120408
High120408 — Turbocharger Boost Pressure Control Fault
Description
What This Code Means
Code 120408 indicates that boost control was disabled as a protective response to another fault in the boost system. The engine control unit (DME) deactivates boost control to prevent engine damage when a related sensor or actuator fails, such as the boost pressure sensor or the wastegate actuator.
Symptoms
Symptoms
- Loss of engine power
- Reduced boost pressure
- Limp mode
- Check Engine light on
Causes and fixes
Diagnosis and Repair
- Read the fault codes with ISTA.
- Check the boost pressure sensor and its wiring.
- Inspect the wastegate actuator for mechanical binding.
- Check the vacuum lines and solenoids.
- Replace faulty components as needed.
Possible secondary damage
Secondary Issues
Ignoring the fault can lead to turbocharger damage, catalytic converter failure from a rich mixture, or engine damage from detonation.