2000 MR2 Reset Check Engine Light

[dmcanulty]

My daughter's check engine light came on following a stop at the gas station. How do we reset this light to make sure it wasn't a problem with the fuel tank lid?

[Gairloch]

Can even do one better. Our cars are OBD I so you can pull the code by using a paperclip to jumper the TE1 and E1 terminals on the diagnostic box then count the flashes of the CEL. You can find a more in depth explanation of the procedure and a list of code definitions here: http://www.off-road.com/toyota/tech/codes/. You can find the diagnostic box in the engine bay driver's side on the trunk firewall.

I am 99% sure that the fuel tank lid doesn't have any sensors on it.

[Zero turbo]

my check engine light is on, can i know what is the problem by reading the diagnostic box??

[Gairloch]

If you pull the code it'll tell you what the ECU thinks is wrong. This isn't necessarily what is actually wrong but it'll give you a good starting place.

When you're ready to clear the code (It'll stay there until you kill the battery or intentionally clear it) you can find directions on how to do so in the BGB. I can't look at it from work but the url is www.mr2-tech.com.

[Nad1370]

Originally Posted by Gairloch

Can even do one better. Our cars are OBD I so you can pull the code by using a paperclip to jumper the TE1 and E1 terminals on the diagnostic box then count the flashes of the CEL. You can find a more in depth explanation of the procedure and a list of code definitions here: http://www.off-road.com/toyota/tech/codes/. You can find the diagnostic box in the engine bay driver's side on the trunk firewall.

I am 99% sure that the fuel tank lid doesn't have any sensors on it.

He has an OBD-2 vehicle. I don't think the jumper trick will work.

The tank lid doesn't have any sensors but the Evap system does. If you left the gas cap loose it will set a code usually PO440. It could also set 3 codes 440, 441, 446.
Loose gas cap will set a code because the evap system can't pressurize and detects a leak.

Best bet is go to and Autozone and have the code read for free.
If you really want to clear it w/out knowing what the code is. Then just pull the 15amp EFI fuse in the engine compartment for 10 sec.

[dmcanulty]

Just wanted to say thanks for your input...sounds like good advise! Happy Holidays!

[mr2nsilvias15]

on an OBD2 system i wouldent recomend jumpering anything if you take it to your local advance auto parts, pepboys or one of the many automotive stores they can read the codes for free and tell you what the code is for i have an obd2 reader so if you posted the code my computer would tell me what it was but it would be pointless since they can tell you right there

[Gairloch]

Whoops, didn't catch the year of the vehicle in the title when I posted. D'oh!

[QuadCamSix]

Or, if you screw the gas cap back on and the light goes out it was just an evap code and will clear itself from the computer after a few starts No need to check anything. I see this all the time when people dont put the gass cap on tight enough.

[heritage36]

Yeah, the right way to deal with it if you have the patience is to just tighten the cap and it should go off within two consecutive passing trips. If you do not want to wait to find out, not sure if this would work or not for sure, but try pulling the ECU fuse or just disconnecting the battery, just remember to let the computer relearn the idle (let it run until the fans cycle a few times at idle).

[dmcanulty]

Again, thanks to everyone for their input. Turns out, we did take it to AutoZone to have it tested. Turns out, it was the Oxygen Sensor. We ended up buying the part, and with the help of an Autozone employee, was able to install the sensor ourselves...saving $$$! But we've got to give you all credit!

We've been told that the light will go out after a few days.

Again, thanks!