Lc9 p0521
02-17-2015, 03:13 PM
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Lc9 p0521 2011 Sierra 1500 LC9. Texas Speed DOD delete. Comp 210/224 VVT cam.
I bought the truck a few weeks ago and it dropped the lifter almost immediately. I probably drove it 3 times. Has 123k miles on the dot. Pulled the valve covers and it was spotless so went ahead and ordered the DOD delete and the comp 210/224 cam from texas speed. Installed it and drove it very delicately to the tuner about 40 miles away. (He pulled the DOD in the code so I could drive it there). He did a road tune with HP Tuner and I drove back with no issues. I plugged my scanner in and had a pending P0521 code.
Usually the code will stay pending but occasionally throws a check engine light. When it throws the check engine light it always does it around 1200 rpm at operating temperature of about 180-185 per my scanners freeze data. Oil pressure is always 20-25ish when it does this. I Changed the oil, truck has no metal in oil indicating any crazy wear or lack of oil pressure. Engine runs great, makes no strange noises, and makes great power.
I installed a new AC delco oil pressure switch from the dealer and still have all the same readings and the same issue.
Cold idle just over 40psi (all per dash guage)
Hot idle just over 20 Psi.
Cruising is around 25-35 Psi Hot
Wide open throttle jumps above 40psi Hot.
It has been explained to me by a few GM techs that this is acceptable as the afm/vvt motors rely on oil volume more than oil pressure and use bigger oil passages for this.
What in the world could cause this code? Code it be bad code in the tune? I have had a few people who tune suggest pulling the code from the tune since the oil pressure is ok.
I bought the truck a few weeks ago and it dropped the lifter almost immediately. I probably drove it 3 times. Has 123k miles on the dot. Pulled the valve covers and it was spotless so went ahead and ordered the DOD delete and the comp 210/224 cam from texas speed. Installed it and drove it very delicately to the tuner about 40 miles away. (He pulled the DOD in the code so I could drive it there). He did a road tune with HP Tuner and I drove back with no issues. I plugged my scanner in and had a pending P0521 code.
Usually the code will stay pending but occasionally throws a check engine light. When it throws the check engine light it always does it around 1200 rpm at operating temperature of about 180-185 per my scanners freeze data. Oil pressure is always 20-25ish when it does this. I Changed the oil, truck has no metal in oil indicating any crazy wear or lack of oil pressure. Engine runs great, makes no strange noises, and makes great power.
I installed a new AC delco oil pressure switch from the dealer and still have all the same readings and the same issue.
Cold idle just over 40psi (all per dash guage)
Hot idle just over 20 Psi.
Cruising is around 25-35 Psi Hot
Wide open throttle jumps above 40psi Hot.
It has been explained to me by a few GM techs that this is acceptable as the afm/vvt motors rely on oil volume more than oil pressure and use bigger oil passages for this.
What in the world could cause this code? Code it be bad code in the tune? I have had a few people who tune suggest pulling the code from the tune since the oil pressure is ok.
