Is it safe to reset the ECU?

[T4RBoarder]

Is it safe to pull the neg battery cable off to reset the ECU on these 4th Gens? It was nothing on the 3rd gens but with all the additional computers and stuff I don't wanna hurt anything or make it go into limp mode.

 

[T4RSpectreSix]

I could be wrong on this, but as far as I know - I think doing this will require you to re-enter your factory radio station presets and require you to "normalize" your windows and moonroof.

It could impact other aspects I am unaware of - although considering how often batteries get disconnected during maintenance and so forth, I can't imagine it being too big of a deal.

 

[jharris2]

Disconnecting the negative cable won't hurt anything, but it will cause you to reinitialize the stuff that T4RSpectreSix mentions. Look at it this way -- if it weren't safe to disconnect the cable, there wouldn't be lots of repair instructions where step 1 is to disconnect it.

 

[toto]

See this thread for instructions for resetting things after you disconnect the battery.

 

[Nuke]

Is it even necessary to lift a battery lead to do a reset in the 4th gens? On the 3rd gens, all you needed to do was pull the EFI fuse.

 

[T4RBoarder]

Thanks Guys! Thats just what I needed to see

 

[T4RBoarder]

OK I got another question for ya guys. I pulled the neg cable, hooked back up, reset windows/sunroof, then i went for a drive.
When I started it up it kinda hesitated right after it started and then at every light when I stopped the RPMs would drop and act like it was going to die. This happened for probably about 5 miles and its been fine ever since.

Is this normal after a reset?

 

[CJ3Flyr]

Yes, you're good to go :bigok: The computer has to 'learn' the specifics of your engine based on data it collects as it drives. Once it does that it can manage the engine better. It's a little like a Windows computer though; once in a while a total fesh start is good thing...

:cheers:

 

[Temptedhazel]

Idiot it down please

I am trying to reset my own codes. I have an 03 4.7 4runner and have just replaced my throttle body. ( its the pcode that showed up when I put it on the computer for a vsc issue.) Unhooked the battery for days. Same problem and idiot lights still on. I am not a mechanic and don't understand what is being said. Could someone please dumb it down for me so I can attempt this? Thanyou

 

[asdfman7]

I am trying to reset my own codes. I have an 03 4.7 4runner and have just replaced my throttle body. ( its the pcode that showed up when I put it on the computer for a vsc issue.) Unhooked the battery for days. Same problem and idiot lights still on. I am not a mechanic and don't understand what is being said. Could someone please dumb it down for me so I can attempt this? Thanyou

If you had the battery disconnected and still have the light after reconnecting then something is still triggering the check engine light...

You need to take it some where and recheck the codes.

 

[RonJR]

Or get one of these.
OBDII Scanner Code Reader Can Oxgord MS300 OBD2 Scan Diagnostic Tool | eBay

Honestly folks, for $15 you can't be running to Autozone all the time. If you care enough about your 4runner maintenance to be frequenting this board, you need your own OBD2 scanner.