The engine control module (ECM) learns the airflow through the throttle body to ensure the correct idle. The learned airflow values are stored within the ECM. These values are learned to adjust for production variation and will continuously learn during the life of the vehicle to compensate for reduced airflow due to throttle body coking. Anytime the throttle body airflow rate changes, for example due to cleaning or replacing, the values must be relearned.
An engine that had a heavily coked throttle body that has been cleaned or replaced may take several drive cycles to learn out the coking. To accelerate the process, the scan tool has the ability to reset all learned values back to zero. A new ECM will also have values set to zero.
The idle may be unstable or a DTC may set if the learned values do not match the actual airflow.
Note:
Do NOT perform this procedure if DTCs are set. Refer to Diagnostic Trouble Code (DTC) List - Vehicle.
Note:
During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn.
Customer Satisfaction Procedure
Your satisfaction and goodwill are important to your dealer and to Chevrolet.
Normally, any concerns with the sales transaction or the operation of the vehicle
will be resolved by your dealer's sales or service departments. Sometimes, however,
despite the best intentions of all concerned, ...
Steering Angle Sensor Centering
The steering angle sensor does not require centering often. Centering of the
steering angle sensor might be required after certain service procedures are performed.
Some of these procedures are as follows:
Wheel alignment
Steering gear replacement
Steering column replacement
Collision ...
All Seasons Tires Description
Most GM vehicles are equipped with steel belted all-season radial tires as standard
equipment. These tires qualify as snow tires, with a higher than average rating
for snow traction than the non-all season radial tires previously used. Other performance
areas, such as wet traction, rolling ...