Automatic Transmission Mechatronics
The transmission runs a Mechatronics Control Unit which is also known as a Transmission Control Module Mounted to a Main Control Valve Body Unit.
Yes, you read it correctly the TCM is mounted inside the transmission submerged in ATF. This may sound crazy but it is very practical as it limits most of the common outside failures. With the TCM now directly connected to the valve body there is less chance of wiring, sensor, current and resistance issues as most of the needed Inputs and all of the outputs are located within millimetres of the TCM.
Inputs Located on the Valve Body
Input Speed Sensor
Output Speed Sensor
Transmission Fluid Temp Sensor
Park Cylinder Position Sensor
Outputs Located on the Valve Body
MV-1 Solenoid (Black Connector) – When off its is Open and Exhausting Oil
This is powered on every gear except when 3rd gear is engaged.
EDS-1 Solenoid (Green Connector) – When off its is Open and Exhausting Oil
This is powered on in 1st gear, 2nd gear, 3rd gear & 4th gear.
EDS-2 Solenoid (Yellow Connector) – When off its is Closed and Holding Oil Pressure
This is powered on in 1st gear, 2nd gear, 4th gear & 6th gear.
EDS-3 Solenoid (Green Connector) – When off its is Open and Exhausting Oil
This is powered on in 2nd gear & 6th gear.
EDS-4 Solenoid (Yellow Connector) – When off its is Closed and Holding Oil Pressure
This is powered on in Park, Neutral, 2nd gear & 3rd gear.
EDS-5 Solenoid (Yellow Connector) – When off its is Closed and Holding Oil Pressure
This is powered on in as the Pressure Control Solenoid (PCS).
EDS-6 Solenoid (Green Connector) – When off its is Open and Exhausting Oil
This is powered on as the Torque Converter Clutch Solenoid (TCC).
With these units being so compact and when removed everything is at your fingertips you would expect fixing problems would be easy? Well not really. The great thing is, there is always a part number or parts list available which makes ordering simple.
Replacing Mechatronic Units
These units are very simple to swap out with a new unit but at what cost? Once you install a new unit you would expect it's just a case of bolt in and drive away. Unfortunately, it's not that easy, when these units are purchased new they have a blank TCM with no programming. When the new unit is installed it needs to have the TCM Flash Uploaded with original software or updated software from the manufacture.
Flashing the TCM
Now in South Africa we don't have regular access to Flash Files like in some other countries. This means we are limited to how we go about preforming this task.
The unit can be bought and fitted by a repair shop then towed to a local dealer for reprogramming. However, it's recommend to check with the dealer that they can do this as they may want to perform the entire job rather than just the programming.
The unit can be bought from a different country with a flash already preformed which then just needs fitting. However, any issues with freight, programming or Vehicle details with blow out your costs.
Using an aftermarket scan tool with access to flash files can also be done. However, you could track down workshops who specialise in pacific models with these scanners and use their services to complete the job. Just be sure they are confident in preforming the task as you don't want to buy another mechatronics unit.
Second Hand Mechatronics
These are available from different suppliers either transmission wreckers or remanufactured from Transmission Specialists. The units will need to be model pacific to allow the programming of the TCM to match the vehicle as the last thing you need is communications issues between Modules.
Flashing Second Hand Units
This would be ideal however its unknown to us if it can be done. In theory if you had a Ford Mechatronics Unit and bolted it into a BMW Transmission and then re-flashed the unit with a BMW file. This would make the job and life a lot easier and cheaper.