Fuel System Monitoring

Most fuel systems continually shift their base calibration to compensate for changes in atmospheric pressure, temperature, fuel composition, component variations, and other factors. This adaptive behavior is normal as long as it remains within the design limits of the system.

When conditions occur which cause the fuel system to operate outside of its design parameters, for example, a skewed air flow meter signal, incorrect fuel pressure, or other mechanical problems, the OBD-II system is designed to detect this abnormal operating condition. If the condition occurs for longer than a specified amount of time, a DTC will be stored. When a DTC stores, the engine speed, load, and warm-up status is stored in a retrievable serial data freeze frame.

Major OBD-II Features

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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