TCUs Continental 7G-tronic (722.9) First, Second and Third Generation

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We remanufacture the part you send. Prices are exclusive of VAT and possible shipping costs. Offer only applies to garages and dealers and not to individuals.

Can be remanufactured

OBDII Description
P0705 Component Y3/8s1 selection range sensor is defective
P0717 The signal from component (sensor) Y3/8n1 is not available
P0718 Component (sensor) Y3/8n1 is defective
P0720 Output speed sensor circuit malfunction
P0721 The transmission output speed signal is implausible, when compared to the wheel RPM signal
P0722 Output speed sensor no signal
P0723 Output speed sensor is defective
P2200 The signal from component (sensor) Y3/8n2 is not available
P2201 Component (sensor) Y3/8n2 is defective
P2550 Component (sensor) Y3/8n3 is defective
P2767 The signal from component (sensor) Y3/8n2 is not available
P2768 Component (sensor) Y3/8n2 is defective

It is rare, but in theory these sensor problems can also be caused by a deviation at the magnetic sensor rings. Think of abnormalities such as damage to and/or iron grinding of the ring. So it is always a good idea to check them properly.

Remanufacture may be possible

OBDII Description
P0894 Transmission component slipping
P2204 The signal from component (sensor) Y3/8n1 is not available
P2205 Component (sensor) Y3/8n1 is defective
P2206 The signal from component (sensor) Y3/8n3 is not available
P2207 The value of component Y3/8n3 is implausible
P2502 Implausible gear or transmission slipping
P2505 Gear not engaged or transmission slipping
P2711 Unexpected mechanical gear disengagement

These error codes normally appear as soon as the software detects a problem through the signals from the speed sensors. If a speed sensor is not working properly, these error codes can be activated incorrectly. If these error codes appear in combination with the error codes from the previous table, have the TCU remanufactured first and delete all error codes after assembly. There is a good chance that these error codes will stop appearing after that.

P2806 Component (sensor) Y3/8s1 is not learned

If error code 2806 is active, the diagnostic device will not display the switching positions. The TCU will have to be re-taught. If the fault persists, the switching position sensor is defective. We can replace these during remanufacture.

If in doubt, please contact our Customer Service.

Cannot be remanufactured

OBDII Description
P2716 Pressure control solenoid electrical
P2783 Clutch actuator temperature too high

When the car is in limp mode: This error code indicates (extreme) wear of the lockup clutch. Assuming that the temperature measurement is correct: check whether the magnets in the sump pan are full of (iron) swarf. If this is indeed the case, then it can be assumed that the lock-up clutch is really damaged. It is advisable to replace the entire gearbox including the torque converter, because the iron swarf has now spread throughout the entire transmission.

In addition, the oil cooler needs to be flushed However, if the oil cooler is equipped with a thermostat, rinsing is not possible. The oil cooler must therefore be replaced.

P0748 Pressure control solenoid “A” electrical
P0778 Pressure control solenoid “B” electrical
P0798 Pressure control solenoid “C” electrical
P2716 Pressure control solenoid “D” electrical
P2725 Pressure control solenoid “E” electrical
P2734 Pressure control solenoid “F” electrical
P2759 Torque converter lockup clutch control solenoid
P2810 Pressure control solenoid “G” electrical

When the car is in limp mode: The above error codes may indicate one or more defective solenoid valves, but the problem may also be somewhere else.

Let’s repair an 7G-Tronic(722.9)TCU

Found on the majority of Mercedes vehicles, the 7G-Tronic is the equivalent of the DSG mechatronic for Volkswagen Group vehicles. The 7G-Tronic was first introduced in 2003 on all Mercedes models with 8-cylinders that had a seven-speed gearbox. Because it was lightweight and reliable, the TCU and gearbox were soon added to certain 6-cylinder diesel engines as well. Despite being used as a seven-speed gearbox, the 7G-Tronic in-fact has nine gears - seven driving gears and two reverse. The two reverse gears were introduced to give the car an easier and more comfortable drive when using reverse.

Common faults and fault codes

The 7G-Tronic is located on the valve body inside the gearbox, it is likely to encounter prolonged periods of intense heat that can build up within the gearbox. Because of this, it is likely that the TCU could develop various kinds of faults over time, causing the vehicle to suffer from:

  • Vehicle will not start
  • Poor or unable to change gears
  • Sudden loss of drive when driving
  • Clutch slipping

These faults could be caused by a series of varying fault codes, which could include:

  • Y3/8N1 – Turbine speed sensor
  • P0717 – The signal from component Y3/8n1 (Turbine speed sensor (VGS)) is not available
  • P0718 – Component Y3/8n1 (Turbine speed sensor (VGS)) is defective
  • Y3/8N2 – Internal speed sensor
  • P2200 – The signal from component Y3/8n2 (Internal speed sensor (VGS)) in not available
  • P2201 – Component Y3/8n2 (Internal speed sensor (VGS)) is defective
  • P2767 – The signal from component Y3/8n2 (Internal speed sensor (VGS)) in not available
  • P2768 – Component Y3/8n2 (Internal speed sensor (VGS)) is defective Other internal speed sensor error codes: P2204, P2205, P2206, P2207
  • Y3/8N3 – Output speed sensor
  • P0722 – Output Speed Sensor No Signal
  • P0723 – Output Speed Sensor (VGS) is defective
  • Y3/8S1 – Transmission range sensor
  • P0705 – Transmission Range Sensor Circuit Malfunction
  • P2716 – Pressure Control Solenoid “D” Electrical

Remanufacturing process

When sending in the 7G-Tronic we only require the TCU plate and not the (metal) valve body it is attached too. We will always test the TCU on a gearbox set-up to simulate the unit like it is on the vehicle. Testing it first enables us to confirm if we are able to find the reported fault(s) with the unit.

If we do find faults with the TCU, we will conduct a full remanufacture of the unit. We will always follow this with an End of Line (EOL) test which will allow us to approve that the remanufacture has resolved all the reported faults.

Other potential faults

It has been known that failures elsewhere on the vehicle can produce the same or similar faults to the 7G-Tronic. We will always suggest technicians to complete full testing before sending any unit to us, which should include – full diagnosis check, checking for broken or corroded wires, faulty sensors or mechanical damage to the gearbox itself. If you believe the 7G-Tronic to faulty, please continue and complete the Remanufacture Order Form.

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