It can be as simple as a restriction in the air intake (dirty filter) or a leak in the air intake to as severe as a turbo. I will attach a flow chart along with possible causes to help you diagnosis the problem. For some of the test there are special tools needed, but you can do some with out the tools and maybe find the problem with out them.
If you still need help just reply, if not click ACCEPT when we are done.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Diagnostic Test
Q: Do you have other DTC's? YES: Repair other boost related DTC's first
Q: Were any restrictions found? YES: Replace the Air Filter or repair the Intake air system for restriction.
NO: Go To 3
Q: Was any damaged found? YES: Replace The Turbo charger.
NO: Go To 4
Q: Were any leaks detected? YES: Repair leaking intake air system.
NO: Go To 5
Q: Are the boost pressure and ambient air pressure sensors within 6 in Hg of each other? YES: Go To 6NO: Replace the Boost pressure sensor.
NOTE: The reading on the boost pressure sensor may be slightly lower than the regulated pressure.Q: Does the boost pressure sensor reading increase with the regulated air pressure? YES: Go To 7NO: Replace the Boost Pressure sensor.
Q: Is the Wastegate seized in the open position? YES: Replace the Turbocharger.
NO: Test Complete.