A/C Efficiency Check

Air-conditioning efficiency measurement (R134a)
64 50 ...

Before the air-conditioning efficiency measurement, a number of conditions must be met:
1. Ensure the electrical system integrity by checking the fault memory (no faults in the fault memory).
2. Provide a thermometer with a separate display element.
Position a thermometer with a separate display element approx. 5 cm under the headlining at the height of the B-pillar. Route the display element from the vehicle interior outwards.
3. Perform the check in a suitable work bay with an ambient temperature between 20° C (68° F) and 30° C (86° F).
Heat up the vehicle interior:
- The A/C button is not activated on heating up
- Close all windows and doors
- Set the recirculated-air mode
- Select air distribution footwell and defrosting
- Maximum temperature setting
- Maximum blower speed
- Run the engine at approx. 2000 rpm until operating temperature is reached, then idle speed

Air-conditioning efficiency measurement:
Once the vehicle interior has reached a temperature of 50° C (122° F), switch on the air-conditioning compressor. After 3 - 4 minutes, the temperature at the evaporator temperature sensor must be ≤ 15° C (59° F).