I have a superchips vivid linq that I just bought. I have pretty much determined that the tuner is OK but my truck has some issues with tuning. My truck is a 2004 Silverado 2500HD with the LB7 Duramax. The tuner won't read that the ignition is on. I keep getting an error code stating "error verify the ignition is on" even though it's in the run position. I was told by superchips to plug the tuner into my other vehicle which is a 2002 Yukon Denali and verify that the tuner was communicating properly. It was, and I was able to get to the opening screen fine. So the tuner seems to be working like it should. I was able to compare the OBD II connectors to eachother, they are both GM with the same 4 pins. Pin #16 has the same constant power, and with the key on pin #2 has under 1 volt. Both of the grounds, which are the only other wires going to the port are both working as I used them to test for power at pin #2 and #16. All the fuses that would be an issue with a power drain were pulled and the truck is on a charger at 14 volts. Superchips tech has ran out of ideas. Any thoughts?

 

Aftermarket alarm or remote start by any chance? Some of those tap into the purple data wire on the OBD2 plug. Those interfere with Tunercat OBD2 on 03+ trucks and I have to disconnect the wire tap. Some aftermarket stereos interfere also and I have to pull the radio fuse to get communication.

 

No alarm, no remote start. Can't see anything tapped into the purple wire unless it's way down stream somewhere. I have most of the fuses, including the onstar, info, radio, radio amp removed with the same result.

 

I really don't know anything about that Superchips tuner but you say it works on your 2002 Yukon Denali. This sounds like a gas vehicle. This shows a different part # for GM gas and GM diesels. I would guess that Superchips tech would have verified you are using the right tuner. Are they saying the one you have will work on both gas and diesel vehicles?
VIVID LINQ

 

Ironically there site only list 2004 2500 with a gas engine. But if you go under 2004 3500 it shows the LB7 and the LBZ

It shows part number 128550 for the Diesel and 128650 for the Gas.

If there are different part numbers for gas and diesel there is probably a reason.

Are you sure you got the correct part number as you said it worked with the Gas vehicle and not the Diesel???

If you have the correct part number, Make sure the Pin is seated in the OBD 2 connector properly on the truck. Also make sure the wire is clean with no breaks or corrosion. You may have to check it for continuity at the fuse box to the connector.

 

Check your CIGAR fuse. I'd bet it's blown.

 

He said both vehicles have the same constant power on pin 16 using the ALDL grounds as a reference.

 

This is usually the most common issue if you haven't already been asked to check it.

 

I did check the 15 amp cigar fuse and it was fine. Swapped it out anyway and still the same problem. Use that as the charger for my phone all the time with no issues.

Superchips had me connect to the other OBD II port on the denali just to see if it would do anything different. The software on the VIVID is for a 6.6L LB7 Duramax so it wouldn't work to tune. The point is, it isolated the problem to something weird with my 04 trucks OBD II connector.

 

What's strange is that all the other functions of the tuner work fine. It connects to the vehicle and reads the milage, RPM, coolant temp etc... and I told that to superchips who told me that the tuning function uses a different pin. Which is impossible because there are only 4 wires. 1 for data, 1 for 12v constant, and 2 grounds. I also have an ELM 327 that I got an engine link app for. I can read all the trucks info with the exception of the fuel level on that as well. I'm at a loss.