P0234-BOOST PRESSURE SENSOR NEGATIVE DEVIATION

For a complete wiring diagram Refer to Section 8W

When Monitored:
With the engine running.
Set Condition:
The Boost Pressure Sensor indicates actual turbocharger boost is less than the ECM setpoint.

Possible Causes

AIR FILTER

AIR RESTRICTION

AIR LEAKS

BOOST CONTROL VACUUM SUPPLY

BOOST PRESSURE ACTUATOR

TURBOCHARGER

Diagnostic Test

1. CHECK FOR ACTIVE DTC

NOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.

NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.

NOTE: Ensure all turbocharger inlet and outlet tubes are connected properly, without damage and restriction before continuing with this test.

NOTE: If DTC P0401 or P0402 is present with this DTC, diagnose P0401 or P0402 before diagnosing this DTC.

Turn the ignition on.
With the scan tool, erase ECM DTCs.
Test drive the vehicle.
Monitor the scan tool for ECM DTCs.

NOTE: A clogged Boost Pressure Solenoid Air Filter can cause this DTC to set. Inspect this filter and replace as necessary before continuing with this test.

Did this DTC set again?

Yes

Go To 2

Test Complete.

2. 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 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Go To3

3. AIR RESTRICTION

NOTE: Inspect all air intake and turbocharger related tubes for damage, restriction or poor connection. Any of these conditions can cause a this DTC to set.

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

Were any problems found?

Yes

Repair or replace as necessary.