diagnosing with code readers

bwolsen · May 13, 2004

I am having trouble finding the root the noise in my truck. (see my other posts). My question is, can I still plug a code reader in to find a problem if my check engine light has not come on yet? In other words, is it possible that the reader would let me know of a problem before the truck would?

Frank S · May 13, 2004

No,code readers only work if a code has been thrown to trigger the SES light.

If you are wanting something for in depth diagnostics you'll need a laptop or handheld with software such as Autotap or AutoEnginuity as you can get a much more detailed look as to what is going on.Even then you may not find anything wrong.

Import Hater · May 13, 2004

And even after that, you may not know what to look for. I can look at a live data stream and tell if a engine is not running the way it should just by looking at fuel trims, o2 readings, and values from some of the other sensors. But then again, I've seen hundreds of different live data streams and I have an idea of what's normal and what's not. An induvidual owner who only scans just their vehicle, and doesn't really have a "database" to compare to...could have a problem staring them in the face and not really see it.

Rob