Ignition on for Coding?

[MPN1]

When coding, does the ignition need to be on inbetween reading the ecu and then writing back to the ecu?
Thank you.

[OneTwenty]

Yes, full ignition on with all lights.

Some say have the engine running, but I don't do that as it's in the garage and would kill me.

[Nyxeris]

With NCSExpert or ISTA/P it's always ignition on, engine off.

Having the engine running while coding is potentially very dangerous, and it's better to never, ever do it. Even if what you're doing doesn't directly affect the DME, if you're making changes in a gateway module like the CAS or FRM, both of which are on the PT-CAN, there's a non-zero chance of causing real damage to the engine.

Same as pressing "process car". Sometimes it works, more often than not it fails, sometimes when it fails it bricks ECUs. There's no actual benefit to coding the modules which don't need to be coded as part of what you're doing, so it's better to never do it and just process the specific ECUs instead.

Using service functions in INPA or ISTA/D is a different story, but as a general rule for coding, always ignition on engine off.

[MPN1]

Thank you.
I wasn't sure if I could have switched the ignition off while I played about with NCS Dummy, and then switched it back on to code the car.
I was just worried about the battery getting low, coding is all new to me and I'm not the quickest.
I'll probably connect another battery with leads under the bonnet to be on the safe side.

[Nyxeris]

Sorry, got the wring end of the stick there - if you're just playing with TRC/MAN files and not actually poking around inside modules you definitely don't need to be connected for that, might even be better that you aren't as you won't be rushing!

Plug in and generate your files, then go indoors, back them up, and make your changes. You can go back out, plug in, and write the manipulated files whenever it's convenient. If you're worried about battery levels, connect a charger in the meantime.

Bimmercode makes this type of coding much easier, for what it's worth. The £30 was definitely worth it for the convenience.

[MPN1]

Sorry, got the wring end of the stick there - if you're just playing with TRC/MAN files and not actually poking around inside modules you definitely don't need to be connected for that, might even be better that you aren't as you won't be rushing!

Plug in and generate your files, then go indoors, back them up, and make your changes. You can go back out, plug in, and write the manipulated files whenever it's convenient. If you're worried about battery levels, connect a charger in the meantime.

Bimmercode makes this type of coding much easier, for what it's worth. The £30 was definitely worth it for the convenience.

Ok, so I'll have the ignition on for NCS Expert until I've created a trc file.
Switch the ignition off, change my files with Dummy or altering trc file.
Create a man file.
Switch ignition back on and write files to car.

Then take a look at getting Bimmercode.