Where do I find the answers to check engine light codes for 1994 geo metro

According to:

code 12

everything is fine, you just need to take the fuse out of the diagnostic slot.

have you checked the fuse box INSIDE the car?? usually there are 2, one in the engine compartment, one either on the drivers or passengers side area

look in your owners manual or go to the library and look in a "Chilton's Auto Manual it will show you

check the timing belt it might have broken

if the car is driven less than 5k a year than it sits for awhile, so there could be carbon buildup in the engine and intake this would cause the emissions to be bad but wouldn't through a code. you can do things like run a can of seafoam through the vacuum lines and through the gas tank. read the directions on the can and check the vacuum diagram that should be under the hood of your car to make sure you put the seafoam in the right line. to answer your question about the codes, NO you can not pull codes if the light isnt on. unless the light is burnt out and you just dont know its on. you can check that when you first put the key in the accessory position the check engine light should come on for a few seconds and then go out - so you know if the lights bad or not.

check under the dash panel near steering columnalso there is one in the engine compartment/ Please rate my response thank you very much

Sounds like the converter clutch is engaging. Maybe converter selonoid? Should get put on scanner to be sure.

On 1989- 1995 Geo Metros, code 51 signifies EGR system failure. most of the time when I have seen this code, the electrical plug on the EGR control solenoid has "wiggled" loose, but it can be caused by a number of things. The EGR control solenoid is mounted near the EGR valve and connected to it by vacuum hoses.

you cannot check the codes in a metro at least not too many tech can thecheck engine light is only a light that comes on if a system or systems fail or malfunction and will cause the car to fail emissions on that old of a car the light will do no harm on but I do believe the only people who have the equipment to check is the Chevy Dealer
Please give me a good rating if you found this information useful
www.aceautomotive1.com

Code 46 is indeed the trouble code for the Idle Speed Controller which is that big black box thingy on your throttle body. A lot of Chilton-type manual books omit that code because the ISC isn't found on pre 94 Metros. The ISC is a computer controlled auto-adjuster for the engine idle.

An important note: code 46 is often caused by misadjusted distributor timing. As you probably know, timing affects the idle, and if improper timing moves the idle beyond the ISC's adjustment range, the check engine light will come on and diagnostics will return code 46.