Here is the stats on the truck

2007 Hummer H2, stock other then a Magnuson Supercharger.

Installed the blower, loaded Magnuson tune that came with supercharger kit. As well very well truck drove great other then two issues.

- Horrid gas milage around the city.
- Randomly would go into power reduction mode (pull over, turn key off for 30sec, fixed)

The owner came to me to fix it, and I said that it shouldn't be an issue.

However.....

It has no codes in the ECU or the TCU, other then a Class 2 Data whatever error.
I was really expecting to see something like a MAP, or MAF, or ETC code of some sort to put the truck into a power reduction mode so many times.



Anyways, I tuned the ECU to pick up the milage (which worked big time) yet I couldn't find ANYTHING out of line in the Magnuson tune as far as something that would cause the power reduction mode. (Not that I expected to, their base tunes are always nearly spot on if the cars/trucks are in fact stock, with no issues) So I figured it was a fluke and let it go.

Guy calls again, says its still doing it. Talk to GM about it, they said it was a throttle pedal problem, and they could fix it. Well it gets the new pedal and its still having the issue.

Finally I told them to have GM flash the truck to the latest stock OEM GM program, and I would build a complete base tune from that. Well, I did that..... and you guessed it... .same result.


Whats fustrating is the following..

1) This thing can go weeks on end without going into that mode. Then sometimes it will do it 3 times in like 15min. There doesn't seem to be any rhyme or reason to it, and its gonna make me pull my hair out.

2) NOOOOO CODES to even help figure it out, other then that Class 2 Data Bus.


The truck has an Aftermarket Radio in it, so I figured that was the issue with the Databus? Is that correct?

Has anyone had this issue....?
Is he going to have to pull the blower off, and see if it does it stock?



Thanks in advance.