From Ross-Tech Wiki

16618/P0234/000564 - Boost Pressure Regulation: Limit Exceeded (Overboost Condition)

Possible Symptoms

  • Malfunction Indicator Light (MIL) ON
  • Boost Pressure too high
  • Reduced Power Output

Possible Causes

  • Hoses incorrectly connected, disconnected, blocked or leaking
  • Boost Pressure Control Valve (N75) faulty
  • Boost Pressure Sensor (G31) faulty
  • Turbo Charger stuck/faulty

Possible Solutions

  • Check Charge Pressure Control System
    • Perform Output Test (to check the Turbo Charger)
    • Perform Basic Setting (to check the Charge Pressure Control)
    • Perform Pressure Test to locate Leaks
  • Check/Replace Boost Pressure Control Valve (N75)
  • Check/Replace Boost Pressure Sensor (G31)
  • Check/Replace Turbo Charger