It works! I did a thing!
I went over to my dad's house this evening and convinced him to let me use his truck ('06 3500 4WD, 6.0/4L80E) as a guinea pig. He's been having some issues with persistent (but very intermittent) check engine lights due to P0442 (EVAP small leak) codes. He's had it checked and smoke tested multiple times, our usual mechanic can't find anything wrong. Apparently it's not an uncommon problem in the GMT800 world. I figured I'd check and see if there was anything I could do to reduce the frequency of that check engine light in the DST software.
I had one small hiccup getting the JETFlash program to connect to the PCM in the truck. On my first attempt to read the PCM there was no communication and it would throw an error message after about 10 seconds. I checked the quick start PDF for any kind of troubleshooting, there was none. So I poked around in the JETFlash menus for a minute and found that you need to go to Setup>Comm Port and manually select which port your hardware is on. Very simple to do, as any port that your USB box isn't connected to will read as "invalid port" in the menu. Simply select the one that doesn't have that notation next to it. After I did that I was able to connect and read the PCM with no issues, it did take about 10 minutes though. I saved the file and made sure I labeled it correctly as the stock tune.
After I grabbed that file I started looking at it in the tuning software. I discovered that in the "Emissions Diagnostics" menu there's an entry for the P0442 code with a check box and a drop down menu. The options in the drop down are:
MIL on 1st Error (Type A)
MIL on 2nd Error (Type B)
No MIL (Type C)
No Error Reporting (Type X)
By default the box next to the entry was checked, and Type A was selected in the drop down menu. I changed the menu to Type B, and then saved the change to a new file. I verified that the change had been implemented by closing the tuning software and re-opening that file, my change was still there.
After that the moment of truth... I set everything up according to the instructions and prepared to flash my new file to the truck's PCM. It took about two minutes and the truck made some strange noises in the process, but everything went well. I disconnected everything and shut the key off, then waited a few seconds and started the truck. It fired right up and nothing caught on fire, so mission accomplished. I don't know if I made anything better, but at least now I know the software is installed correctly and the hardware is functional. If it turns out that this change was a bad idea I can always go back to the stock tune.
I have a couple of questions for
@1998_K1500_Sub and anyone else who has experience with JET DST... Both regarding the options I encountered for diagnostic codes. First, what does "MIL on 2nd Error (Type B)" actually mean? Is that second error
total or
consecutive? Also does unchecking the box next to the entry basically have the same effect as setting the drop down menu to Type X?
On another note I was going to disable VATS while I was in there, but I could only find one option related to it and kind of wanted confirmation from someone else before I tried it. It's under Switches>Calibration Options, and the option is "VATS Fail-Enabled Option (X=Enabled)" with a check box next to it. The box is not checked by default. Am I correct in assuming that checking this box will prevent the PCM from looking for a VATS signal?
