Hi guys, my check engine light stays on all the time, How do you get the codes from a 98, 12 valve , I tryed to cycle the ing. switch 3 times and nothing.

 

The key-on, key-off trick only works on 2000 model years and up.
The code readers from your local parts store will access some codes but not all.
It takes a DRB tool (like the one the dealer uses) to acess and clear all codes.

 

Thanks guys, I gess I'll have to see a dealer for my light.

 

Actually the key off/on trick works on all 2nd gen trucks except '98&'99
Instead of reading the numbers on pre '98 you have to count the number of times the check engine light flashes.
'98&'99 require a code reader.
You're still out of luck but just to clarify for others.
Autozone will read your codes for free.

 

Infidel is correct (as usual) about the prior years and counting the flashes.

My experience with Autozone was they're using the off-the-shelf cheapie code reader that showed no codes on my 99 when I was having tranny troubles.
Using the DRB at my local dealer, the techs pulled 3 codes that Autozone couldn't see.

 

Just to add some more to the mix, disconnecting the battery should clear the codes but obviously won't help as to what's going on.