I just replaced a warped head and got all back together no leakes etc. Decided to run codes and came up with 3!! 12, 24, and 31 Where should I start? My manual says 12=RPM signal, 24= intake air temp sensor, 31= air flow meter or short between Vc and E2. Are these 3 related? Not sure if I am posting this in the right place.
Tks Bill

 

24 and 31 suggest the VAFM is not plugged in or some other issue with the wiring.
Check everything around / on top of the air filter.

12 is no NE signal input to the ECU within 2 seconds of starting to crank the engine.
Check the wiring around the ignition coil and make sure all the plugs are clean and securely connected.

BTW- what is the year / engine?

 

that did it , all seems well again!!
thanks very much
Bill

 

you're welcome.
Also, to clear the codes, you can disconnect the battery for a minute or so to reset the ECU. If the problems are fixed, the codes won't come back.

 

If I have no flashing check engine light, then there are no current diagnosed code problems? and if I access the diagnostic system the codes that appear are previous issues and stored codes?

 

If you don't clear the code(s), most of them will still be stored even if the the problem is repaired so you have to clear them as I described above. You'll know there are no codes stored if you're in the diagnostics mode and the check engine light flashes a steady on-off pattern.