Manual Operation of Memory Function Seat Not Working

Manual Operation Of Memory Function Seat Not Working

Fault symptoms
Manual operation does not work.

Probable cause of fault
Fault in lead or switch.

Diagnostic help
The switch position can be read using the diagnostic tool.

Check the wiring
Touch the wiring harness at several different points and in different directions to reveal intermittent faults, breaks and short-circuits in the harness. Monitor the multimeter, test lamp or diagnostic
instrument during the test.

Diagnostic procedure

1. Check whether the fault Is on the switch side or the motor side
^ Turn the ignition key to the ON position.

^ Connect the diagnostic tool to the vehicle and contact Control Module, PSM.

^ Carry out all functions of the seat and check that the value on the diagnostic tool is OFF and changes to ON when the switch is activated.

^ Seat forward

^ Seat Towards Rear
^ Seat Front Up
^ Seat Front Down
^ Seat Rear Up
^ Seat Rear Down
^ Backrest Upright
^ Backrest Recline

Test results OK?
YES
^ The fault is on the motor side.
^ Go to point 2.
NO
^ The fault is on the switch side.
^ Go to point 7.

2. Identify function

Which function is faulty?
LEGROOM ADJUSTMENT
^ Go to point 3.
SEAT FRONT
^ Go to point 4.
SEAT REAR
^ Go to point 5.
BACKREST
^ Go to point 6.

3. Check wiring harness between control module and motor, legroom adjustment
^ Unplug the connector, motor legroom adjustment: (357Da).

^ Connect a test lamp between pins 1 and 2 of the female connector.

^ Activate the switch in both directions.

^ The lamp should light in both directions. The red light for one direction and the green light for the other. (Note that if the seat is at the end position, the motor can only be activated in one direction using the switch).

Test results OK?
YES
^ Replace: motor legroom adjustment
^ Go to point 16.
NO
^ Repair or replace the wiring.
^ Go to point 16.

4. Check wiring harness between control module and motor, front
^ Unplug connector, motor seat front: (357Db).

^ Connect a test lamp between pins 1 and 2 of the female connector.

^ Activate the switch in both directions.

Test results OK?
YES
^ Replace: motor seat front
^ Go to point 16.
NO
^ Repair or replace the wiring.
^ Go to point 16.

5. Check wiring harness between control module and motor, rear
^ Unplug connector, motor seat rear: (357Dc).

^ Connect a test lamp between pins 1 and 2 of the female connector.

^ Activate the switch in both directions.

Test results OK?
YES
^ Replace: motor seat rear
^ Go to point 16.
NO
^ Repair or replace the wiring.
^ Go to point 16

6. Check wiring harness between control module and motor, backrest
^ Unplug connector, motor backrest: (357Dd).

^ Connect a test lamp between pins 1 and 2 of the female connector.

^ Activate the switch in both directions.

Test results OK?
YES
^ Replace: motor backrest.
^ Go to point 16.
NO
^ Repair or replace the wiring.
^ Go to point 16.

7. Check switch function
^ Unplug connector, switch PSM: (357D).

^ Connect a test lamp between pin 10 and a good grounding point in the male connector.

^ The test lamp should light.

Test results OK?
YES
^ Go to point 8.
NO
^ Repair or replace the wiring.
^ Go to point 16.

8. Check legroom adjustment, forward
^ Connect a jumper lead between pin 6 and pin 10 of the male connector.

^ Read: seat forward
^ The diagnostic tool should show ON when the jumper lead is connected and OFF when it is removed.

Test results OK?
YES
^ Go to point 9.
NO
^ Repair or replace the wiring.
^ Go to point 16.

9. Check legroom adjustment, back
^ Connect a jumper lead between pin 7 and pin 10 of the male connector.

^ Read: seat back
^ The diagnostic tool should show ON when the jumper lead is connected and OFF when it is removed.

Test results OK?
YES
^ Go to point 10.
NO
^ Repair or replace the wiring.
^ Go to point 16.

10. Check front up
^ Connect a jumper lead between pin 3 and pin 10 of the male connector.

^ Read: seat front up
^ The diagnostic tool should show ON when the jumper lead is connected and OFF when it is removed.

Test results OK?
YES
^ Go to point 11.
NO
^ Repair or replace the wiring.
^ Go to point 16.

11. Check front down
^ Connect a jumper lead between pin 2 and pin 10 of the male connector.

^ Read: seat front down
^ The diagnostic tool should show ON when the jumper lead is connected and OFF when it is removed.

Test results OK?
YES
^ Go to point 12.
NO
^ Repair or replace the wiring.
^ Go to point 16.

12. Check rear up
^ Connect a jumper lead between pin 5 and pin 10 of the male connector.

^ Read: seat rear up
^ The diagnostic tool should show ON when the jumper lead is connected and OFF when it is removed

Test results OK?
YES
^ Go to point 13.
NO
^ Repair or replace the wiring.
^ Go to point 16.

13.Check rear down
^ Connect a jumper lead between pin 4 and pin 10 of the male connector.

^ Read: seat rear down
^ The diagnostic tool should show ON when the jumper lead is connected and OFF when it is removed.

Test results OK?
YES
^ Go to point 14.
NO
^ Repair or replace the wiring.
^ Go to point 16.

14. Check backrest forward
^ Connect a jumper lead between pin 9 and pin 10 of the male connector.

^ Read: backrest forward
^ The diagnostic tool should show ON when the jumper lead is connected and OFF when it is removed.

Test results OK?
YES
^ Go to point 15.
NO
^ Repair or replace the wiring.
^ Go to point 16.

15. Check backrest back
^ Connect a jumper lead between pin 8 and pin 10 of the male connector.

^ Read: backrest back
^ The diagnostic tool should show ON when the jumper lead is connected and OFF when it is removed.

Test results OK?
YES
^ Replace: switch PSM
^ Go to point 16.
NO
^ Repair or replace the wiring.
^ Go to point 16.

16. Final check
^ Delete the diagnostic trouble codes in all systems.

^ Carry out a function check.

Test results OK?
YES
^ The steps taken to rectify the fault were correct.
NO
^ See "Before changing a control module."