2004 Monte SS glitch?

[02GTP]

used hp tuners on my buddies 2004 supercharged monte carlo ss. all i did was clear the rear o2 codes. it read the vcm just fine. but when i did "write calibration only" the car didnt like that. it kept changing from fast write to slow write and the car beeped alot and seemed pissed. it worked but it took like half an hour. my mustang never does that and takes the same time it does the read the vcm. it then popped up a bunch of U and P codes for lost communication and a bunch of other weird crap. anyone ever hear of this?

[Bill@HPTuners]

Likely either a battery issue or inline module fighting with our software over the same bus.

[RWTD]

If the car has OnStar, this is what's giving you fits! Simple fix: Unplug the harness from the rearview mirror. Been there, done that with the Montes.

[Perforator]

Does he have any PAC modules and a aftermarket radio? I have to pull the fuse for my radio to successfully flash my car.

[IndeedSS]

I have an 04 Impala SS with On-Star, no add-on devices connected to the bus, stock radio and haven't had any issues what-so-ever, other than a handful of communication codes. Those codes showed up the first time I used the HPT, but they don't seem to have negatively affected anything.

Hope it's something quick and easy for you to figure out.

[02GTP]

wow thanks for all the info, didnt expect it so quick. i will try the onstar thing next time. thanks again!

[RWTD]

Yeup, just unplug the harness from the back of the rearview mirrow and it'll flash perfectly.