A/C Idle-Up Circuit Check (Equipped With A/C)

A/C amplifier sends an idle-up signal to PCM when A/C compressor clutch is in operation. PCM will activate Idle Speed Control (ISC) motor. ISC opens throttle plate to control engine speed to prevent rough idle or stalling condition. To check A/C idle-up circuit, see CIRCUIT TEST C1-2 under CIRCUIT TESTS.