My dad has a 03 scsb 4.8, and the other day it started running bad. He didnt do anything about it and its running right again. The check engine light was on so he asked me to check it today. I hooked up my scanner and it did nothing. Nothing on the screen whatsoever, then hooked it to my 02 and its working fine. Is there a fuse or something for the obd2 or could there be something else wrong? Also when I went to check it the ses light didnt come on. For a while the truck sounded like it had a cam in it ( completely stock ) and now it runs perfect.

 

Go under the hood and open the fuse box there's 4 blue and a red in a straight row check the blue one one is blowen

 

Cigarette lighter fuse is the same as the ODBII, make sure it's not blown.

 

Alright I will check tomorrow. Thanks guys

 

x2 its that.

 

Seems to be fairly common, had mine do that once. I never even use the cig lighter or plug anything into it.

 

same here! I've blown that thing twice. Each time I was like

 

Yeah me too.. I hate that damn fuse. It needs more amps!