1998-2000 Subaru WRX and STI Link Ecu G4X
Link ECU G4X Subaru WRX & STI V5–V6 PlugIn ECU — WRX6X (228-4000)
Upgrade your Subaru WRX or STI with the Link ECU G4X WRX6X PlugIn ECU. This advanced standalone engine-management system installs inside the factory ECU enclosure and connects to the original wiring loom, giving you complete control over fuel, ignition, boost and advanced motorsport functions.
Designed for compatible Version 5 and Version 6 Subaru WRX and STI models with the turbocharged EJ20 engine, the WRX6X delivers modern engine-management capabilities without requiring a complete standalone wiring harness.
FREE Link ECU USB Tuning Cable — $70 Value
Every WRX6X purchased from Kugan Tuning includes a compatible Link ECU USB tuning cable at no additional cost. Connect your laptop directly to the ECU for configuration, diagnostics, data logging and professional tuning.
Why Choose the Link G4X WRX6X?
- Designed for compatible Subaru WRX and STI V5–V6 applications
- Supports turbocharged EJ20 engines
- Installs inside the factory OEM ECU enclosure
- Connects to the original engine wiring loom
- No complete standalone wiring harness required
- Advanced fuel, ignition and boost control
- Launch control, anti-lag and flat-shift capability
- Expandable inputs and outputs
- CAN communication
- 512 MB of onboard data-logging memory
- FREE Link ECU USB tuning cable included—a $70 value
- FREE Kugan Tuning remote setup support included—a $297 value
Suitable Applications
- Subaru Impreza WRX Version 5
- Subaru Impreza WRX Version 6
- Subaru Impreza STI Version 5
- Subaru Impreza STI Version 6
- GC8F chassis
- GC8G chassis
- MY1999 and MY2000 vehicles
- Production dates from September 1998 through August 2000
- Manual-transmission vehicles only
Important Compatibility Information
- Compatible with manual-transmission vehicles only
- Designed for compatible Subaru WRX and STI V5–V6 EJ20 applications
- Compare your factory ECU connector and pinout with the product photos before ordering
- Compatibility depends on the factory ECU connector and pinout—not only the model year, chassis or engine
- A dedicated intake-air-temperature sensor is highly recommended
- Most factory vehicle functions are supported, but availability can vary by model and market
- Modified vehicles and engine swaps may require additional wiring, sensors and configuration
- Professional installation and calibration are strongly recommended
Powered CAN Connection—Version 1.4 and Newer
Version 1.4 and newer WRX6X PlugIn ECUs use Link ECU’s four-pin powered CAN connector and cannot use the older CANPCB cable.
Use the Link ECU CANJST4 cable, part number 101-0198, to connect compatible CAN devices. This connection provides:
- CAN communication
- Protected 12V power supply
- Ground connection
- Self-resetting fuse rated for 3 amps of continuous current
The CANJST4 cable is sold separately unless specifically included with your order. Earlier ECU revisions may use a different CAN connection, so verify the hardware revision before purchasing a CAN cable.
G4X Engine-Management Features
- Up to 6D fuel and ignition mapping
- Sequential fuel injection
- Precision closed-loop camshaft control where applicable
- Digital triggering with support for OEM trigger patterns
- OEM idle-control hardware support
- 5D boost control with three switchable tables
- Boost control based on gear, vehicle speed or throttle position
- Launch control
- Anti-lag
- Flat-shift control
- QuickTune automated fuel tuning
- Individual-cylinder correction
- Gear-based fuel, ignition and boost compensation
- Real-time selectable fuel, ignition and boost maps
- Continuous onboard barometric correction
- Staged injection
- Knock control with configurable knock windows
- Hall-effect, variable-reluctance and optical trigger-sensor support
- CAN communication
- Onboard statistics recording
- 512 MB of onboard data-logging memory
I/O Expansion Options
XS Connector 1
- Sensor ground
- Low-current 5V sensor supply
- Digital input 8
- Digital input 9
- Analog voltage input 8
- Analog voltage input 9
- Ignition output 7
- Ignition output 8
Expansion Connector 2
- Sensor ground
- Low-current 5V sensor supply
- Digital input 5
- Digital input 7
- Analog voltage input 5
- Analog voltage input 6
- Temperature input 2
- Temperature input 3
What’s Included
- Link ECU G4X Subaru WRX6X PlugIn ECU
- FREE Link ECU USB tuning cable—a $70 value
- FREE Kugan Tuning remote setup support—a $297 value
An external intake-air-temperature sensor and CANJST4 cable are not included unless selected separately.
FREE Remote Setup Support — $297 Value
Purchase your Link ECU from Kugan Tuning and receive complimentary remote setup support to help prepare the ECU and vehicle for startup and professional tuning.
Remote setup support includes:
- Remote ECU connection and setup assistance
- Basemap selection guidance
- Initial ECU configuration assistance
- Startup configuration review
- Sensor and input verification
- Guidance preparing the vehicle for professional tuning
This support helps identify configuration and sensor problems early, reducing unnecessary troubleshooting and wasted dyno time.
Custom remote tuning and dyno tuning are not included unless separately purchased. Successful startup and vehicle operation depend on correct compatibility, installation, wiring, mechanical condition and ECU calibration.