Cars Technical Articles - DTC P0234 Sets After Turbocharger Replacement

DTC P0234 Sets After Turbocharger Replacement

- Edited: Jan 26, 2023
- Popularity: 36 Views


Vehicles Affected:

  • 2020-2023 Buick Encore GX
  • 2021-2023 Chevrolet Trailblazer


After the replacement of the turbocharger on some 2020-2023 Encore GX and 2021-2023 Trailblazer models equipped with the 1.2L engine (RPO LIH), DTC P0234 (Engine Overboost) may set in the Engine Control Module (ECM) along with an illuminated Check Engine MIL. In some cases, there also may be reduced engine performance as the ECM will limit the amount of available boost pressure.


If these conditions are present after the turbocharger has been replaced or repaired, clear the DTC and use GDS2 to perform the Intake System Learned Values Reset.

The Service Information procedure instructs to complete the Intake System Learned Values Reset when the Turbocharger Wastegate Solenoid Valve is replaced or serviced.

Service Procedure:

Chevrolet Buick Turbo Diagram

The ECM learned integrator value of the turbocharger wastegate solenoid must be reset to ensure proper operation after the repair, replacement or service of several components. If the reset is not performed, additional codes can set after component replacement.

For example, if there is an issue with the boost system, the ECM may increase wastegate actuator solenoid pulse-width modulation in order to achieve the boost target. When the turbo or solenoid is replaced to correct the issue, the learned values must be reset or they will have the opposite effect on engine performance, leading to the overboost condition.

TIP: Be sure to always complete all steps in a repair procedure, including resetting any modules or values, as outlined in Service Information.

Chevrolet Buick Turbo Diagram