Clogged Fuel Injectors
Faulty Oxygen sensor
Fuel injection problem
Engine mechanical condition
Engine Light ON (or Service Engine Soon Warning Light)
The Fuel Trim Cylinder Balance diagnostic detects a rich or lean cylinder to cylinder air/fuel ratio imbalance in each bank. The diagnostic monitors the pre-catalyst heated oxygen sensor (HO2S) signal’s frequency and amplitude characteristics by calculating an accumulated voltage over a predetermined sample period. An imbalance is indicated when multiple samples of the accumulated voltage are consistently higher than the desired value.