Manufacturer communication — 2006 GMC YUKON DENALI XL

• Applies to 1999-2013 GMC Savana, Sierra and Yukon (among many other listed GM models) with a V-8 gas engine (note: the Yukon range runs to 2013).

  the passage

  1999-2013 GMC Savana, Sierra, Yukon

• Customers may complain of a slight rough idle with no DTCs or other engine performance concerns, and comparison vehicles may show the same concern.

  the passage

  Some customers may complain of a slight rough idle with no DTCs or additional engine performance concerns and comparison vehicles may exhibit the same concern.

• In some instances an occasional misfire registers on the Tech 2 at idle, but no DTCs are stored.

  the passage

  In some instances, an occasional misfire may also register on the Tech 2 when the engine is idling but no DTCs will be stored.

Steps to confirm (in the document’s order)

• Compare the concern to a like vehicle; if it is worse than the like vehicle, complete SI diagnosis and repair as necessary.

  the passage

  Compare the concern to a like vehicle. If the concern is worse than a like vehicle, complete SI diagnosis and repair as necessary

Caution

• If SI diagnosis for Rough, Unstable, or Incorrect Idle is inconclusive, or the concern is the same as on the like vehicle, treat it as an idle characteristic of the vehicle and attempt no repairs.

  the passage

  If SI diagnosis for Rough, Unstable, or Incorrect Idle have been completed and are inconclusive or if the concern is the same as the like vehicle, this should be considered an idle characteristic of the vehicle and no repairs should be attempted.