Mazda RX-7 FD 1992-2002 (13B-REW twin-turbo) → Haltech Nexus S3 HT-213000 (auto)
Mazda RX-7 FD 1992-2002 (13B-REW twin-turbo) — Haltech — Nexus S3
Drawn by Michael Gnankou · Rev 0 · proposal · 2026-10-08
Before you start
| Status | proposal · not yet verified: nobody has reported building and running this harness |
|---|---|
| Open errors | none |
| Size of the job | 55 wires · 8 connectors · 0 part lines |
| Tools | Crimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink |
| Order of work | 1. Check every part against the parts list. 2. Cut and label every wire (labels: Export → Wire labels). 3. Crimp and pin connector by connector, ticking the build checklist. 4. Run the bench test with nothing plugged in and the battery disconnected. 5. Only then connect the ECU and power up. |
Build checklist
Tick each box as you go. Continuity: meter from end to end, expect under 1 Ω.
| Wire | From | To | Gauge | Colour | Cut | Label | Crimp A | Crimp B | Pin A | Pin B | Continuity |
|---|---|---|---|---|---|---|---|---|---|---|---|
| W1 | OEM-D-4A | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | OEM-D-4E | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | SP-14V-1 | NEXUSS3-A-18 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | SP-14V-1 | NEXUSS3-A-25 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-A-1AF | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-A-1AJ | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-A-1L | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | SP-GND-1 | NEXUSS3-A-10 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-GND-1 | NEXUSS3-A-11 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | OEM-A-1AB | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | OEM-A-1X | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-C-3AB | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-C-3S | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | SP-0V-1 | NEXUSS3-C-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-C-3A | NEXUSS3-C-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-C-3R | NEXUSS3-C-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | SP-0V-1 | NEXUSS3-C-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-C-3U | NEXUSS3-C-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | SP-0V-1 | NEXUSS3-C-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-C-3O | NEXUSS3-C-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-D-4AF | NEXUSS3-A-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-D-4AJ | NEXUSS3-A-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-D-4AN | NEXUSS3-A-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-A-1Q | NEXUSS3-A-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-A-1U | NEXUSS3-A-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-A-1Y | NEXUSS3-A-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-A-1AC | NEXUSS3-A-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-D-4C | NEXUSS3-A-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-A-1AA | NEXUSS3-A-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-A-1AE | NEXUSS3-A-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-A-1S | NEXUSS3-A-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-A-1W | NEXUSS3-A-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-A-1H | NEXUSS3-A-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-D-4D | NEXUSS3-A-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-D-4F | NEXUSS3-A-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-D-4G | NEXUSS3-A-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-D-4I | NEXUSS3-A-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-D-4K | NEXUSS3-A-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-D-4L | NEXUSS3-A-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-A-1C | NEXUSS3-A-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-A-1E | NEXUSS3-A-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-A-1G | NEXUSS3-A-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-A-1I | NEXUSS3-A-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-D-4AH | NEXUSS3-C-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-C-3I | NEXUSS3-C-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W46 | OEM-C-3D | NEXUSS3-C-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W47 | OEM-C-3W | NEXUSS3-C-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W48 | OEM-C-3T | NEXUSS3-C-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W49 | OEM-C-3V | NEXUSS3-C-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W50 | OEM-C-3H | NEXUSS3-C-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W51 | OEM-D-4Q | NEXUSS3-C-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W52 | OEM-D-4AA | NEXUSS3-C-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W53 | OEM-D-4S | NEXUSS3-C-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W54 | OEM-D-4V | NEXUSS3-C-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W55 | OEM-D-4W | NEXUSS3-C-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ |
Bench test (before first power-up)
Battery disconnected, ECU and every sensor unplugged. Meter on resistance. Each pair below must read open (OL): a reading means a pinched wire, a stray strand or a mis-pinned cavity. Then check continuity of every wire (last column of the build checklist).
| # | Probe A | Probe B | Expect | Why | Reading |
|---|---|---|---|---|---|
| 1 | NEXUSS3-A-10 | NEXUSS3-A-18 | open (OL) | power ground must not touch +12 V supply | |
| 2 | NEXUSS3-A-10 | NEXUSS3-C-25 | open (OL) | power ground must not touch 5 V sensor reference | |
| 3 | NEXUSS3-C-2 | NEXUSS3-A-18 | open (OL) | sensor ground must not touch +12 V supply | |
| 4 | NEXUSS3-C-2 | NEXUSS3-C-25 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 5 | NEXUSS3-C-25 | NEXUSS3-A-18 | open (OL) | 5 V sensor reference must not touch +12 V supply |
Revisions
| Rev | Label | By | Date |
|---|---|---|---|
| No revisions yet. | |||
Schematic
Connectors
NEXUSS3-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Injector 1 | — | W24 | — | 0.5 | OEM-A-1Q | — | — | — |
| 10 | Battery ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| 11 | Battery ground | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| 12 | DPO 2 | — | W35 | — | 0.5 | OEM-D-4F | — | — | — |
| 13 | Ignition switch input | — | W28 | — | 0.5 | OEM-D-4C | — | — | — |
| 14 | DPO 3 | — | W36 | — | 0.5 | OEM-D-4G | — | — | — |
| 15 | DPO 4 | — | W37 | — | 0.5 | OEM-D-4I | — | — | — |
| 16 | DPO 5 | — | W38 | — | 0.5 | OEM-D-4K | — | — | — |
| 17 | DPO 6 | — | W39 | — | 0.5 | OEM-D-4L | — | — | — |
| 18 | +12V switched input | — | W3 | — | 0.85 | SP-14V-1 | — | — | — |
| 19 | HBO 1 | — | W29 | — | 0.5 | OEM-A-1AA | — | — | — |
| 2 | Injector 2 | — | W25 | — | 0.5 | OEM-A-1U | — | — | — |
| 20 | HBO 2 | — | W30 | — | 0.5 | OEM-A-1AE | — | — | — |
| 21 | HBO 3 | — | W31 | — | 0.5 | OEM-A-1S | — | — | — |
| 22 | HBO 4 | — | W32 | — | 0.5 | OEM-A-1W | — | — | — |
| 23 | CAN 1 High | — | — | — | — | — | — | — | — |
| 24 | CAN 1 Low | — | — | — | — | — | — | — | — |
| 25 | +12V switched input | — | W4 | — | 0.85 | SP-14V-1 | — | — | — |
| 26 | ECR output | — | W33 | — | 0.5 | OEM-A-1H | — | — | — |
| 27 | Ignition 1 | — | W21 | — | 0.5 | OEM-D-4AF | — | — | — |
| 28 | Ignition 2 | — | W22 | — | 0.5 | OEM-D-4AJ | — | — | — |
| 29 | Ignition 3 | — | W23 | — | 0.5 | OEM-D-4AN | — | — | — |
| 3 | Injector 3 | — | W26 | — | 0.5 | OEM-A-1Y | — | — | — |
| 30 | Ignition 4 | — | — | — | — | — | — | — | — |
| 31 | Ignition 5 | — | — | — | — | — | — | — | — |
| 32 | Ignition 6 | — | — | — | — | — | — | — | — |
| 33 | Ignition 7 | — | — | — | — | — | — | — | — |
| 34 | Ignition 8 | — | — | — | — | — | — | — | — |
| 4 | Injector 4 | — | W27 | — | 0.5 | OEM-A-1AC | — | — | — |
| 5 | Injector 5 | — | W40 | — | 0.5 | OEM-A-1C | — | — | — |
| 6 | Injector 6 | — | W41 | — | 0.5 | OEM-A-1E | — | — | — |
| 7 | Injector 7 | — | W42 | — | 0.5 | OEM-A-1G | — | — | — |
| 8 | Injector 8 | — | W43 | — | 0.5 | OEM-A-1I | — | — | — |
| 9 | DPO 1 | — | W34 | — | 0.5 | OEM-D-4D | — | — | — |
NEXUSS3-C
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Trigger + | — | W16 | — | 0.5 | OEM-C-3R | — | — | — |
| 10 | AVI 1 | — | W44 | — | 0.5 | OEM-D-4AH | — | — | — |
| 11 | AVI 2 | — | W45 | — | 0.5 | OEM-C-3I | — | — | — |
| 12 | AVI 3 | — | W46 | — | 0.5 | OEM-C-3D | — | — | — |
| 13 | AVI 4 | — | W47 | — | 0.5 | OEM-C-3W | — | — | — |
| 14 | AVI 5 | — | W48 | — | 0.5 | OEM-C-3T | — | — | — |
| 15 | AVI 6 | — | W49 | — | 0.5 | OEM-C-3V | — | — | — |
| 16 | AVI 7 | — | W50 | — | 0.5 | OEM-C-3H | — | — | — |
| 17 | AVI 8 | — | — | — | — | — | — | — | — |
| 18 | AVI 9 | — | — | — | — | — | — | — | — |
| 19 | SPI 5 | — | W55 | — | 0.5 | OEM-D-4W | — | — | — |
| 2 | Trigger - | — | W17 | — | 0.5 | SP-0V-1 | — | — | — |
| 20 | SPI 6 | — | — | — | — | — | — | — | — |
| 21 | CAN 2 High | — | — | — | — | — | — | — | — |
| 22 | CAN 2 Low | — | — | — | — | — | — | — | — |
| 23 | Knock 1 | — | W20 | — | 0.5 | OEM-C-3O | — | — | — |
| 24 | Knock 2 | — | — | — | — | — | — | — | — |
| 25 | +5V | — | W15 | — | 0.5 | OEM-C-3A | — | — | — |
| 26 | Signal ground | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| 27 | AVI 10 | — | — | — | — | — | — | — | — |
| 28 | AVI 11 | — | — | — | — | — | — | — | — |
| 29 | WBI 1 Heater + | — | — | — | — | — | — | — | — |
| 3 | Home + | — | W18 | — | 0.5 | OEM-C-3U | — | — | — |
| 30 | WBI 1 Input | — | — | — | — | — | — | — | — |
| 31 | WBI 1 Pump | — | — | — | — | — | — | — | — |
| 32 | WBI 1 Nernst | — | — | — | — | — | — | — | — |
| 33 | WBI 1 Heater - | — | — | — | — | — | — | — | — |
| 34 | WBI 1 Cal | — | — | — | — | — | — | — | — |
| 4 | Home - | — | W19 | — | 0.5 | SP-0V-1 | — | — | — |
| 5 | SPI 1 | — | W51 | — | 0.5 | OEM-D-4Q | — | — | — |
| 6 | SPI 2 | — | W52 | — | 0.5 | OEM-D-4AA | — | — | — |
| 7 | SPI 3 | — | W53 | — | 0.5 | OEM-D-4S | — | — | — |
| 8 | SPI 4 | — | W54 | — | 0.5 | OEM-D-4V | — | — | — |
| 9 | +8V | — | — | — | — | — | — | — | — |
OEM-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1AA | OMP stepper phase B1 | — | W29 | — | 0.5 | NEXUSS3-A-19 | — | — | — |
| 1AB | Sensor ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| 1AC | Injector 4 (rear secondary) | — | W27 | — | 0.5 | NEXUSS3-A-4 | — | — | — |
| 1AE | OMP stepper phase A1 | — | W30 | — | 0.5 | NEXUSS3-A-20 | — | — | — |
| 1AF | Power ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| 1AJ | Power ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 1C | Idle speed control (ISC) solenoid | — | W40 | — | 0.5 | NEXUSS3-A-5 | — | — | — |
| 1E | Turbo charge control solenoid | — | W41 | — | 0.5 | NEXUSS3-A-6 | — | — | — |
| 1G | Purge solenoid | — | W42 | — | 0.5 | NEXUSS3-A-7 | — | — | — |
| 1H | Cooling fan relay (low speed) | — | W33 | — | 0.5 | NEXUSS3-A-26 | — | — | — |
| 1I | Turbo charge relief solenoid | — | W43 | — | 0.5 | NEXUSS3-A-8 | — | — | — |
| 1K | Turbo pre-control solenoid | — | — | — | — | — | — | — | — |
| 1L | Power ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 1M | Turbo control solenoid | — | — | — | — | — | — | — | — |
| 1O | Boost control solenoid | — | — | — | — | — | — | — | — |
| 1Q | Injector 1 (front primary) | — | W24 | — | 0.5 | NEXUSS3-A-1 | — | — | — |
| 1S | OMP stepper phase B2 | — | W31 | — | 0.5 | NEXUSS3-A-21 | — | — | — |
| 1U | Injector 2 (rear primary) | — | W25 | — | 0.5 | NEXUSS3-A-2 | — | — | — |
| 1W | OMP stepper phase A2 | — | W32 | — | 0.5 | NEXUSS3-A-22 | — | — | — |
| 1X | Sensor ground | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 1Y | Injector 3 (front secondary) | — | W26 | — | 0.5 | NEXUSS3-A-3 | — | — | — |
OEM-C
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 3A | +5V sensor supply | — | W15 | — | 0.5 | NEXUSS3-C-25 | — | — | — |
| 3AB | Sensor ground | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 3D | O2 sensor (narrowband) | — | W46 | — | 0.5 | NEXUSS3-C-12 | — | — | — |
| 3G | Fuel pressure regulator control (PRC) solenoid | — | — | — | — | — | — | — | — |
| 3H | OMP position sensor | — | W50 | — | 0.5 | NEXUSS3-C-16 | — | — | — |
| 3I | Throttle position (TPS, full range) | — | W45 | — | 0.5 | NEXUSS3-C-11 | — | — | — |
| 3O | Knock sensor | — | W20 | — | 0.5 | NEXUSS3-C-23 | — | — | — |
| 3R | Crank position (CAS NE) | — | W16 | — | 0.5 | NEXUSS3-C-1 | — | — | — |
| 3S | Sensor ground (CAS) | — | W13 | — | 0.5 | SP-0V-1 | — | — | — |
| 3T | Intake air temperature (IAT) | — | W48 | — | 0.5 | NEXUSS3-C-14 | — | — | — |
| 3U | Home position (CAS G) | — | W18 | — | 0.5 | NEXUSS3-C-3 | — | — | — |
| 3V | Fuel temperature | — | W49 | — | 0.5 | NEXUSS3-C-15 | — | — | — |
| 3W | Coolant temperature (ECT) | — | W47 | — | 0.5 | NEXUSS3-C-13 | — | — | — |
OEM-D
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 4A | ECU main power (+12V via main relay/ECR) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| 4AA | Brake pedal switch | — | W52 | — | 0.5 | NEXUSS3-C-6 | — | — | — |
| 4AF | Ignition front trailing | — | W21 | — | 0.5 | NEXUSS3-A-27 | — | — | — |
| 4AH | MAP sensor (PIM) | — | W44 | — | 0.5 | NEXUSS3-C-10 | — | — | — |
| 4AJ | Ignition rear trailing | — | W22 | — | 0.5 | NEXUSS3-A-28 | — | — | — |
| 4AN | Ignition leading (wasted spark) | — | W23 | — | 0.5 | NEXUSS3-A-29 | — | — | — |
| 4B | Battery constant (+12V) | — | — | — | — | — | — | — | — |
| 4C | Ignition switch / start signal | — | W28 | — | 0.5 | NEXUSS3-A-13 | — | — | — |
| 4D | Air pump clutch relay | — | W34 | — | 0.5 | NEXUSS3-A-9 | — | — | — |
| 4E | ECU main power (+12V via main relay/ECR) | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 4F | Fuel pump speed relay | — | W35 | — | 0.5 | NEXUSS3-A-12 | — | — | — |
| 4G | Fuel pump relay | — | W36 | — | 0.5 | NEXUSS3-A-14 | — | — | — |
| 4I | A/C relay | — | W37 | — | 0.5 | NEXUSS3-A-15 | — | — | — |
| 4K | Cooling fan relay (low speed) | — | W38 | — | 0.5 | NEXUSS3-A-16 | — | — | — |
| 4L | Cooling fan relay (high speed) | — | W39 | — | 0.5 | NEXUSS3-A-17 | — | — | — |
| 4M | Tachometer output | — | — | — | — | — | — | — | — |
| 4Q | Vehicle speed sensor | — | W51 | — | 0.5 | NEXUSS3-C-5 | — | — | — |
| 4S | Clutch switch | — | W53 | — | 0.5 | NEXUSS3-C-7 | — | — | — |
| 4V | A/C request | — | W54 | — | 0.5 | NEXUSS3-C-8 | — | — | — |
| 4W | Power steering pressure switch | — | W55 | — | 0.5 | NEXUSS3-C-19 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W10 | — | 0.5 | OEM-A-1AB | — | — | — |
| 1 | — | — | W11 | — | 0.5 | OEM-A-1X | — | — | — |
| 1 | — | — | W12 | — | 0.5 | OEM-C-3AB | — | — | — |
| 1 | — | — | W13 | — | 0.5 | OEM-C-3S | — | — | — |
| 1 | — | — | W14 | — | 0.5 | NEXUSS3-C-26 | — | — | — |
| 1 | — | — | W17 | — | 0.5 | NEXUSS3-C-2 | — | — | — |
| 1 | — | — | W19 | — | 0.5 | NEXUSS3-C-4 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-D-4A | — | — | — |
| 1 | — | — | W2 | — | 0.85 | OEM-D-4E | — | — | — |
| 1 | — | — | W3 | — | 0.85 | NEXUSS3-A-18 | — | — | — |
| 1 | — | — | W4 | — | 0.85 | NEXUSS3-A-25 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W5 | — | 0.85 | OEM-A-1AF | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-A-1AJ | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-A-1L | — | — | — |
| 1 | — | — | W8 | — | 0.85 | NEXUSS3-A-10 | — | — | — |
| 1 | — | — | W9 | — | 0.85 | NEXUSS3-A-11 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-A-1AA | OMP stepper phase B1 | hbridge_out | NEXUSS3-A-19 | HBO 1 | hbridge_out | single_source | |
| OEM-A-1AB | Sensor ground | sensor_ground | NEXUSS3-C-2 + NEXUSS3-C-26 + NEXUSS3-C-4 | Trigger - + Signal ground + Home - | sensor_ground + trigger_in | single_source | |
| OEM-A-1AC | Injector 4 (rear secondary) | injector_out | NEXUSS3-A-4 | Injector 4 | injector_out | single_source | |
| OEM-A-1AE | OMP stepper phase A1 | hbridge_out | NEXUSS3-A-20 | HBO 2 | hbridge_out | single_source | |
| OEM-A-1AF | Power ground | ground | NEXUSS3-A-10 + NEXUSS3-A-11 | Battery ground + Battery ground | ground | single_source | |
| OEM-A-1AJ | Power ground | ground | NEXUSS3-A-10 + NEXUSS3-A-11 | Battery ground + Battery ground | ground | single_source | |
| OEM-A-1C | Idle speed control (ISC) solenoid | low_side_out | NEXUSS3-A-5 | Injector 5 | injector_out | single_source | |
| OEM-A-1E | Turbo charge control solenoid | low_side_out | NEXUSS3-A-6 | Injector 6 | injector_out | single_source | |
| OEM-A-1G | Purge solenoid | low_side_out | NEXUSS3-A-7 | Injector 7 | injector_out | single_source | |
| OEM-A-1H | Cooling fan relay (low speed) | low_side_out | NEXUSS3-A-26 | ECR output | low_side_out | single_source | |
| OEM-A-1I | Turbo charge relief solenoid | low_side_out | NEXUSS3-A-8 | Injector 8 | injector_out | single_source | |
| OEM-A-1K | Turbo pre-control solenoid | low_side_out | — | — | — | single_source | |
| OEM-A-1L | Power ground | ground | NEXUSS3-A-10 + NEXUSS3-A-11 | Battery ground + Battery ground | ground | single_source | |
| OEM-A-1M | Turbo control solenoid | low_side_out | — | — | — | single_source | |
| OEM-A-1O | Boost control solenoid | low_side_out | — | — | — | single_source | |
| OEM-A-1Q | Injector 1 (front primary) | injector_out | NEXUSS3-A-1 | Injector 1 | injector_out | single_source | |
| OEM-A-1S | OMP stepper phase B2 | hbridge_out | NEXUSS3-A-21 | HBO 3 | hbridge_out | single_source | |
| OEM-A-1U | Injector 2 (rear primary) | injector_out | NEXUSS3-A-2 | Injector 2 | injector_out | single_source | |
| OEM-A-1W | OMP stepper phase A2 | hbridge_out | NEXUSS3-A-22 | HBO 4 | hbridge_out | single_source | |
| OEM-A-1X | Sensor ground | sensor_ground | NEXUSS3-C-2 + NEXUSS3-C-26 + NEXUSS3-C-4 | Trigger - + Signal ground + Home - | sensor_ground + trigger_in | single_source | |
| OEM-A-1Y | Injector 3 (front secondary) | injector_out | NEXUSS3-A-3 | Injector 3 | injector_out | single_source | |
| OEM-C-3A | +5V sensor supply | vref | NEXUSS3-C-25 | +5V | vref | single_source | |
| OEM-C-3AB | Sensor ground | sensor_ground | NEXUSS3-C-2 + NEXUSS3-C-26 + NEXUSS3-C-4 | Trigger - + Signal ground + Home - | sensor_ground + trigger_in | single_source | |
| OEM-C-3D | O2 sensor (narrowband) | lambda_nb_in | NEXUSS3-C-12 | AVI 3 | analog_in | single_source | |
| OEM-C-3G | Fuel pressure regulator control (PRC) solenoid | low_side_out | — | — | — | single_source | |
| OEM-C-3H | OMP position sensor | analog_in | NEXUSS3-C-16 | AVI 7 | analog_in | single_source | |
| OEM-C-3I | Throttle position (TPS, full range) | analog_in | NEXUSS3-C-11 | AVI 2 | analog_in | single_source | |
| OEM-C-3O | Knock sensor | knock_in | NEXUSS3-C-23 | Knock 1 | knock_in | single_source | |
| OEM-C-3R | Crank position (CAS NE) | trigger_in | NEXUSS3-C-1 | Trigger + | trigger_in | single_source | |
| OEM-C-3S | Sensor ground (CAS) | sensor_ground | NEXUSS3-C-2 + NEXUSS3-C-26 + NEXUSS3-C-4 | Trigger - + Signal ground + Home - | sensor_ground + trigger_in | single_source | |
| OEM-C-3T | Intake air temperature (IAT) | temp_in | NEXUSS3-C-14 | AVI 5 | analog_in | single_source | |
| OEM-C-3U | Home position (CAS G) | trigger_in | NEXUSS3-C-3 | Home + | trigger_in | single_source | |
| OEM-C-3V | Fuel temperature | temp_in | NEXUSS3-C-15 | AVI 6 | analog_in | single_source | |
| OEM-C-3W | Coolant temperature (ECT) | temp_in | NEXUSS3-C-13 | AVI 4 | analog_in | single_source | |
| OEM-D-4A | ECU main power (+12V via main relay/ECR) | power_in | NEXUSS3-A-18 + NEXUSS3-A-25 | +12V switched input + +12V switched input | power_in | single_source | |
| OEM-D-4AA | Brake pedal switch | digital_in | NEXUSS3-C-6 | SPI 2 | digital_in | single_source | |
| OEM-D-4AF | Ignition front trailing | ignition_out | NEXUSS3-A-27 | Ignition 1 | ignition_out | single_source | |
| OEM-D-4AH | MAP sensor (PIM) | analog_in | NEXUSS3-C-10 | AVI 1 | analog_in | single_source | |
| OEM-D-4AJ | Ignition rear trailing | ignition_out | NEXUSS3-A-28 | Ignition 2 | ignition_out | single_source | |
| OEM-D-4AN | Ignition leading (wasted spark) | ignition_out | NEXUSS3-A-29 | Ignition 3 | ignition_out | single_source | |
| OEM-D-4B | Battery constant (+12V) | power_in | — | — | — | single_source | |
| OEM-D-4C | Ignition switch / start signal | digital_in | NEXUSS3-A-13 | Ignition switch input | digital_in | single_source | |
| OEM-D-4D | Air pump clutch relay | low_side_out | NEXUSS3-A-9 | DPO 1 | low_side_out | single_source | |
| OEM-D-4E | ECU main power (+12V via main relay/ECR) | power_in | NEXUSS3-A-18 + NEXUSS3-A-25 | +12V switched input + +12V switched input | power_in | single_source | |
| OEM-D-4F | Fuel pump speed relay | low_side_out | NEXUSS3-A-12 | DPO 2 | low_side_out | single_source | |
| OEM-D-4G | Fuel pump relay | low_side_out | NEXUSS3-A-14 | DPO 3 | low_side_out | single_source | |
| OEM-D-4I | A/C relay | low_side_out | NEXUSS3-A-15 | DPO 4 | low_side_out | single_source | |
| OEM-D-4K | Cooling fan relay (low speed) | low_side_out | NEXUSS3-A-16 | DPO 5 | low_side_out | single_source | |
| OEM-D-4L | Cooling fan relay (high speed) | low_side_out | NEXUSS3-A-17 | DPO 6 | low_side_out | single_source | |
| OEM-D-4M | Tachometer output | tacho_out | — | — | — | single_source | |
| OEM-D-4Q | Vehicle speed sensor | digital_in | NEXUSS3-C-5 | SPI 1 | digital_in | single_source | |
| OEM-D-4S | Clutch switch | digital_in | NEXUSS3-C-7 | SPI 3 | digital_in | single_source | |
| OEM-D-4V | A/C request | digital_in | NEXUSS3-C-8 | SPI 4 | digital_in | single_source | |
| OEM-D-4W | Power steering pressure switch | digital_in | NEXUSS3-C-19 | SPI 5 | digital_in | single_source |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-D-4A | SP-14V-1 | 0.85 | no route | ECU main power (+12V via main relay/ECR) | — | |
| W2 | OEM-D-4E | SP-14V-1 | 0.85 | no route | ECU main power (+12V via main relay/ECR) | — | |
| W3 | SP-14V-1 | NEXUSS3-A-18 | 0.85 | no route | +12V switched input | — | |
| W4 | SP-14V-1 | NEXUSS3-A-25 | 0.85 | no route | +12V switched input | — | |
| W5 | OEM-A-1AF | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W6 | OEM-A-1AJ | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W7 | OEM-A-1L | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W8 | SP-GND-1 | NEXUSS3-A-10 | 0.85 | no route | Battery ground | — | |
| W9 | SP-GND-1 | NEXUSS3-A-11 | 0.85 | no route | Battery ground | — | |
| W10 | OEM-A-1AB | SP-0V-1 | 0.5 | no route | Sensor ground | — | |
| W11 | OEM-A-1X | SP-0V-1 | 0.5 | no route | Sensor ground | — | |
| W12 | OEM-C-3AB | SP-0V-1 | 0.5 | no route | Sensor ground | — | |
| W13 | OEM-C-3S | SP-0V-1 | 0.5 | no route | Sensor ground (CAS) | — | |
| W14 | SP-0V-1 | NEXUSS3-C-26 | 0.5 | no route | Signal ground | — | |
| W15 | OEM-C-3A | NEXUSS3-C-25 | 0.5 | no route | +5V sensor supply | — | |
| W16 | OEM-C-3R | NEXUSS3-C-1 | 0.5 | no route | Crank position (CAS NE) | — | |
| W17 | SP-0V-1 | NEXUSS3-C-2 | 0.5 | no route | Trigger - | — | |
| W18 | OEM-C-3U | NEXUSS3-C-3 | 0.5 | no route | Home position (CAS G) | — | |
| W19 | SP-0V-1 | NEXUSS3-C-4 | 0.5 | no route | Home - | — | |
| W20 | OEM-C-3O | NEXUSS3-C-23 | 0.5 | no route | Knock sensor | — | |
| W21 | OEM-D-4AF | NEXUSS3-A-27 | 0.5 | no route | Ignition front trailing | — | |
| W22 | OEM-D-4AJ | NEXUSS3-A-28 | 0.5 | no route | Ignition rear trailing | — | |
| W23 | OEM-D-4AN | NEXUSS3-A-29 | 0.5 | no route | Ignition leading (wasted spark) | — | |
| W24 | OEM-A-1Q | NEXUSS3-A-1 | 0.5 | no route | Injector 1 (front primary) | — | |
| W25 | OEM-A-1U | NEXUSS3-A-2 | 0.5 | no route | Injector 2 (rear primary) | — | |
| W26 | OEM-A-1Y | NEXUSS3-A-3 | 0.5 | no route | Injector 3 (front secondary) | — | |
| W27 | OEM-A-1AC | NEXUSS3-A-4 | 0.5 | no route | Injector 4 (rear secondary) | — | |
| W28 | OEM-D-4C | NEXUSS3-A-13 | 0.5 | no route | Ignition switch / start signal | — | |
| W29 | OEM-A-1AA | NEXUSS3-A-19 | 0.5 | no route | OMP stepper phase B1 | — | |
| W30 | OEM-A-1AE | NEXUSS3-A-20 | 0.5 | no route | OMP stepper phase A1 | — | |
| W31 | OEM-A-1S | NEXUSS3-A-21 | 0.5 | no route | OMP stepper phase B2 | — | |
| W32 | OEM-A-1W | NEXUSS3-A-22 | 0.5 | no route | OMP stepper phase A2 | — | |
| W33 | OEM-A-1H | NEXUSS3-A-26 | 0.5 | no route | Cooling fan relay (low speed) | — | |
| W34 | OEM-D-4D | NEXUSS3-A-9 | 0.5 | no route | Air pump clutch relay | — | |
| W35 | OEM-D-4F | NEXUSS3-A-12 | 0.5 | no route | Fuel pump speed relay | — | |
| W36 | OEM-D-4G | NEXUSS3-A-14 | 0.5 | no route | Fuel pump relay | — | |
| W37 | OEM-D-4I | NEXUSS3-A-15 | 0.5 | no route | A/C relay | — | |
| W38 | OEM-D-4K | NEXUSS3-A-16 | 0.5 | no route | Cooling fan relay (low speed) | — | |
| W39 | OEM-D-4L | NEXUSS3-A-17 | 0.5 | no route | Cooling fan relay (high speed) | — | |
| W40 | OEM-A-1C | NEXUSS3-A-5 | 0.5 | no route | Idle speed control (ISC) solenoid | — | |
| W41 | OEM-A-1E | NEXUSS3-A-6 | 0.5 | no route | Turbo charge control solenoid | — | |
| W42 | OEM-A-1G | NEXUSS3-A-7 | 0.5 | no route | Purge solenoid | — | |
| W43 | OEM-A-1I | NEXUSS3-A-8 | 0.5 | no route | Turbo charge relief solenoid | — | |
| W44 | OEM-D-4AH | NEXUSS3-C-10 | 0.5 | no route | MAP sensor (PIM) | — | |
| W45 | OEM-C-3I | NEXUSS3-C-11 | 0.5 | no route | Throttle position (TPS, full range) | — | |
| W46 | OEM-C-3D | NEXUSS3-C-12 | 0.5 | no route | O2 sensor (narrowband) | — | |
| W47 | OEM-C-3W | NEXUSS3-C-13 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W48 | OEM-C-3T | NEXUSS3-C-14 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W49 | OEM-C-3V | NEXUSS3-C-15 | 0.5 | no route | Fuel temperature | — | |
| W50 | OEM-C-3H | NEXUSS3-C-16 | 0.5 | no route | OMP position sensor | — | |
| W51 | OEM-D-4Q | NEXUSS3-C-5 | 0.5 | no route | Vehicle speed sensor | — | |
| W52 | OEM-D-4AA | NEXUSS3-C-6 | 0.5 | no route | Brake pedal switch | — | |
| W53 | OEM-D-4S | NEXUSS3-C-7 | 0.5 | no route | Clutch switch | — | |
| W54 | OEM-D-4V | NEXUSS3-C-8 | 0.5 | no route | A/C request | — | |
| W55 | OEM-D-4W | NEXUSS3-C-19 | 0.5 | no route | Power steering pressure switch | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (10)
| Severity | Code | Subject | Message |
|---|---|---|---|
| warn | LOAD_UNKNOWN | NEXUSS3-A-26 | NEXUSS3-A-26 "ECR output" drives OEM-A-1H Cooling fan relay (low speed) (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| info | NET_FAMILY | OEM-A-1C ↔ NEXUSS3-A-5 | OEM-A-1C "Idle speed control (ISC) solenoid" [low_side_out] is wired to NEXUSS3-A-5 "Injector 5" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-A-1E ↔ NEXUSS3-A-6 | OEM-A-1E "Turbo charge control solenoid" [low_side_out] is wired to NEXUSS3-A-6 "Injector 6" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-A-1G ↔ NEXUSS3-A-7 | OEM-A-1G "Purge solenoid" [low_side_out] is wired to NEXUSS3-A-7 "Injector 7" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-A-1I ↔ NEXUSS3-A-8 | OEM-A-1I "Turbo charge relief solenoid" [low_side_out] is wired to NEXUSS3-A-8 "Injector 8" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-A-1X ↔ NEXUSS3-C-4 | OEM-A-1X "Sensor ground" [sensor_ground] is wired to NEXUSS3-C-4 "Home -" [trigger_in]. Trigger return tied to sensor/trigger ground: correct for single-ended trigger inputs. |
| info | NET_FAMILY | OEM-C-3T ↔ NEXUSS3-C-14 | OEM-C-3T "Intake air temperature (IAT)" [temp_in] is wired to NEXUSS3-C-14 "AVI 5" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | NET_FAMILY | OEM-C-3V ↔ NEXUSS3-C-15 | OEM-C-3V "Fuel temperature" [temp_in] is wired to NEXUSS3-C-15 "AVI 6" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | NET_FAMILY | OEM-C-3W ↔ NEXUSS3-C-13 | OEM-C-3W "Coolant temperature (ECT)" [temp_in] is wired to NEXUSS3-C-13 "AVI 4" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | UNMAPPED | OEM | 5 optional OEM pins are not mapped: OEM-A-1K Turbo pre-control solenoid; OEM-A-1M Turbo control solenoid; OEM-A-1O Boost control solenoid; OEM-C-3G Fuel pressure regulator control (PRC) solenoid; OEM-D-4M Tachometer output |
Accepted (1)
| Code | Subject | Reason | By |
|---|---|---|---|
| REQUIRED_UNMAPPED | OEM-D-4B | Battery-constant (memory) feed of the stock ECU: the new ECU has no such input, so it is not needed. | mapping-proposal |
Notes
Auto-mapped by auto_map() from the library pin data on 2026-10-06. Review every wire against both manuals before building. Not wired: - OEM-D 4B: Battery constant (+12V): Haltech Nexus S3 has no battery-constant input; not needed - OEM-A 1K: Turbo pre-control solenoid: no free low_side/ls_hs/injector/hbridge on Haltech Nexus S3 - OEM-A 1M: Turbo control solenoid: no free low_side/ls_hs/injector/hbridge on Haltech Nexus S3 - OEM-A 1O: Boost control solenoid: no free low_side/ls_hs/injector/hbridge on Haltech Nexus S3 - OEM-C 3G: Fuel pressure regulator control (PRC) solenoid: no free low_side/ls_hs/injector/hbridge on Haltech Nexus S3 - OEM-D 4M: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on Haltech Nexus S3
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | vendor_doc | Haltech: Nexus S3 Plug 'n' Play adapter QSG (Subaru WRX/STI ADM, HT-186300) — ECU Connector A & C pinout | https://www.haltech.com/product/ht-186300-nexus-s3-plug-n-play-adapter-harness/ | archive | 2026-10-05 | 3cab7cd337c2 |
| 4 | vendor_doc | Haltech: Nexus S3/S2 ECU Overview (QSG) — specifications | https://store.haltech.com/product/ht-213000-nexus-s3-ecu-only/ | archive | 2026-10-05 | 388299668207 |
| 4 | vendor_doc | Haltech: RX7 FD Series 7-8 Nexus PnP adapter pinout (HT-186338) | https://www.haltech.com/wp-admin/admin-ajax.php?action=ht_get_file&id=681af8c0cc78f3b6860e615e&op=1 | — | — | — |
| 2 | forum | defreezemotorsport: MS3 FD3S 16-bit ECU pinout | https://defreezemotorsport.ru/doku.php?id=ms3:fd3s162 | — | — | — |