Required Cooling Output Not Reach, Malfunction Notification
Required Cooling Output Not Reach, Malfunction Notification
Test Continuation "The A/C compressor actuation is switched off"
Continuation of test: "Pressure in refrigerant circuit increases"
• The pressure in the refrigerant circuit depends on several factors. However, in general, the pressure should not exceed 20 bar (290 psi) at an ambient temperature of 20 to 25 °C (68 to 77 °F). Pressures up to 31 bar (450 psi) may occur due to extremely high performance under severe conditions (such as in southern countries with a hot climate, "stop and go" traffic and high humidity).
• At ambient temperatures below 25 °C (77 °F), pressure in refrigerant circuit does not normally exceed 16 bar (coolant fans run and cool condenser).
• The Climatronic control module calculates the pressure in the coolant circuit via the A/C pressure/temperature sensor (G395) and displays it using the Vehicle diagnostic tester in "Guided Fault Finding".
• At an absolute pressure less than approximately 1.8 bar (26 psi) and greater than approximately 32 bar (464 psi), the Climatronic control module does not switch on the A/C compressor (the A/C compressor regulator valve is not actuated). The A/C compressor is only switched on once the absolute pressure becomes greater than 1.8 bar (26 psi) or less than 16 bar (232 psi).
• Additional information regarding the pressure in the refrigerant circuit can be found in Guided Fault Finding using the Vehicle diagnostic tester in "Guided Fault Finding"
• If the pressure in the refrigerant circuit or the engine coolant temperature is too high, the Climatronic control module regulates the compressor performance (to avoid sudden A/C compressor cut-off). As soon as pressure in refrigerant circuit exceeds 30 bar (435 psi) (absolute pressure), full A/C compressor performance is only enabled again after pressure has become less than 27 bar (391 psi), or coolant temperature exceeds 115 °C (239 °F) (it is switched off completely at 118 °C (244 °F)).