LMM "Trailer Brake System Service" message after DSP OS flash.

[LReiff]

I have tuned 2 LMM trucks recently that have thrown this message after a full flash to a custom DSP OS. I have the one truck scheduled to come back on 7/5/12 so I can check it out. Any help or insite on the matter would be greatly appreciated. Is this coincidence? Are other having this issue?

I have not yet tried reverting to the non DSP OS to see if the issue resolves but that will be one of the first things I plan to try.

[GMC-2002-Dmax]

did you use the stock tune file when you made the DSP5 script ???

[Dmaxink]

If you put a tire size of over 34" in...it will trigger this.

[LReiff]

did you use the stock tune file when you made the DSP5 script ???

Initially yes. Then I switched OS to see if that made a difference, non.

If you put a tire size of over 34" in...it will trigger this.
Ok. The one coming in has the tire size set near 30". He running 225/75/R17 tires. I was messing with it last evening right before I made this post.

This truck had an H&S tuner on it before I tuned it. Would a clean flash from the dealer possibly fix it?

The other truck has 33-34" tires but was a stock OS before it lost exhaust and got tuned...unless a previous owner had messed with it, doubtful though.

[GMC-2002-Dmax]

Pm me the VIN# only and I'll see if I have a stock-unmolested file I can send over

[LReiff]

PM sent.

[LReiff]

Any new ideas on this? The guy want to tow his 5er next week and no trailer brakes makes it impossible!

[JoshH]

What have you tried so far? Have you set all the speedometer parameters back to stock or installed the stock tune or at least the stock OS?

[GMC-2002-Dmax]

Vin # you PM'd me comes up an invalid on GM-TIS

[LReiff]

GMC-2002-Dmax sent me a clean OS with the proper segments for the truck and I built the tune off that and it still pops the message. Then I hooked up a Snap-on Modis and checked the EBCM (electronic brake control module) data and it told me the trailer brake system is still disabled. I guess the only option at this time is to visit the dealer.

The other truck that left with this same message on the dash, fixed it's self. I talked to the owner over the weekend and he tells me the message disappeared and the trailer brakes work fine.

Thanks for the help!

[JoshH]

Did you return the truck to stock and see if it starts working again?

[LReiff]

^ yes.

I'm looking over the tune file right now, I see that I have B1501 as disable. Could that also disable the EBCM?

[JoshH]

When you say yes, do you mean you tried it, or do you mean it starts working?

[LReiff]

I tried it and as far as I know it doesn't fix the issue. This issue appearantly came about when the truck got flashed with the xrt-pro. Tony got me the proper OS with the correct segments (according to TIS) and I started over with that. The OS that I read out of the truck after the xrt-pro was removed is the proper OS number but it has totally screwed up segments.
The guy that owns the truck is out of town this week and he had to take the truck. I'll know more in the following weeks once it comes back. Maybe it will have corrected itself by next week but I don't see how unless its something that simply needs to go through a relearn procedure.

[JoshH]

Gotcha. Hopefully you can get it all sorted out.

[LReiff]

I had the truck to the dealer this week to get this sorted out and they are baffled. First they said it was a bad TBCM so they replaced it and got no change. Then I twisted their arm a wee bit and convinced them to reflash every other module on the truck to be sure it wasn't a segment issue, which it's not. Now they are saying it has a bad EBCM. I guess we'll know in a week when it goes back to be finished.

TBCM = trailer brake control module

EBCM = ABS motor/pump/computer, it's all one unit on the new trucks

[Motorzane]

You can buy the EBCM separate from the pump/motor. I think they are $220 list at the dealer

[LReiff]

I'm only going by what the tech told me. I guess he'll get an eye opener when he only gets a module to install! So far everything is being covered by warranty.