Dutchman

When the shop hooked up my 2005 Mustang to get inspected, they said that although the car appeared "ready" many if, not all, of the codes were reading N/A and it wasn't communicating with their computer. They also verified the N/A status via a separate handheld scanner. I have a screenshot of the scanner, but cannot posted it here.

The vehicle is running great, no issues. It does have a Diablosport tune and it has had it for years, no changes there and never had an issue. The only other recent change was that I had the stepper motors replaced in the instrument cluster.

XGC JACOBS

I have a BAMA tuner on mine, but put it back to stock before i had my emissions done and passed. I would start with removing that Diablo tuner then having it rechecked. I don't know what Diablos setup does, but i know any tuner can affect 02 readings and catalyst readings, however you did say you've never had a problem before. Have you recently had any check engine lights cleared or anything fixed for a CEL and had it reset? You should take it to a shop that has the capability of reading your 02 and catalyst monitors and see if they are reading, this is most likely your problem.

gmoran1469

You need to contact Diablosport and ask them if their tune turns any of the sensors off. My Brenspeed 93OCT Track tune turns my rear O2 sensors off and I have to put it back to stock and run it till they are in the ready state to pass inspection.

Dutchman

I tried disconnecting the battery for a couple of hours, no change they were still reading N/A. I then restored my factory settings from my Diablosport. Now I see that some are "Not Ready", which I think is an improvement over N/A. I will get it through a drive cycle and then hopefully that will solve the issue. Then I will decide if I want to put the tune back in, probably will.