Nexus Plug-in IO Expansion Harness 2.5m (8)

Overview

The Nexus Plug-in IO Expansion Harness transforms your Nexus R3 or R5 ECU from basic engine management into a comprehensive monitoring and tuning platform. This 2.5-metre harness unlocks critical auxiliary inputs through your ECU's expansion connector, giving you real-time data on wideband AFR, intake temps, flex fuel content, and fuel/oil pressures — essential feedback for serious performance builds and track applications.

Technical Specifications

• Part Number: HT-189002
• Length: 2.5 metres (8 feet)
• Connector Type: Nexus auxiliary plug interface
• Input Channels: 8 auxiliary sensor connections
• Wire Gauge: OEM-specification automotive grade
• Temperature Rating: Engine bay rated (-40°C to +125°C)

Why You Need This

Every serious engine build needs comprehensive monitoring, but the standard Nexus plug-in loom only covers basic engine management. Without auxiliary sensors, you're flying blind on critical parameters like air-fuel ratios, intake temperatures, and fuel system pressures. This harness solves that limitation by providing properly terminated connections for wideband O2 sensors, IAT sensors, flex fuel sensors, and pressure transducers — all feeding real-time data back to your Nexus ECU for logging, protection strategies, and closed-loop tuning.

We see this harness on virtually every built engine that comes through our workshop — from turbocharged Honda B-series conversions requiring precise AFR monitoring, to high-pressure fuel system setups on LS swaps where fuel pressure feedback prevents lean conditions under load. The 2.5-metre length provides sufficient reach for most engine bay configurations, including rear-mounted turbo setups and front-mount intercooler applications where sensors are positioned away from the ECU.

ECU & System Compatibility

Designed specifically for Nexus R3 and R5 plug-in ECUs equipped with the auxiliary connector. The harness interfaces directly with the ECU's expansion port to provide additional analog and digital inputs for advanced engine monitoring and closed-loop control strategies.

What's in the Box

• Nexus IO Expansion Harness (2.5m length)
• Pre-terminated auxiliary sensor connectors
• ECU auxiliary plug connector
• Installation documentation

Complete Your Build

Most customers fitting this expansion harness also add wideband O2 sensors for AFR monitoring, intake air temperature sensors for density correction, and fuel pressure sensors for system protection. Our technical team can recommend the specific sensor package for your application and confirm compatibility with your Nexus setup. With UK stock and same-day despatch, we'll have your complete monitoring solution ready for installation and tuning.