Supersedes Technical Service Bulletin Group 87 number 12-37 dated November 16, 2012. Air conditioning is inoperative. The HVAC blower functions normally. Battery discharged; however, when charged, there is no bus silence when vehicle ignition is off. The A/C pressure/temperature sensor, G395, leaks refrigerant. This causes sensor G395 to show an incorrect or implausible value when reading MVBs. An incorrect signal or a low refrigerant level in the system can cause the air conditioning compressor to deactivate. The LIN cable connecting the vehicle electrical system control module, J519, to sensor G395 is pinched or cut. This affects the A4/S4, A5/S5 Coupe and Cabriolet, and Audi Q5 vehicles. The A6 and A8 are not affected by this type of failure. The pressure sensor G395/G65 sends an incorrect signal that prevents bus silence and the battery is discharged. Sensor G395 is a LIN slave of the vehicle electrical system control module. The vehicle electrical system control module transfers the information provided by the sensor via the comfort data bus to the climate control module, J255.
