LMM OS 12628594 (NQG) Option

Hi All, looking for some better details about this Engine Operation version 12628777. It's from a floor shift transfer case truck, and changes the operation of pins X-1 57 & 82 [AWDSIG & AWDLOW].

Been playing with both versions, and the difference is how the ECM selects Torque Reference Tables under A, B, and C, that I've noted so far. Might it be an option to add these selection under "System"?

If you swap ECM from a floor shift truck into a dial shift transfer case, it's not going to respond correctly to canbus commands. And visa versa.

Attachment 22715

There is probably more than just one little change to making that work.

I'll bet it's a single bit switch like the oil temp signal pin on the E38.

I never even noticed this existed till I tried to force one into low range tables by triggering those pins. Worked on one ecm but not another. Also controls if State07 reports correctly, or msg to trigger dash light is sent out to bcm.

On the canbus version, state is controlled by 2 bits. One for front axle active, other notified of low range mode. I thought vss input signal was also related, but that seems to be different pin switch issue.

Sent from my SAMSUNG-SM-G890A using Tapatalk

Quote:

---

Originally Posted by kidturbo

I'll bet it's a single bit switch like the oil temp signal pin on the E38.

---

You can't compare 'logic' between Bosch ECM's and GM's own :laugh:

Quote:

---

Originally Posted by GMPX

You can't compare 'logic' between Bosch ECM's and GM's own [emoji23]

---

Valid point... lol

Sent from my SAMSUNG-SM-G890A using Tapatalk

For now, does anyone happen to have a list of all the known "Engine Operation ID's" under this particular OS?

Guessing that's our identifying maker to determine if the file is coded for trucks with TCCM or ones without. Is there only two, or is there twenty two possibilities?

LMM engine op 2007.5

12646908, 12646910, 12646928, 12634934, 12646940, 12646941, 12632396,12632399,12633757, 12631780

LMM engine op 2008

12646908, 12646910, 12646916, 12646917, 12646920, 12646921, 12646938, 12646942, 12646943

LMM engine op 2009

12630483, 12630484, 12634941, 12633755, 12633757, 12633758, 12633759, 12633760, 12628778, 12628694

LMM engine op 2010

12631780, 12631784, 12631785, 12620398

FWIW - on the older LS1B PCM's, the transfer case "style" was found under the System segment. The easiest way to start deciphering this part of the code, aside from having a complete disassembly, is to look at this section in hex. This is how I started to try and find differences between tunes based on the same OS.

Quote:

---

Originally Posted by GMC-2002-Dmax

LMM engine op 2007.5

12646908, 12646910, 12646928, 12634934, 12646940, 12646941, 12632396,12632399,12633757, 12631780

LMM engine op 2008

12646908, 12646910, 12646916, 12646917, 12646920, 12646921, 12646938, 12646942, 12646943

LMM engine op 2009

12630483, 12630484, 12634941, 12633755, 12633757, 12633758, 12633759, 12633760, 12628778, 12628694

LMM engine op 2010

12631780, 12631784, 12631785, 12620398

---

Well that narrows it down a bunch...

Thank you for the list. As i figured, couldn't be simple A or B option.

Playing with this on bench further I noticed the version I have been testing transmits a msg ID 0x2D1 on the HS bus. That is same ID the TCCM uses to notify ECM of TC position on dash knob trucks. So if you load wrong version, both TCCM and ECM are squawking same messages, and BCM likely has issues with that.

Sent from my SAMSUNG-SM-G890A using Tapatalk

Ok onto something simpler for time being.

Has anyone stumbled onto the switch that sets source for VSS input??

Both above versions I've tested only want to use VSS data from CANbus. Like previous models, this OS will accept a pulse speed input on VSS HI, but only for a few seconds, then it times out. But the VSS PID continues to read the incoming pulse signal. However all speed related tables will stop responding to it, and output to BCM defaults to 327.68mph. Send it some correct VSS data over HSLAN and everything is happy. Guessing this one might be similar to the gassers..