DTC P0534: Low A/C Cycling Period

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.

P0534 - LOW A/C CYCLING PERIOD

Description:	Indicates frequent A/C compressor clutch cycling.
Possible Causes:	Mechanical A/C system concern (such as low refrigerant charge, damaged A/C cycling switch) Intermittent open between the cycling pressure switch and the powertrain control module (PCM) Intermittent open in the IGN RUN circuit to cycling pressure switch (if applicable)
Diagnostic Aids:	An intermittent open circuit, although possible, is unlikely. This test is designed to protect the transmission. In some strategies, the PCM unlocks the torque converter during A/C clutch engagement. If a concern is present that results in frequent A/C clutch cycling, damage could occur if the torque converter is cycled at these intervals. This test detects this condition, sets the DTC and prevents the torque converter from excessive cycling.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
All	-	-	GO to KM: Air Conditioning Clutch Relay (A/CCR) Circuit STEP KM11.