Air Conditioning Compressor Signal AC

The A/C signal to the ECU is used to determine when the air conditioning compressor is loading the engine. The signal is used primarily as an indication to increase ISC air flow to stabilize idle speed. The A/C input is also used by the ECU to modify ignition timing and deceleration fuel cut parameters during compressor operation periods. When the A/C signal is high and the IDL contact is closed, the ECU limits minimum ignition spark advance angle. Additionally, decel fuel cut rpm is increased. In the event that this signal malfunctions, idle quality may suffer and driveability during deceleration could be affected.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

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