Electrical seat adjustment (with CODE 275) - GF91.29-P-0009CEA

MODEL 204.0 /2 with CODE (275) Memory package (driver seat, steering column, mirrors) with CODE (242) Electrically adjustable front passenger seat with memory as of model year 2009 /YoM 08 

MODEL 204.3 with CODE (275) Memory package (driver seat, steering column, mirrors) with CODE (242) Electrically adjustable front passenger seat with memory 

MODEL 204.9 with CODE (275) Memory package (driver seat, steering column, mirrors) with CODE (242) Electrically adjustable front passenger seat with memory 

Function requirements, general 

• No engine start (circuit 50 OFF)
• No undervoltage (U < 9.3 V)

The electronic ignition lock control unit transmits the circuit status and the on-board electrical system voltage via interior CAN.

Electrical seat adjustment (ESA [ESE]), general 

The ESA [ESE] enables the electrical adjustment of the driver and front passenger seat. The driver and front passenger seat can be adjusted as follows:

• Seat fore/aft position
• Backrest angle
• Seat height
• Seat inclination
• Head restraint height

Moreover, it is possible to store and move to the particular seat position.

On the driver-side, the positions of the outside mirrors and the steering column are also stored and retrieved via the memory function.

The ESA [ESE] comprises the following partial functions:

• Function sequence for manual adjustment 
• Function sequence for saving and retrieving seat positions 
• Function sequence for head restraint presetting 
• Normalization function sequence 
• Function sequence for position measurement 
• Function sequence for antilock device 
• Fault handling function sequence 

Function sequence for manual adjustment 

The manual adjustment function comprises the following subfunctions:

• Function sequence for manual adjustment of driver seat 
• Function sequence for manual adjustment of front passenger seat 
• Priorities 

Function sequence for manual adjustment of driver seat 

The manual adjustment is operated via the left front seat adjustment switch group. The left front seat adjustment switch group is read via the left door LIN by the left front door control unit. The left front door control unit transmits the request from the left front seat adjustment switch group to the driver seat control unit via the interior CAN. To adjust, hold down the switches in the front left seat adjustment switch group until the desired position is reached.

The driver seat control unit actuates the following motors directly to match the request:

• Driver seat fore/aft adjustment motor
• Driver seat height adjustment motor
• Driver seat inclination adjustment motor
• Driver seat head restraint adjustment motor
• Driver seat backrest inclination adjustment motor

Function sequence for manual adjustment of front passenger seat 

The manual adjustment is operated via the right front seat adjustment switch group. The right front seat adjustment switch group is read in via the right door LIN by the right front door control unit. The right front door control unit transmits the request from the right front seat adjustment switch group to the front passenger seat control unit via the interior CAN. To adjust, hold down the switches in the front right seat adjustment switch group until the desired position is reached.

The front passenger seat control unit actuates the following motors directly to match the request:

• Front passenger seat fore/aft adjustment motor
• Front passenger seat height adjustment motor
• Front passenger seat inclination adjustment motor
• Front passenger seat head restraint adjustment motor
• Front passenger seat backrest inclination adjustment motor

Priorities 

The seat adjustment is divided up into 2 groups and 3 priorities. Each adjustment in a group is independent from an adjustment in another group.

If several adjustment requests are received in a group by the driver seat control unit, then the adjustment request with the higher priority is executed.

The priorities are determined as follows:

Group 1

• Priority high, backrest angle
• Priority medium, head restraint height
• Priority low, seat inclination

Group 2

• Priority high, seat fore/aft position
• Priority medium, seat height

Additional function requirements for saving and retrieving seat positions 

• ESE normalized

Function sequence for saving and retrieving seat positions 

The function for saving and retrieving seat positions comprises the following partial functions:

• Function sequence for saving and retrieving driver seat positions 
• Function sequence for saving and retrieving front passenger seat positions 

Function sequence for saving and retrieving driver seat positions 

There are two button operation options for storing the seat position:

• Hold down left front memory function switch (S22s6) and then press left front memory switch 1 (S22s7), left front memory switch 2 (S22s8) or left front memory switch 3 (S22s9) for the corresponding memory location
• Press left front memory switch function for t > 100 ms. Press left front memory switch 1, left front memory switch 2 or left front memory switch ≤≤3 within 0.2 s to 3 s for the corresponding memory location

The status of the switches is read in via the left door LIN and transmitted to the driver seat front door control unit via the interior CAN. The driver seat control unit stores the current position of the seat.

To actuate the stored position, press left front memory switch 1, left front memory switch 2 or left front memory switch 3 until the desired end position is reached. Releasing leads to immediate termination of the adjustment procedure.

Function sequence for saving and retrieving front passenger seat positions 

There are two button operation options for storing the seat position:

• Hold down right front memory function switch (S23s6) and then press right front memory switch 1 (S23s7), right front memory switch 2 (S23s8) or right front memory switch 3 (S23s9) for the corresponding memory location
• Press right front memory switch function for t > 100 ms. Press right front memory switch 1, right front memory switch 2 or right front memory switch ≤3 within 0.2 s to 3 s for the corresponding memory location

The status of the switches is read in via the right door LIN and transmitted to the front passenger seat front door control unit via the interior CAN. The front passenger seat control unit stores the current position of the seat.

To actuate the stored position, press right front memory switch 1, right front memory switch 2 or right front memory switch 3 until the desired end position is reached. Releasing leads to immediate termination of the adjustment procedure.

Successful storage of the seat position is acknowledged by the instrument cluster with an acknowledgment tone.

Abort conditions:

Moving to a stored position is interrupted during:

• Manual seat adjustment
• Manual mirror adjustment (only driver)
• Manual steering column adjustment (driver only)
• When additional memory switches are pressed

Additional function requirements for head restraint presetting 

• Normalized seat fore/aft position
• Normalized head restraint height

Function sequence for head restraint presetting 

The height of the head restraint is preset automatically by the driver seat control unit or the front passenger seat control unit depending on the seat fore/aft position. If the seat is moved forward, the head restraint moves down. If the seat is moved rearward, the head restraint moves up. The head restraint is adjusted in stages.

The head restraint presetting function can be switched on and off in the driver seat control unit or front passenger seat control unit using the diagnosis and is coded country-specifically using the Software Calibration Number (SCN).

Additional function requirements for normalization 

• Circuit 15R ON

Normalization function sequence 

Normalization is important for the assignment of the absolute adjustment position and the position recorded by the driver seat control unit. Normalization must be performed during initial startup or in a denormalized condition.

To carry out the normalization procedure, it is necessary to drive to the following mechanical end stops:

• Front end stop of fore/aft adjustment and backrest angle
• Downstop of seat inclination, seat height and head restraint height

For normalization, the corresponding switch in the seat adjustment switch group must remain actuated for t = 250 ms after the mechanical end stop has been reached.

Upon successful normalization, the driver seat control unit or front passenger seat control unit switches off the corresponding seat adjustment motor. The normalization procedure should be performed via diagnosis for initial startup. Circuit 15R must be switched on while doing so.

An adjustment is denormalized, if the signal of the corresponding Hall sensor is not received. The Hall sensors are allocated to the particular adjustment motors. The denormalization procedure can also be performed via diagnosis.

Function sequence for position measurement 

The seat adjustment motors are equipped with Hall sensors. The signals from the Hall sensors are read in and evaluated by the driver seat control unit or front passenger seat control unit.

Function sequence for antilock device 

If a defective Hall sensor is detected for t > 2 s, the corresponding adjustment function is switched off by the driver seat control unit or front passenger seat control unit.

Reactivation in the same adjusting direction is not permitted until the corresponding switch has been released for approx. t ≥2 s. Reactivation in the opposite adjustment direction is possible immediately.

Fault handling function sequence 

The driver seat control unit or front passenger seat control unit checks the requests for seat settings it has received for plausibility. Adjustment requests for the same adjustment function in an opposite direction (e.g. backrest adjustment forward//back simultaneously) are rejected. Correct requests for other adjustment functions remain unaffected.

The plausibility of a manual adjustment request for a memory adjustment is checked by the left front door control unit or right front door control unit.

	Electrical function diagram for seat adjustment (ESA [ESV])		PE91.29-P-2050-97FAB
	Overview of system components, electric seats		GF91.29-P-9992CE