This bulletin provides a procedure to address customer concerns of a high-pitched ?chirp?, ?squeak? or ?cricket? sound heard coming from the engine?s Direct Injection (DI) high-pressure fuel pump. Not all DI pumps may exhibit this sound. Some vehicles may have components which in combination with certain fuel temperatures and / or formulations, may result in aeration of the fuel within the body of the pump and cause this sound. This result is non-detrimental to the vehicle.
Production changes have been made to eliminate the source of the sound.