One problem related to power steering pump has been reported for the 2003 GMC Sierra 3500. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 GMC Sierra 3500 based on all problems reported for the 2003 Sierra 3500.
Power steering and/or braking may become inoperative or drasticly reduced performance when used at same time because power steering pump is also power brake pump and system does not have enough pressure or flow capacity to supply both steering and braking together. This could result in loss of control of vechicle.