The 0AM DSG Mechatronic Transmission Control Unit (TCU) is a critical component in Volkswagen, Audi, SEAT, and Škoda vehicles equipped with the 7-speed DQ200 DSG gearbox. While this transmission is known for its efficiency and performance, it is also prone to common failures, particularly those related to the mechatronic unit.
Mechatronic Anatomy
For those unfamiliar with the 0AM DSG mechatronics, the unit is essentially made up of two main components.
Valve body: This half is a hydraulic control unit which operates pistons that control the gear selectors and clutches. It works under hydraulic pressure and does the manual work of the unit.
TCU: Short for Transmission Control Unit, this is the brain of the unit. It controls all the sensors and signals needed to operate both the mechatronic and operation of the gearbox.
Common DSG
Mechatronic Fault Codes
One of the most frequent issues affecting the 0AM DSG Mechatronic TCU involves faults P173A, P173B, P173C, and P173D, which indicate gear position sensor failure. These fault codes can cause various drivability issues, including gear shifting problems, transmission warning lights, or even total gearbox failure.
What Do the Fault Codes Mean?
Each of these codes relates to a problem with the gear position sensors inside the DSG Mechatronic Unit:
- P173A – Gear Position Sensor 1 Signal Implausible
- P173B – Gear Position Sensor 2 Signal Implausible
- P173C – Gear Position Sensor 3 Signal Implausible
- P173D – Gear Position Sensor 4 Signal Implausible
These fault codes indicate that the TCU is unable to accurately determine the gear selection, leading to errors in transmission operation.
Symptoms of Gear
Position Sensor Failure
If your vehicle’s 0AM DSG Mechatronic TCU is experiencing gear position sensor faults, you may notice:
- Erratic or delayed gear shifting
- Flashing PRNDS lights on the dashboard
- Transmission entering limp mode
- Loss of drive or inability to select gears
- Harsh or jerky shifting
- Error messages such as "Gearbox Malfunction"
Causes of Gear
Position Sensor Damage
The gear position sensors are embedded within the DSG Mechatronic Unit, and their failure is typically due to:
- Electrical faults or sensor degradation
- Fluid contamination inside the mechatronic unit
- Excessive heat causing circuit board failure
- Wiring harness damage or loose connections
- Manufacturing defects in early DSG models
- Excessive gear selector movement or full failure
Diagnosing the 0AM DSG
Mechatronic Fault Codes
If your vehicle is displaying any of the P173A, P173B, P173C, or P173D fault codes, proper diagnosis is essential:
- Scan for Fault Codes: Use a professional diagnostic tool like VCDS, ODIS, or Autel to read the transmission errors.
- Check Transmission Fluid Condition: Contaminated fluid can cause sensor failures.
- Inspect Wiring and Connectors: Look for loose connections, corrosion, or broken wires.
- Test the Mechatronic Unit: If multiple gear position sensors are failing, the mechatronic unit may require replacement or repair.
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Inspect for Physical Damage: Examine the gear position sensors for wear or breakage, as well as potential damage to the selector forks that could affect sensor readings.
Repair Solutions for DSG
Mechatronic Gear Sensor Faults
If you are experiencing P173A, P173B, P173C, or P173D, consider the following solutions:
- Software Update/Reprogramming: Some faults can be corrected with a firmware update from the manufacturer.
- Mechatronic Repair or Replacement: If the damage is severe, replacing or refurbishing the mechatronic unit is necessary.
- Gear Selector Replacement: In some cases, replacement of the selector forks is required.
- Check Transmission Fluid and Filters: If contamination is found, a DSG fluid and filter change might help prevent further damage.
- Professional DSG TCU Rebuild Services: Some companies offer repairs for the 0AM DSG Mechatronic TCU, replacing faulty components on the TCU however we have found these unreliable compared to replacement TCU on the 0AM models.
Preventing DSG
Mechatronic Failures
To prolong the lifespan of your DSG gearbox and TCU, follow these preventive measures:
- Regular DSG fluid changes every 40,000 miles
- Avoid aggressive driving that can stress the transmission
- Use manufacturer-recommended transmission fluid
- Address early warning signs before they worsen
Need Workshop Repairs?
Contact our workshop today on 01462 835335 or email us on info@eco-torque.co.uk, if you need help with your gearbox.
Need 0AM DSG Gearbox Parts?
Find our product range here.
Get In Touch
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For specific enquiries, please reach out to us directly using the contact details provided below.
For more information contact
Eco Torque today
Tel: 01462 835335
Email: info@eco-torque.co.uk
Eco Torque Ltd, Unit 1A Portland Industrial Estate, Hitchin Road, Arlesey, United Kingdom, SG15 6SG