A vehicle is brought in for repair with the complaint of poor fuel economy. A diagnostic scan tool is attached to the DLC with the vehicle at operating temperature, and the technician determines that the pre-catalyst oxygen sensor voltage is biased high and the injector pulse width is long, and both STFT and LTFT are high. All of the following conditions could cause this EXCEPT:
A) high fuel pressure
B) open coolant temperature sensor circuit
C) TP sensor voltage fixed high
D) MAP sensor output indicates high load condition

Question

Quizplus · Accepted Answer

High fuel pressure would cause the fuel trims to be negative, not positive.

A Vehicle Is Brought in for Repair with the Complaint