TT Quattro Coupe V6-3.2L (CBRA) (2008)
High Pressure Sensor / Switch: Testing and Inspection
High Pressure Sensor, Checking Pressure Signal
Special tools, testers and auxiliary items required
‹› Assembly Tool (T10118)
‹› The cooling output cannot be checked when the High Pressure Sensor (G65) is removed. The Climatronic Control Module (J255) will not switch
on the A/C compressor. Refer to Vehicle Diagnosis, Testing and Information System VAS 5051 under "Guided Fault Finding".
‹› After switching off the A/C compressor on this vehicle, it may take a long time until the pressure on the high pressure side (the expansion valve is
cold and the pressure on the low pressure side increases quickly after switching off, the expansion valve closes and the refrigerant can flow slowly
on the low pressure side.
‹› Depending on the version of the High Pressure Sensor (G65), an insufficient measuring value for the pressure in the refrigerant system will be sent
by the High Pressure Sensor (G65) at low outside temperatures (lower than 5 °C) (even though the A/C system is OK and the refrigerant circuit is
properly filled). The Climatronic Control Module (J255) part number " 8J0 820 043" up to index "AJ" can register an incorrect DTC memory
entry at low outside temperatures (lower than 5 °C) (DTC memory entry: High Pressure Sensor (G65) "lower values are not met") If the fault is
displayed as a sporadic fault at an outside temperature greater than 5 °C, calculated by the A/C system, and if the A/C function is OK, then clear
the DTC memory (no additional steps are necessary). On the Climatronic Control Module (J255 ) part number "8J0 820 043" starting with index "
AK",this fault does not appear.
Test Sequence
The High Pressure Sensor (G65) - item B - is at the right on the bottom of the condenser.
-
Disconnect electrical connector - A -.
Routing 3-pin connector on High Pressure Sensor (G65)
1. Ground
2. Signal output - Square wave signal to Climatronic Control Module (J255) A/C control head
3. Terminal "75" (positive)
‹› With electrical connector - A - disconnected, the A/C compressor is not switched on.