Open Loop Operation

Open loop operation means that the ECU is not correcting the air/fuel ratio based on oxygen sensor information. The ECU ignores exhaust oxygen sensor information even if the sensor is detecting an excessively rich or lean mixture. There are certain operating conditions where it is not desirable to operate the system in closed loop due to risk of catalyst overheating and driveability concerns. These conditions are:

• Engine starting

• Cold engine operation

• Moderate to heavy load operation

In open loop operation, a correction coefficient of 1.0 is used.

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.

Get My Free Ebook

Post a comment