Initial Inspection and Diagnostic Overview

A/C System in Passenger Compartment, General Information

• If there is a malfunction in the system, first check DTC memory of front A/C control head Climatronic Control Module (J255) (and of Rear A/C Control Head (Climatronic) (E265)).

• If no malfunction is indicated, read out measuring value block of front A/C control head Climatronic Control Module (J255) and actuate any faulty component via the "output Diagnostic Test Mode (DTM)" function.

• Servicing operations on A/C system that are possible without opening refrigerant circuit => [ A/C Refrigerant System, Servicing Notes ] A/C Refrigerant System, Servicing Notes

• Servicing operations on A/C system that require the refrigerant circuit to be opened => [ A/C Refrigerant System, Servicing Notes ] A/C Refrigerant System, Servicing Notes

• Electrical testing of the various control motors, potentiometers and sensors is described in Guided Fault Finding.

• After completion of repair perform the following:

- Check DTC memory of front A/C control head Climatronic Control Module (J255) (and of Rear A/C Control Head (Climatronic) (E265)) and erase any DTCs displayed.

- Check coding of front A/C control head Climatronic Control Module (J255).

- If necessary, check adaptation of front A/C control head Climatronic Control Module (J255) and of Rear A/C Control Head (Climatronic) (E265) (not installed in all vehicles, optional equipment).

- Perform basic setting of A/C system via front A/C control head Climatronic Control Module (J255) and Rear A/C Control Head (Climatronic) (E265) (not installed on all vehicles, optional equipment).