A/C Pressure/Temperature Sensors

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Audi SQ5, 2024 Audi Q5 e, 2024 Audi Q5, 2023 Audi SQ5, and 2023 Audi Q5 e. However, it is still accessible from the selected car via links, so may be relevant.

There are different versions of this sensor with different functions and with different names. For the exact name, allocation and information about the respective function, refer to Refrigerant Circuit (vehicle-specific Service Information).

WARNING:

There is a risk of freezing.

Refrigerant may leak out if the refrigerant circuit is not discharged.

There are different versions of this sensor (sensor for a connection on the refrigerant circuit with or without a valve). Refer to Refrigerant Circuit (vehicle-specific Service Information).

Before loosening the sensor threaded connection, check the version. Refer to Refrigerant Circuit (vehicle-specific Service Information).
On a sensor for a connection on the refrigerant circuit without a valve. The refrigerant must be extracted before loosening the threaded connection. If the sensor is not removed within 10 minutes after extraction, pressure may build up in refrigerant circuit due to evaporation. Extract the refrigerant again.

Sensor for Connection with Valve on Refrigerant Circuit

NOTE:

There are different versions of this sensor with different functions and with different names. For example, the following illustrated A/C Pressure/Temperature Sensor -G395- is installed on an Audi A4, Audi Q5, and Audi Q5 hybrid. Refer to Refrigerant Circuit (vehicle-specific Service Information).

There are various designations, depending on the function and the vehicle. Refer to Refrigerant Circuit (vehicle-specific Service Information).

Possible names for this sensor

Fig 1: A/C Temp/Pressure Sensor G65 / G395

Courtesy of AUDI OF AMERICA, LLC

A/C Pressure/Temperature Sensor -G395- (for example on Audi Q5 hybrid)
High Pressure Sensor -G65- (for example on Audi A4)
Refrigerant Circuit Pressure Sensor -G805- (for example on Audi A3 e-tron)

NOTE:

The Refrigerant Circuit Pressure Sensor -G805- is installed instead of the High Pressure Sensor -G65- or the A/C Pressure/Temperature Sensor -G395-, for example. Refer to Refrigerant Circuit (vehicle-specific Service Information).

There are different versions of the A/C Pressure/Temperature Sensor -G395-, the Refrigerant Circuit Pressure Sensor -G805- and the High Pressure Sensor -G65-. Depending on the version, they currently only differ externally by the part number. Therefore pay attention to the correct allocation when replacing (for the part number, refer to the Parts Information). Reason: These sensors produce different signals that can only be evaluated by the respective control modules. Refer to Vehicle Diagnostic Tester (function "OBD" or "Guided Fault Finding" for the A/C system) and Refrigerant Circuit (vehicle-specific Service Information).
When voltage is applied, the A/C Pressure/Temperature Sensor -G395- and the Refrigerant Circuit Pressure Sensor -G805- exchange information via the data bus (for example via the "LIN bus") with the corresponding control module. The relevant control module uses this information to calculate the pressure (and temperature) in the refrigerant circuit and any faults detected are reported to the control module.
The A/C Pressure/Temperature Sensor A/C Pressure/Temperature Sensor -G395- transmits the measured value for the refrigerant circuit pressure and the measured temperature to the connected control module. The Refrigerant Circuit Pressure Sensor Refrigerant Circuit Pressure Sensor -G805- only transmits the measured value for the refrigerant circuit pressure to the connected control module. Even if only the pressure signal is evaluated on most vehicles, no Refrigerant Circuit Pressure Sensor Refrigerant Circuit Pressure Sensor -G805- is or will be installed in a vehicle in which an A/C Pressure/Temperature Sensor A/C Pressure/Temperature Sensor -G395- is intended. Refer to the Parts Information.
The temperature measured by the A/C Pressure/Temperature Sensor -G395- differs from the actual refrigerant temperature in the refrigerant circuit because of the A/C Pressure/Temperature Sensor A/C Pressure/Temperature Sensor -G395- version and its component location. Therefore it is not currently evaluated by all control modules and is not used to regulate the A/C system. Refer to Refrigerant Circuit (vehicle-specific Service Information).
For example, the Climatronic Control Module -J255- display control head or the Vehicle Electrical System Control Module -J519- use this information to calculate the refrigerant circuit pressure and activates the control modules downstream (radiator fan control module, engine control module, etc.) via the data bus. These control modules then actuate, for example, the A/C Clutch -N25-, the radiator fans and the motor. Refer to Vehicle Diagnostic Tester (function "OBD" or "Guided Fault Finding" and Refrigerant Circuit (vehicle-specific Service Information).

Sensor for Connection without Valve on Refrigerant Circuit

NOTE:

There are different versions of this sensor with different functions and with different names. For example, the following illustrated A/C Pressure/Temperature Sensor -G395- is installed on an Audi Q7 e-tron. Refer to Refrigerant Circuit (vehicle-specific Service Information)

There are various designations, depending on the function and the vehicle. Refer to Refrigerant Circuit (vehicle-specific Service Information).

Possible names for this sensor

Fig 2: A/C Temp/Pressure Sensor G395 -- G826 -- G827

Courtesy of AUDI OF AMERICA, LLC

A/C Pressure/Temperature Sensor -G395- (for example on Audi Q7 e-tron)
A/C Pressure/Temperature Sensor 2 -G826- (for example on Audi Q7 e-tron)
A/C Pressure/Temperature Sensor 3 -G827- (for example on Audi Q7 e-tron)

There are different versions of this sensor -A-. Depending on the version, their exterior currently only differs in part number, or in imprinted designation -B- with the same part number. Therefore pay attention to the correct allocation (part number and designation) when replacing. Refer to the Parts Information and Refrigerant Circuit (vehicle-specific Service Information).

These sensors exchange information with the respective control module via the data bus (for example via the "LIN bus") when voltage is applied. The relevant control module uses this information to calculate the pressure (and temperature) in the refrigerant circuit and any faults detected are reported to the control module. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

The respective control module uses this information to calculate the refrigerant circuit pressure and to activate the control modules or components downstream (radiator fan control module, pumps, valves etc.) via the data bus according to the specifications. Use the in the "Guided Fault Finding" function and refer to Refrigerant Circuit (vehicle-specific Service Information).