64 50... A/C performance test

Observe the following conditions prior to the A/C performance test: 

1. Connect diagnosis system. Check of the fault memory (no faults in the fault memory).
2. Attach a thermometer with separate display element to the head restraint. Lay display element outwards out of passenger compartment.
3. Perform the test in a suitable workshop area with an ambient temperature above 18° C.
4. Vehicle temperature should be approximately the same as the ambient temperature in the workshop.
5. Engine must be at operating temperature (does not apply for electric vehicles).

Heat passenger compartment: 

• "A/C button" is not  activated during the heating process
• Close all windows and doors.
• Set air recirculation function.
• Select air distribution mode for footwell and defrosting.
• On vehicles with CID:  In A/C menu (CID) in Air distribution index tab: select 100 % footwell for driver and front passenger and 100 % defrosting for driver (this applies here to driver and front passenger)
• Maximum temperature setting
• Maximum blower speed
• Start engine (does not apply for electric vehicles)

Cool down passenger compartment: 

Switch on air conditioning compressor with "A/C button" at a vehicle interior temperature of 45 °C (measured at the head restraint).

On vehicles with MAX-AC button: 

• Activation of MAX-AC (= maximum cooling power)

On vehicles without MAX-AC button: 

• Set maximum cooling power by means of following steps:
  • Setting minimum temperature
  • Blower setting maximum
  • Stratification maximum cold (4 blue bars)
  • Only ventilation open
  • Close remaining flaps (air outlet only  from center fresh air grille, left and right)

After 5 minutes measure both ventilation temperatures with a thermometer at the same time (fresh air grille center, left and right). The measured temperature must be ≤ 16 °C and the difference between right and left may not be greater than 2 °C.

If one or both temperature specifications is not reached, drain-off HEATING AND AIR CONDITIONING SYSTEM . Measure amount of refrigerant drawn off.

If drawn-off quantity does not correspond to SPECIFIED FILL QUANTITY : supplement refrigerant and repeat test.

If capacity is correct, continue troubleshooting by pressure measurement.