GF46.11-P-0001RC Steering Wheel Heater (LRH), Function
GF46.11-P-0001RC Steering wheel heater (LRH), function
- with CODE (443) Steering wheel heater
Function requirements, general
^ C. 15R On
The terminal status is transmitted from the EIS control unit (N73) via the interior CAN to the SIH, AIRSCARF and steering wheel heater control unit (N25/7).
Steering wheel heater general
It is possible to heat the steering wheel rim using the steering wheel heater.
The steering wheel heater is comprised of the following partial functions:
^ Manual on/off function sequence
^ Automatic switch off function sequence
Manual on/off function sequence
Operation takes place via the steering wheel heater switch (S59/1s2) on the steering column tube module (N80).
The steering wheel heater is switched on and off by a rotary motion of the steering wheel heater switch.
The request from the steering wheel heater switch is read in by the steering column tube module and transmitted via the interior CAN to the SIH, AIRSCARF and steering wheel heater control unit.
The SIH, AIRSCARF and steering wheel heater control unit actuates the steering wheel heater electronics (A74) as a result of this and thus energizes the heater coil (R22/4r1) in the steering wheel rim. At the same time the steering wheel heater function indicator (S59/1e1) in the steering wheel heater is actuated by the SIH, AIRSCARF and steering wheel heater control unit.
The steering wheel heater electronics measures the surface temperature of the steering wheel rim via the heater coil temperature sensor (R22/4b1) and regulates this to T = 35 degrees C.
Correct operation of the steering wheel heater is detected by the SIH, AIRSCARF and steering wheel heater in that every t = 15 s (± 3 s) a flank change in the power consumption occurs. The first current pulse is set at the latest t = 3 s after switching on the steering wheel heater.
In heating mode a current pulse is produced every t = 15 s (± 3 s) by interrupting the steering wheel heater for t = 200 ms (± 50 ms).
In the heating interval every t = 15 s (± 3 s) a current pulse is produced by energizing the heater coil I > 4.2 A for t = 200 ms (± 50 ms).
Automatic switch off function sequence
The timer control of t = 15 min is realized by the SIH, AIRSCARF und steering wheel heater control unit.
The steering wheel heater is shut off automatically after the period of time has elapsed.
The timer control of the steering wheel heater can be parameterized via STAR DIAGNOSIS in the SIH, AIRSCARF and steering wheel heater control unit.
Other shutoff criteria:
Shutting off during the starting process of the engine:
The timer control continues running, the steering wheel heater function indicator remains on. No under voltage is detected during start-up.
Shutting off after circuit 15R Off:
If circuit 15C continues to be On, the timer control continues running fort = 5 min. If circuit 15R is now switched on again, then the steering wheel heater is also switched on.
Shutting off in the event of under voltage:
In the event of under voltage the SIH, AIRSCARF und steering wheel heater control unit shuts off the steering wheel heater.
The timer control continues running and the steering wheel heater function indicator flashes.
Switching on again is only possible after a permissible voltage is applied again.
Shutting off in the event of overtemperature:
If the interior temperature value T > 30 degrees C from:
- Automatic heater control and operating unit (N18) (without code (580) Automatic air conditioning and without code (581) Comfort automatic air conditioning)
- AAC [KLA] control and operating unit (N22) (with code (580) Automatic air conditioning)
- Comfort AAC control and operating unit (N22/7) (with code (581) Comfort automatic air conditioning)
Reports via the interior CAN to the SIH, AIRSCARF und steering wheel heater control unit, this switches off the steering wheel heater.
The shutoff temperature of the steering wheel heater can be parameterized via STAR DIAGNOSIS in the SIH, AIRSCARF and steering wheel heater control unit.
If no plausible interior temperature value is present, the outside temperature value is used instead.
Cutting out in the event of over voltage:
In the event of over voltage the SIH, AIRSCARF and steering wheel heater control unit cuts out.
The timer control continues running, the function indicator of the steering wheel heater remains on. Switching on again is only possible after a permissible voltage is applied again.
Cutting out in the event of a hardware defect of the steering wheel heater electronics:
If the current pulses do not come at the expected point in time or assume undefined values, the SIH, AIRSCARF and steering wheel heater control unit switches off the steering wheel heater and the steering wheel heater function indicator.
A flank change must occur with t = 3 s once the steering wheel heater has been switched on again. If the flank changes do not appear in the specified time frames, in addition a fault message is stored in the SIH, AIRSCARF and steering wheel heater control unit.
