DTC Advanced Diagnostics: P0234 (2.0L Engine) (2024 2025)
DTC P0234 : Turbocharger Overboost Problem
General Description
The boost pressure control monitor is utilized to detect possible errors of the turbocharger system. The turbocharger consists of two elements, a turbine and a compressor, which are connected by a single shaft. The boost control apparatus consists of turbocharger wastegate control actuator that is connected to the turbocharger wastegate control valve passing through the turbine housing. The electronically controlled turbocharger wastegate control valve delivers the resulting boost pressure. In order to provide boost pressure control diagnosis, the actual boost pressure upstream of the throttle valve is monitored against desired boost pressure under certain conditions. There are two types of boost pressure control deviation errors distinguished. If either of the following errors is detected, the PCM detects a malfunction and stores a DTC.
- Overcharging error: Negative boost pressure control deviation. The actual boost pressure exceeds the desired boost pressure value.
- Undercharging error: Positive boost pressure control deviation. The desired boost pressure exceeds the actual boost pressure value.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 0.5 seconds or more |
| DTC Type | One drive cycle, MIL on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Difference between upstream throttle valve pressure and ambient pressure | 35 kPa (263 mmHg, 10.4 inHg) | - |
| Vehicle speed [Vehicle Speed] | 2 mph (3 km/h) | - |
[ ]: HDS Parameter
Malfunction Threshold
The difference between commanded upstream throttle valve pressure and measured upstream throttle valve pressure is 20 kPa (150 mmHg, 5.9 inHg) - 100 kPa (750 mmHg, 29.6 inHg) or more for at least 0.5 seconds.
Possible Cause
The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- Turbocharger wastegate control actuator stuck
- Leakage in turbocharger system
Confirmation Procedure
Operating Condition
- Start the engine. Hold the engine speed [Engine Speed] at 3, 000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.
- Drive the vehicle at engine speed [Engine Speed] 3, 200 rpm or more with high load.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, the freeze data, and the on-board snapshot are stored in the PCM memory.
Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.