A/C Pressure/Temperature Sensor -G395-, CHECKING PRESSURE SIGNAL

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NOTE:

The cooling output cannot be checked when the A/C Pressure/Temperature Sensor -G395- is removed. The Climatronic Control Module -J255- display and control head does not switch on the A/C compressor using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.

To check the measured values for the A/C Pressure/Temperature Sensor -G395- using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

The A/C Pressure/Temperature Sensor -G395- exchanges information with the Vehicle Electrical System Control Module -J519- via a local Data Bus. The Vehicle Electrical System Control Module -J519- transmits the data via the Data Bus to the Climatronic Control Module -J255- display and control head.

The temperature measured by the A/C Pressure/Temperature Sensor -G395- differs from the actual refrigerant temperature because of the A/C Pressure/Temperature Sensor -G395- design and its component location. Therefore it is not currently evaluated and is not used to regulate the A/C system.

Only the A/C Pressure/Temperature Sensor -G395- may be installed for this vehicle.

After switching off the A/C compressor in this vehicle, it may take a relatively long time for the pressure on the high pressure side to decrease. This is because the expansion valve is "cold" and the pressure on the low pressure side increases quickly after shutting the compressor off, then the expansion valve closes and the refrigerant flows slowly to the low pressure side.

Preliminary work

-- Turn off the ignition.

-- Remove the upper lock carrier cover. Refer to LOCK CARRIER COVER, REMOVING AND INSTALLING .

-- Disconnect the connector -A-.

Fig 1: Disconnecting Electrical Connector

Courtesy of AUDI OF AMERICA, LLC

Routing for the 3-pin connector on the A/C Pressure/Temperature Sensor -G395- -A-.

Ground
Signal output - via the local Data Bus to the Vehicle Electrical System Control Module -J519-
Terminal "75" (positive)

Test sequence:

-- Turn on the ignition.

-- Check the ground and positive connection to the terminal -A-.

-- Check the connection and the function of the A/C Pressure/Temperature Sensor -G395- using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.

NOTE:

The A/C compressor (A/C Compressor Regulator Valve -N280-) is not actuated when the connector -A- is disconnected.

The A/C Pressure/Temperature Sensor -G395- is an electronic control module over which exchanges information with the Vehicle Electrical System Control Module -J519- via a local Data Bus using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.