Heating Performance - With Automatically Regulated A/C System
Heating Performance - With Automatically Regulated A/C System
Test Requirements
• Coolant circuit has been bled according to specifications.
• All air guides, covers and seal OK and properly installed.
• Air flow through dust and pollen filter not obstructed by dirt.
• Engine is warm.
• DTC memory of Climatronic Control Module (J255) display and control head was checked and erased, basic setting was performed using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.
• The Climatronic Control Module coding has been checked using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.
• The Climatronic Control Module adaptation has been checked using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.
• Vehicle not exposed to sunlight
Heating Performance, checking
- Close hood.
- Close doors, windows and sun roof.
- Initiate a Guided Fault Finding on the A/C system using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.
- Open all dash panel vents.
- Start engine and let it run for several minutes with maximum cooling output (A/C compressor is switched on, temperature preselect "LO" for left and right sides).
- Read the measured values for the left vent temperature sensor (G150) and right vent temperature sensor (G151) using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.
- Check and compare the displayed measured values.
• Temperature maximum 12 °C (depending on ambient temperature), deviation between measured values less than 3 °C.
- Set air distribution to instrument panel vents.
- Set temperature preselect for left side (driver side) on Climatronic Control Module (J255) to "Hi".
- Read the left vent temperature sensor and right vent temperature sensor displayed measured values.
Specified Values
• In the display field with the measured value for the left vent temperature sensor the temperature goes above 55 °C when the engine temperature is approximately 90 °C. In the display field with the measured value for the right vent temperature sensor the temperature goes up less than 10 °C.
- Set temperature preselect for right side (front passenger side) on Climatronic Control Module (J255) to "Hi".
- Read the displayed measured values for the left vent temperature sensor and right vent temperature sensor.
Specified Values
• In the display field with the measured value for the right vent temperature sensor, the temperature increases to approximately the engine temperature; the difference between the display fields for the measured fields of the left vent temperature sensor and the right vent temperature sensor is less than 8 °C.
- Set temperature preselect for driver side on Climatronic Control Module (J255) to "Lo".
- Read the displayed measured values for the left vent temperature sensor and right vent temperature sensor.
Specified Values
• Temperature for left side (driver side) decreases within 5 minutes to less than 12 °C depending on ambient temperature.
- If necessary, perform this test step for front passenger side in the same way.
If the specified values are not reached, check the following:
- Ventilation of coolant circuit.
- Incorporation of heater core for heater in A/C unit into coolant circuit.
- Activation and function of left temperature door motor (V158) and of right temperature door motor (V159) using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.
- Foam seal on heater core for heater of A/C unit. Refer to=> [ Heater Core ] Heater Core.
- Function of temperature doors in air distribution housing. Refer to=> [ Air Routing and Distribution in Passenger Compartment ] Air Routing and Distribution In Passenger Compartment.
- Coolant regulator (engine coolant may not warm properly if regulator is malfunctioning).