2003 Other GMC Models P1291 code

what model?what engine size?what were the 3 codes.need more info.

2003 GMC 7500 with a duramax deisel 3 engine code 2 wheel drive with manual transmission. Scanner is showing a P1291 code description unavailable.

this is info is not helping.is the vehicle a kodiak or a top kick?is it a c4 c5 c6 c7 c8 model?what engine size. 6.6L or 8.1L? what were the other 2 codes? I ran the p1291 nothing comes up.before I can help I need to know what model and engine size first.

2003 GMC C7500 7.8L Duramax diesel the engine code on the vin # is a 3. The P1291 comes up on the scanner as description unavaliable. I google searched the P1291 and all I could find was information on the dodge and ford P1291.

p1291 is pressure control valve 2 signal voltage excessivly high.The PCV is used to adjust supply pump discharge amount so as to adjust common rail pressure. Discharge amount from the supply pump to the common rail is determined by continuity timing to PCV.I hope this helps,post back with any other questions.

Where would the pressure control valve be located?

it's on the side of the engine block below the fuel filter,there are 2 pc solenoids.