Steering Wheel Heater (LRH), Function - GF46.11-P-0001GW
Model 463
as of model year 2013
with code VL0 (Heated steering wheel)
Shown on vehicles as of 03.04.2018, except model 463.342
Shown on vehicles up to 02.04.2018 or model 463.342
Function requirements, general
- Terminal 15R On:
As of 02.04.2018 (except model 463.342) the electronic ignition lock control unit sends the status of circuit 15 over the suspension FlexRay, steering column tube module control unit and the steering wheel CAN to the steering wheel electronics.
Up to 02.04.2018 or with model 463.342 the electronic ignition lock control unit sends the status of circuit 15 over the suspension CAN 1, steering column tube module control unit and the steering LIN to the steering wheel electronics.
- Interior temperature T < 30°C:
As of 02.04.2018 (except model 463.342) the climate control unit sends the interior temperature value over the interior CAN, electronic ignition lock control unit, suspension FlexRay, steering column tube module control unit and the steering wheel CAN to the steering wheel electronics.
Up to 02.04.2018 or for model 463.342 the climate control and operating unit sends the interior temperature value over the interior CAN, electronic ignition lock control unit, suspension CAN 1, steering column tube module control unit and the steering LIN to the steering wheel electronics.
Steering wheel heater, general
It is possible to heat the steering wheel rim using the steering wheel heater.
The steering wheel heater function includes the following subfunctions:
- Manual on/off function sequence
- Function sequence for automatic switch off
Manual on/off function sequence
The steering wheel heater switch integrated into the steering column adjustment and the steering wheel heater switch are used for operation. The steering wheel heater is switched on or off by turning the steering wheel heater switch.
The request of the steering wheel heater switch is read in by the steering column tube module control unit and as of 03.04.2018 (except model 463.342) sent over the steering wheel CAN or up to 02.04.2018 or for model 463.342 over the steering LIN to the steering wheel electronics. Based on this, the steering wheel electronics activates the steering wheel heater heating element in the steering wheel rim.
For visual feedback about the steering wheel heater, the steering wheel electronics sends the request to switch on the steering wheel heater indicator lamp as of 03.04.2018 (except model 463.342) over the steering wheel CAN or up to 02.04.2018 or for model 463.342 over the steering LIN to the steering column tube module control unit, which directly actuates the steering wheel heater indicator lamp.
The heating element temperature sensor measures the surface temperature of the steering wheel rim and transmits the value to the steering wheel electronics.
The steering wheel electronics regulates the surface temperature of the steering wheel rim to T = 35°C.
Function sequence for automatic switch off
The steering wheel heater is switched off automatically if one of the following events occurs:
- Switch-off by timer control
The timer control is implemented by the steering wheel electronics. After expiry of t = 15 minutes, the steering wheel heater is switched off. The steering wheel heater timer control can be parameterized through the diagnosis tester.
- Shut-off in the event of a hardware defect
If an actuation of the steering wheel heater is detected without an existing request or function requirement, then the steering wheel heater is switched off and a fault message is stored in the fault memory.
- Switch-off in the event of overtemperature
If the interior temperature exceeds T = 30°C, the steering wheel heater is switched off. The steering wheel heater indicator lamp remains on. If the vehicle interior temperature drops below T = 30°C, the steering wheel heater is automatically switched on again. The cutout temperature of the steering wheel heater can be parameterized through the diagnosis tester.
As of 02.04.2018 (except model 463.342) the climate control unit sends the interior temperature value over the interior CAN, electronic ignition lock control unit, suspension FlexRay, steering column tube module control unit and the steering wheel CAN to the steering wheel electronics.
Up to 02.04.2018 or for model 463.342 the climate control and operating unit sends the interior temperature value over the interior CAN, electronic ignition lock control unit, suspension CAN 1, steering column tube module control unit and the steering LIN to the steering wheel electronics.
If no plausible interior temperature value is present, the outside temperature value is used instead.
- Switch-off in the event of a fault (short circuit, overload or line break)
The steering wheel electronics detects a possible short circuit, overload or a line break in the respective steering wheel heater heating element and deactivates the power supply. The fault sources that have been listed can be diagnosed individually using a diagnostic tester.
- Switch-off during engine start
The steering wheel heater is switched off briefly when the engine is started. The timer control continues running, the steering wheel heater indicator lamp also remains on. No undervoltage assessment takes place during startup.
- Switching off by means of energy management
In order to prevent the battery from discharging in all driving cycle phases, the state of charge is continuously evaluated. Depending on the situation, the steering wheel heater is also switched off if necessary.
If the steering wheel heater is switched off, the steering wheel heater indicator lamp initially remains switched on. If the on-board electrical system reaches the specified voltage again with a subsequent period of t = 3 min, the steering wheel heater is automatically started. If the shutoff lasts for longer than t = 3 min, the steering wheel heater indicator lamp is also switched off. If the shutoff continues and the function is requested again, the steering wheel heater indicator lamp lights up for t = 1.5 s and then goes out again.
- Switch-off after circuit 15R OFF
The steering wheel heater is also switched off when circuit 15R is switched off. If circuit 15C remains ON, the timer control runs on for t = 5 minutes. If circuit 15R is now switched on again, the steering wheel heater is also switched on.
- Shutoff at end of diagnosis
After diagnosis has finished, the steering wheel heater is switched off.
| Function schematic of electrical system for steering wheel heater | Model 463 (except 463.342) as of model year 2019 with code VL0 (Heated steering wheel) | PE46.11-P-2050-97ZGB | |
| Model 463 (except 463.342) as of model year 2013 up to model year 2019 with code VL0 (Heated steering wheel) Model 463.342 as of model year 2013 with code VL0 (Heated steering wheel) | PE46.11-P-2050-97ZGA | ||
| Overview of system components of comfort heating systems | GF91.30-P-9990GW |