Which sensors faults are commonly cited as causing ECU fueling miscalibration?

• A. MAP sensor, MAF sensor, and O2 sensor faults do not affect fueling.
• B. MAP/MAF/ECT sensor faults, calibration drift, or software corruption can shift fuel maps or timing.
• C. Ignition coil faults are the only cause of miscalibration.
• D. Fuel pump failure is the sole cause of miscalibration.

Answer: (B)

Fueling decisions in the ECU hinge on sensor data that describe how much air is entering the engine and how hot it is, so the computer can use the right fuel map and timing. When sensors that feed this data—specifically the MAP, MAF, or ECT—are faulty, or when their readings drift over time, or when the software that stores or applies the fuel map gets corrupted, the ECU ends up commanding the wrong injector durations or timing. That is why faults in MAP, MAF, or ECT, along with calibration drift or software corruption, are common reasons for fueling miscalibration—the map is effectively shifted or misapplied.

To see why the other possibilities aren’t the main culprits: ignition coil faults affect spark timing and combustion, not the fuel map the ECU uses to decide how much fuel to inject. A fuel pump failure changes fuel delivery pressure or volume rather than the ECU’s commanded fueling based on sensor inputs. And while an O2 sensor fault can cause the system to adjust fuel in closed-loop operation, the fundamental miscalibration typically traces back to the sensor signals that drive the fuel map or to the map itself.