I've had a few issues with my 09fx4 over the last few years but the only one that cost me money is the Check Engine Light. I bought a new scan gauge and had it connected to the truck for about a week. After disconnecting it and driving around for a few weeks the CEL came on. Used the scan gauge to get the code P0605 - ECM memory checksum error. Tried to clear it but kept coming back.

The dealer charged me $139 to diagnose and reflash the PCM. They said the it was caused by a tuner or other device. Any one else have a similar issue?

 

Doubt that the Scangauge caused it. It is passive. I've had the scangauge on an '05 5.4 and a '12 Eco and have never had an engine light of any kind.

 

In less you tryed to program the PCM the only other thing it could be is the scan gauge it should not do any thing to the truck but it might have caused it you never know with computers that code is set when the PCM ROM is interrupted and the scan gauge reads the ROM so you never know i might contact scan gauge and see what they say

 

I've used the scangauge in my 2010 since I got it and no issues or codes. Doubt it's caused by the scangauge.

 

That's what I thought. Maybe it was a coincidence. Either way I guess the check engine light diagnosis was not covered under power train warranty. Had the exhaust manifold replaced at the same time and that was covered.

Don't really want to use the scangauge anymore be because it might have scrambled the memory. The only interesting thing I did find out with the scangauge was that the deceleration fuel cut-off really does work on the 5.4.

 

I'm not sure what the scangauge costs, but a tuner can read codes, and so much more.