LB7: ECM help

[Kat]

Pat isn't here. So I thought I would post this.

Customer had engine out of truck. Put everything thing back. Truck starts and runs but has security light. When he tries to read the tune. He is getting boot loader error and is giving him garbage for a Vin #.

Any suggestions?

 

[ripmf666]

Could try the relearn 3 11 mins deal with key on and key off to let the bcm learn vin might help mot sure.

 

[Kat]

Could try the relearn 3 11 mins deal with key on and key off to let the bcm learn vin might help mot sure.

I thought about that. But, if he cranks the truck it will start won't it

 

[ripmf666]

You said the truck is running already, If he turns it to the run spot just before start and leaves it on for 11 min 3 times then starts it it might take the light away.The BCM might need to lean itself to the ecm.

 

[Vrabel]

If that doesnt work, turn off key. pull BCM fuse. Let sit a few min. replace fuse. Put key in run pos for 10-15 min. turn off key. then start.

 

[rgullett83]

if vin is garbage, sounds like the ecm is corrupt, but try the relearn procedure

 

[rgullett83]

here you go kat forward this to him.


30 Minute Learn Procedure

1. <LI type=1>Turn ON the ignition, with the engine OFF. <LI type=1>Attempt to start the engine, then release the key to ON; the vehicle will not start. <LI type=1>Observe the SECURITY telltale; after approximately 10 minutes the telltale will turn OFF. <LI type=1>Turn OFF the ignition, and wait 5 seconds. <LI type=1>Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes; the vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK. Important: The vehicle learns the Passlock Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
   <LI type=1>Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password.
2. With a scan tool, clear any DTCs, if needed. History DTCs will self clear after 100 ignition cycles.

 

[Kat]

here you go kat forward this to him.


30 Minute Learn Procedure

1. <LI type=1>Turn ON the ignition, with the engine OFF. <LI type=1>Attempt to start the engine, then release the key to ON; the vehicle will not start. <LI type=1>Observe the SECURITY telltale; after approximately 10 minutes the telltale will turn OFF. <LI type=1>Turn OFF the ignition, and wait 5 seconds. <LI type=1>Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes; the vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK. Important: The vehicle learns the Passlock Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
   <LI type=1>Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password.
2. With a scan tool, clear any DTCs, if needed. History DTCs will self clear after 100 ignition cycles.

The problem is the Engine will start when he tried this earlier

 

[SIKDMAX]

Pull FICM relay/fuse or another one of that type so it will crank but not start.

 

[rgullett83]

just barely bump the key to the crank position, and let off, if you just bump it, it shouldn't start. Also what year lly? 01-02, or 03-04.

 

[Kat]

just barely bump the key to the crank position, and let off, if you just bump it, it shouldn't start. Also what year lly? 01-02, or 03-04.

It's an LB7, but I forgot if it was and 02 or 03.

 

[ripmf666]

I would not even try to start it got to the run the security light should stay on for 10 to 11 mins turn key off then back to the run just before cranking over do not crank over same thing light on for 10 to 11 mins it should go out then do this one last time, After this turn off then start it and see if the security light stays off and everything reads right.

When doing the relearn you do not want to try and start the truck til after the 3 rd time.

 

[bigblaze]

If that doesnt work, turn off key. pull BCM fuse. Let sit a few min. replace fuse. Put key in run pos for 10-15 min. turn off key. then start.

Well I am the guy with the problem. I have not had time to post until now. I have tried all of the above except I cannot locat the BCM fuse ! If I looke at the serial # of my ecm and the vin it is all written in a different language it seems! I seen another post with a similar problem and it sounds like my ECM might be Fubar. I have a couple of Ecms and tcms but what blows is I loose a license! From what I understand efilive might replace my license, I guess I need to find out about that!

Thanx for all of the input and ideas and Thanx for Posting the thread KAT! If anyone has any additional ideas they would be greatly aprreciated! See ya