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9G 725.9 TCU Tune
Purchase 9G 725.9 TCU Tune
  • SKU: 05-725-00162-8

    9G 725.9 TCU Tune

  • $1,699.00 $1,699.00 $1,444.15 $1,444.15

    2026 Labor Day Sale 15% off: $254.85

  • Prop 65 warning
    Warning

    This product can expose you to chemicals including carbon black, silica - crystalline, formaldehyde, and lead which are known to the State of California to cause cancer, and lead, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Manufacturer Weistec
Transmission Family 725.9
UPC 810089563507
Tuning Method Cypher TCU Flash Tool or Cypher Pro Dealer
year make model trim engine
2021 Mercedes-Benz GLC63 AMG S Coupe (C253) Twin Turbo 4L V8 (M177)
2021 Mercedes-Benz GLC63 AMG Coupe (C253) Twin Turbo 4L V8 (M177)
2021 Mercedes-Benz C63 AMG T-Modell (S205) Twin Turbo 4L V8 (M177)
2020 Mercedes-Benz C63 AMG T-Modell (S205) Twin Turbo 4L V8 (M177)
2019 Mercedes-Benz C63 AMG T-Modell (S205) Twin Turbo 4L V8 (M177)
2026 Mercedes-Benz GLC43 AMG Coupe (C254) Turbocharged 2L I4 (M139)
See more

Product Description



What is the Flashtool and what does the Flashtool do?

The Cypher Flash Tool is an tool that allows for at home control module flashing via the vehicle's OBD2 port. With this tool, it is possible to flash a Weistec TCU tune on your vehicle from the comfort of your own garage, as well as flash updates to a Weistec CPC. Certain vehicles can even have the ECU flashed using the Cypher Flash Tool.


Benefits of doing a TCU Tune?

The Weistec TCU tune results in faster and more firm shifts. This is accomplished with faster target shift times and running higher line pressure which also has the added benefit of reducing slip and increasing the torque capacity of the transmission. With higher line pressure, the clutches in the transmission are clamped harder making for better grip which directly allows the transmission to hold more torque. With less slip and faster shifts, the lifespan of the transmission is typically improved as well. This is a great upgrade for any supported vehicle whether it is stock or modified.


Key Features

  • Faster Shifts

  • Firmer Shifts

  • Increased Line Pressure

  • Increased Software Torque Limits

How Do You Get Your 9G 725.9 TCU Tune Tuned?

Follow these steps — this is what your specific vehicle needs and supports.

2

Choose Your Tune Stage

3

Core Improvements

Standard with this tune
  • Increased Line Pressure
  • Firmer Shifts
  • Faster Shifts
  • Increased Torque Capacity
  • Increased Software Torque Limits
  • Improved Street and Track Performance
4

Free Add Ons

5

Pick Your Tuning Method

See the full tuning process →
1Selected

Cypher Plus

Order a Cypher Plus and tune your car yourself from your phone, entirely through the MyFlasher app. Watch how it works.

2Selected — Pick return shipping at checkout

Mail It In

Remove your ECU or TCU and mail it to us for tuning. Required for some applications.

3Selected — Pick Will call at checkout

In Person

Bring your vehicle, or just your ECU/TCU, to our Anaheim, CA headquarters. Call 714-202-0005 or email sales@weistec.com to schedule.

4Selected — Order through your local dealer

Cypher Pro Dealer

Visit a certified Cypher Pro Dealer near you. Find one with our dealer locator.

6

Complete The Upgrade

An ECU tune alone won't remove all factory limits or fix how power reaches the ground. Add these to round out the upgrade with no limitations.
Read the full CPC & TCU breakdown →

What is a CPC module?

The CPC (Central Powertrain Control) is a separate control unit that manages things like the active exhaust valves, radiator fan, intercooler pumps, and speed limiter. On many newer Mercedes-Benz vehicles, it also houses torque limiters that can hold back an ECU tune from reaching its full potential.

What is a TCU tune?

A TCU (transmission control unit) tune delivers faster, firmer shifts with higher line pressure, reducing clutch slip and increasing the transmission's torque capacity. It's a worthwhile upgrade on its own, or paired with an ECU tune for a fully sorted powertrain.

Your Total  

Good to Know

  • This is a reflash of your original module, not a stand-alone unit.
  • Power gains vary by vehicle, modifications, fuel, and operating conditions (ambient temperature, altitude, etc.).
  • New or upgraded spark plugs are always recommended when tuning.
  • Product may not be emissions compliant. Check local laws prior to installation.
  • Always use a battery charger during programming.