What Causes a 722.9 Transmission To Fail and Can It be Fixed?

Title: Mercedes-Benz 722.9 Mechatronic Conductor Plate TCM Repair Service

The 722.9 transmission is a great design that can be found in hundreds of thousands of Mercedes-Benz vehicles built from the mid-2000s up until around 2020. Mercedes vehicles are known for impeccable construction and a long service life. But even if the rest of your ‘Benz is in great shape, there are some repairs that could be so costly that the vehicle is considered mechanically totaled. One such repair is a failed automatic transmission. In the case of the 7G-Tronic it doesn’t have to be that way if you are willing to get at the root of a common failure point: The 722.9 conductor plate. If you are lucky, you can remove the 722.9 valve body and repair the conductor plate before damage occurs to other parts of the transmission. 

What is the Mercedes-Benz 722.9 Mechatronic Conductor Plate?

Gone are the days when automatic transmissions operated purely on hydraulic pressure and throttle input. Today’s modern transmissions are packed with sensors, solenoids, and wiring all designed to work together for efficient gear selection. The 722.9 7G Mechatronic 7-speed transmission is an impressive successor to the previous 5G-Tronic 5-speed transmission, but at the cost of increased complexity. The conductor plate is attached to the transmission valve body and acts at the transmission control module. Each conductor plate is programmed to work with its paired transmission, making it difficult to just swap out a new or used unit. 

(embed video https://www.youtube.com/watch?v=4imP7gpuooI)

Signs of a Failing Mercedes-Benz 722.9 Mechatronic Conductor Plate

If something seems off with how your Mercedes-Benz drives, don’t just ignore it. You may notice the following signs of a conductor plate problem:

• Intermittent gear shifting 
• Delayed shifting
• Rough gear changes
• Transmission goes into limp home mode
• Transmission is stuck in one gear
• Can’t manually select gears

If any of the problems listed above sound familiar, UpFix has the solution.

If you have a good OBD II diagnostic tool you can scan the on-board computer for stored transmission trouble codes:

• P0705
• P0715
• P0716
• P0717
• P0718
• P0720
• P0721
• P0722
• P0723
• P2200
• P2201
• P2204
• P2205
• P2206
• P2207
• P2766
• P2767
• P2768

Your scan may also show that the signal from the following components is not available or defective:

• Y3/8N1 Turbine Speed Sensor
• Y3/8N2 Internal Speed Sensor
• Y3/8N3 Output Speed Sensor
• Y3/8S1 Selection Range Sensor

While not the only problems associated with a bad conductor plate, these are the most common problems we’ve found.

What Goes Wrong with the Mercedes-Benz 722.9 Mechatronic Conductor Plate?

Due to the complexity of the unit and the harsh environment inside the transmission, the speed sensors are a common failure point. Compounding the issue are multiple speed sensors. If the transmission can’t tell how fast things are moving, it can’t choose the proper gear at the right moment. The result can be gear shifting mayhem or no shifting at all.

Keep in mind there are three different versions of the 722.9 7G Mechatronic transmission conductor plate, each with its own software programming. They ARE NOT interchangeable. Luckily you can determine which version you have by looking near the part number, there will be a large 1, 2 or 3 denoting the version.

UpFix can repair the 922.9 conductor plate in the following models:

C-Class

2011–2018 C63 AMG and C63 AMG Black Series models (W204) 

2014 C180 models (W205)

E-Class

2009–2016 E200 AMG 7G-Tronic and E63 AMG models ( W212) 

2009–2013 E200 AMG 7G-Tronic models (W212) 

S-Class

2013–2017 all models (W222) except Maybach S 500 and Maybach S 500 4MATIC

2017–2020 V12 only models (W222) 

SLK-Class

2011–2015 models (R172)

CLK-Class

2005–2010 models (C209, post facelift)

Why Choose UpFix?

If you are ready to put an end to the shifty antics of your 722.9 7G Mechatronic transmission, then UpFix has the solution. Our team of expertly trained technicians have earned certifications for IPC, J-STD, and General PCB troubleshooting. We use high-tech BGA rework stations that can handle delicate, sophisticated repairs for the highest results. Our state-of-the-art Weller soldering irons create precision soldered joints for long-lasting connections. At UpFix we have the skills and the equipment to do electronic repairs right.

Removing your original conductor plate is an involved process, but not one outside the realm of a confident DIYer. You will need to remove the transmission drain pan and valve body, so be prepared with a good service manual. 

This service is for the conductor plate only, so you will need to carefully separate it from the valve b