Air/Fuel Mixture

Air/Fuel Mixture Specifications
The technician should be aware that diagnosis and testing of the Air/Fuel mixture is a function of the Powertrain Control Module (PCM) based on various engine sensor inputs, engine load etc.., to develop the fuel calculation and strategy to control fuel injector pulse width.

Diagnosis should begin at the Powertrain Management System level, where testing begins with Diagnosis by Symptom, and is narrowed to testing of a "specific" subsystem and it's related wiring and components. Following the appropriate diagnostic routines may prevent misdiagnosis and unnecessary component replacement. Refer to Powertrain Management/Testing and Inspection/Procedures.