MX-5 Miata NA6 1990-93 (B6-ZE, 1.6) → Haltech Nexus S3 HT-213000 (auto)
MX-5 Miata NA6 1990-93 (B6-ZE, 1.6) — Haltech — Nexus S3
Drawn by Michael Gnankou · Rev 0 · proposal · 2026-10-04
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 | — | W19 | — | 0.5 | OEM-2-U | — | — | — |
| 10 | Battery ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| 11 | Battery ground | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| 12 | DPO 2 | — | W24 | — | 0.5 | OEM-2-I | — | — | — |
| 13 | Ignition switch input | — | — | — | — | — | — | — | — |
| 14 | DPO 3 | — | — | — | — | — | — | — | — |
| 15 | DPO 4 | — | — | — | — | — | — | — | — |
| 16 | DPO 5 | — | — | — | — | — | — | — | — |
| 17 | DPO 6 | — | — | — | — | — | — | — | — |
| 18 | +12V switched input | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 19 | HBO 1 | — | — | — | — | — | — | — | — |
| 2 | Injector 2 | — | W20 | — | 0.5 | OEM-2-V | — | — | — |
| 20 | HBO 2 | — | — | — | — | — | — | — | — |
| 21 | HBO 3 | — | — | — | — | — | — | — | — |
| 22 | HBO 4 | — | — | — | — | — | — | — | — |
| 23 | CAN 1 High | — | — | — | — | — | — | — | — |
| 24 | CAN 1 Low | — | — | — | — | — | — | — | — |
| 25 | +12V switched input | — | W3 | — | 0.85 | SP-14V-1 | — | — | — |
| 26 | ECR output | — | — | — | — | — | — | — | — |
| 27 | Ignition 1 | — | W17 | — | 0.5 | OEM-1-G | — | — | — |
| 28 | Ignition 2 | — | W18 | — | 0.5 | OEM-1-H | — | — | — |
| 29 | Ignition 3 | — | — | — | — | — | — | — | — |
| 3 | Injector 3 | — | W21 | — | 0.5 | OEM-2-Y | — | — | — |
| 30 | Ignition 4 | — | — | — | — | — | — | — | — |
| 31 | Ignition 5 | — | — | — | — | — | — | — | — |
| 32 | Ignition 6 | — | — | — | — | — | — | — | — |
| 33 | Ignition 7 | — | — | — | — | — | — | — | — |
| 34 | Ignition 8 | — | — | — | — | — | — | — | — |
| 4 | Injector 4 | — | W22 | — | 0.5 | OEM-2-Z | — | — | — |
| 5 | Injector 5 | — | — | — | — | — | — | — | — |
| 6 | Injector 6 | — | — | — | — | — | — | — | — |
| 7 | Injector 7 | — | — | — | — | — | — | — | — |
| 8 | Injector 8 | — | — | — | — | — | — | — | — |
| 9 | DPO 1 | — | W23 | — | 0.5 | OEM-1-E | — | — | — |
NEXUSS3-C
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Trigger + | — | W13 | — | 0.5 | OEM-2-E | — | — | — |
| 10 | AVI 1 | — | W25 | — | 0.5 | OEM-2-O | — | — | — |
| 11 | AVI 2 | — | W26 | — | 0.5 | OEM-2-N | — | — | — |
| 12 | AVI 3 | — | W27 | — | 0.5 | OEM-2-Q | — | — | — |
| 13 | AVI 4 | — | W28 | — | 0.5 | OEM-2-P | — | — | — |
| 14 | AVI 5 | — | — | — | — | — | — | — | — |
| 15 | AVI 6 | — | — | — | — | — | — | — | — |
| 16 | AVI 7 | — | — | — | — | — | — | — | — |
| 17 | AVI 8 | — | — | — | — | — | — | — | — |
| 18 | AVI 9 | — | — | — | — | — | — | — | — |
| 19 | SPI 5 | — | W33 | — | 0.5 | OEM-1-V | — | — | — |
| 2 | Trigger - | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| 20 | SPI 6 | — | W34 | — | 0.5 | OEM-2-L | — | — | — |
| 21 | CAN 2 High | — | — | — | — | — | — | — | — |
| 22 | CAN 2 Low | — | — | — | — | — | — | — | — |
| 23 | Knock 1 | — | — | — | — | — | — | — | — |
| 24 | Knock 2 | — | — | — | — | — | — | — | — |
| 25 | +5V | — | W12 | — | 0.5 | OEM-2-K | — | — | — |
| 26 | Signal ground | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 27 | AVI 10 | — | — | — | — | — | — | — | — |
| 28 | AVI 11 | — | — | — | — | — | — | — | — |
| 29 | WBI 1 Heater + | — | — | — | — | — | — | — | — |
| 3 | Home + | — | W15 | — | 0.5 | OEM-2-G | — | — | — |
| 30 | WBI 1 Input | — | — | — | — | — | — | — | — |
| 31 | WBI 1 Pump | — | — | — | — | — | — | — | — |
| 32 | WBI 1 Nernst | — | — | — | — | — | — | — | — |
| 33 | WBI 1 Heater - | — | — | — | — | — | — | — | — |
| 34 | WBI 1 Cal | — | — | — | — | — | — | — | — |
| 4 | Home - | — | W16 | — | 0.5 | SP-0V-1 | — | — | — |
| 5 | SPI 1 | — | W29 | — | 0.5 | OEM-1-C | — | — | — |
| 6 | SPI 2 | — | W30 | — | 0.5 | OEM-1-N | — | — | — |
| 7 | SPI 3 | — | W31 | — | 0.5 | OEM-1-P | — | — | — |
| 8 | SPI 4 | — | W32 | — | 0.5 | OEM-1-Q | — | — | — |
| 9 | +8V | — | — | — | — | — | — | — | — |
OEM-1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Constant +12V | — | — | — | — | — | — | — | — |
| B | ECU power +14V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| C | Start signal | — | W29 | — | 0.5 | NEXUSS3-C-5 | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | W23 | — | 0.5 | NEXUSS3-A-9 | — | — | — |
| G | Ignition 1 (coils 1+4, wasted spark) | — | W17 | — | 0.5 | NEXUSS3-A-27 | — | — | — |
| H | Ignition 2 (coils 2+3, wasted spark) | — | W18 | — | 0.5 | NEXUSS3-A-28 | — | — | — |
| N | Wide-open throttle switch | — | W30 | — | 0.5 | NEXUSS3-C-6 | — | — | — |
| P | Power steering pressure switch | — | W31 | — | 0.5 | NEXUSS3-C-7 | — | — | — |
| Q | A/C request | — | W32 | — | 0.5 | NEXUSS3-C-8 | — | — | — |
| V | Neutral/clutch switch | — | W33 | — | 0.5 | NEXUSS3-C-19 | — | — | — |
OEM-2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Power ground | — | W4 | — | 0.85 | SP-GND-1 | — | — | — |
| B | Power ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| C | Power ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| D | Power ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| E | Crank position (CAS NE) | — | W13 | — | 0.5 | NEXUSS3-C-1 | — | — | — |
| F | AFM ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| G | Cam position (CAS G) | — | W15 | — | 0.5 | NEXUSS3-C-3 | — | — | — |
| I | Tachometer output | — | W24 | — | 0.5 | NEXUSS3-A-12 | — | — | — |
| K | +5V sensor supply | — | W12 | — | 0.5 | NEXUSS3-C-25 | — | — | — |
| L | Idle switch (TPS) | — | W34 | — | 0.5 | NEXUSS3-C-20 | — | — | — |
| N | O2 sensor | — | W26 | — | 0.5 | NEXUSS3-C-11 | — | — | — |
| O | Air flow meter (AFM) | — | W25 | — | 0.5 | NEXUSS3-C-10 | — | — | — |
| P | Intake air temperature (IAT) | — | W28 | — | 0.5 | NEXUSS3-C-13 | — | — | — |
| Q | Coolant temperature (ECT) | — | W27 | — | 0.5 | NEXUSS3-C-12 | — | — | — |
| U | Injector 1 | — | W19 | — | 0.5 | NEXUSS3-A-1 | — | — | — |
| V | Injector 2 | — | W20 | — | 0.5 | NEXUSS3-A-2 | — | — | — |
| Y | Injector 3 | — | W21 | — | 0.5 | NEXUSS3-A-3 | — | — | — |
| Z | Injector 4 | — | W22 | — | 0.5 | NEXUSS3-A-4 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W10 | — | 0.5 | OEM-2-F | — | — | — |
| 1 | — | — | W11 | — | 0.5 | NEXUSS3-C-26 | — | — | — |
| 1 | — | — | W14 | — | 0.5 | NEXUSS3-C-2 | — | — | — |
| 1 | — | — | W16 | — | 0.5 | NEXUSS3-C-4 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-1-B | — | — | — |
| 1 | — | — | W2 | — | 0.85 | NEXUSS3-A-18 | — | — | — |
| 1 | — | — | W3 | — | 0.85 | NEXUSS3-A-25 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W4 | — | 0.85 | OEM-2-A | — | — | — |
| 1 | — | — | W5 | — | 0.85 | OEM-2-B | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-2-C | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-2-D | — | — | — |
| 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-1-A | Constant +12V | power_in | — | — | — | single_source | |
| OEM-1-B | ECU power +14V (main relay) | power_in | NEXUSS3-A-18 + NEXUSS3-A-25 | +12V switched input + +12V switched input | power_in | single_source | |
| OEM-1-C | Start signal | digital_in | NEXUSS3-C-5 | SPI 1 | digital_in | single_source | |
| OEM-1-E | Malfunction indicator lamp (MIL) | low_side_out | NEXUSS3-A-9 | DPO 1 | low_side_out | single_source | |
| OEM-1-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | NEXUSS3-A-27 | Ignition 1 | ignition_out | single_source | |
| OEM-1-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | NEXUSS3-A-28 | Ignition 2 | ignition_out | single_source | |
| OEM-1-N | Wide-open throttle switch | digital_in | NEXUSS3-C-6 | SPI 2 | digital_in | single_source | |
| OEM-1-P | Power steering pressure switch | digital_in | NEXUSS3-C-7 | SPI 3 | digital_in | single_source | |
| OEM-1-Q | A/C request | digital_in | NEXUSS3-C-8 | SPI 4 | digital_in | single_source | |
| OEM-1-V | Neutral/clutch switch | digital_in | NEXUSS3-C-19 | SPI 5 | digital_in | single_source | |
| OEM-2-A | Power ground | ground | NEXUSS3-A-10 + NEXUSS3-A-11 | Battery ground + Battery ground | ground | single_source | |
| OEM-2-B | Power ground | ground | NEXUSS3-A-10 + NEXUSS3-A-11 | Battery ground + Battery ground | ground | single_source | |
| OEM-2-C | Power ground | ground | NEXUSS3-A-10 + NEXUSS3-A-11 | Battery ground + Battery ground | ground | single_source | |
| OEM-2-D | Power ground | ground | NEXUSS3-A-10 + NEXUSS3-A-11 | Battery ground + Battery ground | ground | single_source | |
| OEM-2-E | Crank position (CAS NE) | trigger_in | NEXUSS3-C-1 | Trigger + | trigger_in | single_source | |
| OEM-2-F | AFM ground | sensor_ground | NEXUSS3-C-2 + NEXUSS3-C-26 + NEXUSS3-C-4 | Trigger - + Signal ground + Home - | sensor_ground + trigger_in | single_source | |
| OEM-2-G | Cam position (CAS G) | trigger_in | NEXUSS3-C-3 | Home + | trigger_in | single_source | |
| OEM-2-I | Tachometer output | tacho_out | NEXUSS3-A-12 | DPO 2 | low_side_out | single_source | |
| OEM-2-K | +5V sensor supply | vref | NEXUSS3-C-25 | +5V | vref | single_source | |
| OEM-2-L | Idle switch (TPS) | digital_in | NEXUSS3-C-20 | SPI 6 | digital_in | single_source | |
| OEM-2-N | O2 sensor | lambda_nb_in | NEXUSS3-C-11 | AVI 2 | analog_in | single_source | |
| OEM-2-O | Air flow meter (AFM) | analog_in | NEXUSS3-C-10 | AVI 1 | analog_in | single_source | |
| OEM-2-P | Intake air temperature (IAT) | temp_in | NEXUSS3-C-13 | AVI 4 | analog_in | single_source | |
| OEM-2-Q | Coolant temperature (ECT) | temp_in | NEXUSS3-C-12 | AVI 3 | analog_in | single_source | |
| OEM-2-U | Injector 1 | injector_out | NEXUSS3-A-1 | Injector 1 | injector_out | single_source | |
| OEM-2-V | Injector 2 | injector_out | NEXUSS3-A-2 | Injector 2 | injector_out | single_source | |
| OEM-2-Y | Injector 3 | injector_out | NEXUSS3-A-3 | Injector 3 | injector_out | single_source | |
| OEM-2-Z | Injector 4 | injector_out | NEXUSS3-A-4 | Injector 4 | injector_out | single_source |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-1-B | SP-14V-1 | 0.85 | no route | ECU power +14V (main relay) | — | |
| W2 | SP-14V-1 | NEXUSS3-A-18 | 0.85 | no route | +12V switched input | — | |
| W3 | SP-14V-1 | NEXUSS3-A-25 | 0.85 | no route | +12V switched input | — | |
| W4 | OEM-2-A | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W5 | OEM-2-B | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W6 | OEM-2-C | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W7 | OEM-2-D | 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-2-F | SP-0V-1 | 0.5 | no route | AFM ground | — | |
| W11 | SP-0V-1 | NEXUSS3-C-26 | 0.5 | no route | Signal ground | — | |
| W12 | OEM-2-K | NEXUSS3-C-25 | 0.5 | no route | +5V sensor supply | — | |
| W13 | OEM-2-E | NEXUSS3-C-1 | 0.5 | no route | Crank position (CAS NE) | — | |
| W14 | SP-0V-1 | NEXUSS3-C-2 | 0.5 | no route | Trigger - | — | |
| W15 | OEM-2-G | NEXUSS3-C-3 | 0.5 | no route | Cam position (CAS G) | — | |
| W16 | SP-0V-1 | NEXUSS3-C-4 | 0.5 | no route | Home - | — | |
| W17 | OEM-1-G | NEXUSS3-A-27 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W18 | OEM-1-H | NEXUSS3-A-28 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W19 | OEM-2-U | NEXUSS3-A-1 | 0.5 | no route | Injector 1 | — | |
| W20 | OEM-2-V | NEXUSS3-A-2 | 0.5 | no route | Injector 2 | — | |
| W21 | OEM-2-Y | NEXUSS3-A-3 | 0.5 | no route | Injector 3 | — | |
| W22 | OEM-2-Z | NEXUSS3-A-4 | 0.5 | no route | Injector 4 | — | |
| W23 | OEM-1-E | NEXUSS3-A-9 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W24 | OEM-2-I | NEXUSS3-A-12 | 0.5 | no route | Tachometer output | — | |
| W25 | OEM-2-O | NEXUSS3-C-10 | 0.5 | no route | Air flow meter (AFM) | — | |
| W26 | OEM-2-N | NEXUSS3-C-11 | 0.5 | no route | O2 sensor | — | |
| W27 | OEM-2-Q | NEXUSS3-C-12 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W28 | OEM-2-P | NEXUSS3-C-13 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W29 | OEM-1-C | NEXUSS3-C-5 | 0.5 | no route | Start signal | — | |
| W30 | OEM-1-N | NEXUSS3-C-6 | 0.5 | no route | Wide-open throttle switch | — | |
| W31 | OEM-1-P | NEXUSS3-C-7 | 0.5 | no route | Power steering pressure switch | — | |
| W32 | OEM-1-Q | NEXUSS3-C-8 | 0.5 | no route | A/C request | — | |
| W33 | OEM-1-V | NEXUSS3-C-19 | 0.5 | no route | Neutral/clutch switch | — | |
| W34 | OEM-2-L | NEXUSS3-C-20 | 0.5 | no route | Idle switch (TPS) | — |
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 (4)
| Severity | Code | Subject | Message |
|---|---|---|---|
| info | NET_FAMILY | OEM-2-F ↔ NEXUSS3-C-4 | OEM-2-F "AFM 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-2-I ↔ NEXUSS3-A-12 | OEM-2-I "Tachometer output" [tacho_out] is wired to NEXUSS3-A-12 "DPO 2" [low_side_out]. Tacho as a low-side output: check the tach needs a pull-up. |
| info | NET_FAMILY | OEM-2-P ↔ NEXUSS3-C-13 | OEM-2-P "Intake air temperature (IAT)" [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 | NET_FAMILY | OEM-2-Q ↔ NEXUSS3-C-12 | OEM-2-Q "Coolant temperature (ECT)" [temp_in] is wired to NEXUSS3-C-12 "AVI 3" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
Accepted (1)
| Code | Subject | Reason | By |
|---|---|---|---|
| REQUIRED_UNMAPPED | OEM-1-A | 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 2026-10-04. Review every wire against both manuals before building. Not wired: - OEM-1 A: Constant +12V: Haltech Nexus S3 has no battery-constant input; not needed - NEXUSS3-A 13: Ignition switch input: not fed (the stock ECU has no ignition-sense pin); feed it from a switched-ignition source
Sources
| Reliability | Kind | Title | URL |
|---|---|---|---|
| 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/ |
| 4 | vendor_doc | Haltech: Nexus S3/S2 ECU Overview (QSG) — specifications | https://store.haltech.com/product/ht-213000-nexus-s3-ecu-only/ |
| 4 | vendor_doc | Link G4X MX5X install manual (NA 1.6/1.8) | https://linkecu.com/documentation/MX5X.pdf |