Possible Deviation From Specified Value During The Pressure Test (10 Of 12)
WARNING: This page is about a different variant/trim than selected.
| Possible Deviation from Specified Value during the Pressure Test |
- High pressure normal or too high
- Low pressure too high.
- A/C compressor noise (particularly after switch-on)
- The required cooling output is not attained in the front heater and A/C unit evaporator and/or in the evaporator for cooling the high-voltage components.
|
| Possible causes for the deviation from specified value and their solutions |
- Activation of the A/C compressor is faulty. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function.
- If one of the valves installed in the refrigerant circuit is faulty or does not work correctly. Refer to Refrigerant Circuit
(vehicle-specific Service Information).
- One in or on the removed refrigerant circuit pressure/temperature sensor or temperature sensor sends incorrect values. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function. Refer to OVERVIEW - A/C SYSTEM
.
- Too much refrigerant in the circuit.
- Too much refrigerant oil in the circuit.
-- Check the measured values of the different pressure/temperature sensor and temperature sensor when operating the A/C system, and replace the components with incorrect measured values. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function. Refer to OVERVIEW - A/C SYSTEM
.-- Check the activation and function of the A/C compressor and service using the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function.-- Check the function and activation of the various valves and pressure/temperature sensors installed in the refrigerant circuit via the pressure distribution in the refrigerant circuit. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function. Refer to Refrigerant Circuit
(vehicle-specific Service Information).-- If no malfunction can be determined, extract the refrigerant from the refrigerant circuit.
- If quantity of refrigerant extracted is substantially greater than specified capacity:
-- Fill the refrigerant circuit and repeat the test.
- If quantity of refrigerant extracted roughly corresponds to specified capacity:
-- Check the activation and function of the A/C compressor and the valves installed in the refrigerant circuit (shut-off valve and expansion valve). Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function.-- Depending on the result, service the activation or replace the faulty component (shut-off valve, expansion valve, or A/C compressor as well as the receiver/dryer/dryer). Refer to Refrigerant Circuit
(vehicle-specific Service Information).-- If no malfunction can be determined, there may be too much refrigerant oil in the circuit, clean the refrigerant circuit (flush with refrigerant R1234yf. Refer to REFRIGERANT CIRCUIT, CLEANING
. |
| Final Procedures |
| -- Charge the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, CHARGING
.-- Repeat the test. Refer to ELECTRICALLY-DRIVEN A/C COMPRESSOR, CHECKING PRESSURE WITH A/C SYSTEM SWITCHED ON . |