Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pressure Sensor And Switch On Refrigerant Circuit
There are different versions of the pressure sensor and switch with different functions and with different names. Refer to REFRIGERANT CIRCUIT (R1234YF 2 OF 3) , or REFRIGERANT CIRCUIT (Climate control) , or REFRIGERANT CIRCUIT (R1234YF 3 OF 3) .
Switching pressures, removing and installing switches as well as switch arrangement and version. Refer to REFRIGERANT CIRCUIT (R1234YF 2 OF 3) , or REFRIGERANT CIRCUIT (Climate control) , or REFRIGERANT CIRCUIT (R1234YF 3 OF 3) .
- The high pressure sensor shown is installed for example on a Golf 7 and Audi A3. Refer to REFRIGERANT CIRCUIT (R1234YF 2 OF 3)
, or REFRIGERANT CIRCUIT (Climate control)
, or REFRIGERANT CIRCUIT (R1234YF 3 OF 3)
.
- When voltage is applied, a version of the pressure sensor generates a square-wave signal, this signal changes along with the pressure in the system. The other version of the pressure sensor when voltage is applied it exchanges information with the control module via the Data Bus (for example via the "LIN Bus") with the cosponsoring control module. Refer to Wiring Diagram and use the Vehicle Diagnostic Tester in the A/C system "Guided Fault Finding" function. For this reason pay attention to the correct version of the pressure sensor.
- There are different versions of the pressure sensor, their exterior currently only differs in part number, for this reason pay attention to the allocation when replacing. Refer to the Parts Information for the correct part number. Reason: These sensors produce different signals that can only be evaluated by the respective control modules. Use the Vehicle Diagnostic Tester "Guided Fault Finding" function for the A/C system. Refer to REFRIGERANT CIRCUIT (R1234YF 2 OF 3) , or REFRIGERANT CIRCUIT (Climate control) , or REFRIGERANT CIRCUIT (R1234YF 3 OF 3) .
- One version of the pressure sensor only transmits the measured value for the refrigerant circuit pressure to the connected control module. The other version transmits the measured value for the refrigerant circuit pressure and the measured temperature to the connected control module, for this reason pay attention to the version.
- The downstream control modules use this signal to calculate the refrigerant circuit pressure and activate the radiator fan and the motor, the A/C Clutch -N25- correspondingly or to change the activation of the A/C Compressor Regulator Valve -N280- using the Vehicle Diagnostic Tester in the A/C system "Guided Fault Finding" function. Refer to REFRIGERANT CIRCUIT (R1234YF 2 OF 3) , or REFRIGERANT CIRCUIT (Climate control) , or REFRIGERANT CIRCUIT (R1234YF 3 OF 3) .
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.