View Full Version : LMM DSP5 Immobilizer relink problem
MattS
March 4th, 2014, 02:42 PM
I have an 07 LMM truck in here for a customer, Autocal was purchased from another vender with a preloaded tune for the DSP5 and loss of emissions stuff. Long story short the original ecm was bricked, the company the customer bought the Autocal from sent a used ecm preloaded with the DSP5 tune. The used ecm needs to have the Immobilizer relearned through GM's TISWeb, I went to do this and the GM program locks after downloading the file, it locks on "receiving ecu status". I am aware that once a DSP5 tune is flashed into these ecu's it can no longer be read out, is this lock causing the GM TIS to not be able to read out the ecu status? Anyone ran across this problem? Any help would be great
GMPX
March 4th, 2014, 03:41 PM
You can also do the Auto-relearn (I am copying the text from a tune description)
To relink the VATS to a new / exhange ECM perform the following steps -
1 - Turn ON the ignition for 5 seconds (do not start yet).
2 - Attempt to start the engine (it should not run), then just turn the key back to the 'ON' position.
3 - Leave the key in this position until the SECURITY lamp turns off (length of time is specified by this calibration). << Normally 10 minutes
4 - Turn the ignition off for 15 seconds.
5 - Repeat the steps 1 - 4 the number of times specified in {G1214} "VATS Relearn Count". << Normally 3
6 - The engine should now start as the VATS codes have been learnt by the ECM.
MattS
March 5th, 2014, 04:03 AM
Thanks for the fast response. The Auto-relearn according to GM, Mitchell Prodemand and my on trial the 30 min will only learn a replacement key it will not relearn the immobilizer prerelease password. The VATS timer in the tune is {G0302} and the count is {G0304}. This ECM seems to have the timer turned down because the security light turns off in 10 sec after attempting to start while trying to do the auto-learn. I did not make this tune, we are a State emissions station and I will not make a tune that removes / disables any emissions component on a vehicle I know is for on road use. I have no problem letting someone else take the liability, I didn't even install the Autocal in the beginning. I don't have this tune it was preloaded in the used ECM so I can't check the VATS count or timer and the maker of the tune doesn't want to send it to me for obvious reasons. A new ECM will relearn with the Auto-learn because it has not learned a prerelease password yet. The used ECM needs to be hooked to GM's TISWEB to do the VATS prerelease password relearn. Looking at the VATS data in the ECM the key is valid but the ECM challenge is invalid. Is this tune going to have to be retuned to stock to relearn the prerelease password? If I force the immobilizer relearn will it cause a problem in DSP5 tune/ECM? Has anyone ran into this before? Thanks for any help.
MattS
March 5th, 2014, 01:23 PM
Update: Found the problem. I talked to Rob at #%^&*, he is the one who did the tune, the VATS were already set to disable in the tune. It turns out the pink wire on X2 pin 21 was broken inside the insulation right at the connector, when I pulled the X2 up to check all the powers and grounds everything checked fine, but when plugged into the ECM the connection would fail. The broken wire is what caused the original ECM to fail part way through the flash, the wire must have been making a partial connection but failed part way through the flash. FYI without power on X2 pin 21 it looks like a VATS fail, the ECM will communicate and read all the sensors correctly. The TISWeb will go most of the way through the process of both immobilizer relearn and a full reflash before failing without power on x2 21, the V2 does the same thing, will go though most of a reflash before failing. Thankfully the replacement ECM was not damaged. The good news is Rob was able to recover the first ECM, it was just missing the operating system, the reason I could not is I was trying to do it in the truck not my bench harness. That's a good lesson: If it fails in the truck, try the bench harness BEFORE wasting two days! Sometimes I forget the simple stuff.
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