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After getting a CEL that was due to a dirty MAF, my service adviser at the dealer told me of an ingenious way to reset the ECU without having to take a cable off the battery.

All you do is remove the fuse as notated for about 15 seconds, and the ECU resets itself. It does not affect the "learning" of the ECU.

 

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The one circled is the EFI1 fuse. They are marked inside the lid. EFI1 clears DTCs and "Freeze frame data" (what the conditions were when the DTC(s) occurred). In my experience, it also gives you a little more power until the ECU/ECM relearns how to optimise for economy and emissions (it sure isn't trying to optimize for power, or if it is trying, fails). Same effect on ECU as removing battery cable. At least that is what my understanding of the situation is.

Note: legend inside lid is flipped. Locate the relays inside the lid vs what you see (may have to turn it around) then you'll be able to ID the fuses. There are some unused slots. I think my legend says "ECM" or something like that instead of EFI1, but it's called EFI1 in the BGB. AM2 is two slots to the rear of that. There is an AM1, but it's in fuse block 3 inside the passenger compartment.
 

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Thanks for the info Don and Beanie...

The BGB does, specifically mention EFI1. I guess Toyota chose that one because its farther down the line to the ECU. I've edited my previous posts to reference this fuse, instead. AFAIK, AM2 has worked for people (and I think I used it once before I got my PDA Dyno software), but there's probably a reason Toyota prefers the EFI1 fuse.
 

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Interesting note regarding horsepower increase after reset
Beanie said
"In my experience, it also gives you a little more power until the ECU/ECM relearns how to optimize for economy and emissions "

I have heard of this effect elsewhere.It seems our ECU has a couple of prime directives which don't include horsepower but economy & emissions.
I have noticed this effect with butt dyno and wonder how many installed mods like CAI fool the installer into thinking the mod was the cause of horsepower increase.The effect seems to last a day or two.
 
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