Mechatronic transmission

August 27, 2013 | By | Reply More

BMW has always been a company that leads the way with technological advancements. One important development was the Mechatronic transmission. It’s been installed in many models, so we need to be more familiar with its do’s and don’ts.

The plastic transmission oil pan should be one of the tips that let you know you are working on a Mechatronic transmission. Do not remove the pan when the transmission is hot as it can become distorted as it cools. Also, use a torque wrench when reinstalling to prevent over-tightening and cracking.]

The plastic transmission oil pan should be one of the tips that let you know you are working on a Mechatronic transmission. Do not remove the pan when the transmission is hot as it can become distorted as it cools. Also, use a torque wrench when reinstalling to prevent over-tightening and cracking.]

There are many reasons BMW pushes the envelope of technological development. Sometimes it’s for ease of manufacture, but mostly it’s to improve the driving experience. Increasing government regulations on emissions and fuel mileage also prompt development, and this is nowhere more true than with the automatic transmission. BMW engineers decided that one of the best ways to lower emissions and increase average fuel economy was the redevelopment of the automatic transmission. This blossomed into the implementation of the new Mechatronic transmission BMW co-developed with ZF. It represents some significant innovations such as an internally-mounted EGS control unit, shift-by-wire, and an electronic parking lock, to name only a few. These transmissions have been around since 2002 — over 10 years! — and now require service. We need to become more familiar with what is possible and what is not when attempting to diagnose, repair, and service these units. This information will lead to more cost-effective repairs for the customer and more profitable service work for you. First, let’s go over how this transmission works.

Mechatronic 101

You can drain the fluid by removing this plug. Don’t over-tighten past the marks on the plug as you can crack the housing and cause a leak. If you are changing the fluid, save and measure it so you know how much to put back in. BMW recommends only its own transmission fluid for these units.

You can drain the fluid by removing this plug. Don’t over-tighten past the marks on the plug as you can crack the housing and cause a leak. If you are changing the fluid, save and measure it so you know how much to put back in. BMW recommends only its own transmission fluid for these units.

When drivers enter a car with a Mechatronic transmission, they insert the ignition key and attempt to crank the engine with the push-to-start button. The DME control unit is in control of the Integrated Supply Module (IVD), which contains the two relays that activate the starter motor. The DME looks at the EWS (for a theft condition), the CAS module for the start request, and the selector lever setting. The DME will only operate the starter relay if it can verify that the vehicle is in Park. This is done through the PT Can bus. The EGS control unit tells the DME control unit that the transmission is in Park or Neutral, and the engine is allowed to be cranked and start. There is also a redundancy feature built into the control units for safety reasons. A signal wire connects the EGS module directly with the CAS. The EGS control unit supplies battery voltage to this wire to allow the engine to crank. Both of these systems need to function if the engine is going to crank and start.

 

Login to continue reading this article.

Not a member? Register for FREE access.


Lost your password?

Tags: ,

Category: Drivetrain, the bimmer pub

Leave a Reply

You must be logged in to post a comment.