2006 - 2009 Cadillac XLR and XLR-V: Service Bulletin: #PIP4021D: High Pitch Whine or Buzz Noise Heard From Under The Vehicle - (Feb 21, 2019)

#PIP4021D: High Pitch Whine or Buzz Noise Heard From Under The Vehicle - (Feb 21, 2019)

Supersession Statement

This PI Was Superseded To Update Models And Model Years. Please Discard PIP4021C.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern

Customers may comment that they hear a high pitched tone or whine type noise from the vehicle with  the key on and engine off, or for up to one minute after the vehicle has been shut off. The noise should  be heard from outside the vehicle only or with a window open.

It will be most noticeable in an enclosed  area (i.e. garage, car wash...etc).   

Recommendation/Instructions

The whine/tone may be caused by the internal transmission solenoids being commanded to minimum  line pressure by the TCM.

This noise should be considered an operating characteristic and no repairs  should be attempted.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.