EGR content
Check the damper in the EGR valve, the control cylinder and the proportional valve by activating the components with Scania Diagnos. Check the wedge in the venturi. Check whether there are leaks in the EGR system. Check the mass flow sensor.
What you'll see
No driver-visible symptom recorded.
System reaction
The engine control unit switches off the EGR system and calibration of the mass flow sensor is switched off.
Diagnostic depth
The amount of EGR gases returned is too low, the amount of EGR gases cannot be increased to the required level.
The fault can be due to any of the following:- The flap in the EGR valve cannot be opened. This may be because the damper is jammed, or the control cylinder pressure is insufficient, or because there is internal leakage in the control cylinder.- The proportional valve may be faulty. - The flap in the venturi insert may be stuck in the open position. - Leakage in the recirculation of EGR gases. - The mass flow indicator may be indicating too high a value, resulting in the engine control unit concluding that the engine is receiving too low an amount of EGR gases.