Code No. P0234: Waste Gate System Malfunction


FUNCTION



  • The engine-ECU checks that the engine is not overcharged by always monitoring intake air volume.
  • The engine-ECU protects the engine by shutting off fuel when an overcharged condition is detected.

TROUBLE JUDGMENT


Check Conditions
  • Engine is running.
  • Waste gate solenoid valve is normal.
Judgment Criterion
  • An excess air intake, which will not occur with a normal use, is detected.
FAIL-SAFE AND BACKUP FUNCTION
  • Fuel is cut in abnormal engine overboost condition.

PROBABLE CAUSES



  • Failed supercharging pressure control system
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check supercharging pressure.

  • Check supercharging pressure (Refer to GROUP 15 - On-vehicle Service - Supercharging Pressure Check ).

Q. Is the check result normal?
Go to Step 2.
Repair.

STEP 2. Check supercharging pressure control system.

  • Check supercharging pressure control system (Refer to GROUP 15 - On-vehicle Service - Supercharging Pressure Control System Check ).

Q. Is the check result normal?
Go to Step 3.
Repair.

STEP 3. Check waste gate actuator itself.

  • Check waste gate actuator itself (Refer to GROUP 15 - On-vehicle Service - Waste Gate Actuator Check ).

Q. Is the check result normal?
Go to Step 4.
Replace the waste gate actuator.

STEP 4. M.U.T.-III diagnosis code.

  • Reconfirmation of diagnosis code.

Q. Is diagnosis code set?
Replace the engine-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).