Haltech Nexus S3 ECU & Toyota Celica GT-S 2003-2005 Plug 'n' Play Adapter Harness Kit (HT-651022)

The final GT-S 2ZZ-GE is one of the best naturally aspirated engines Toyota built for the road, and a proper standalone tune shows exactly why.

The Toyota Celica GT-S 2ZZ-GE is a high-revving driver-focused platform, and standalone ECU support opens what the factory management keeps locked down. The Tuned By Shawn PNP Wiring Harness Kit for the Haltech Nexus connects directly to your factory harness without any permanent modifications, giving the Haltech Nexus full standalone engine control. No cutting, no splicing, fully reversible.

Advantages

• Sharp throttle response tuned precisely to your setup
• Fuel and ignition timing calibrated to your actual modifications, not Toyota's conservative baseline
• Idle stability that's locked in across temperature ranges
• A tune built to support whatever modifications you're running
• Engine behavior that matches the intent of the car rather than working around it

Features

• Plug-and-play fitment for 2003-2005 Toyota Celica GT-S 2ZZ-GE, manual transmission
• Compatible with Haltech Nexus R3, R5, S2, and S3 ECUs
• No cutting or splicing of factory wiring
• OEM-quality connectors, USA-built by Boomslang Fabrication
• Fully reversible, factory harness preserved
• For competition and off-road use

The Details

Built specifically for this vehicle's connector layout with OEM-spec connectors and correct wire gauge throughout. Your factory harness stays completely untouched and the car can return to stock at any time. The Haltech Nexus takes full engine control once installed, giving your tuner a clean vehicle-specific foundation to build a proper map from.

Kit Includes

• 1x Boomslang PNP wiring harness for 2003-2005 Toyota Celica GT-S 2ZZ-GE
• Haltech Nexus S3 ECU
• Air Temp Sensor - Small Thread Thread: M14 x 1.5

Fitment

2003-2005 Toyota Celica GT-S, Manual Transmission.