Left negative battery cable off for almost 24 hours with EFI fuse pulled and as soon as I put the key in and turned key to ON position (not cranking) the check engine light came on.
I thought OBD1 should not store code/s until it runs for a while. Is this correct?

 

I'm pretty sure the CEL, Battery, and Oil Pressure lights are always on when you have the key turned to On with the engine off.

 

Uhm thats normal....

 

yes that is what mine does

 

Thats normal...

Also there is no need to have the battery cable and EFI fuse out for that long.
30-45 seconds tops and it deletes all codes.
is your best friend when it comes to questions like these.

 

ok. ok. stupid brain fart. but I just started it and check engine light stays on.
I had an o2 code and just replaced with new NGK/NTK o2 and it still running like crap.

 

Oxygen sensor code: #5

Knock sensor code: #51 #52

Im thinking you may POSSIBLY be reading the code wrong...
But im not a hundred percent sure...



http://www.troublecodes.net/Toyota/