Manifold air pressure

Charge pressure sender G31 The charge pressure sender is located upstream of the throttle valve control part.

The Motronic supplies the sender with a voltage of 5 volts and earth. The signal which the sender generates is a pressure- proportional voltage ranging from 0 to 5 volts.

At atmospheric pressure (at sea-level), the voltage is approx. 2.5 volts. The signal is used for charge pressure control.

The Motronic also needs information on charge pressure so that it can take counter- measures if the maximum permissible pressure is exceeded.

Substitute function and self-diagnosis: If sender G31 fails, the charge pressure is controlled via the characteristic curve (engine speed-dependent). This will result in a deficiency of engine power.