Mercedes-Benz 7G-Tronic: P0705 Fault Code – Diagnosis & Repair

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

TCUs

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The P0705 fault code indicates that there is a malfunction within the transmission range sensor circuit , specifically in the Continental 7G-tronic (722.9). This TCU was first introduced for the 2003 model year, specifically in Mercedes models fitted with a V8 and later extended across the range. 

Produced until 2019, the 7G-Tronic unit commonly fails in models like the E-Class, ML & C-Class. The Gearbox computer is crucial for the optimal operation of the transmission; it determines the position of the gear lever and transmits this information to the ECU. Problems with this sensor can lead to numerous drivability issues. 

P0705 Fault Code: Which cars does it affect? 

• Mercedes-Benz C-Class (W204)
• Mercedes-Benz E-Class (W211, W212)
• Mercedes-Benz S-Class (W221)
• Mercedes-Benz GL-Class (X164)
• Mercedes-Benz ML-Class (W164)
• Mercedes-Benz CLS-Class (W218)
• Other models with the 722.9 transmission

P0705 Fault Code: The Symptoms

The following symptoms may indicate a problem with the transmission range sensor:

• The gear indicator is not working correctly
• The transmission does not shift or shifts unusually
• The vehicle does not start
• The transmission goes into limp mode
• The engine management light is illuminated 
• The transmission performance is reduced 

P0705 Fault Code: The Fix 

The most effective solution for a Mercedes transmission with the fault code P0705 is to have the 722.9 TCU remanufactured. This often includes replacing or repairing various sensors, as well as inspecting and repairing any other internal components that may be damaged.

ACTRONICS offers an effective solution for the Continental 7G-tronic (TCU), where the module is thoroughly tested and equipped with new components to ensure a long lifespan and reliable operation. Do you have any questions? Please feel free to contact us!