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Home >> Saab >> 2001 >> 9-3 Base, 4D Hatchback, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 9 (TRIONIC T7 Fuel Control System) >> Fault Diagnosis Fault Codes >> DTC P0171: Long Term Fuel Trim Multiplicative. Max Value, Air/Fuel too Lean. >> Diagnostic help

Diagnostic help

WARNING: This page is about a different car, the 2003 Saab 9-3 and 2002 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

The engine's fuel requirement is 25% greater under partial load than that which the control module has calculated using information from the mass air flow sensor.

Fault diagnosis first determines if the pressure sensors indicate about the same value with the ignition ON, as the mass air flow sensor is then compared with the intake air pressure. If the pressure sensors are OK but the mass air flow sensor value is not correct, the mass air flow sensor must be changed. Air leaks will not generate this trouble code.

If the air quantity is OK, then the fuel supply is checked, i.e. pressure, response, pump flow and finally the injectors.

Functions in the diagnostic tool related to the fault: