One problem related to auxillary tank has been reported for the 2002 GMC Yukon. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2002 GMC Yukon based on all problems reported for the 2002 Yukon.
38. 5 gallon gas tank can only be filled to 2/3 to 3/4 level because the dual gas tank design does not allow gasoline vapors to evacuate, trapping the gas vapors in the tank where they could conceivably explode. Although the design of this chassis is two years old, the dealer's service manager was unaware of the problem. The mechanic contacted gm, and they are aware of the problem, but would not disclose the extent of the problem, what they are doing to remedy it, or when customers can expect the design defect to be fixable.