When in normal drive I am experiencing a shunt when coming to rest at junctions when it changes down into what I believe could be 2nd gear.

 

Also noticed on Monday after accelerating up a slip road to motorway speed it gave a big shunt when I lifted off for it to settle in gear at 70 mph.

 

The strange thing is it has never done this when in Sport mode whether using the paddles, tiptronic or left in sport auto.

 

The car was remapped a few months ago by Simon at Emaps and I have since had the gearbox oil changed.

 

Mileage has not long turned 70k miles.

 

Could this be a dodgy sensor or some kind of ECU fault? It has been recently serviced and no mention of faults appearing from the indy specialist.

When did it start doing this?  Was it just after the re-map?

 

More than likely the re-map or retro fitting the paddle shifts will have upset the electronics in the gearbox ECU.  It wasn't designed for a re-map nor was it designed for a paddle shift.

 

What you are experiencing is a hard shift, which is caused by the electronics telling the hydraulics to change gear in a different way than it was intended to do.  The question is what is the faulty electronic signal.  These signals come from the wheel sensors, engine rpm, oil temp, cat temp, throttle position etc.  The re-map could have caused a change in engine rpm in relation to throttle position under the same loads which is confusing it somewhat. 

 

Was anything else looked at in the 'box when the fluid was changed? 

 

Have you got different sized tyres front and rear or different from standard spec?  Or are the tyres on one axle more worn than on the other?  Having different rolling radii of tyres can upset the electronics as the speed of the car is measured from the wheel sensors which the 'box then uses to judge when to change gear.

 

Andrew

 

I don't recall this ever happening before the re-map was done and the wheels are standard BMW.

I had 18" M parallels fitted with good tread and have since fitted my winter set which are 17" E39 sport wheels & winter tyres and it has done this hardshift on both sets.

 

Think I will try Simon at E-maps (who done it originally) and see about getting it removed or am I better to take it to BMW instead.

 

BMW will need to blank it and re-programme it from start I think which would cost you plenty.

 

Would be worth going back to the re-map guy and ask for his opinion, he should be able to undo and reset to default.

 

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