DTC Advanced Diagnostics: P0234 (2.0L Engine)

DTC P0234: Turbocharger Overboost Problem

General Description

Courtesy of HONDA, U.S.A., INC.

Courtesy of HONDA, U.S.A., INC.

The powertrain control module (PCM) controls the turbocharger boost pressure so that the boost pressure to the engine does not exceed the set upper pressure limit. When the boost pressure increases abnormally, a malfunction of the turbocharger control system is determined and fuel cut and throttle restriction control is done to protect the powertrain.

Monitor Execution, Sequence, Duration, DTC Type

Execution	Continuous
Sequence	None
Duration	1.0 second or more
DTC Type	One drive cycle, MIL on

Enable Conditions

Condition	Minimum	Maximum
Engine coolant temperature [ECT Sensor 1]	155.9 deg.F (68.8 deg.C)	-
Other	No change of boost pressure upper limit

[ ]: HDS Parameter

Malfunction Threshold

Either one of conditions is met for at least 1 second, and fuel cut-off is operated for engine protection.

The boost pressure is 170 - 300 kPa (1, 276 - 2, 250 mmHg, 50.3 - 88.7 inHg) or more*
The intake air pressure is 249.1 - 293.8 kPa (1, 868.6 - 2, 203.4 mmHg, 73.63 - 86.82 inHg) or more*

*: Varies with driving conditions.

Possible Cause

NOTE: 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 valve stuck close failure
Turbocharger wastegate control actuator stuck close failure
Turbocharger wastegate control valve bypass clogged
PCM internal circuit failure (BARO sensor)
Turbocharger boost sensor internal failure

Confirmation Procedure

Operating Condition

Start the engine. Hold the engine speed [Engine Speed] at 3, 000 rpm without load (in P or N) until the radiator fan comes on.
Drive at engine speed [Engine Speed] at 1, 500 rpm or more for at least 1 second.

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.