I recently had a new update from GM installed on my truck and now am receiving an error and it won't read the PCM. Anyone experience this and if so how did you correct it?
LMM: Can't read PCM after new GM update
- Thread starter Mac Daddy
- Start date
thats your issue...
i cant remember how to fix this issue but i believe it has to do with either a bench flash into the ecm or using a tech2 or something.
basically, you screwed the pooch leaving the tune in there
i cant remember how to fix this issue but i believe it has to do with either a bench flash into the ecm or using a tech2 or something.
basically, you screwed the pooch leaving the tune in there
Using EFILive to read/program. I had a 120hp tune installed and the mechanic only told me it was the latest GM update (he was vague)
Update your V2's firmware and you need to re load the stock tune file. Then load the TIS stock file if you have one. Then the tune. Always load the original stock tune when truck goes to dealer. Likely the mechanic now has a 120hp tune as well.
The other may be a result of a bad ground. ABS module's ground to frame will cause error with V2 when flashing/reading.
Im certainly not an expert but have had similar issues after dealer visit. My other LB7 wouldn't start after dealer reflash and 45 over injectors installed by dealer. I just reflashed my stock tune, cranked it, shut it down, then loaded my tune.
Good luck
The other may be a result of a bad ground. ABS module's ground to frame will cause error with V2 when flashing/reading.
Im certainly not an expert but have had similar issues after dealer visit. My other LB7 wouldn't start after dealer reflash and 45 over injectors installed by dealer. I just reflashed my stock tune, cranked it, shut it down, then loaded my tune.
Good luck
I've never seen EFILive not be able to flash an LMM ECM unless there is some other issue (possibly outdated software/firmware or a wiring issue on the truck). Are you able to connect to the truck and read data from the ECM?
What does having a tune overwritten by a stock gm calibration via a mdi or tech2 have to do with not being able read the ecm? As far as I know, the gm flash procedure doesn't care whats there and as long as it can unlock the ecm, it'll overwrite whatever is there and you'll be back to stock.
Now, if gm is implementing a new seed/key algorithm, then thats a different story.
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I guess the real question is why did you have an update done in the first place? Were you having a problem you were hoping would be resolved by an updated calibration from GM? If everything was fine before this, don’t worry about reading out the stock file; just flash your old tune back in over the top of it.
I am able to connect and read ECM...but when the Scan is complete a message pops up "Cannot merge calibration with CPU system file C:\Program Files\EFILive\V7.5\Configuration\M97.ext"
Upgraded to the latest EFILive updates (Firmware & BootBlock) and it worked like a charm. Thanks to all for the input and advice!