M3 E46 SMG fault...

[Dk5491]

Hi Guys, wondering if someone can offer a bit of help..

I have an M3 E46 2002 model with SMG gearbox and it has been brilliant until i took it on its first track day on Friday. After a couple of laps round Donington, the gearbox dropped into neutral and i had no drive whatsoever. After maybe 7 seconds, it popped back into gear and i could continue for a bit until it dropped into neutral again, so of course i had to head back to the pits.

The SMG cog dash light came on shorty followed by the engine management light. I switched off, let it cool for a bit, then started her up again. Both lights had gone out so i just tootled around the paddocks to see if there were any problems and it felt good as new, nothing wrong at all. So i put it down to a glitch and went out on track again and for the first lap everything was fine, then the same thing happened all over again, dropped into neutral, lights on dash, back to the pits.

This cut the track day short and after letting the car cool down for a while a drove home and all was well with the car once again. The SMG cog dash light went out but the engine management light stayed on until the next day. I used the car on Saturday to drive to my friends house and it was fine, no dash lights, no dropping into neutral, nothing. Sweet as a nut. I've owned the car just over a year and it has never put a foot wrong until Friday so i don't think its a genuine mechanical fault but maybe a sensor issue or something else.

I checked the SMG fluid level when it was cool on Saturday and that seemed fine so I'm wondering if anyone has experienced a similar issue? Every other thread a read about this seems to be concerning a car suffering from a constant problem, dropping into neutral most of the time during normal driving on the roads. Mine only happened on track however and it works perfectly fine on the roads so its a slightly different scenario.

I bought this car as a weekend car and for the occasional track day so obviously i want to be able to rely on it for track days going forwards.

[SS2.]

Sounds like a classic overheating issue - whether that's a genuine overheat, or a sensor falsely reporting an overheat remains to be seen.

I never had this happen to me when I had an E46 SMG but I do recall reading about a workaround which involved replacing / bypassing a certain resistor.

A quick Google or a visit to one of the specialist M3 forums would be a good start.

[Dk5491]

Thanks SS2. I have come across the resistor fix and there seems to be mixed success as to whether it solves the issue or not.

I'm hoping to take it to an Indy to get diagnostics on it soon and hope that sheds a bit of light on the source of the problem.

If it works perfectly fine in normal day to day driving, is it fairly safe to assume it doesn't require a new pump? I'm wary that as soon as i take it to a garage thats probably the first thing they will say...

[SS2.]

Dk5491 said:

If it works perfectly fine in normal day to day driving, is it fairly safe to assume it doesn't require a new pump?

Maybe, probably, who knows.

Where are you based ? When my SMG started misbehaving, I took it to Bartley Garage near Southampton - they were superb.

[Dk5491]

I'm in Leicestershire, so Southampton is a bit far really. If you know of any SMG specialist my way, please let me know. I'm looking at Auto Technik in Lutterworth as they have a good reviews but they aren't gearbox specialists.

[SS2.]

Again, I'd ask for recommendations on some of the specialist M3 forums.

Personally, I'd not be at all keen giving the car to someone who didn't have a comprehensive understanding of the SMG 'box.

[Dk5491]

Yep, my thoughts exactly I would much prefer the garage to have at least come across this kind of problem before.

I'll keep looking, and possibly post on 'M3 Cutters' too. Cheers