Heating Performance - With Manually Regulated A/C System

Heating Performance - With Manually 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.

• The A/C control module (J301) DTC memory was checked and erased, basic setting was performed 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 the engine and let it run for a few minutes with maximum cooling output. The A/C compressor is switched on, the indicator lamp in the AC button comes on and the temperature rotary switch is turned all the way to "cold".

- Set the air flow direction to "instrument panel vents" via the air distribution rotary switch.

- Set speed 4 on fresh air blower rotary switch.

- Measure temperature of the air flowing out of left and right instrument panel vents using a thermometer.

- Compare the measured values with the displayed measured value from the evaporator vent temperature sensor (G263). The measured values may not be smaller and after 5 minutes be greater than maximum 3 °C, than the value of the evaporator vent temperature sensor.

Target values:

• Temperature maximum 12 °C, depending on ambient temperature, the difference between the measured values is less than 3 °C.

- Set the highest possible temperature (temperature rotary switch turned all the way to "warm").

- Measure temperature of the air flowing out of left and right instrument panel vents using a thermometer.

Specified Values

• Temperature increases to greater than 55 °C at an engine temperature of approximately 90 °C, deviation between the left and right side is less than 8 °C.

- Set the lowest possible temperature (turn the temperature rotary switch all the way to "cold").

- Measure temperature of the air flowing out of left and right instrument panel vents using a thermometer.

Specified Values

• Temperature decreases within 5 minutes to less than 12 °C depending on ambient temperature.

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 temperature regulator door motor (V68) , check 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).