APR TCU Upgrade - 8 Speed Tiptronic (AL552 ZF 8HP55) (B9)

Fits 2018+ Audi S4, S5, SQ5, RS4, and RS5

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Part # TCU-AL552 Be the first to write a review

APR TCU Upgrade - 8 Speed Tiptronic (AL552 ZF 8HP55) (B9)

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This part is legal for sale or use on Emissions Controlled Vehicles, Uncontrolled (Non-Emissions Controlled) Vehicles, and Racing Use Only Vehicles because it does not affect vehicle emissions and is not covered by emissions regulations.

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APR's TCU Upgrade dramatically improves upon the transmission's function, drivability, and performance through a myriad of enhancement and custom features. Normal daily driving is smoother as we've improved upon the normal quirks and complaints associated with the driving experience. Sporty driving is far more capable with increased torque capacity, clamping pressure, torque management during shifts, AMAX in all gears, and optimized shift point! Both scenarios are optimized to deliver faster acceleration by matching the power output delivered by our ECU Upgrades. Lastly, the software loads to the factory TCU through the OBD-II port, resulting in a clean and headache-free install.


  • Faster up and down shifts in all modes
  • Optimized shift points for faster acceleration and smoother driving
  • Shift points for both stock and big turbo setups (B9 S4/S5/SQ5) at no additional charge
  • Increased maximum allowable torque for higher output
  • Increased clutch clamping pressure to hold more torque
  • Optimized torque management during shifts for smoother and stronger shifts
  • AMAX maximum acceleration shifting mode enabled on all gear shifts
  • Manual mode auto 1-2 shift disabled
  • Increased maximum RPM on big turbo software (B9 S4/S5/SQ5)
  • Works perfectly with our ECU Upgrades
  • Flash counter does not increase with each flash
  • Direct OBDII port flash (No TCU removal)
  • Free lifetime updates
  • 30 day money back guarantee
Brand APR
Emission Code5
Install TypeDealer Installed
Product TypeECU Upgrade
Transmission OrientationLongitudinal
Transmission TypeAutomatic
Part NumberTCU-AL552

This part is legal for sale or use on Emissions Controlled Vehicles, Uncontrolled (Non-Emissions Controlled) Vehicles, and Racing Use Only Vehicles because it does not affect vehicle emissions and is not covered by emissions regulations.
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Performance notes: When updating the TCU, always check for and update to the latest ECU version, if available. We have only validated our TCU upgrades while using our ECU upgrades. When not using both in combination, various behaviors and features may not be predictable or as described. Compatibility notes: Most 2023+ model year vehicles are not currently compatible due to a locked TCU.

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    Maximum transmission torque capacity (Clutch pressure/current)

    To prevent clutch slip as much as physically possible on the factory clutches, we’ve increased the torque capacity of the transmission to its physical limits. Too much slip can cause excessive wear and damage the clutches. This can happen during gear shifts, transient response, and more, and is mostly on high powered vehicle setups with lots of grip. Clutch pressure is configured to be dynamic and will only increase as necessary. It does not run at the maximum allowable pressure and current at all time.

    Optimized wide open throttle shift points

    The factory wide open throttle shift points were designed to match the factory output of the vehicle. With tuning, they can be optimized future to improve acceleration times. For the best results our ECU and TCU upgrade must be used together. We have specific maps for the factory turbo, and our big turbo setups.

    Optimized shift strategies

    Depending on the vehicle mode, type of shift, braking vs accelerating, and more, the transmission will deliver different shifting strategies. We’ve smoothed part throttle / low torque situations for a comfortable normal drive while giving a more aggressive shift at full torque / high RPM for track driving purposes. Shift speeds are increased, and maximum acceleration modes (AMAX) are enabled in gears.

    The APR Difference

    Who we are - We’re a global automotive engineering firm nestled in Opelika, Alabama. Our 80,000ft² state-of-the-art facility is home to some of the best engineers in the industry, who have mastered hundreds of engine management systems. We have multiple engine and chassis dynos, and the resources necessary to create our TCU Upgrades in-house, from the ground up! We're not a new company either. We've been around since the 90's and we have a strong financial backing to ensure we'll be here to support you for decades to come!

    What we do - We optimize everything to make your transmission more capable. We don’t take shortcuts, and we don’t take risks. We do it the right way.

    How we differ - With our proprietary calibration and direct ram access data logging tools and operating system code changes, we’re able to make some of the best TCU upgrades, without needing costly end user adjustments.

    Purchasing, Guarantee, and Updates

    Purchasing Options¹:

    1. Do-it-yourself: Purchase an APR Ultralink to connect your vehicle to the Ultralink Marketplace where you can shop, configure, and install APR software!†
    2. Do-it-for-me: Locate an APR Dealer and at their location they will sell and install APR software.

    Money-Back Guarantee: Try our Software Upgrades for up to 30 days, risk free! If you are not satisfied, have it removed and refunded.²

    Free Updates: If we make an update, add a standard feature, or if the manufacturer issues an update, you are entitled to a free update.³

    1. Availability: APR Software may not be available for all vehicles. Stages, programs, and features may not be available for all ECUs.
    2. Money Back Guarantee: Excludes some Software Upgrades, such as those included with a hardware purchase. Labor charges are at the discretion of the installer.
    3. Free updates: Subject to availability. Labor charges are at the discretion of the installer. Applicable to the original purchaser. Second hand owners may inquire with an APR Dealer about a software license transfer fee.
    †. Excludes APR Plus. Excludes some platforms. Dealer participation will vary. Visit our product page for details.

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      *Free Shipping & Handling only offered to the contiguous US on orders over $149, excludes clearance parts and oversized packages.

      Some parts are not legal for use in California or other states with similar regulations.