Mercedes-Benz 722.9 Conductor Plate TCM Failure Overview and Solution

Mercedes-Benz 722.9 Conductor Plate TCM Failure Overview and Solution

25th Apr 2017

mercedes 722.9 TCM repair The 722.9 (7G Tronic) transmission is Mercedes-Benz's 5th generation automatic transmission with 7 forward and 2 reversing gears first introduced in 2004. While providing improvements in overall shift comfort and driver experience throughout the gear set, they are unfortunately prone to failure, specifically in the speed sensors on the Conductor Plate / Transmission Control Module (TCM).

For the consumer or independent automotive shop, this failure can be a significant event for several reasons. First, Mercedes-Benz classifies this Conductor Plate (TCM) as a "theft-related part," making it difficult to purchase as an individual or small shop. Secondly, a replacement TCM is not "plug and play" on the vehicle. The new TCM still needs to be "married" to the vehicle, which requires SCN coding/programming abilities that most individuals do not have access. Lastly, the replacement costs for parts, labor and programming for this issue can range from $2,000-$4,000, depending on the type of TCM your vehicle is running. Fortunately, we have developed a Mercedes-Benz 722.9 Conductor Plate TCM Repair solution for your original TCM that resolves all of these issues with a fast, one-business-day turnaround.

Conductor Plate / TCM Versions

mercedes tcm versions vgs1 vgs2 vgs3 example There are three different versions of the TCMs in the 722.9 transmissions commonly identified as VGS1, VGS2, and VGS3. Overall, the differences between the three are subtle, and the failure modes are similar. You can identify which TCM you have by the label/engraving on the main plate of the TCM for your vehicle. The first generation TCM is the VGS or VGS1 and typically ran from model years 2004-2007. The next two versions followed and are identified as VGS2 or VGS3. The major difference for the consumer in the three occurs when you try to purchase a new TCM. For the VGS1 version, you MUST purchase the conductor plate AND the valve body, if buying new. This is a significant cost increase over just buying the TCM. You can still purchase the TCM only for VGS2 and VGS3 versions. We can repair any version of the 722.9 TCM to help you avoid the high cost of replacement parts and programming.

Common Failures

Typically a TCM failure is the result of the loss of one or more speed sensor signals. When this occurs, the vehicle will go into limp mode. This mode means that in drive the transmission will not shift out of 2nd gear allowing you to get the vehicle home or to a shop but significantly limits the ability to operate your vehicle. The components that fail usually cause the following error codes:

Y3/8N1 (Turbine Speed Sensor)

  • 0717 - The signal from component Y3/8N1 (Turbine Speed Sensor (VGS)) is not available
  • 0718 - The signal from component Y3/8N1 (Turbine Speed Sensor (VGS)) is defective

Y3/8N2 (Internal Speed Sensor)

  • 2766 - Excessive RPMs have occurred at component Y3/8N2 (Internal Speed Sensor (VGS))
  • 2767 - The signal from component Y3/8N2 (Internal Speed Sensor (VGS)) is not available
  • 2768 - The signal from component Y3/8N2 (Internal Speed Sensor (VGS)) is defective

There may be other failures of the TCM, some of which are also repairable. Please give us a call directly at 1-800-547-2049 if you have other codes to determine how we can help.

Clearing Codes/Limp Mode 

tcm repair reset codes scanning tool Once you have installed a repaired TCM, your vehicle will still be in limp mode. To get the vehicle into normal operation, you must clear the stored codes in the vehicle modules with a Mercedes STAR scanner or equivalent. This process includes clearing the body and transmission codes. Most automotive shops have the tools needed to do this; however, some smaller shops or do-it-yourselfers may only have the inexpensive code readers that will not clear the codes. We can provide you a rental scan tool for you to use to clear the vehicle codes when we send out your repaired TCM. This tool comes with the instructions to clear all the codes and is very simple to use. Once finished, you ship the scan tool back to us.

Programming Help

There may be a situation where you have a known good TCM that you would like to put in your vehicle instead of doing a repair. For this to work, it needs to be the same version (VGS1, 2 or 3) and it needs to be virginized and then SCN Coded to your vehicle. Many shops have the ability to do the SCN coding required to marry or personalize the TCM to the vehicle but they cannot virginize/initialize it to get the process started. We can help by virginizing the TCM so that it can be set up on your vehicle. If you need help virginizing your conductor plate, then give us a call a 1-800-547-2049 to find out how we can help.

Component Identification

When reading codes on a Mercedes STAR or equivalent scan tool, you will get component specific information to help pinpoint the issues in the conductor plate.

mercedes 722.9 transmission control plate components

  • Y3/8n1: Turbine or Input Speed Sensor
  • Y3/8n2: Internal or Middle Speed Sensor
  • Y3/8n3: Output Speed Sensor
  • Y3/8n4: Electrohydraulic Control Module
  • Y3/8n1: Turbine or Input Speed Sensor
  • Y3/8n2: Internal or Middle Speed Sensor
  • Y3/8n3: Output Speed Sensor
  • Y3/8n4: Electrohydraulic Control Module
  • Y3/8s1: Range Sensor
  • Y3/8y1-8: Shift Solenoids

Please contact us at 1-800-547-2049 if you have any questions, or click the button below to learn more about our Conductor Plate TCM repair solution.