no check engine but can it still throw codes?
 

The reason I ask is because I feel my truck is underpowered and I want to see if it has any codes that will help me but it has no check engine light so does that mean there are no codes to throw?

If a code was triggered, at some point the SES light would have come on. It would disappear after a certain number of drive cycles, but would remain in the computer's history temporarily.

When you cycle your key does the check light flash?

I think that I have seen some codes that have not triggered the ses light. The last one was 'too long to get to closed loop'. Didnt trigger the light but led me to a magenal thermostst. Some codes clear after a fixed number negative post tests Some can only be reset by a scan tool.

Ok I'll just hook it up and see then. Have a feeling its a cat problem but nothing to back it up but a hunch lol.

And no codes lol thanks all.