Remote operation of seats

Fig 1: Identifying Input / Output Signals For Remote Operation Of Seats

Courtesy of VOLVO CARS OF NORTH AMERICA.

There are three memories in the power seat module (PSM) which store the seat positions for a maximum of 3 remote controls. There are also three further memory positions which can be stored from the control panel. The seat can store a total of six different memory positions.

Cars with power seats with memory have a personal setting function. Using this function, the positions of the mirrors and seat can be stored individually for each remote control (a maximum of three remote controls, i.e. remote memory positions 1, 2 and 3).

The customer parameters in the power seat module (4/52) determine whether the remote memory for the seat is activated or not.

From model year 2003 inclusive the remote control memory for the mirrors can also be switched off. This is done using a customer parameter in the driver's door module (DDM) (3/126) and passenger door module (PDM) (3/127). "Programming of the remote control settings" for seats and mirrors is carried out via VIDA vehicle communication.

The signal from the remote control is transmitted to the upper control module (UEM) (4/70) when the car is locked or unlocked. The upper electronic module (UEM) also identifies which remote control is being used. The central electronic module (CEM) (4/56) receives this information from the upper electronic module (UEM). The central electronic module (CEM) identifies and stores the remote control which is being used and determines the data to be sent to the power seat module (PSM) (4/52), driver door module (DDM) (3/126) and passenger door module (PDM) (3/127). This is done when the door is opened.

For model year 2003 the central electronic module (CEM) transmits information about which remote control locked the car.

From model year 2003 inclusive , the central electronic module (CEM) transmits information about which remote control locked the car and which unlocked the car.

If the position of the seat is changed, the power seat module (PSM) (4/52) stores the new position before reverting to sleep mode.

Remote memory positions are stored in the power seat module (PSM) in the following cases:

10 minutes after the door has been opened
1 minute after the door has been closed
With the ignition off
When the key is removed from the ignition switch
When a new remote control is activated.

The remote memory positions for the door mirrors are stored for the driver door module (DDM) and passenger door module (PDM) in the following cases:

When the key is removed from the ignition switch
When a new remote control is activated.

When the car is unlocked, the power seat module (PSM) uses the information about which remote control unlocked the car. This is so that the correct remote memory position can be selected (i.e. the seat position last set by the driver for this remote control). When the door is opened the seat starts to move to the programmed remote memory position. The seat can be stopped by pressing one of the buttons on the control panel.

If the car is opened with a key, the memory settings for the seat are not affected. Remote operation of the seat is not possible if the key is in the ignition switch.

On model year 1999-2002 cars, the system may exhibit unwanted properties. Only information about which remote control unlocked the car is transmitted, a new memory position is not stored if the car was unlocked before this. This is because when a car door is opened and the power seat module (PSM) switches into active mode, the module is unable to identify which remote control is being used.

In addition, when a door is open, it takes 10 minutes before the power seat module (PSM) switches to sleep mode. If this occurs, and the customer then attempts to set a new seat position, the information about which remote control opened the door will have been lost and a new memory position will not be stored.