LB7: Cannot communicate with ECM

[Josh2002cc]

My buddy has a 03 GMC that currently has a bullydog tune flashed in. We have tried many a times to unload that POS and it just freezes as if something is wrong. So I hook my efi up to it and try to read the ECM with no luck. It says "cannot communicate with ECM". As I watch the efi try to do it's thing, I can see where is says it is "initializing ECM step 1-4" but then it says "no response from ECM" and keeps trying until it kicks me out.

So then I try to do a flash on the ECM, same thing except it says I am locked out from the ECM and cannot tune it until the current tune is removed.

I then try the full reflash with no luck, same as listed above.

Anyone have any recomendations?

 

[dracing70]

u need to get that bully crap out of there..

 

[JustinD]

Check the cigar fuse, does the OBDII port have power? Also make sure all aftermarket equipment (stereo, radar, alarm) all that stuff with try to communicate and screw you up.

I have had this issue with an 03 truck before come to find out the alarm guys used the OBDII as a place to pick up power for their system.

 

[Josh2002cc]

u need to get that bully crap out of there..

Exactly, that is my issue. However, How do I do this since I cannot communicate with the ECM to override it?

 

[BLKLMM]

Try removing some fuses in the panel, we had same problem in my buddies 01 truck with the edge.

 

[duramaximizer]

You may have to go to a dealer to get it reflashed to stock. I have had tons of issues with bullydog stuff.

 

[BLKLMM]

here is fuses to pull
http://www.pacificp.com/pdf/Duramax Hot+2ETRACE-07-10v4.pdf

it is meant for ppe but we used it to get stupid edge out of truck

 

[SgtKilroy]

If you have an aftermarket radio, disconnect it and reconnect your stock radio when you flash it. Mine was doing exactly the same thing.

 

[Josh2002cc]

here is fuses to pull
http://www.pacificp.com/pdf/Duramax Hot+2ETRACE-07-10v4.pdf

it is meant for ppe but we used it to get stupid edge out of truck

I tried that with no luck.

Thanks though.

 

[Josh2002cc]

If you have an aftermarket radio, disconnect it and reconnect your stock radio when you flash it. Mine was doing exactly the same thing.

Stock radio.

 

[Josh2002cc]

Can I try a 01 ecm in an 03 truck?

 

[sweetdiesel]

Can I try a 01 ecm in an 03 truck?

Yes and the full flash to his op systym

 

[sweetdiesel]

Can u log?

 

[Josh2002cc]

I can try. Log what?

 

[sweetdiesel]

Normal d max pid

 

[MMLMM]

did you check what the voltage was at the obd? That or stick it on a batt charger while you try to reflash....

 

[TheBac]

Did you check that fuse Justin recommended?

My old ECM did the same thing. The bootloader wouldnt initialize, couldnt even read what was in it. Had to get a new ECM.

 

[TrentNell]

Try pulling the negative cable on the battery for 10 minutes , then re-connect and try a full flash. and X2 on the battery charger being connect , i have had low battery voltage do some weird stuff before .

 

[whitetrash21]

I have had this issue with an 03 truck before come to find out the alarm guys used the OBDII as a place to pick up power for their system.

That's whats up with my 05. Alarm guys tied into OBD line to power the remote start. However, the quadzilla and EFI wouldn't recognize the ECM. Had to unplug the alarm wire, flash the tunes in/out and plug the wire back in. That resets the remote start so it doesn't work right. Not sure how they get away with that shit but.....

Check the wires coming off the OBD for a wire spliced in to power an alarm/acc feature.