Haltech Nexus R5 pinout and specs

Checked against the maker's documents 27 September 2026

Haltech Nexus R5 is a 124-pin wire-in Haltech ECU on 5 connectors: A (34 pins), B (26 pins), C (34 pins), D (26 pins) and E (4 pins).

It has 18 injector outputs and 12 ignition outputs. The injector drivers are peak-and-hold, so low-impedance injectors run without a resistor pack. The ignition outputs are logic-level. Smart coils plug straight in; dumb coils need an igniter in between.

There are 2 dedicated trigger inputs, each happy with a VR or a Hall sensor. Two knock inputs cover both banks of a V engine. It has 2 onboard wideband controllers, so a sensor wires straight in. MAP is an external sensor on an analog input.

Drive-by-wire is native: 2 throttles from its own H-bridge outputs. Three CAN buses handle dashes, PDMs and expansion. The maker rates the 5V sensor supply at 400 mA in total.

Spec sheet

Which builds it suits

Of the 58 swap presets in the planner, 28 fit as they are and 29 fit with add-ons; 1 does not fit at all. The add-on it asks for most often is the Haltech HPI8 High Power Igniter (8-channel). Where it falls short, it is usually not enough knock inputs. The planner fills anything a preset leaves open with its ordinary defaults, so your own build may land differently.

It runs the GM LS6 (Gen3 5.7 alum), GM LSA (Gen4 6.2 alum, S/C), Nissan VQ35DE Rev-Up (2005-06) and Subaru EJ/FA EJ25 turbo dual-AVCS (EJ257 2008+) presets with nothing added. The Ford Coyote 5.0 Gen3 (2018-23) needs Haltech HPI8 High Power Igniter (8-channel). The Subaru EJ/FA FA20DIT (WRX turbo 2015+) needs a direct-injection driver module. It can't run the BMW S54 (3.2 NA I6, E46 M3): not enough knock inputs.

Plan a build around the Haltech Nexus R5

Pin table

By connector: A carries 8 injector outputs, 8 ignition outputs and 4 H-bridge outputs; B carries 10 injector outputs, 4 ignition outputs and 4 digital inputs; C carries 2 trigger inputs, 2 knock inputs and 11 analog inputs; D carries 12 analog inputs and 12 high-current outputs; E carries 4 high-current outputs.

Other Haltech ECUs

The closest Haltech unit is the Haltech Nexus S3. Against it, this one has 18 injector outputs (the Nexus S3 has 8), 12 ignition outputs (the Nexus S3 has 8), 2 wideband controllers (the Nexus S3 has 1) and 3 CAN buses (the Nexus S3 has 2).

• Haltech Nexus S3
• Haltech Elite 2500
• Haltech Elite 2000
• Haltech Nexus R3 VCU

Source: Haltech documentation for the Nexus R5

Always verify against the manufacturer's manual and your tuner before wiring.