Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › P0003a code on a 20011 Gmc 2500hd › Reply To: P0003a code on a 20011 Gmc 2500hd October 20, 2020 at 9:11 am #986778 Richard KirshyParticipant If you plan on driving to the shop, I would suggest you take it very easy as to not to put any strain on the system. Best to avoid an expensive repair at all costs.