Description below. pls help as I just bought this car.

Something interesting about the CEL, I think this info may help isolate the problem

  • It looks like the MAF may be new, but I will confirm that on weekend, looks like previous buyer found this problem and went for MAF originally, maybe he found something worse and traded in?

  • CEL goes off when you turn the car off and may not come back on for a week or two if i drive slowly enough and with low enough revs, something is surely triggering this?? so I am going to trigger it whilst my friend is filming the dash on the weekend as its hard to keep eyes on road/dash at same time.

  • Once or twice i seen it go on at lower speeds, I am pretty sure one time I was going up a hill, and another time I had something about 20 Kilos in the back I was moving around

It was quite a large item, a portable steel single bed I had in the back. I was only rolling along and the light came on :o what does this mean??

  • 1
    There isn't enough data. You need to log the major engine PIDs and post the log or do some testing and edit your question to provide info. What year is your Celica?
    – Ben
    Oct 19, 2018 at 20:54

1 Answer 1


P0171 can be caused by a vacuum leak, low fuel pressure, clogged fuel injector. Vacuum leak is most common.

  • Guys I seen a guy called Paulster look at a similar issue, is there any chance he can look at this one also? Oct 19, 2018 at 14:13
  • You should provide some data at different operating conditions such as fuel trims, rpm, o2 volts, load, maf, fuel pressure etc.
    – Milison
    Oct 19, 2018 at 16:14

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