Operation CHARM: Car repair manuals for everyone.

Test Step 5






Test Step 5

Pressure signal of the high pressure sensor (G65)













The pressure and thus the duty cycle change with the ambient temperature in a refrigerant circuit filled with the correct amount of refrigerant.

The duty cycle and pressure calculated by the Climatronic control module (J255) A/C control head are indicated in the measured value block (display group "001").

The signal that is transferred when the pressure in the refrigerant circuit is approximately 5 to 6 bar corresponds to an approximate duty cycle of 22% (with compressor not engaged, an ambient temperature of 20°C, and a properly filled refrigerant circuit).

The signal transmitted at an absolute pressure in the refrigerant circuit of approx. 16 bar corresponds to a duty cycle of approx. 50%. This only occurs when the compressor is off under extreme conditions (e.g. very high ambient temperature and a hot engine).