P0299

P0299-TURBOCHARGER UNDERBOOST CONDITION

For a complete wiring diagram refer to Diagrams/Electrical

- When 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.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.


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.

Is the status Active for this DTC?

Yes

- Go To 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Checking for an Intermittent DTC


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

- Replace the Air Filter element
- Perform the ECM Verification Test Ver. 1. ECM Verification Test

No

- Go to 3


3. CHECK FOR INTAKE SYSTEM RESTRICTIONS

NOTE: Damaged, restricted or poorly connected intake and turbocharger related tubes can cause this DTC to set.

Inspect all air intake, crankcase vent and turbocharger related hoses/tubes and connections.

Were any problems found?

Yes

- Repair or replace as necessary.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test

No

- Go to 4


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

- Repair or replace as necessary.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test

No

- Go to 5


5. REPLACE THE BOOST PRESSURE SERVO MOTOR

Replace the Boost Pressure Servo Motor.

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

- Replace the Turbocharger assembly.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test

No

- Test complete.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test