Hey guys, hoping someone has seen this problem before...

My parents have a 2003 Silverado 5.3 RCSB. The CEL is not illuminating every time they start the truck. Sometimes it does, sometimes it doesn't. The problem is that this is actually causing them to fail their emission testing. They tell my Dad that if the CEL doesn't illuminate, even if there are NO fault codes, he can't pass them.

Any idea what the issue could be? Or should I just tell them to take it to a Chevy dealer?

Thanks,
Jonathan

 

It probably never will come on every time. You should wait about 12 seconds between turning the key off and back on to check for the CEL.

 

Take it by the local parts store and have them scan it for pending codes. If no codes, have them do an I/M monitor test and see which one is not completed.