Manufacturer communication — 2006 GMC YUKON DENALI XL

• 2014 and prior passenger cars and light duty trucks.

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  Models: 2014 and Prior Passenger Cars and Light Duty Trucks

• The customer notices a noise or vibration that seems abnormal and may not have been there when the vehicle was new.

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  Some customers may notice a noise or a vibration in their vehicle that seems to be abnormal and may not have been there when the vehicle was new.

Possible causes

• Tubular assist steps (step bars/nerf bars) that touch both the frame and the cab without insulation carry normal drivetrain vibrations and pulses into the passenger area.

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  For example, the popular tubular assist steps (a.k.a. "step bars/nerf bars") that may contact the frame of the truck and the cab without any type of insulation are a noise transfer path source for normally operating drivetrain vibrations / pulses into the passenger area of the vehicle.

• Other known contributors are running boards, bug shields, sun visors, vent shades, emergency lights, custom grilles, ski racks and bicycle racks.

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  Some other known contributors to noise and vibrations are running boards, bug shields, sun visors, vent shades, emergency lights, custom grilles, ski racks, bicycle racks.

Steps to confirm (in the document’s order)

1. The first diagnostic step is to look over the vehicle for any aftermarket (non-GM) accessories.

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   The first step in diagnosis of a concern of this nature is to evaluate the customer’s vehicle for any aftermarket (non-GM) accessories.

2. These items have to be removed to judge whether they contribute to the concern.

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   Removal of these items, while many times not popular with the customer, is necessary in order to evaluate whether they contribute to the customer's concern.

Caution

• If the root cause is a non-GM aftermarket accessory, no warranty claim is to be filed; the repair is customer pay.

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  If the root cause is identified as a non-GM aftermarket accessories product, a warranty claim should NOT be filed against the repair, rather, this should be customer pay item.