P0299-TURBOCHARGER UNDERBOOST CONDITION

For a complete wiring diagram Refer to Section 8W



Possible Causes
INTERMITTENT DTC
CLOGGED AIR FILTER
INTAKE AIR RESTRICTION
INTAKE AIR LEAK
BOOST PRESSURE SERVO MOTOR
TURBOCHARGER

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)



Diagnostic Test

1. CHECK FOR ACTIVE DTC

Turn 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.

NOTE: 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?

Yes


No

2. CHECK THE AIR FILTER

Turn 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?

Yes


No

3. CHECK FOR INTAKE SYSTEM RESTRICTIONS

NOTE: Damaged, 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?

Yes


No

4. CHECK FOR INTAKE SYSTEM AIR LEAKS

Remove 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?

Yes


No

5. REPLACE THE BOOST PRESSURE SERVO MOTOR

Replace the Boost Pressure Servo Motor in accordance with the Service Information.

NOTE: 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?

Yes


No