How does the ecu sense the car is overboosting?

 

A/F ? .........
Boost levels are recorded onto the ecu from the factory.
Anyone else?

Or am i totally wrong on this

 

MAP sensor.......i guess

 

There's a MAP sensor. Bertune nailed it. It sits on the intake plenum.

 

The map sensor actually isn't really how it tells.. its the MAF sensor and the curve.. the ECU expects a particular MAF Hz (Airflow) reading at particular RPM's and load, if the MAF value is higher than its max reading for a particular RPM, it throws an overboost code.

I think the MAP sensor on our cars is only used under vacuum, its a 1 bar sensor as far as I can tell and doesnt read high enough to tell if the car is in normal boost, let alone overboost.