are u ready for my super-newbie question

[9i]

please don't laugh but what is ECU and what does it do and why so many people have talked about resetting it , looking up codes...etc waht does it all mean http://www.newcelica.org/ubb/confused.gif

[vvtlikick]

ECU - Engine Control Unit

The ECU is the computer that runs the engine. It decides how much fuel to inject and when, and decides when to trigger the sparkplugs, among other things.

Modern ECUs are pretty smart, resetting the ECU makes it forget what it's learned, letting it get off to fresh start when learning to compensate for a intake/exhaust/etc.

You check the ECUs error codes to discover what problem caused the ECU to trigger the CEL (Check Engine Light).

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<FONT size="1"><FONT COLOR="GRAY">2000 TOYOTA CELICA GT-S 6 SPEED</FONT c></FONT s>

[coOOlcelica]

Originally posted by 9i:
please don't laugh but what is ECU and what does it do and why so many people have talked about resetting it , looking up codes...etc waht does it all mean http://www.newcelica.org/ubb/confused.gif

HEY WHERE IN NORTHERN VIRGINIA ARE YOU FROM???

[9i]

vvtlikick : how does one "check" ECU error code ?

coOOlcelica : I currently livein Manassas but it's a long nasty comute from work(Reston) I will move out probably to Centreville or closer. ut I can't afford the high rent near Herndon since I dumped all my $$$ into the new Celica <IMG SRC="http://www.newcelica.org/ubb/smilies/cwm32.gif" border=0>

[vvtlikick]

Originally posted by 9i:
vvtlikick : how does one "check" ECU error code ?You buy a OBD (On-Board Diagnostic) scanner (like the AutoTap (http://www.autotap.com/) ) and plug it in to the OBD port (I think it's under the dash near the hood release).



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[GTS LAID]

in the toyota lingo its referred to as an ECM... try to figure that one out.. hehe

[GTS LAID]

you can use a generic scan tool or the toyota scan tool (much more expensive). you can use the ECU monitor to look up different variables within the car. For example when I blew up my engine the print-out read 11,000 something RPM at 84mph... why would i reset the ECU.. so that they dont see this... why didnt I reset the ECU.. cause I had nothing to hide. and i told them this by proving to them that i knew how to reset it (pull fuses 19,20,24 from engine fuseblock) or use the battery technique.. either way they're replacing the engine... another reason you'd want to reset the computer is after you've changed something that affects one of the variables that the ECU reads.. by resetting it you're telling it to adjust itself to new variables.. which it'll do quite nicely most of the time...

[xav3x]

kinda off topic.. but... so my lil computer knows i went 138mph the other day?? lol

[CelicaNamja79]

ECU

Engine Control Unit

it is a on board computer that controls your car....

[kocheroni]

just curious if anyone here has an OBD tester. I'd like to just see what it looks like and what options it gives you, like how many things come up when you scan your car. Seems like a neat thing to have if ur larry. Hehe, j/k larry.

http://community.webshots.com/photo/25201042/25201141RAZCoTNClP

[GTS LAID]

there are lots of diffenent types of OBD testers.. th toyota one gives you the most options by letting you actively run some tests from it.. fuel pressure, etc...

theres also something called the autotap.. its a plamOS software package that comes with a cable that plugs into your OBD port and relays to you lots of info getting collected by all the sensors.

And yes your car "knows" you did 138 mph the other day... the on board computer storage capacity varies with the amount of fluctuation in the data but is typically about 20 minutes of driving worth.

nothing an ECM reset cant take care of