LB7:ECM will not accept tune - Wiring Harness?

[dlowman]

Earlier this week, I purchased a Duramileage EZTuner. I followed the instructions in the manual and it downloaded my stock program from my ECM. I then tried to upload a tuner program and it loaded. However, when I started the truck it was in limp mode and the "battery not charging" message was on my dash. I then tried to load one of the other programs and it loaded, but the engine still started in limp mode with the battery not charging message displayed. I called the tech support and they walked me trought trying to reload my stock program, but the tuner kept giving some type of comm error. After trying to upload the stock program, the truck would not even start. The tech support said that the ECM was locked up. They overnighted me an ECM with a stock program, which I installed and the truck started right up. The Tech support then walked me through uploading one the the tuner programs and the tuner kept giving comm errors. They told me to send back my old ECM in exchange for the one the sent me and send back the tuner, which they would refund my payment. They said I had a wiring harness problem which they had run into 3 or 4 times before with 2004 LB7 engines.
How can I check to verify that their excuse is valid without locking up another ECM?? Did they just have a glitch or is there really something wrong with my wiring?

[Kennedy]

I highly doubt that you have a wiring harness problem. Probably more of a tuning problem. I prefer to do these ECM's on the bench. Then it's done with no worries or risk of losing an ECM core.

[greatwhite]

Does your truck have onstar?

I've had a few problems with modules "listening in" on the data bus while re-flashing a pcm.

The onstar system seems to be a big offender, I usually pull the fuse for it if the vehicle has one.

Other modules on the bus can also cause problems.

This is why they will usually program without fail on a bench rig and can be hit and miss in the vehicle.

I mostly work in 16216588 pcms (6.5) these days, someone like Mr Kennedy (who works in DMax stuff) is probably the best source for info in this case. But those are my experiences when I dabble in the newer stuff....

[SoTxPollock]

JK, couldn't help but smile about your comment about the new truck, being build one day after your birthday and delivered 7 days later. Sometimes it just works out that way.

When I bought my truck in 02, we had scoured the lot and computer looking for the exact truck I wanted, then we drove all the way to the back of the lot under a shade tree sat a truck that looked exactly like what I wanted, the salesman said, yeah I can let you have that truck. The guy special ordered it and then changed his mind and didn't want it. The odometer had 2 miles on it.
My old football number was 22, when I got the truck home the truck build date was 02/22/02. When I saw that I knew that was meant to be my truck. It's probably the only one with a cd player radio with a cassette player built in. Never seen another one exactly like it. I know no one got to hot rod it before I bought it. The way I break them in, they never wear out.

[More Power]

It's easy to miss something while uploading/downloading a tune. So many of the individual systems in these trucks are monitored by the computer that you have to make sure the doors are shut and everything is either off or its fuse pulled to prevent a semi-automated activation (like OnStar). I screwed up a load one time that required a visit to the dealership to have them reflash the ECM. They know me quite well, and just smiled when I asked them to do a reflash... ;)

[Kennedy]

I haven't pulled a fuse, shut a door or anything while tuning in a long time now. Then again I haven't loaded a generic tuner in about equally as long. While most of my tuning is done on the bench, I do still load some for drive in customers.

Sotx

My 02 had (now Pioneer) the CD radio plus the cassette deck built in below along with Computer Climate Control. Not much more you could add back then.