PRE-RELEASE
Steering wheel control, Sentronic
| Steering wheel control, Sentronic |
| General |
The steering wheel control consist of 3 units (9 switches) integrated in the steering wheel and airbag module. The steering wheel control provides SID information as to which of the switches is activated.
SID supplies +5V to the steering wheel control via pin 22 and grounds it via pin 9.
The 9 steering wheel switches consist of 9 resistors connected in series. When a button is pressed, the relevant switch is grounded; see table below.
When a connector is pressed, the total resistance in the circuit changes, as does the voltage value which SID then reads.
The horn switch (41) is connected in parallel with the steering wheel switches. When it is pressed, pin 22 is grounded directly to pin 9.
The table shows the correlation between the voltage on pin 22 and the switch that is activated.
|
Switch
|
Voltage (V)
|
Resistance (Ohms)
|
|
Horn
|
0
|
0
|
|
Shift gear up (+)
|
0,4
|
44
|
|
Shift gear down (-)
|
0,8
|
95
|
|
VOL -
|
1,2
|
160
|
|
VOL +
|
1,7
|
242
|
|
SRC (select audio source)
|
2,1
|
347
|
|
SEEK >>
|
2,5
|
494
|
|
<< SEEK
|
2,9
|
709
|
|
NXT (settings for audio sources)
|
3,3
|
1041
|
|
Normal
|
4,0
|
2511
|
SID uses the information from the steering wheel control to activate the horn, provide TCM information on upshifts/downshifts and to send bus information for audio functions.
For additional information on controlling the automatic gearbox using the steering wheel controls, see Sentronic .
| Diagnosis |
In the event of an open/short-circuit to B+ or a short-circuit to ground for more than 5 min, DTC B2371 is generated.
