P0238

DTC P0238 TC Boost Sensor Circuit High Voltage






Circuit Description

The PCM operates a solenoid to control boost. This solenoid is normally open. By providing a ground path, the PCM energizes the solenoid which then allows vacuum to pass to the wastegate valve. During normal operation, the PCM compares its wastegate duty cycle with the boost signal and makes corrections in the duty cycle accordingly.

Conditions for Running the DTC

The engine speed is less than 3506 RPM.

Conditions for Setting the DTC

The boost pressure is greater than or equal to 4.8 volts (202 kPa).

Action Taken When the DTC Sets

^ The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive drive trip the diagnostic runs and tails.
^ The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the Failure Records store this information. If the diagnostic reports a failure on the second consecutive drive trip, the Freeze Frame records the operating conditions at the time of failure and updates the Failure Records.

Conditions for Clearing the MIL/DTC

^ The PCM will turn the MIL off after three consecutive trips without a fault condition.
^ A History DTC will clear after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. Use of a scan tool will clear the DTC codes.

Diagnostic Aids

Very little boost can be attained by revving the engine in neutral.

An intermittent can be caused by the following:

^ Poor connections
^ A rubbed through wire insulation
^ A broken wire inside of the insulation

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

3. This step will determine if the PCM is responding to a low signal voltage. This will indicate that the PCM is OK.

9. If the scan display is still less than or equal to 9 kPa by disconnecting the PCM the short to voltage is in the wiring.

10. If the voltmeter value stays the same by disconnecting the PCM the short to battery voltage is in the wiring.