Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

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Refrigerant Pressure Sensor / Switch: Testing and Inspection

A Tech 1 scan tool displays A/C refrigerant pressure in psi. The sensor's range and corresponding display should be in the range of 0 to 450 psi. A sensor or circuit problem should set DTC 66. A poor ground at the sensor will result in a fixed high pressure value on the Tech 1 scan tool display. Testing and Inspection