A/C System Control and Regulation Components Inside Passenger Compartment

A/C System Control and Regulation Components Inside Passenger Compartment

• If there is an A/C system malfunction, check the event memory of the Climatronic control module (J255) (and the Rear A/C display control head (E265) using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function. If another control module displays an instruction to read out the event memory, also read out the event memory for this control module (for example the Vehicle electrical system control module (J519) or the Comfort system central control module (J393) ).

• Certain components of the A/C system (for example, the A/C compressor regulator valve (N280) , the A/C pressure/temperature sensor (G395) ) are not evaluated directly by the Climatronic control module or their measured values are not evaluated directly by the Climatronic control module. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• If no malfunction is displayed, read out the relevant measured values of the control head, the Climatronic control module (and the Rear A/C display control head) and actuate any problematic component via the "output diagnostic test" function of the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• Electrical test of the various control motors, potentiometers, and sensors can be conducted using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• Certain A/C system functions can be switched on and off via the MMI (Multi Media Interface) under the "A/C system" function in the "Car"/"Car systems" menu. The A/C system control can also be influenced via presettings in the MMI (Multi Media Interface) under the "A/C system" function in the "Car"/"Car systems" menu. Therefore, first check the presetting in the MMI in the case of a problem with these components. Refer to Infotainment/MMI operating instructions.

• Temperature-dependent resistance values of the various temperature sensors are stored in tables. These can be called up using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• Repairing the A/C system without opening the refrigerant circuit, refer to => [ Refrigerant Circuit Components Overview ] Refrigerant Circuit Components Overview.

• Repair work on the A/C system that requires opening the refrigerant circuit, refer to => [ Refrigerant Circuit, Servicing ] Refrigerant Circuit, Servicing.

After completion of the repair work, perform the following steps on the Climatronic control module and the Rear A/C display control head, if present, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function:

- Read out the event memory and erase any displayed entries.

- Check the coding.

- Check the adaptation as necessary.

- Perform the basic setting.

Overview

• => [ A/C System - Front Passenger Compartment Overview ] A/C System - Front Passenger Compartment Overview.

• => [ Rear Passenger Compartment Overview ] Rear Passenger Compartment Overview.