Emergency Relearn on ECM works on LBZ

[Kat]

Someone left me a message that they got there truck started. Here is how you do it in case anyone every needs to swap ECM's

Try to start it, then turn the key back to run. DO NOT TURN IT TO OFF.

Wait 11 minutes (time it).

Try to start again, then turn key back to run. ditto.

On the third cycle, it will ignore the VIN differences in the various modules and will start.

This is how you get a busted truck on the side of the road running when you fry the PCM. You put in a PCM from any other truck of the same type engine, and go through the procedure.

A Tech2 can do the same thing in 1 minute instead of 30 minutes.

OR.... Fire up your scan tool, connect to the ECM, activate DVT select "Learn Now" under "VATs Relearn".

If for some reason that doesn't work, and you need to go through the long relearn process and can flash your ECM, go to G0302, change it from 600 seconds (10 minutes) to 10 seconds, so it'll be:
Turn ignition on
Try to start (it won't)
Leave ignition on.
In 10 seconds exactly the SECURITY (lock) light will turn off.
Try to start (it won't)
Leave ignition on.
In 10 seconds exactly the SECURITY (lock) light will turn off.
Try to start (it won't)
Leave ignition on.

In 10 seconds, the light will go out, and it will start up, and will "marry" the ECM to the BCM permanently.

 

[BIG DIPPER]

Good to know......

 

[tinman22]

just to be clear... is this turn to start ( as in crank it) then release and let it sit in the "run" position and let it sit?

 

[Kat]

just to be clear... is this turn to start ( as in crank it) then release and let it sit in the "run" position and let it sit?

Yes, you try to crank and then release it to the run position and let it sit.

 

[McRat]

DOH!!!

While I have done this with LLY's and LB7's, when I tried an LBZ it appeared not to work.

I guess I must have done something wrong.

 

[LarryJewell]

Good info

 

[tinman22]

cool . good to know in case of an oops

 

[Lonnie]

Kat,
That procedure will definitely work on your Corvette as well. I did that with a PCM swap on a Z06. You typically wait until the "service engine light" flashes, which is just over 10 minutes, so your 11minute delay works. Third time it runs....

 

[LBZ]

Kat, can we make this a sticky??

I'm sure it's going to come up again!!

 

[Kat]

Kat, can we make this a sticky??

I'm sure it's going to come up again!!

Done

 

[ripmf666]

LOL ears burning Kat lol.

first ecm didnt work guess no vin in it,
Turn key to run wait 11 min's,after that turn key of for split second then right back to run postion dont try to start wait 11 mins again or til the security light goes off in left corn of cluster,after that 11 mins turn key off for 3rd and last time for split second and back to run do not try starting wait 11 mins last time after the 11 mins or light is out turn key off the try starting, truck will start and run, if you check vin with efi live v2 will read the wrong vin but all runs great.

Thanks
Kat and Pat

 

[Killerbee]

...This is how you get a busted truck on the side of the road running when you fry the PCM. You put in a PCM from any other truck of the same type engine, and go through the procedure.

so another OS can be installed without a reflash? I didn't think this was possible. :hug:

 

[ripmf666]

When I did the swap it worked for me,I bought the extra ecm from the diesel place and it was another OS then mine and truck started up after I did this.

 

[Killerbee]

Good to know! Thanks

 

[WanaDmaxsub]

A little OT here....but...
This same (30 min) procedure works on a Saturn ION when you have to replace the ignition switch. The only thing I'll add is that you have to turn the key off after the last 10 cycle before you start the car. If you don't you have start all over again.

 

[ripmf666]

A little OT here....but...
This same (30 min) procedure works on a Saturn ION when you have to replace the ignition switch. The only thing I'll add is that you have to turn the key off after the last 10 cycle before you start the car. If you don't you have start all over again.

This is built into all Gm built cars and truck, You also have to turn it off on the trucks to on the last cycle.

 

[andrewvega24]

Security light isn't turning off?

 

[HDLBZ]

Someone left me a message that they got there truck started. Here is how you do it in case anyone every needs to swap ECM's

Try to start it, then turn the key back to run. DO NOT TURN IT TO OFF.

Wait 11 minutes (time it).

Try to start again, then turn key back to run. ditto.

On the third cycle, it will ignore the VIN differences in the various modules and will start.

This is how you get a busted truck on the side of the road running when you fry the PCM. You put in a PCM from any other truck of the same type engine, and go through the procedure.

A Tech2 can do the same thing in 1 minute instead of 30 minutes.

If i would do this will my old ecm still work by just plugging it back in ?

 

[ripmf666]

If i would do this will my old ecm still work by just plugging it back in ?

Yes it will.

 

[HDLBZ]

Yes it will.

thank you
I would like to get one of the ecm's programed with a switch installed does anyone on here do custom ecm's?