E85 Automatic Transmission warning light (Intermittent)

[Sailorman]

MY 93000 mile 2.5 E85 (2004) has been little used since Christmas. Taking it out yesterday for a decent run I was greeted with the dashboard warning light that spells Auto-transmission problem. I switched off, consulted the handbook, then re-started and the light did not re-appear. Drove 50 miles, stopped for 2 hours, re-started, no light.

This morning, started up and, warning light was back. Stopped and then re-started after a minute or so, no more light.

Put my diagnostic device to work, it returned error code EGS/SMG 3C, which I have discovered means Transmission Switch.

Any advice on how to treat this appreciated. My local BMW specialists have a long lead time for appointments, and I hope to be driving the Z quite a bit until its MOT in early May. Am I likely to get stranded?

Thanks
Sailorman

[deltasierra]

Any Automatic transmission workshop will trouble shoot the ZF gearbox it’s fitted to many brands.

[Johnbmwz4]

I had the same problem with my old E85. I lived with it for a couple of years then get it replaced for around £350 from a gearbox specialist not a BMW specialist.

[Neil CR]

I had similar last year
have the DME relay checked out
Cheap fix if its that

[Rockhopper]

Position switch - about £300-£350 at a gearbox place.

Odd that checking out the DME relay fixed this issue, its nothing to do with the automatic gearbox.

[enuff_zed]

The switch is underneath and exposed to the elements. If you can find a way to get under it you could try cleaning the electrical plug first.

[Sailorman]

Thanks to all Forum Members who have replied.

As I can't get under the car I guess it's off to my garage to seek help.

Sailorman

[enuff_zed]

Thanks to all Forum Members who have replied.

As I can't get under the car I guess it's off to my garage to seek help.

Sailorman

Out of interest, where are you? Worth checking if any members are close enough with facilities to help you.

[Sailorman]

Lymington, between Southampton and Bournemouth.

My Z has to live outside under a cover and our drive slopes so it's not an ideal working place.

I started the car this am to see if the warning light came on. It didn't. Maybe just lack of use and damp.

Sailorman

[enuff_zed]

Lymington, between Southampton and Bournemouth.

My Z has to live outside under a cover and our drive slopes so it's not an ideal working place.

I started the car this am to see if the warning light came on. It didn't. Maybe just lack of use and damp.

Sailorman

Fingers crossed.
My wife's 2.5i auto has done it maybe half a dozen times in four years.
Each time I turn it off, move the selector a few times then try again and it works. Hers has never failed after start up though.
You can also try starting in 'N' instead of 'P'.

[Sailorman]

Many thanks for the tips. I'll give it/them a try.

[enuff_zed]

Odd that checking out the DME relay fixed this issue, its nothing to do with the automatic gearbox.

Maybe he meant this?

Screenshot 2024-03-08 125005.png (49.82 KiB) Viewed 129 times

Screenshot 2024-03-08 125050.png (188.3 KiB) Viewed 129 times

[Sailorman]

enuff_zed, you are a mine of information. I'll make sure all these contacts are clean.

[Neil CR]

Position switch - about £300-£350 at a gearbox place.

Odd that checking out the DME relay fixed this issue, its nothing to do with the automatic gearbox.

i
I had had the auto gearbox light come up and had a sensor replaced and 6 months later light was back on. Went to bmw for a warranty fix which threw up more issues
Eventually took it back to an independent who diagnosed the DME relay which fixed the issue

[Sailorman]

Thanks, Rockhopper. I reckon it IS the DME Relay. Happily the light has not reappeared on 2 occasions so maybe it was sticky after a period of no-use. We wait to see.