DTC P0234 (Flash Code 42) Turbocharger Overboost Condition (RZ4E-TC)

1. DTC P0234 description

The boost pressure sensor is installed to the air duct, and is integrated with the CAC temperature sensor. The boost pressure sensor changes the signal voltage in accordance with changes in air pressure in the air intake pipe. The ECM monitors the boost pressure sensor signal. If the ECM detects an excessively high signal voltage, the DTC is set. This indicates that the boost pressure is excessively high.

2. Condition for setting DTC P0234

Condition for running the DTC

The battery voltage is 9 to 16 V.
The ignition voltage is 9 to 16 V.
The ignition switch is ON.
The engine is running.
DTCs P0047, P0237, P0238, P060B, and P1655 are not set.

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC P0047 (Flash Code 249) Turbocharger Boost Control Solenoid Circuit".

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC P0237 (Flash Code 32) Turbocharger Boost Sensor Circuit Low".

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC P0238 (Flash Code 32) Turbocharger Boost Sensor Circuit High".

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC P060B (Flash Code 36) Internal Control Module A/D Processing Performance".

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC P1655 (Flash Code 59) Sensor Reference Voltage 4 Circuit".

Condition for setting the DTC

The ECM detects that the actual boost pressure is more than the desired boost pressure by the predetermined value or more for 10 seconds or more under a particular condition.

3. Action taken when DTC P0234 sets

Euro4: The ECM illuminates the MIL. Refer to Action taken when DTC sets - Type A (Euro4).
Except Euro4: The ECM illuminates the check engine warning light. Refer to Action taken when DTC sets - Type A (Except Euro4).

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC type definitions".

The ECM limits the fuel injection quantity.
The ECM inhibits pre-injection.
The ECM inhibits the EGR control.
The ECM inhibits the cruise control.

4. Condition for clearing DTC P0234

Euro4: Refer to Condition for clearing the MIL/DTC - Type A or Type B (Euro4).
Except Euro4: Refer to Condition for clearing the check engine warning light/DTC - Type A or Type B (Except Euro4).

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC type definitions".