04 Duramax read issue

[skimphish]

I've read that the 05 LLY's have issues with reading/writing, but I have a 04 LB7 and it isn't wanting to read the entire VCM. It gets to a point (usually 3x.xx%) and then tries to read the TCM. At this point it says that the access has been denied.

So whats the deal/fix? Do I pull the radio fuse and such?

[Bill@HPTuners]

Try reading in low speed mode for starters ie high speed mode box unchecked.

[MikeOD]

I've had constant issues with a friends 2003 LB7 truck...the only difference in low speed mode is that I have to wait longer for it to not work.

[alextremetj]

Same issues here. Not sure whats going on with it.

[jeromy rogers]

Same issue here

[tokymon]

pull radio fuses, comand start fuses, and even abs fuse

[Varndellroy]

Has anyone had any luck getting this resolved. My 03 LBZ same problem. The only thing it has is exhaust brake. Could this be the problem?

[Lennydmaxguy]

Has anyone had any luck getting this resolved. My 03 LBZ same problem. The only thing it has is exhaust brake. Could this be the problem?

The radio is the most common culprit, especially aftermarket units with a chime module. There's lots of info on which fuses to pull to shut it down. Worst case scenario, you could access the communication splice pack and connect only the ECM (or TCM respectively). SP205 is the number IIRC.

[SUTTERERMAN85]

I have to pull my radio fuse every single time to read or flash the ecm but it works every time for my on my 05 LLY. Doing the TCM is a real PITA though. I have to try repeatedly for sometime 15 mins, turning everything off and back on, pull fuses that are not needed that interfere with the CanBus like ABS, Radio, etc. I finally get it to work on high speed though. I do the ECM and TCM seperate.