Possible Deviation From Specified Value During The Pressure Test (7 Of 11)
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| Possible Deviation from Specified Value During the Pressure Test |
- The required cooling output is not attained in the heater and A/C unit evaporator (and in the evaporator for battery cooling).
- The high pressure pipe corresponds to the specified value
- Low pressure quickly drops to specified value or lower.
|
| Possible causes for the deviation from specified value and their solutions |
- A/C compressor activation or functionality malfunctioning.
- Constriction or obstruction in refrigerant circuit
-- Check the activation and function of the A/C compressor and service. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function of the A/C system and the battery regulation. If not error can be determined run hand over refrigerant circuit to check for differences in temperature. Refer to Refrigerant Circuit
(vehicle-specific Service Information).-- If difference in temperature is found at one component: If the hose or pipe is kinked or constricted, replace this component. Refer to Refrigerant Circuit
(vehicle-specific Service Information). If there is a blockage clean the refrigerant circuit (flush with refrigerant R1234yf). Refer to REFRIGERANT CIRCUIT, CLEANING
.
- There is too little refrigerant in the refrigerant circuit.
-- Extract refrigerant from the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, DISCHARGING
.-- If the extracted refrigerant quantity is significantly less than the specified capacity (more that 100 g (3.5 oz). Refer to Technical Data
(vehicle-specific Service Information), and look for leaks and correct. Refer to LEAKS, FINDING
.-- If the extracted refrigerant quantity corresponds to the capacity or is only slightly smaller (maximum 100 g (3.5 oz)) check the expansion valve and shut-off valve for function. Refer to Technical Data
(vehicle-specific Service Information) and Refrigerant Circuit
(vehicle-specific Service Information).
- The expansion valve for the evaporator in the heater and A/C unit is faulty. Refer to Refrigerant Circuit
(vehicle-specific Service Information).
- A refrigerant shut-off valve is faulty (closed). Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"
function for the A/C system and the battery regulation. Refer to Refrigerant Circuit
(vehicle-specific Service Information).
-- If equipped check the function of the installed shut-off valve. Refer to Refrigerant Circuit
(vehicle-specific Service Information).-- Replace the expansion valve for the evaporator in the heater and A/C unit. Refer to Refrigerant Circuit
(vehicle-specific Service Information). |
| 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 . |