P0234-TURBOCHARGER OVERBOOST CONDITION

For a complete wiring diagram, refer to the Wiring Information.

When Monitored:
With the engine running and the Powertrain Control Module (PCM) attempting to govern Turbocharger boost pressure.
Set Condition:
The Boost Pressure Sensor indicates actual Turbocharger boost pressure is greater than the PCM set point for engine boost for eight seconds.

1. CHECK FOR ACTIVE DTC

1.	Turn the ignition on.

2.	With the scan tool, clear DTCs in the PCM.

3.	Test drive the vehicle.

4.	With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

2. CHECK THE AIR FILTER

1.	Turn the ignition off.

2.	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 in accordance with the service information.
Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

3. CHECK FOR AN AIR RESTRICTION

1.	Inspect all air intake, crankcase vent, charge air cooler and Turbocharger related tubes for damage, restriction or poor connection.

2.	Inspect the exhaust system and related tubes for damage, restriction or poor connection.

Were any problems found?

Yes

4. CHECK FOR INTAKE SYSTEM AIR LEAKS

1.	Remove the Crankcase Vent Heater.

2.	Remove the Mass Air Flow Sensor from the Turbocharger inlet tube.

3.	Seal off and/or plug the Turbocharger inlet tube where the MAF sensor was removed.

4.	Connect the Evaporative Emissions Leak Detector (EELD) 8410 to the Crankcase Vent Heater port in the intake duct and begin injecting smoke into the intake system.

5.	Observe all intake system components for evidence of smoke leakage.

Is there evidence of smoke leakage?

Yes

Replace the Turbocharger Assembly in accordance with the service information.
Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).