How can I check why my and check Engine light is on

[anthony mendoza]

I don't have a Scanmaster tool so how can I find out why my check engine light is on

 

[fast86gn]

Most auto parts stores will scan for free in hopes that they sell you a part. The port is just under the dash drivers side.

All of the codes are listed on www.gnttype.org

 

[pacecarta]

pull the code with a paperclip
http://gnttype.org/maint/malf.html

 

[bpman1234]

I used this before the sm came out.

 

[anthony mendoza]

I used this before the sm came out.

What's that and what do I do with that

 

[pacecarta]

its just a two prong metal key that jumps the A and B pin on the ALDL plug under the radio pod
..a paperclip or piece of wire can do the same thing

 

[bpman1234]

Same thing as using paper clipe but gm use to make these .but you put it on the aldl top 2 on the right and turn key on but not running and you will get code 12 3 times telling you that you are on diagnostic mode then if you have any mal code it will stsrt flashing something like 2then 3 for like code 23 .it will do it 3 times then if you have any other mal code it will do it agsin