Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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Information on CAN



Information Transmitted Via The CAN Interface

The system communicates the following climate relevant operating and ambient conditions via the CAN interface:
- Outside temperature (via CAN from the front end control unit)
- Coolant temperature
- Vehicle speed (to assess the fresh air intake temperature)
- Engine speed
- Request 'Defrost rear windshield/door mirrors' (status on/off via CAN on the vehicle electrical system control unit)
- Cabriolet top open/closed
- Sun sensor
- Dimming (from instrument cluster)
- Wipe/wash signal
- Request 'Seat heating left' (status: on/off via CAN on the vehicle electrical system control unit)
- Request 'Seat heating right' (status: on/off via CAN on the vehicle electrical system control unit)
- Interior temperature (actual temperature via CAN to vehicle electrical system control unit)
- Request - a/c compressor (status on/off via CAN on the DME engine control unit)
- Pressure signal (indirect request for condenser cooling through provision of coolant pressure via CAN)
- A/C shutdown (e.g. high and low pressure shutdown)
- Diagnosis
- Stationary period since "ignition off" (from instrument cluster)
- Steering angle sensor - If control module detects lots of steering angle changes it drops the temperature a little without changing the driver's selection (for comfort of driver)