While discussing LTFT and STFT when the STFT number is -20 and the LTFT number is -20: Technician A says these numbers indicate the PCM is trying to decrease fuel delivery. Technician B says these numbers indicate a normal condition. Who is correct?
A) A only
B) B only
C) both A and B
D) neither A nor B

Question

Quizplus · Accepted Answer

Technician A is correct because STFT (Short Term Fuel Trim) and LTFT (Long Term Fuel Trim) numbers at -20 indicate the Powertrain Control Module (PCM) is reducing fuel delivery to compensate for a perceived rich condition.

While Discussing LTFT and STFT When the STFT Number Is