355: can LTFT be reset?

Yes but I don’t know how long it takes
Years ago when I used to shut the power off via the disconnect switch, my ltft would reset.
I believe this is why you need to let the car idle for a while when starting it again.

you could try over night as that should work. Don’t think anyone has asked this in years so post how it goes.

 

Carmellini has a 5.2 car. There is still some debate over what happens to faults and fuel trims with a battery reset.

 

There is no need for a battery, the info could be stored in an EEPROM chip.

 

No internal batteries. EEPROMs

https://en.wikipedia.org/wiki/EEPROM

Electrical charges are stored on chips. A bit like capacitors, but keep their charge indefinitely (or at least for a long time).

(EDIT: Miro beat me by 10 milliseconds)

 

LTFT is constantly being adjusted. So if you did something that would effect fuel trim you should see LTFT change pretty quickly. LT doesn't really mean Looooog term between adjustments. It means that the adjustment should be stable over a longer term. STFT change with throttle and load application. But if you make a repair to a component like a O2 sensor or MAF that was not operating correctly, or a misfire, thus pushing LTFT high or low, LTFT should response to the repair over a short drive.

 

No this cannot be reset from my investigation that I have undertaken. It changes pending the parameters sent to the ecu from the sensors. If there is a fault it will CEL. If you clear the fault it will come back until you fix the problem then read within +/-10% or you will get another CEL. A bottle of injector cleaner cleaned my trims up a little. Well and truely within spec now