Nexus R3 Terminated Harness for Ford Barra

• BA Series Barra 240T (XR6T)

• BF Series Barra 190 (NA Falcons + Territory) Barra 245T (XR6T)

• FG Series Barra 270T (XR6T)

• Direct plug-in to Nexus R3 VCU

• Terminated engine bay and in-cabin connections

•  CAN connectivity for Haltech CAN devices (e.g., dash displays, keypads, etc.)

• Sensor connections (e.g., Crank, cam, temperature, pressure, position, speed, etc.)

• Direct wideband lambda sensor connection

• Dual knock sensor support (Bosch sensors)

• Injector sub-harness options (EV1, EV6, Denso)

• Ignition sub-harness options (to suit factory ignition coils using external Haltech igniter)

• Direct VCU control for thermofan, fuel pump, and starter

• Compatible with BA, BF and FG Drive By Wire throttle systems (sub-harnesses included)

• Alternator control connection options

• Transmission wiring breakout connector

• Spare inputs and outputs located in both the cabin and the engine bay.

General Installation Warning

A Nexus series ECU or VCU allows connection to your laptop via the Nexus Software Programmer (NSP) using the included USB cable, without the need for +12V power. This feature conveniently lets you set up your ignition, injector, and various other outputs before initially powering up the control unit using this harness. Turning on the control unit with incorrect configurations can lead to damage to both the engine and control unit components.

This wiring harness is not designed to provide grounding for your engine. Ensure your engine is adequately grounded using a grounding or earthing strap to connect your engine to the battery.

Avoid creating sparks or using electrical devices near flammable substances. Always disconnect the battery cables when working on the electrical systems of your vehicle. Make sure all fuel system components and wiring are installed away from heat sources, properly shielded if necessary, and in well-ventilated areas.

After installation, double-check for any fuel leaks and ensure that no wiring is left exposed or uninsulated to avoid the risk of a fire from a spark or short circuit.

Do not charge or disconnect the battery while the engine is running. Doing so could expose the control unit to an unregulated power supply, which might lead to control unit failure.

What’s in the bag?

• Nexus Ford Barra terminated harness (HT-186405)

• Nexus Ford Falcon BA/BF APP adaptor harness (HT-186131)

• Nexus Ford Falcon FG APP adaptor harness (HT-186132)

• Nexus Ford Barra BA/BF throttle adaptor harness (HT-186165)

• Nexus Ford Barra FG throttle adaptor harness (HT-186166)

• Nexus 2 pin BA alternator adaptor (HT-186125)

• Nexus 3 Pin BF/FG alternator adaptor (HT-186127)

• Cabin adaptor harness (HT-186130)

• Opposing connectors and pins to use with boost control solenoid, spare inputs and outputs, and transmission breakout.

Available adaptors and sub-harnesses (sold separately)

• HT-186010 - i6 Sumitomo (Denso) primary injector harness

• HT-186004 - i6 Timer (EV1) primary injector harness

• HT-186007 - i6 GT150 (USCAR EV6) primary injector harness

• HT-130345 - Ford Barra ignition sub-harness BA/BF

• HT-130347 - Ford Barra ignition sub-harness FG

• HT-186069 - Nexus 6 cylinder igniter adaptor

• HT-020036 - Nexus High Power Igniter

Harness Pinout Diagram

Harness Connections

Ignition Switch Input

The ignition switch input (pink) wire must be connected to a switched +12V source to turn the Nexus R3 VCU on. When connecting this wire to the ignition key switch, it is important to make sure to use the main ignition wire (i.e., not accessory) so it doesn’t lose power when the key is in the “Start” position, causing the VCU to momentarily turn off. The pink ignition switch input wire comes out of the connector for spare cabin inputs and outputs, where the APP adaptor is also integrated.

Nexus R3 VCU Battery Connection

For correct operation, the battery positive and battery negative must be connected to the Nexus R3 VCU at all times.

The Nexus R3 VCU’s positive (red) terminal must be connected to the positive (+) terminal of the battery. It is recommended to use a 150A fuse (sample CF fuse shown below) in this connection. Use the supplied red Surlok connector, along with a red 4 AWG battery cable (sold separately), to complete the connection.

The Nexus R3 VCU’s negative (black) terminal must be connected to the negative (–) terminal of the battery using the supplied black Surlok connector, along with a black 4 AWG battery cable to complete the connection.

Starter Motor Control

The Ford Barra terminated harness features a high-current output wire that can supply +12V (25A) to the starter solenoid when needed to engage the starter motor.

This wire is terminated with a spade terminal that connects directly into the starter solenoid.

The output is controlled by the VCU via the HCO 25A 1 pin, which is assigned to the starter control function in the VCU settings.

Controlling the starter also requires a starter switch signal to be connected to the VCU.

A white wire is fitted to the cabin connector and is pinned to AVI 1 (pin 8) for this purpose.

This wire must be connected to the starter switch signal from the ignition key switch.

Alternatively, the starter switch signal can be assigned to any available AVI/SPI within NSP, or to a CAN keypad button if your setup includes one.

Alternator

This harness is equipped with a 2‑pin DTM connector to provide switched +12V power to alternators, as well as a DPO for ECU alternator control, if required.

Additionally, the harness kit includes alternator adapter harnesses to suit the most common Ford Barra engine alternators, with the following connectors:

HT-186125: Nexus 2 pin BA alternator harness

HT-186127: Nexus 3 pin BF/FG alternator harness

HT-186127 

Crank and Cam Sensors 

The inline‑six Ford Barra engines with dual VCT on both the intake and exhaust camshafts use a crank sensor located toward the front of the engine

behind the crank pulley, and two cam sensors positioned at the rear of the cylinder head, one on each side.

The Nexus R3 Ford Barra terminated harness supports all three sensors using factory connectors, with branches laid out and labelled accordingly.

Additionally, each branch features switched 12V and sensor ground wires looped beneath the heat shrink to support aftermarket Hall Effect sensor conversions.

Knock Sensors

The Ford Barra terminated harness features two knock sensor connectors that plug into the factory knock sensors located on the side of the engine block below the intake manifold.

Using these knock sensors allows the Nexus R3 VCU to detect knock and control ignition timing as part of the VCU’s knock control strategy.

Intake and Exhaust VCT

This terminated harness features two VCT solenoid connections terminated with factory plugs. VCT, or Variable Camshaft Timing, allows for optimised engine performance, reduced emissions, and

improved fuel efficiency compared to engines with fixed camshaft timing.

NOTE: This engine is equipped with continuously variable cam timing on both the intake and exhaust cams, with up to 60 degrees of adjustment range.

A unique characteristic of this engine is that the intake camshaft is at full advance in its default state.

The ECU controls intake cam timing by retarding the camshaft as additional duty cycle is applied to the control solenoid.

This results in an intake cam target angle table that may appear unusual, resembling a conventional cam timing table that has been retarded by 60 degrees.

The exhaust camshaft follows a similar convention; however, this behaviour is typical for most other engines. Ford also defines an arbitrary reference

point as zero degrees, which corresponds to approximately ‑10 degrees (10 degrees of retard) in Haltech terminology. This difference in reference points is one of the reasons Haltech cam timing

tables appear different from those used by other Ford Barra ECU tuning platforms.

Dual Intake Runners

The Ford Barra terminated harness is fitted with a 2‑pin DTM connector set to wire a dual intake runner solenoid, if the engine is equipped with one.

A dual intake runner system allows the intake manifold airflow path to switch between short and long runners depending on engine speed and load.

This effectively optimises engine performance at both low and high RPM.

Fuel Injector Breakout 

The Nexus Ford Barra terminated harness uses an injector breakout connector that plugs into multiple types of injector sub‑harnesses (sold separately).

The choice of sub‑harness depends on the type of injector connectors being used.

Each injector plug is labeled accordingly to easily identify which injector on the engine it connects to.

Ignition Coil Breakout

The Nexus Ford Barra terminated harness uses an ignition coil breakout connector that allows the use of the factory 2-pin non-ignited ignition coils, with

the following sub-harnesses (sold separately):

HT-130345 - Barra ignition sub-harness BA/BF

HT-130347 - Barra ignition sub-harness FG

HT-186069 - 6 cylinder igniter adapter

HT-020036 - High Power Igniter

Refer to the diagram below for connection reference.

WARNING:  The factory Ford Barra 2‑pin ignition coils do not have internal igniters.

For this reason, the Haltech HPI external igniter and Nexus 6‑cylinder igniter adaptor harness must be installed between the ignition coil breakout connector and the Ford Barra ignition sub‑harness, as shown

above.

The Haltech HPI enables the ECU to correctly drive these ignition coils. Connecting a 2‑pin, non‑ignited ignition coil directly to the ECU via the ignition coil breakout, without an external igniter

module such as the Haltech HPI, will result in damage to both the ECU and the ignition coils.

R35 Ignition Coils and Bracket Kit

Alternatively, Haltech offers a kit (HT-120205) that includes the use of R35 ignition coils, an R35 coil ignition harness, ignition coil bracket and all mounting hardware.

The kit plugs directly to the ignition coil breakout connector and does not require the external igniter.

TMAP Sensor

The inline-six Ford Barra engines feature a four-pin Manifold Absolute Pressure (MAP) sensor and an Intake Air Temperature (IAT) sensor combined into asingle assembly.

This type of sensor is supported by the Nexus Ford Barra terminated harness through a dedicated flying lead branch and will need to be terminated by the installer using either of the two

connector sets included, depending on the sensor connector type used on BA/BF and FG engines.

Refer to the pinout information and connector images below for wire termination guidance.

Coolant Temperature Sensor

The Barra engine coolant temperature sensor (often referred to as the cylinder head temperature sensor) is located at the rear of the cylinder head, near the firewall, and is supported by the

Ford Barra terminated harness using the factory connector.

This sensor is “dry,” meaning it measures cylinder head temperature rather than being directly immersed in coolant. However, it operates on the same principle as a conventional coolant

temperature sensor and is configured in NSP in the same manner.

Oil and Fuel Pressure Sensors

This harness plugs directly into Haltech oil and fuel pressure sensors using the Delphi 3-pin pressure sensor connector shown below.

While oil and fuel pressure sensors are not required for the engine to run, they are highly recommended to enable the VCU to make fueling adjustments and provide engine protection.

Boost Control

The Ford Barra terminated harness features a dedicated 2 pin DTM connector for wiring a Haltech boost control solenoid.

A 3-port boost solenoid, such as the HT-020400, is suitable for performance applications and provides much more stable control over the desired boost pressure.

Thermofan Control

This harness provides direct thermofan control using the Red/Orange 10AWG cable.

Use this cable to supply +12V power directly to the thermofan and leverage VCU functions, such as setting the fan’s on/off temperature threshold, activating the fan with air-conditioning,or deactivating the fan when the vehicle reaches a specified speed (vehicle speed sensor is required).

Wideband Lambda Sensor

The Ford Barra terminated harness is equipped with a DTM‑6 connector that plugs into a Haltech wideband hardware pack and is directly controlled by the wideband controller built into the Nexus R3 VCU. Wideband hardware packs are available with either a Bosch LSU4.9 sensor (HT-010746) or NTK sensor (HT-010747).

Using a wideband lambda sensor allows the VCU to utilise functions such as closed‑loop fuel control, where the VCU targets the desired fuel mixture for any RPM and engine load combination.

It also enables the VCU to implement engine protection strategies when it detects that the fuel mixture is running too lean.

Fuel Pump Control

The harness also provides direct fuel pump control using the Red/Yellow 10AWG terminated cable.

Use this cable to supply +12V power directly to the fuel pump, allowing the VCU to prime the pump when the system is turned on and to implement

safety functions, such as automatically turning the pump off when the VCU no longer detects an RPM signal.

Throttle Breakout Connector

Accelerator Pedal Position

To complete the DBW throttle system, two Accelerator Pedal Position (APP) sub‑harnesses are also included to suit the following APP sub-harnesses:

 • APP sub-harness (BA/BF)

 • APP sub-harness (FG)

The above sub‑harnesses plug into the 6‑pin DTM connector labelled APP, which is integrated into the 26‑pin Cabin IO connector.

The cabin connector also includes a dedicated pin (Pin 21) designed for connection to a brake pedal switch, as part of the DBW control strategy. This brake pedal input signal is expected to read +12V whenever the brake pedal is pressed.

A/C Clutch and Pressure Switch

The Ford Barra terminated harness features factory connectors that plug directly into the A/C compressor clutch connector and A/C pressure switch.

Allowing the ECU to directly control the A/C compressor provides several advantages, including the ability to enforce a minimum engine run time after startup before engaging the compressor, and

to automatically disengage the compressor at high engine speeds.

Connecting the A/C pressure switch also enables the ECU to monitor system pressure and only allow compressor engagement when the pressure is within the approved operating range.

Transmission Breakout Connector

The transmission breakout connector on the Ford Barra terminated harness can be used to wire in transmission sensors and wiring, or to interface with a CAN‑based Haltech transmission controller.

Pinout information is provided below, and an opposing connector and pin set is included in the kit.

Fuel Fuel Sensor

The Ford Barra terminated harness also features an optional connector that plugs into a Haltech Flex Fuel Sensor.

Using a Flex Fuel Sensor enables the VCU to make real-time adjustments to optimize the tune for varying ethanol blends.

  Haltech CAN connection

This harness is equipped with 4 pin DTM connectors—one at the cabin end and the other at the engine bay end of the harness.

These CAN connectors are designed to connect to Haltech CAN devices (e.g., display dash, keypad, PDM), which further expand the functionality of the application.

If you are using multiple Haltech CAN devices, a Haltech CAN Hub can be used to increase the number of available connection ports.

Spare Inputs and Outputs

The Nexus Ford Barra terminated harness features two connectors with spare inputs and outputs that can be used to wire in additional sensors, switches, or to control relays, solenoids, warning lights, or

other devices you want the VCU to control.

The connector located at the cabin end of the harness is labelled “Cabin” and uses a 26-pinconnector.

The other connector, labelled “Spare” is located at the engine bay end of the harness and uses a 12-pin DTM connector.

Both opposing connectors are supplied in the kit, with pinout information provided below for reference.