Malfunction Determination - Cooling Output of Front A/C System OK But Required Values Not Achieved In Rear - Basic System

Malfunction Determination - Cooling Output of Front A/C System OK but Required Values Not Achieved In Rear - Basic System

• For testing the cooling output in the rear, the temperature of the air from the rear center console vents is measured with a thermometer.

Requirement for this test:

• The cooling output of the A/C system was checked and is OK. Refer to => [ Cooling Output, Checking ] Cooling Output, Checking.

- Ensure that the air outlet from the rear footwell vents (under the front seats) is not blocked by floor mats or other objects.

- In the "Read measured values" function of the Climatronic control module (J255) , select the display group with the measured values of the evaporator vent temperature sensor (G263) using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

- Repeat the cooling performance test. Refer to => [ A/C Unit, Checking Cooling Output ] A/C Unit, Checking Cooling Output.

- Use a thermometer to measure the temperature of the air from the vents in the left and right rear center console (the measured values correspond to the temperatures previously measured by the evaporator vent temperature sensor (G263) , permissible deviation + 9° C (48 °F). Refer to => [ Cooling Output, Checking ] Cooling Output, Checking).

• Since the air cooled by the A/C unit must flow backward through the air guide channel under the center console, it may take some time for the air at the rear vents to reach the required values.