Link G4X WRX104X Plug-In ECU, Subaru WRX STI 2004-2007 and WRX 2006, 2.5L EJ25 (Pins A1-A3 Wired)

The WRX104X is Link's G4X plug-in ECU for the 2004-2006 GD and GG Impreza WRX and STI with the 2.5-litre EJ25, the generation Link calls Version 10. The Link board slides into the factory ECU case, drives the factory electronic throttle directly, and ships with a startup map. Link makes two V10 units, so check your factory ECU connector before ordering.

Fits

• North American WRX STI 2004-2007 (EJ257) and WRX 2006 (EJ255), where pins A1-A3 on the factory ECU connector are wired
• Subaru Impreza WRX and WRX STI, GD/GG (Link's Version 10), 2.5L EJ25, 2004-2006

Before you order

• Check pins A1-A3 on your factory ECU connector. Wires in A1-A3: this WRX104X. A1-A3 empty: you need the WRX107X (225-4000). Some late 2006 cars take the WRX107X, so check the pins rather than going by year.
• Manual transmission only.
• Compare the connector on your factory ECU with the header shown in the product photos before ordering.
• These are the 2.5L cars, which Japan never had: in North America that means the 2004-2007 WRX STI (EJ257) and the 2006-2007 WRX (EJ255). Pins A1-A3 on the factory ECU connector decide between the WRX104X and the WRX107X, not the model year.
• No onboard MAP sensor: the ECU reads the factory MAP sensor, which is good for 160 kPa (about 23 psi) of boost, and the sensor can be swapped for a higher-range one.
• Some STIs have a usable factory intake air temperature sensor near the throttle body; on other cars, plan on adding one.
• The factory front oxygen sensor is not connected (Link's pinout lists it as unused), so plan on an aftermarket wideband for closed-loop fuel control.
• Built for high-impedance injectors (over 6 ohms); low-impedance injectors need ballast resistors.
• Installation: the Link board goes into the factory ECU case. It fits two case sizes, with snap-off extensions for the smaller one, and jumpers inside are set for your car's year before fitting.
• It arrives with a base map that gets the engine started; that is a starting point, not a finished tune. Tuning is done in Link's free PCLink software on a Windows laptop, and the USB tuning cable is in the box.

Highlights

• Drives the factory electronic throttle directly.
• AVCS cam control and cam inputs for both banks, plus tumble generator valve control and position inputs.
• Knock input on the factory knock sensor.
• Two CAN buses for a dash, keypad or CAN lambda.
• G4X feature set: flex fuel, open- and closed-loop boost control, dual closed-loop lambda, engine protection limiters, CAN keypad support and a built-in trigger scope.
• Motorsport functions: launch control, anti-lag, traction control, nitrous control, gear shift and paddle shift control, cruise control, and race timer with power management.
• 512 MB of onboard data logging.

Specifications

• Dimensions: 190 x 160 x 30 mm (7.48 x 6.30 x 1.18 in)
• Weight: 260 g (9.17 oz)
• Operating voltage: 6.5-24 V (36 V maximum input)
• Tuning connection: LTW 6-pin USB
• Communications: 2 CAN buses
• In the box: WRX104X ECU, USB tuning cable, anti-static strap, Link stickers, plug-in manual card and product registration card