperature of 85°C is exceeded. The soft top control hydraulic unit temperature sensor senses the hydraulic oil temperature. The soft top control unit reads in the signal of the soft top control hydraulic unit temperature sensor directly and calculates the hydraulic fluid temperature. When the hydraulic oil temperature of 85°C is exceeded, the soft top control control unit triggers the overload protection. This protects the soft top hydraulic unit electric motor from possible thermic overload.
Hydraulic oil temperatures in °C:
Open soft top from closed non-actuated state:
- Enable below 75°C
- Inhibit/interruption above 85°C
Close soft top:
- Enable below 85°C
- Inhibit/interruption above 90°C
The outside temperature is included in the calculation. The outside temperature is recorded by the outside temperature sensor. The front SAM control unit directly reads in the signal from the outside temperature sensor and calculates the outside temperature. Then the front SAM control unit transmits the value for the outside temperature to the soft top control control unit via the interior CAN.
Fault evaluation of the soft top control control unit at an outside temperature of below -15°C:
- No fault in temperature sensor for soft top control hydraulic unit
- Not displayed in instrument cluster in event of timeout errors
- Not saved in event of time-out errors
Fault evaluation of the soft top control control unit at an outside temperature of above -15°C:
- Errors are stored
- Displays in instrument cluster are activated
Control and warning messages
The soft top control control unit evaluates the functional capability of the soft top control continuously.
Malfunctions are displayed in the instrument cluster. For this purpose the soft top control control unit transmits the corresponding information to the instrument cluster via the interior CAN, AMG gateway and user interface CAN.
The message is displayed regardless of the circuit status of circuit 15. Also during comfort opening/closing of the soft top.
Individual messages can be transmitted parallel to other messages. Otherwise, the soft top control control unit transmits only one message to the instrument cluster with the corresponding priority. Messages with same priority cannot be present simultaneously due to the soft top motion sequence.
| Priority | Fault/operation | Symbol | Display text | Warning gong |
|---|---|---|---|---|
| 1 | Soft top unlocked and speed above 8 km/h | Soft top | Soft top locked (red) | Yes |
| 2 | Opening or closing operation active over soft top control switch (active until soft top is locked and hydraulic pump shut off) | Soft top | Soft top in operation (white) | No |
| 2 | Stop mode active | Soft top | Completely open/close soft top (white) | No |
| 2 | Stop mode is active and switched off in 15 s | Soft top | Soft top lowers (white) | Warning gong activated for 20 s |
| 3 | Soft top operation not possible while driving, speed above 60 km/h | Soft top | Reduce speed to 60 km/h (white) | Yes |
| 4 | Soft top operation not possible, because trunk lid is not closed | Vehicle with open trunk lid | Symbol only, no text (white) | Yes |
| 5 | Soft top operation not possible because temperature on soft top control hydraulic unit is too high or voltage too low with engine running | Soft top | Soft top in operation, please wait (white) | Yes |
| 6 | Soft top operation not possible because voltage too low with engine OFF | Soft top | Start engine (white) | Yes |
| 7 | Soft top operation not possible due to error in soft top control control unit or in periphery (on all errors preventing a soft top operation) | Soft top | Soft top, visit workshop (white) | Yes |
If the vehicle is driven faster than 8 km/h when the soft top is locked, a warning gong sounds in addition to the warning message "Lock soft top" in red lettering. Output of this warning message is limited to 10 s. Then the output of a warning gong is inhibited and is only armed by:
- Circuit 15 OFF changes to circuit 15 ON
- Position change of soft top
- Soft top control switch actuated in opposite direction, relocking
- Relocking (after soft top control switch changes from "actuated" to "not actuated")
The warning gong is also actuated when the stop mode is deactivated for 20 s. Actuation starts 15 s before deactivating the stop mode.
| Electrical function schematic for electro-hydraulic soft top | PE77.39-P-2052-97HBA | ||
| Overview of system components for soft top, component description | GF77.30-P-9997RR |