How to fix a p0128 on a gmc sierra 2500hd 8.1l

SOURCE: 2003 GMC SIERRA 2500HD

I have the same issue...what's the fix?

Wade Cook

• 6 Answers
• Posted on Jan 27, 2009

SOURCE: 4X4 inop on 2003 GMC Sierra 2500HD

I have found that when you are going to engauge 4x4 high, it is best to only be going about 3 miles an hour. Not faster, not stopped. It likes some movement to help it mesh. I've had perfect shifts since I started this. Hope it helps. Wade.

SOURCE: 2005 gmc sierra 2500hd heated seat turns off

you have a couple of problems first of all your drivers sd=ide heated heat pad is probably faulty, for your heating problem you may have to get the hvac doors recalibrated.

SOURCE: replacement of water pump on 2004 gmc sierra

Remove or disconnect the following:

Air outlet duct Coolant Inlet radiator hose from the water pump Upper fan shroud Cooling fan and clutch assembly Drive belt Radiator outlet hose from the coolant pump Surge tank hose Heater hose Water pump



DO NOT use cooling system seal tabs (or similar compounds) unless otherwise instructed. The use of cooling system seal tabs (or similar compounds) may restrict coolant flow through the passages of the cooling system or the engine components. Restricted coolant flow may cause engine overheating and/or damage to the cooling system or the engine components/assembly.
Install or connect the following:

Water pump. Install the water pump bolts. Tighten the water pump bolts first pass to 11 ft. lbs. (15 Nm); tighten the bolts final pass to 22 ft. lbs. (30 Nm). Water pump drive belt pulley and bolts (if applicable). Tighten the pulley bolts first pass to 89 inch lbs. (10 Nm); tighten the bolts final pass to 18 ft. lbs. (25 Nm). Surge tank hose Heater hose Outlet radiator hose to the coolant pump Drive belt Cooling fan and clutch assembly Upper fan shroud Inlet radiator hose to the water pump Air inlet duct Coolant

SOURCE: 2007 GMC Sierra 2500HD - adjust headlight aim, mine is too high

every headlamp has two adjusting set screws. One for vertical and horizontal. They are normally a torx driver socket that will turn these screws. If you have a garage use the garage door at night to set the beams reflecting off the door. Centering the truck to a center mark on the door would be helpful when you make the adjustments. That way your headlamps should aim evenly. Please note if your driveway is not level jack up the trucks rear end to make it so. Leveling the vehicle makes the difference before any adjustments are mad