P0234

DTC P0234

CIRCUIT DESCRIPTION
The boost pressure sensor is located in the air induction tubing. The sensor is a transducer that varies voltage according to changes in the air pressure inside the air tubing. The engine control module (ECM) monitors the boost pressure sensor signal for abnormal values. If the ECM detects that the boost pressure sensor signal is excessively high, this DTC will set.

Condition for Running the DTC
- DTCs P0112, P0113, P0116, P0117, P0118, P0237, P0238, P0401, P0403, P0404, P0405, P0406, P0602, P0606, P0642, P0643, P1125, P1404, P2227, P2228 and P2229 are not set.
- The battery voltage is between 10-16 volts.
- The ignition switch is ON.
- The engine is running.

Condition for Setting the DTC
- The ECM detects excessive high boost pressure for longer than 3 seconds.

Action Taken When the DTC Sets
- The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Freeze Frame/Failure Records.
- The ECM limits fuel injection quantity within 70%.

Condition for Clearing the MIL/DTC
- The ECM turns OFF the MIL after 3 consecutive driving cycles when the diagnostic runs and does not fail. (12,000 lbs GVW)
- The ECM turns OFF the MIL when the diagnostic runs and does not fail. (Except 12,000 lbs GVW)
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes after the key is cycled.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic after the ECM turns OFF the MIL.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
- High resistance in the boost pressure low reference return circuit may set this DTC.
- Check the waste gate for a sticking or stuck condition. Refer to Waste Gate Operation in the Engine Mechanical section.
- Use the scan tool to verify the integrity of the boost pressure sensor signal. Compare the sensor values under all load conditions for an excessively high value. Use the scan tool data list values for nominal sensor readings.
- The fuel with which gasoline was mixed may set this DTC.

Test Description
The numbers below refer to the step number on the diagnostic table.
2. A skewed boost pressure sensor value (shifted to a higher pressure) can set this DTC. The Boost Pressure on the scan tool should read near barometric pressure with the key ON and engine OFF.
3. A skewed barometric pressure (BARO) sensor value (shifted to a lower pressure) can set this DTC. The BARO on the scan tool should read near surrounding barometric pressure.

DTC P0234
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views

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