ecko04
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Taycan ACC Retrofit
I purchased a used Taycan some time ago that had everything I was looking for except Adaptive Cruise Control (ACC). Given that the price difference between the vehicle I purchased and the next closest comparable car, based on color combination, mileage, and options, exceeded $10,000, I chose to retrofit ACC rather than compromise on the vehicle itself.
I am not new to Porsche retrofits, working on vehicles, or low voltage electrical design. I also recognized upfront that this Taycan is our sixth vehicle between my wife and me, so downtime and vehicle availability were not a concern.
If you can find a vehicle with ACC already included, that is clearly the best path. However, if you find a Taycan that otherwise meets your criteria and lacks ACC, retrofitting is a viable option. The retrofit cost was approximately $2,500, and I expect it will make longer commutes easier to manage.
The vehicle was already equipped with Lane Keep Assist (LKA) and Night Vision, which simplified the retrofit.
Figure out your programming and coding beforehand. Don't commit to anything until you've figured this out.
Vehicle Configuration
Adaptive Cruise Control (ACC)
Vehicle also had LKA and Night Vision
Components Added
Steering Wheel Angle Sensor
ACC Stalk
Gateway Control Unit (Black Plug -> T54)
Red w/ White (12V Ignition) -> Gateway (Black/Violet 15A). I recommend adding a 10A inline fuse. In the unlikely event of a current spike, the 10A fuse will blow before the 15A Gateway supply. Switched 12V can also be sourced from the passenger side kick panel fuse box, but capturing it at the Gateway is cleaner and more professional.
Brown (Ground) -> Use any suitable chassis ground point on the vehicle, such as in the frunk or behind the wheel liner. Do not connect directly to the negative battery terminal.
Wiring Notes
Pin locations are embossed on each plug. A useful approach is to take a photo with your phone and zoom in.
All wires are to be spliced. DO NOT REMOVE any existing wires.
All signal wires being spliced are either pink or green, with the exception of switched power and ground.
Gateway Control Unit Access (Black T54)
The Gateway Control Unit is located underneath the PCM. To gain unrestricted access, the center console must be removed. This includes removal of the rear lower seat cushion, both front seats, the center console, the lower screen assembly, and the lower duct assembly.
It is possible to access the T54 connector without interior disassembly. However, this approach is significantly more difficult and increases the risk of damaging a wire. If you choose this route, once T54 is unplugged, access the connector from the driver side floorboard.
If a wire is damaged, interior disassembly is required to properly repair it. For this reason, full interior disassembly from the start is strongly recommended to avoid unnecessary rework.
To access the wires, remove the outer shell of the connector. The shell is retained by two small clamps. Lift one clamp, then the other, and the shell will slide off, exposing the wires.
No wires connect to the grey plug on the Gateway.
When reconnecting the black plug, take care to avoid bending pins on the Gateway. Bent pins will require interior disassembly to correct.
Assistance Systems Control Unit (Black Plug -> T81)
This module is easily accessible from the passenger side floorboard. Plug shell disassembly is required for wire access.
Airbag Control Unit (Yellow Plug -> T142)
The Airbag Control Unit is located underneath the center console. It is possible to access this plug without removing the console. Once disconnected, pull the plug toward the driver side to gain additional access.
That said, removing the console provides unobstructed access and is the preferred approach.
This plug does not require shell disassembly. Simply count backward from PIN 142 to locate PIN 133 (Pink) and PIN 132 (Green).
Brake Electronics Control Unit Access (Black Plug -> T46)
Jack the front left corner of the vehicle and use a jack stand for safety. Remove the wheel, then remove the wheel liner. Plug shell disassembly is required for wire access.
Technical Notes
The pink and green wires being spliced are part of the FlexRay bus. Internally, these splices tie into multiple bus segments.
If you place a meter on continuity between green and green, you will see continuity with near zero resistance. If you meter between green and pink along the same bus, you will also see continuity, typically with resistance in the 40 to 50 ohm range. The FlexRay bus measures approximately 100 ohms across the twisted pair at the end of the run.
Interior Disassembly Notes
Ensure both seats are moved as far forward as possible before disconnecting the battery.
Wrap a cloth around the negative battery terminal to prevent accidental reconnection during the install.
Allow at least 10 minutes after disconnecting the negative terminal for bus voltage to fully drain before unplugging any airbag connectors.
Remove the driver side seat through the rear driver side door. This is significantly easier than maneuvering around the steering wheel.
Remove the passenger front seat through the passenger front door. There is ample clearance.
If the vehicle has ambient lighting, take care when removing the cupholder. There are two connectors attached to a fragile LED light ring that can break easily.
PCM Tips
Two small flat head screwdrivers or pick tools are required to remove the PCM from its cage.
Use caution with the PCM harness. It is easy to accidentally pull out the two MOST fiber optic cables, which will disable the amplifier, whether BOSE or Burmester.
Avoid pulling the PCM aggressively. If the fiber cables are damaged, sourcing properly terminated replacements is difficult. Remember that MOST is a loop system. The cable that enters one PCM connector routes to the amplifier, and the return cable completes the loop back to the PCM. The amplifier is located in the passenger floorboard.
Removing the PCM cage is time consuming. It can be removed from the front by loosening the Gateway or from the driver side. Neither approach is straightforward, but it is part of the process.
Activation, Programming, and Coding
For ACC to function, activation, coding, programming, and calibration are all required.
Before ACC sensor calibration can occur, component protection must be lifted to allow programming and coding. This requires a legitimate PIWIS account with FAZIT access. Once that step is completed, the remaining work can be performed using VT4G and a cloned PIWIS.
Porsche explicitly supports retrofits. Factory documentation references retrofit procedures and the steps required to bring added components online. Vehicle configuration data is updated and stored in Porsche’s system so that future software updates also recognize and maintain retrofitted components.
Functional
UPDATE HISTORY
Rev 1 - 12/14/2025 - Original Post
Rev 2 - 12/30/2025 - Fixed errors in wire colors. Added module numbers for ACC/Distance Sensor, ABS and Gateway Control Units
Rev 3 - 1/10/2026 - Photo of functional ACC
I purchased a used Taycan some time ago that had everything I was looking for except Adaptive Cruise Control (ACC). Given that the price difference between the vehicle I purchased and the next closest comparable car, based on color combination, mileage, and options, exceeded $10,000, I chose to retrofit ACC rather than compromise on the vehicle itself.
I am not new to Porsche retrofits, working on vehicles, or low voltage electrical design. I also recognized upfront that this Taycan is our sixth vehicle between my wife and me, so downtime and vehicle availability were not a concern.
If you can find a vehicle with ACC already included, that is clearly the best path. However, if you find a Taycan that otherwise meets your criteria and lacks ACC, retrofitting is a viable option. The retrofit cost was approximately $2,500, and I expect it will make longer commutes easier to manage.
The vehicle was already equipped with Lane Keep Assist (LKA) and Night Vision, which simplified the retrofit.
Figure out your programming and coding beforehand. Don't commit to anything until you've figured this out.
Vehicle Configuration
Adaptive Cruise Control (ACC)
Vehicle also had LKA and Night Vision
Components Added
Steering Wheel Angle Sensor
ACC Stalk
Gateway Control Unit (Black Plug -> T54)
- Translucent (White Stripe) PIN 5 (J428 - ACC Sensor) —> Gateway (J533) PIN 38 (Pink)
- Black PIN 6 (J428 - ACC Sensor) —> Gateway (J533) PIN 37 (Green)
- Gateway (J533) PIN 19 (Green) —> Assistance Control Unit PIN 44 (Green w/ White Stripe)
- Gateway (J533) PIN 1 (Pink) —> Assistance Control Unit PIN 63 (Pink w/ White Stripe)
- Gateway (J533) PIN 20 (Green) —> Airbag Control Unit PIN 132 (Green)
- Gateway (J533) PIN 2 (Pink) —> Airbag Control Unit PIN 133 (Pink)
- Red PIN 2 (J428 - ACC Sensor) —> ABS (J104) PIN 29 (Pink)
- White PIN 3 (J428 - ACC Sensor) —> ABS (J104) PIN 45 (Green)
Red w/ White (12V Ignition) -> Gateway (Black/Violet 15A). I recommend adding a 10A inline fuse. In the unlikely event of a current spike, the 10A fuse will blow before the 15A Gateway supply. Switched 12V can also be sourced from the passenger side kick panel fuse box, but capturing it at the Gateway is cleaner and more professional.
Brown (Ground) -> Use any suitable chassis ground point on the vehicle, such as in the frunk or behind the wheel liner. Do not connect directly to the negative battery terminal.
Wiring Notes
Pin locations are embossed on each plug. A useful approach is to take a photo with your phone and zoom in.
All wires are to be spliced. DO NOT REMOVE any existing wires.
All signal wires being spliced are either pink or green, with the exception of switched power and ground.
Gateway Control Unit Access (Black T54)
The Gateway Control Unit is located underneath the PCM. To gain unrestricted access, the center console must be removed. This includes removal of the rear lower seat cushion, both front seats, the center console, the lower screen assembly, and the lower duct assembly.
It is possible to access the T54 connector without interior disassembly. However, this approach is significantly more difficult and increases the risk of damaging a wire. If you choose this route, once T54 is unplugged, access the connector from the driver side floorboard.
If a wire is damaged, interior disassembly is required to properly repair it. For this reason, full interior disassembly from the start is strongly recommended to avoid unnecessary rework.
To access the wires, remove the outer shell of the connector. The shell is retained by two small clamps. Lift one clamp, then the other, and the shell will slide off, exposing the wires.
No wires connect to the grey plug on the Gateway.
When reconnecting the black plug, take care to avoid bending pins on the Gateway. Bent pins will require interior disassembly to correct.
Assistance Systems Control Unit (Black Plug -> T81)
This module is easily accessible from the passenger side floorboard. Plug shell disassembly is required for wire access.
Airbag Control Unit (Yellow Plug -> T142)
The Airbag Control Unit is located underneath the center console. It is possible to access this plug without removing the console. Once disconnected, pull the plug toward the driver side to gain additional access.
That said, removing the console provides unobstructed access and is the preferred approach.
This plug does not require shell disassembly. Simply count backward from PIN 142 to locate PIN 133 (Pink) and PIN 132 (Green).
Brake Electronics Control Unit Access (Black Plug -> T46)
Jack the front left corner of the vehicle and use a jack stand for safety. Remove the wheel, then remove the wheel liner. Plug shell disassembly is required for wire access.
Technical Notes
The pink and green wires being spliced are part of the FlexRay bus. Internally, these splices tie into multiple bus segments.
If you place a meter on continuity between green and green, you will see continuity with near zero resistance. If you meter between green and pink along the same bus, you will also see continuity, typically with resistance in the 40 to 50 ohm range. The FlexRay bus measures approximately 100 ohms across the twisted pair at the end of the run.
Interior Disassembly Notes
Ensure both seats are moved as far forward as possible before disconnecting the battery.
Wrap a cloth around the negative battery terminal to prevent accidental reconnection during the install.
Allow at least 10 minutes after disconnecting the negative terminal for bus voltage to fully drain before unplugging any airbag connectors.
Remove the driver side seat through the rear driver side door. This is significantly easier than maneuvering around the steering wheel.
Remove the passenger front seat through the passenger front door. There is ample clearance.
If the vehicle has ambient lighting, take care when removing the cupholder. There are two connectors attached to a fragile LED light ring that can break easily.
PCM Tips
Two small flat head screwdrivers or pick tools are required to remove the PCM from its cage.
Use caution with the PCM harness. It is easy to accidentally pull out the two MOST fiber optic cables, which will disable the amplifier, whether BOSE or Burmester.
Avoid pulling the PCM aggressively. If the fiber cables are damaged, sourcing properly terminated replacements is difficult. Remember that MOST is a loop system. The cable that enters one PCM connector routes to the amplifier, and the return cable completes the loop back to the PCM. The amplifier is located in the passenger floorboard.
Removing the PCM cage is time consuming. It can be removed from the front by loosening the Gateway or from the driver side. Neither approach is straightforward, but it is part of the process.
Activation, Programming, and Coding
For ACC to function, activation, coding, programming, and calibration are all required.
Before ACC sensor calibration can occur, component protection must be lifted to allow programming and coding. This requires a legitimate PIWIS account with FAZIT access. Once that step is completed, the remaining work can be performed using VT4G and a cloned PIWIS.
Porsche explicitly supports retrofits. Factory documentation references retrofit procedures and the steps required to bring added components online. Vehicle configuration data is updated and stored in Porsche’s system so that future software updates also recognize and maintain retrofitted components.
Functional
UPDATE HISTORY
Rev 1 - 12/14/2025 - Original Post
Rev 2 - 12/30/2025 - Fixed errors in wire colors. Added module numbers for ACC/Distance Sensor, ABS and Gateway Control Units
Rev 3 - 1/10/2026 - Photo of functional ACC
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Last edited:
