Full Reflash

[Chevy366]

Ok went to do a Custom OS flash but got a warning

"To reduce the risk of failure, EFILive recommends removing
your PCM from the vehicle and using a bench harness to
perform the full reflash.

Alternatively, the PCM may be left in the vehicle, provided
that a star connector is used to isolate the PCM from the
class-2 network during reflashing.

Programming the target PCM in-vehicle, without isolating it
from the class-2 network, is STRONGLY discouraged.

EFILive accepts no responsibilty whatsoever if your PCM is
permanently damaged during a full reflash procedure."

A star connector? Class2 network?
Removing the PCM from vehicle ?

[Tordne]

Just the normal recommendation stuff and that it is your educated risk.

There is a period of a few seconds, where the traffic light indicator is red, where the bootloader on the PCM is updated where you are at risk. Once the traffic light goes amber/yellow there is no more risk than performing a calibration only flash. Thats as I understand it anyway.

I would have performed 10's of full flash operations on my car alone with no issue at all! Holden's may be a little different in that there is nothing but the PCM on the bus - all other modules are ALDL

[joecar]

tunedbyGM,

What Andrew says;

Also, just to increase the safety "envelope", make sure all accessories are turned OFF (stereo, headlights, daytime running lights, dome light (close doors), etc) prior to flashing.

[dc_justin]

tunedbyGM,

What Andrew says;

Also, just to increase the safety "envelope", make sure all accessories are turned OFF (stereo, headlights, daytime running lights, dome light (close doors), etc) prior to flashing.

And if you have an aftermarket stereo with XM, pull the radio fuse.

[joecar]

And if you have an aftermarket stereo with XM, pull the radio fuse.

Good one.

Disable anything that draws current.

[dc_justin]

Good one.

Disable anything that draws current.

Not only that, but as Paul told me when I asked why I couldn't use high speed, aftermarket XM systems have a problem shutting up when asked to do so and can screw up the communications between flashscan and the pcm.

[Chevy366]

Thanks all , but just for kicks , what exactly is a class 2 network and a star connector ?
Just to satisfy my thirst for knowledge .
I have factory OnStar and figured it would need to be disabled , but did not think about XM radio.

[dc_justin]

Thanks all , but just for kicks , what exactly is a class 2 network and a star connector ?
Just to satisfy my thirst for knowledge .
I have factory OnStar and figured it would need to be disabled , but did not think about XM radio.

You shoudl be fine, as those are both GM systems and play nicely on the network. it's when you throw in aftermarket systems that things can get a little problematic.

MY rule of thumb is if you can read at high speed or can perform a calibration-only flash at high speed, you should be able to perform a full flash without problem. On 512Kb PCMs, it's the first 16Kb that are the critical part, on 1MB PCMs, it's the first 32Kb. At high speed, your flash would have to fail in the first 4-5 seconds for there to be a problem...

[joecar]

Ah, ok, so the rule is:
"Disable anything that may interfere with bus comms, and don't use accessories that may cause a voltage-drop/current-draw".

[TAQuickness]

Thanks all , but just for kicks , what exactly is a class 2 network and a star connector ?
Just to satisfy my thirst for knowledge .
I have factory OnStar and figured it would need to be disabled , but did not think about XM radio.

Class 2 network is the communication buss the PCM and other on board modules use to communicate

Star connector is one that removes the PCM from the network for dedicated reflashing.


As far as rule's of thumb go - Only do full flashes at the house. Would suck to have a full flash fail at work or on the side of the road and leave you stranded.