Service engine soon problem

[dylan94sierra]

I just got a 94 GMC sierra 1500 4x4. Everything works and runs good but after about 10 minutes on the road the Service Engine Soon light comes on and stays on, but once the truck is turned off and restarted the light is gone until about 10 minutes. I already replaced the egr as soon as I got it. When the light is one I do not notice a difference in the ride or performance. What could it be and how do I test the codes with the paperclip? Im kind of new here and to GM so thanks in advance

 

[twomanymontes]

Need to pull the code. Use a paper clip and jump terminals A and B

the Data Link connector has 12 pins - a top row of 6 pins and a bottom row of 6 pins. The upper right hand hole/pin is called Pin A, directly to the left of this pin (top row, too) is Pin B. You will need to take a paper clip and stick one end of it into Pin A and then take the other end of the paper clip and stick it into Pin B. Make sure each end is in there tightly.

Turn ignition to on. but do not start the truck. Watch your check engine light and it will flash intermittently to show you the codes. Slow flashes are the first digit and then the fast flashes are the second digit.

Once you have the code, it will help determine the circuit affected.

 

[dylan94sierra]

Thanks for the help, ill have to try it out tomorrow. Is there any common problems with the 5.7 that I should be aware of or am able to prevent in the future?

 

[twomanymontes]

No Problem.

All kinds of issues pop up, every truck is different. Basic maintenance and just checking the truck over periodically for problems is really about all you can do.