Link G4X plug-in Subaru Impreza 04-07 WRX/STI (GD/GG 2.5L models with E-throttle)

$ 2,501.25$ 2,600.00

Incl. Tax (NZ Customers)

Excl. Tax (International Customers)


Link G4X plug-in Subaru Impreza 04-07 WRX/STI (GD/GG 2.5L models with E-throttle)


Link Part #WRX104X (SKU: 224-4000) or #WRX107X (SKU: 225-4000)


The Link G4X range of engine management systems builds upon the previous G4+ ECUs by featuring an all new micro-processor, an upgraded communications chip and expanded data logging. These improvements allow for a more responsive and accurate tune, much faster download speeds and far greater internal data logging capacity.


The Link G4X range of engine management systems are well known for delivering class-leading performance without sacrificing factory levels of drivability. The G4X plug-in ECUs are designed to be the most complete plug-in solution yet.


This 04-07 2.5L WRX/STI plug-in ECU will save you time and money as it will plug straight into the vehicle’s original wiring loom without the need for messy adapter harnesses. It replaces the original circuit board inside the factory ECU enclosure and mounts using the factory brackets.


This Link G4X Subaru WRX/STI plug-in ECU is suitable for the models listed below:


Subaru Impreza WRX & STI Impreza (MY2004-2007 GD or GG chassis series with 2.5L engine, variable cam control and electronic throttle)


There are two different Subaru Impreza WRX 2.5L ECUs available, which cover the 2.5L models through various (often overlapping) years and international markets.


To determine whether either of these two ECU’s are suitable for your application, in the first instance, the following criteria must be meet:


  1. Chassis series = GD or GG
  2. Engine capacity = 2.5L only
  3. Continuously variable camshaft timing = Yes
  4. Electronic throttle = Yes


If the criteria listed above are met, then the information to determine which of the two ECU’s suit your application is as follows:


The correct ECU can be verified by studying the wiring loom. Both ECU’s use the same connector, but have different wiring configurations.


If pins A1, A2 and A3 (see photo below) contain wires, then the correct ECU is the Type 1 version (which Link refer to as the 2004-2006 2500cc version). If these pin contain no wires, then the correct ECU required is the Type 2 version (which Link refer to as the 2007 2500cc version).


It is critical that the correct ECU for the vehicle is installed, failure to install the correct ECU can result in engine component, engine wiring or ECU damage.

Subaru WRX V10 ECU Header Connector


Once the installation is complete, the Link G4X allows a good tuner to achieve an optimal state of tune to get the most out of any combination of modifications.


All Link G4X plug-in ECUs come with a base map. While these maps are designed to help save time for you and your tuner, it is essential that these are used simply as a starting point for further tuning.


The engine can easily be converted to speed density by removing the air flow meter and instead using a suitable MAP and air temperature sensor.  Likewise, this ECU can also be setup to control boost electronically with in-cabin adjustment. This eliminates the need to purchase a separate electronic boost control system.


The vehicle’s original sensors & actuators are used except for the following exceptions:

  • MAP sensor – For all models the factory MAP sensor is supported. These sensors are capable of measuring up to 1.64Bar (23.5psi) boost. If more boost is intended to be used then we do have a direct-fit higher rated MAP sensor available. The airflow sensor is not required.
  • Inlet Air Temp sensor (IAT) – An appropriate IAT sensor (available separately), should be installed just prior the throttle body even on  models that have a factory fitted IAT sensor in the inlet manifold. The factory AFM wiring contains wires which can be used for an aftermarket IAT sensor. Alternatively, if modifying the existing AFM wiring is not desired then an IAT sensor can be wired via the expansion connector on the ECU using the XS loom.
  • Boost control – The factory boost solenoid control wiring is used, however the boost solenoid must be upgraded on applications using an external wastegate or elevated boost levels (these are available from NZEFI).
  • Injectors – The G4X plug-in is NOT designed to be used with low impedance injectors. All the Subaru models this G4X plug-in is designed for use high impedance injectors so no changes are necessary. However if low impedance aftermarket injectors have been fitted then the correct ballast resistors MUST be fitted. These are available from NZEFI.


Extra sensor inputs

The expansion connectors on the Link G4X board is provided to allow the easy connection of additional ECU inputs. The expansion connector on this particular plug-in model provides the following:


Type 1 ECU:

  • 5V Supply
  • Sensor Ground
  • 2 analogue voltage inputs
  • 1 analogue temperature input


Type 2 ECU:

  • 5V Supply
  • Sensor Ground
  • 1 digital inputs
  • 1 analogue voltage inputs
  • 1 analogue temperature input


These may be used for such functions as driver adjustable boost control, and for additional sensors such as wideband lambda input, an alternative method of connecting the map sensor, fuel pressure, oil pressure (the G4x can take steps to protect the engine if these fall out of bounds and they may be displayed on the optional Link dash).



Any redundant outputs may be reconfigured & used for alternative uses, eg extra electric fans, intercooler water spray, shift light, water injection (we NZEFI are happy to assist in details of setting these up).



In addition to the ECU which can be purchased separately, we also offer the following packages:

Basic ECU Package:

Turbo ECU Package:

Please select the appropriate package from the drop down menu.


Additional information

Weight 800 g

Part Type


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