Quiescent current in seat control unit
Topic number

LI91.10-P-049799

Version

3

Design group

91.10 Front seats

Date

01-10-2017

Validity

Model series 203, 209, 210, 211

Reason for change

Damage code deleted

Reason for block

Complaint:

Quiescent current in seat control unit

Cause:

The presence of a quiescent current can have several causes.
These are not always recognized and lead to an increased number of OK components being removed.
Possible Hall sensor faults or normalization faults can exist which can be eliminated without replacing the control unit.

Remedy:

Work through the following test procedure:
1. Power consumption:
Power consumption must be tested using a multimeter.
Quiescent current (CAN not active, the following voltages must be measured (10 V UBatt 15 V):
No-load current (CAN not active, backrest not folded, no seat adjustment): 300 µA
No-load current (CAN not active, backrest folded, no seat adjustment): 20 mA
Operating current (CAN active, no seat adjustment): 200 mA
Should the currents be outside the values described above, the following connectors should be removed in sequence.
Connector 11 (violet): Dynamic seat (FDS) if installed
Connector 8 (transparent): Height release switch (HES)
Connector 7 (pink): Backrest release switch (LES)
Connector 6 (orange): Backrest/head restraint motor (L/K)
Connector 5 (brown): Inclination adjustment (height at front) (HV)
Connector 4 (black): Fore/aft adjustment (LV)
Connector 3 (green): Height adjustment (height at rear) (HH)
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Connector 1 (black): CAN and steering column (CAN, LS)
If after disconnecting all the above listed connectors the current is outside the defined values, the seat control unit
must be replaced.
2. Normalization faults
If a normalization fault is stored without the corresponding Hall sensor fault, an adjustment for this adjustment shaft
must be performed in both directions. This ensures that after an inadvertent erasure of the Hall sensor fault this is set
again.
If the Hall sensor fault is not stored following adjustment in both directions, it is sufficient to carry out a new normalization.
If a Hall sensor fault is stored, see chapter "Hall sensor faults“.
3. Hall sensor faults
If Hall sensor faults are stored, the current status of the seat control unit is recorded first. The following information is
read out for this purpose:
Normalizing position of all shafts (except steering column, is not normalized)
Actual position of all shafts
Fault
Read the switch status for the release switch (note: seat adjustment is not possible if the backrest has been released)
The following test must be carried for all shafts with Hall sensor faults:
Read status (see "Read status“)
Erase fault
Move adjustment shaft for > 2 sec
Read status (see "Read status“)
Move adjustment shaft for > 2 sec in opposite direction
Read status (see "Read status“)
If Hall sensor faults are present after the test sequence, for these adjustment shafts the contacting must be checked
for loose contact and the lines for short circuits.
Hall sensor signal line: check for short circuit to UBatt and ground
Hall sensor ground line: check for short circuit to UBatt
Motor lines: check for short circuit to UBatt
All resistance measurements must be > 1 Mohm
If the wiring harnesses and connections were found to be OK, the seat control unit must be replaced.

Symptoms
Body / Seat / Seat adjustment / Function error
Overall vehicle / Power supply / Battery/On-board electrical system / Battery function / Battery discharges
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Control unit/fault code
Control unit

Fault code

ESA passenger-Electric seat adjustment front passenger (with memory) (ESVB1) (E
(211),CLK (209),C (203))

Fault text
-

Parts
Part number

ES1 ES2 Designation

Quantity Note

EPC

A2118704626

Control unit

1

Left seat control unit

X

A2118704726

Control unit

1

Right seat control unit

X

WIS-References
Document number

Title

ar54.10-p-1030-03p

Check no-load current

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Note

Allocation
Remedy

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