Ignitions and Electrical Wiring Harnesses

Haltech

Nexus S2 Plug-N-Play Adapter Harness Kit

$2,365.00

SKU: HT-212316

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Haltech Nexus S2 is a plug-and-play adapter harness kit designed as a successor to the Elite 1500. It offers enhanced performance and functionality with the processing power of the Nexus platform.

This kit allows for an easy ECU upgrade by plugging directly into your Haltech ECU and factory harness, enabling you to be operational within hours. It includes the Nexus S2 ECU, a plug-and-play adapter harness, an air temp sensor, and an auxiliary I/O plug.
Show original supplier description
The Haltech Nexus S2 Plug 'n' Play Adapter Harness Kit represents a significant upgrade over its predecessor, the Elite 1500, by integrating the robust Nexus platform's processing power with familiar functionalities. This ECU upgrade provides extensive I/O capabilities, including 4 peak/hold injector drivers, 4 low current ignition outputs, and 6 PWM-capable low-side drive outputs. It also features 4 push-pull/half bridge outputs suitable for electronic throttle control, an ECR output, and 11 analog inputs. For engine monitoring and tuning, it incorporates differential trigger and home inputs with adjustable filters, 6 synchronous pulsed inputs, an on-board 4-bar MAP sensor, and an on-board wideband controller supporting NTK and LSU4.9 sensors. Beyond its comprehensive I/O, the Nexus S2 unlocks advanced engine management features. These include long-term learning, stepper motor control, sophisticated closed-loop boost and CO2 control, rotational idle, launch control, traction control, anti-lag systems, dual knock control, and multi-stage nitrous control. It also supports advanced functions like 4-sensor variable cam control, flat shift control, shock travel and ride height control, and advanced torque management. On-board Wi-Fi and extensive data logging up to 300 channels at 1ms sample rates with 128MB of memory are also included. This specific kit is designed for the 1989-1997 Mazda Miata NA with 1.6L and 1.8L engines, specifically those equipped with the 2-plug, 2-row factory ECU and a manual transmission. However, it does not support USDM OBDII 96-97 models, nor Special Edition SE and Anniversary models. For all manual transmission 1.6L variants, the factory throttle position sensor must be unplugged and removed, and a full-range throttle position sensor alternative must be installed to prevent erratic ECU behavior and potential damage. It's important to note that using the Nexus S2 instead of the Nexus S3 may result in the loss of some factory functionalities, as detailed in the quick start guide. This product is intended for off-road/competition use only and may not be legal for use on public roads.
Vehicle Symptoms
  • Engine hesitation under acceleration
  • Rough idle and stalling
  • Check engine light for misfire
  • Poor fuel economy and power loss
Relevant Conversations
  • Haltech Nexus S2 plug and play harness for Subaru WRX
  • Nexus S2 adapter harness installation guide
  • How to install Haltech Nexus S2 ECU in Mazda RX7
  • Nexus S2 vs Haltech Elite 1500 comparison
  • Plug and play harness for Nexus S2 ECU
  • Nexus S2 harness wiring diagram
  • Best aftermarket ECU harness for Nissan 350Z
  • Haltech Nexus S2 review and tuning
  • Engine misfire after ECU swap help
  • Nexus S2 harness compatibility with LS swap

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

Fitment Guaranteed

Don’t gamble
on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandHaltech
Part NumberHT-212316
CategoryIgnitions and Electrical

About MOTORMIA

5,000+ Trusted brands
1M+ Enthusiasts
5M+ Parts sold

Buy with Confidence

Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

View Full Return Policy

Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

View Full Shipping Policy