Haltech HT-189002 Nexus Plug-In IO Expansion Harness 2.5m 8ft Wideband Flex Fuel

Vehicle Fitment

• Universal - Compatible with any vehicle or engine build using a Haltech Nexus Plug-in ECU. No vehicle-specific fitment restrictions.

Fitment Notes

• Designed exclusively for use with Haltech Nexus Plug-in ECUs - connects to the ECU's auxiliary plug to expand sensor input capability.
• Compatible with all Nexus Plug-in ECU variants including those for Nissan Skyline R32/R33/R34 GT-R, Mazda RX-8, GM Delco, and other Nexus Plug-in platforms.
• This harness adds sensor connections not routed through the vehicle's OEM ECU connector - required for wideband O2, flex fuel, air temperature, fuel pressure, and oil pressure sensor integration on Nexus Plug-in builds.
• For DBW (drive-by-wire) throttle expansion on Nexus Plug-in ECU builds, use the companion harness HT-189003 (Nexus Plug-in DBW Expansion Harness) instead or in addition.
• Wideband O2 sensor, air temperature sensor, flex fuel sensor, fuel pressure sensor, and oil pressure sensor are all sold separately - this harness provides the wiring connections only.

Features

• Expands Nexus Plug-in ECU sensor input capability via the ECU auxiliary plug - unlocking wideband O2, flex fuel, air temperature, fuel pressure, and oil pressure monitoring without requiring custom wiring
• Wideband O2 sensor connection enables closed-loop lambda fueling and accurate AFR monitoring directly through the Nexus Plug-in ECU
• Flex fuel sensor connection allows ethanol content detection for flex fuel tuning strategies within NSP software
• Air temperature sensor connection enables intake air temperature correction for more accurate fuel and ignition calculations under varying ambient conditions
• Fuel pressure sensor connection supports fuel pressure monitoring and fuel pressure compensation tables within the ECU calibration
• Oil pressure sensor connection enables oil pressure monitoring and protection strategies including oil pressure warning outputs
• 2.5m (8 ft) harness length provides sufficient reach for routing from the ECU auxiliary plug to the engine bay sensor mounting locations
• Pre-terminated at the ECU auxiliary plug end - plugs directly into the Nexus Plug-in ECU without modification
• Color-coded and labeled wires at the sensor end simplify connection to each individual sensor without reference to a separate pin-out document

Specifications

• Part Number: HT-189002
• Product Name: Nexus Plug-in IO Expansion Harness
• Harness Length: 2.5m (8 ft)
• Compatible ECU: Haltech Nexus Plug-in ECU (all variants)
• Connection Point: ECU Auxiliary Plug
• Sensor Connections Provided: Wideband O2, Air Temperature, Flex Fuel, Fuel Pressure, Oil Pressure
• Sensors Included: No - sensors sold separately
• Fitment: Universal (Nexus Plug-in ECU builds)

Included Components

• 1x Nexus Plug-in IO Expansion Harness - 2.5m (8 ft), pre-terminated at ECU auxiliary plug end

Product Description

The Haltech HT-189002 is the IO Expansion Harness for Haltech Nexus Plug-in ECUs - a purpose-built 2.5m (8 ft) wiring harness that connects to the ECU's auxiliary plug and extends sensor input capability beyond what is available through the vehicle's OEM ECU connector. Nexus Plug-in ECUs retain the original factory ECU connector for direct chassis integration, but this inherently limits the number of sensor inputs directly accessible from that connector. The HT-189002 resolves this by tapping into the auxiliary plug to provide dedicated wiring leads for five additional sensor types: wideband O2, air temperature, flex fuel, fuel pressure, and oil pressure - all of which are essential inputs for a comprehensive performance engine management calibration.

Each of the five sensor connections on the HT-189002 is wired directly to the appropriate input circuit on the Nexus Plug-in ECU via the auxiliary plug, allowing the NSP software to read and utilize these sensor signals for fuel correction, ignition correction, flex fuel compensation, and fluid pressure monitoring or protection strategies. The wideband O2 connection supports closed-loop lambda operation and real-time AFR feedback. The flex fuel connection enables ethanol content detection for E85 or blend tuning. The air temperature sensor supports IAT-based corrections, while fuel and oil pressure monitoring can be used for data logging, warning outputs, or engine protection tables within the calibration.

The harness is pre-terminated at the ECU auxiliary plug end for direct plug-in connection, with color-coded and labeled flying leads at the sensor end to simplify routing and connection to each sensor. All sensors referenced - wideband O2, air temperature, flex fuel composition, fuel pressure, and oil pressure - are sold separately and must be sourced to complete the installation. For Nexus Plug-in builds also requiring DBW (drive-by-wire) throttle expansion, the companion HT-189003 Nexus Plug-in DBW Expansion Harness is available separately. All configuration and sensor calibration is performed within Haltech's NSP software.