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 precatalyst oxygen sensor voltage is biased high, 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