Hi, have one Check Engine Light, the DTC is P0507 according to my ELM327 reader with the Torque app. The GM dealer says the DTC P0509 is present, P0507 is in the history. My local mechanic reads only P0507 with his scan tool too. Is it normal to have that discrepancy? In other words, my reader says Current Fault is P0507, dealer says it is P0509. I did not personally see the dealer scan tool results.


2008 Chevy Express 1500 4.3l, 227K

 

Could be just a difference of software version between the two different code readers. Either way, it looks like related codes, or at least in the same area.

 

https://www.outilsobdfacile.com/data...-code-obd2.php

Idle air control codes.
P0507 Idle Control System RPM higher Than Expected
P0508 Idle Air Control System Circuit Low
P0509 Idle Air Control System Circuit High

With the mileage well over 200k, maybe the IAC valve is gummy

 

Thanks guys, I just thought it was odd that the dealer trouble code was different than what I was pulling up.

 

I didn't even know there was a such thing as "present" and "historical" DTCs.