Possible deviation from specified value during the pressure test (11 Of 32)
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| Possible deviation from specified value during the pressure test |
- The required cooling output is reached at first in the evaporator in the heater and A/C unit (and in the evaporator for battery cooling) after some time or after a longer running time the cooling output is no longer sufficient.
- The high pressure and low pressure are normal.
- After some time the high pressure raises above the specified value, the low pressure corresponds to the specified value or it falls under the specified value.
|
| Possible causes for the deviation from specified value and their solutions |
- Radiator for coolant, condenser is contaminated or the activation of the radiator fan is not OK.
-- Check the activation of the radiator fan and if necessary service. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding
" function of the A/C system.-- Check the condenser and radiator for the condenser for contamination and if necessary clean. Refer to REFRIGERANT CIRCUIT
(vehicle-specific service information) and [FOR ENGINE(S) DDSB, DDSA] RADIATOR/RADIATOR FAN
.
- Activation of function of the A/C compressor (or if equipped the Refrigerant Shut-Off Valve 1 -- or the Refrigerant Shut-Off Valve 2 --) is faulty.
- Moisture in refrigerant circuit
-- Check the activation of the A/C compressor (and if equipped the Refrigerant Shut-Off Valve 1 -- and the Refrigerant Shut-Off Valve 2 --) and the measured value of the Evaporator Vent Temperature Sensor -G263-. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding
" function.-- If the activation of the A/C compressor (and if equipped the Refrigerant Shut-Off Valve 1 -- and the Refrigerant Shut-Off Valve 2 --) as well as the measured value of the Evaporator Vent Temperature Sensor -G263- is OK extract the refrigerant from the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, DISCHARGING
.
- Too much refrigerant in the refrigerant circuit
- Expansion valve malfunctioning.
- If a shut-off valve installed in the refrigerant circuit does not open or opens incorrectly. Refer to REFRIGERANT CIRCUIT
(vehicle-specific service information).
- Moisture in refrigerant circuit
-- Extract refrigerant from the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, DISCHARGING
.-- If the extracted refrigerant quantity is substantially greater (more than 100 g) than the specified capacity. (refer to TECHNICAL DATA
(vehicle-specific service information), there is too much refrigerant in the refrigerant circuit. Fill the refrigerant circuit and repeat the test.-- If the extracted refrigerant quantity meets the specified capacity is only slightly greater than the specified capacity (maximum 100 g) (refer to TECHNICAL DATA
(vehicle-specific service information) too much refrigerant oil is in the refrigerant circuit. Clean the refrigerant circuit (flush with refrigerant R1234yf) (refer to REFRIGERANT CIRCUIT, CLEANING
) fill with the correct quantity of refrigerant and refrigerant oil and repeat the test.-- If equipped, check the function of the installed shut-off valve. Refer to REFRIGERANT CIRCUIT
(vehicle-specific service information).-- Replace the expansion valve and desiccant bag/dryer cartridge (or reservoir/receiver/dryer). Refer to COMPONENTS, REPLACING
and 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 . |
NOTE:
If there is too much refrigerant oil in the circuit, the A/C compressor must be discharged and the reservoir/receiver/dryer (or dryer cartridge) replaced. Refer to REFRIGERANT CIRCUIT
(vehicle-specific service information). After cleaning the refrigerant circuit (flushing with refrigerant R1234yf refer to REFRIGERANT CIRCUIT, CLEANING
) fill it with the correct quantity of refrigerant oil in the refrigerant circuit. Refer to TECHNICAL DATA
(vehicle-specific service information).
Check the measured values of the Evaporator Vent Temperature Sensor -G263- and the activation of the A/C compressor. If the measured value of the Evaporator Vent Temperature Sensor -G263- or the activation of the A/C compressor is faulty, the evaporator can freeze-up or the cooling output is not reached. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding
" function for the A/C system and the battery regulation and refer to COMPONENT LOCATION OVERVIEW - A/C SYSTEM
and A/C COMPRESSOR
(vehicle-specific service information).
With this malfunction, evaporator may ice up although the quantity of refrigerant in circuit is OK.
Likewise, the refrigerant circuit may become iced if there is a malfunction on the Evaporator Vent Temperature Sensor -G263- or / and on the Temperature Sensor after Hybrid Battery Evaporator --. For this concern also pay attention to the measured value of the Evaporator Vent Temperature Sensor -G263- and the Temperature Sensor after Hybrid Battery Evaporator -- (on vehicles with battery cooling module). Use the Vehicle Diagnostic Tester in the "Guided Fault Finding
" function of the A/C system and the battery regulation and refer to COMPONENT LOCATION OVERVIEW - A/C SYSTEM
(vehicle-specific service information).