E63 M6, new gearbox, various faults have now shown up

[junglist]

Background, my M6 had a replacement gearbox, clutch and flywheel under warranty at the end of last year. Sat Nav drive was also replaced as well as the thermostat.

I have to do 1000 miles low load driving to run it in. I've driven it 400 miles so far but this morning the following occurred:

Low speed commuter traffic
Transmission Fault flagged
Control Systems Fault flagged
I'm pretty sure the TPMS Warning also showed very briefly
Centre screen went blank and powered back up several times
Car was still drivable and gears selected seemingly ok using manual paddles

The whole episode lasted about 5 to 10 minutes and then just disappeared and I continued the final mile of my journey ok.
It did not return on my journey home tonight.

I am booked in to the nearest BMW dealership on Wednesday but wanted some pre-emptive thoughts on what it could be from any one on here.
I'm drawn towards the issue being a loose earth cable following the gearbox change (I've checked the battery connections and they are tight)?

Thanks

Edited by junglist on Monday 6th January 19:09

[Schermerhorn]

Could be calibration issues or sensors working over time.

Good thing you have booked it in, this warranty could end up being a God send for you!

[JapFreak786]

As you said could be battery issue. These cars give loads of problems with a worn out battery/loose connection. Friend had several faults come on his E46, turned out to be a faulty alternator not charging enough and draining battery

[junglist]

Car was stood doing nothing for 5 weeks at the dealership waiting for the gearbox job to be done. Could that have been detrimental for the battery? The irony is that the engine fires up quicker now during a cold start than it did before the warranty work. Strange

[junglist]

Diagnosed as needing replacement alternator! I've only done 400 miles in it since picking it up with new gearbox etc.
Does anyone else think that this could have been caused by the car sitting for pretty much 5 weeks while it waited for the gearbox?

[Slippydiff]

junglist said:

Diagnosed as needing replacement alternator! I've only done 400 miles in it since picking it up with new gearbox etc.
Does anyone else think that this could have been caused by the car sitting for pretty much 5 weeks while it waited for the gearbox?

Quite likely would be my guess. Flat battery, then jump started with a booster pack, already tired alternator cries enough trying to put charge into a totally discharged/shot battery.
Trying to prove it is a different matter altogether though

[junglist]

I'll give customer services a "courtesy" call tomorrow to make them aware of my predicament, I'm pretty annoyed with the situation. Obviously I've got my warranty but it's another £250 excess payment within the space of 2 weeks!