Elite 1000/1500 Subaru WRX MY99-00 Plug ‘n’ Play Adaptor Harness

Phase 2 Performance: Elite Adaptor for MY99-00 WRX

The MY99-00 Subaru WRX saw the introduction of the “Phase 2” EJ20 engine architecture, bringing with it updated cylinder heads, coil packs, and a new ECU pinout. The Elite 1000/1500 Plug ‘n’ Play Adaptor Harness is specifically calibrated for this generation (GC8/GF8 Version 5 and 6). It provides a faultless interface between the unique MY99-00 factory wiring harness and a Haltech Elite ECU. This is the definitive solution for owners looking to extract maximum power from the last of the classic GC8 chassis, supporting modifications from basic bolt-ons to fully built time-attack engines.

Engineering for Phase 2 Electronics

This harness addresses the specific electrical changes of the MY99-00 models, including the updated idle control system and the specific wasted-spark ignition coil pack wiring. It is engineered to plug directly into the factory ECU header located in the passenger footwell. The adaptor routes all vital engine signals—including the sensitive inductive crank and cam sensors—via shielded pathways to the Elite ECU, preventing signal noise that can cause ignition breakup at high RPM. The inclusion of an Air Temperature Sensor allows for the removal of the restrictive factory MAF sensor, enabling consistent tuning regardless of intake pipe configuration.

Operational Benefits

Installation is completely reversible, preserving the integrity of the vehicle’s original wiring loom—a critical factor for the appreciating classic WRX market. The harness supports full sequential injection (if wiring is modified/added, otherwise grouped/semisequential as per factory loom limits) and direct fire ignition control. The included auxiliary port allows for future-proofing your build with additional sensors for fuel pressure, oil pressure, or ethanol content, all logged and controlled by the Elite ECU.

Fitment Guide

• Subaru WRX: MY99-00 (Version 5/6 GC8)
• Market: ADM and JDM

Technical Specifications

Summary & Includes

Includes:

• 1 x Injection Molded Plug ‘n’ Play Adaptor Harness
• 1 x M14 x 1.5 Air Temp Sensor with matching plug and pins
• 1 x Auxiliary I/O 16 Pin Tyco plug and pins

Note: Manual transmission only.