745i “Switching Electronics” warning light?

[JMinNJ]

Hi,
Took my 745i for a drive today and noticed this warning light. My german owners maual says it’s the “Schaltelektonik” or “Swtiching Electronics” warning light. It’s the one inbetween the Fasten Seat belts and the P for park. When I restarted the car it was gone. This happen once before a few weeks ago.

I suspect it’s related to the switch modes on the Auto Transmission, S, E, 123. I have never switched it off the E setting since I’ve owned it. Previous owner said he did the same. That would cover the last 15 years.

Anyone know what this warning light could mean?

thanks

John M

[8991XJ]

Check out what the owners manual says about it. bottom of the left column at www.e38.org/e23, your choice a US 735 (86 I think) or ZA 745 with the M88 motor.

[JMinNJ]

Thanks. According the the owners manual is the electronic shift circuit failure warning light. Trans will not shift into 4th gear when illuminated. Only happened on initial cold start. I drove it the rest of the day and it did not come on again. Same as a few weeks ago.
Wonder if its cold weather related? Have to keep an eye on it.

[JMinNJ]

Well, its definitely in limp mode when the light is on. Does the ECU have an effect on the electronic shifting? Or should I suspect the TCU. Ill also be check the TPS.

[Hit Man X]

That light means an electronic fault, not that center console switch, but power to the trans itself. It does not shift period, not just a lack of OD when I have dealt with it. It defaults to full line pressure and you only have reverse via the shifter and third, regardless of drive position.

The ECU and TCU are one unit. Chances are you have issue with the case connector. The internal o-ring leaks to seal it, that is part of the issue and requires dropping the valve body to service this leak. The other issue is the damned harness itself leaks. I trim the rubber down short and clean it until oil free. Then fill it with an oil resistant sealant to seal it.