Fault description

The diagnosis monitors whether the complete secondary air system is functioning plausibly, whether sufficient air is being injected into the system.

Cylinder bank 1:

Differential pressure of secondary air valve too high (>180 mba, preliminary value)

OR

Differential pressure of secondary air valve too low (<50 mba, preliminary value)

OR pressure difference, bank 1 to bank 2 is too high (>80 mbar, preliminary value).

Possible fault cause:

General fault in secondary air system (leakage or obstruction).