For a complete wiring diagram Refer to Section 8WWhen Monitored:With the engine running and the ECM attempting to govern turbocharger boost pressure.Set Condition:The Boost Pressure Sensor indicates actual turbocharger boost is less than the ECM setpoint for engine boost for 0.83 second.Possible CausesINTERMITTENT DTCCLOGGED AIR FILTERINTAKE AIR RESTRICTIONINTAKE AIR LEAKBOOST PRESSURE SERVO MOTORTURBOCHARGERAlways perform the Pre-Diagnostic Troubleshooting procedure before proceeding.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)1. CHECK FOR ACTIVE DTCTurn the ignition on.With the scan tool, Clear DTCs in the Engine Control Module (ECM).Test drive the vehicle.With the scan tool, select View DTCs.If there are any EGR related DTC's, repair the EGR DTC's before continuing with this test.Is the status Active for this DTC?YesGo To 2 NoRefer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)2. CHECK THE AIR FILTERTurn the ignition off.Remove and inspect the Air Filter for soiling or excessive dirt and debris which may cause air flow restriction.Were any of these problems found?YesReplace the Air Filter elementPerform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 33. CHECK FOR INTAKE SYSTEM RESTRICTIONSDamaged, restricted or poorly connected intake and turbocharger related tubes can cause this DTC to set.Turn the ignition off.Inspect all air intake, crankcase vent and turbocharger related hoses/tubes and connections.Inspect the Charge Air Cooler hoses/tubes and connections.Inspect the EGR Air Flow Control Valve to ensure the valve is not stuck in the closed position.Were any problems found?YesRepair or replace as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 44. CHECK FOR INTAKE SYSTEM AIR LEAKSRemove the Crankcase Vent Heater.Remove the Mass Air Flow Sensor from the turbocharger inlet tube.Seal off and/or plug the turbocharger inlet tube where the MAF sensor was removed.Connect smoke machine 84–04 to the Crankcase Vent Heater port in the intake duct and begin injecting smoke into the intake system.Observe all intake system components for evidence of smoke leakage.Is there evidence of smoke leakage?YesRepair or replace as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 55. REPLACE THE BOOST PRESSURE SERVO MOTORReplace the Boost Pressure Servo Motor in accordance with the Service Information.Ensure the Boost Pressure Servo Motor and ECM harness connectors are connected.Test drive the vehicle.With the scan tool, select View DTCs.Is the status Active for this DTC?YesReplace the Turbocharger assembly in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoTest complete.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)