Diagnostic help

WARNING: This page is about a different car, the 2001 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

The three pressure sensors are checked first to make sure they do not deviate more than 10 kPa from each other when the engine is stationary. This check is carried out because the air mass flow is later compared with the intake pressure and must therefore be correct. If there is a deviation in the air mass flow then air leaks are checked for first before the mass air flow sensor is suspected of being faulty.

Then, the charge air control, knock control and fuel supply are checked. Knock control is a normal engine function.

It is difficult to determine the amount of knocking to allow, as this depends on the circumstances.

The following factors increase susceptibility to knocking:

Low octane rating.
High coolant and outdoor temperature.
High altitude.
High engine load.

Functions in the diagnostic tool related to the fault:

Atmosphere absolute pressure, unit kPa.
Charge air absolute pressure, unit kPa.
Manifold absolute pressure, unit kPa.
Airmass deviation from requested, unit %.
Airmass deviation from calculated, unit %.
Max. engine torque at actual RPM, unit %.
Charge air adaptation, unit %.
All values in "AIRMASS DEMAND".
Activate charge air control valve.
For more information, see "READ VALUES" MENU and "ACTIVATE" MENU .