MX-5 Miata NA8 1994-95 (BP-ZE, 1.8, OBD-I) → DTAFast T12 (auto)
MX-5 Miata NA8 1994-95 (BP-ZE, 1.8, OBD-I) — DTAFast — T12
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-12
Before you start
Not confident with automotive wiring? Have a professional harness builder or tuner do it, or check your work before first power-up. A wiring mistake can damage the ECU, the engine or the car, or start a fire.
| Status | draft · not yet verified: nobody has reported building and running this harness |
|---|---|
| Open errors | 1: read the Findings page before cutting any wire |
| Size of the job | 43 wires · 8 connectors · 4 part lines |
| Tools | Crimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink |
| Terminals | 3-1447221-4 |
| 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-1-B | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | SP-14V-1 | T12-C1-31 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | OEM-1-A | T12-C3-26 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-2-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-2-B | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | SP-GND-1 | T12-C1-13 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | SP-GND-1 | T12-C1-14 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | OEM-2-C | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | OEM-2-D | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | OEM-2-F | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | SP-0V-1 | T12-C2-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | SP-0V-1 | T12-C2-33 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-2-K | T12-C2-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-2-E | T12-C2-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-2-G | T12-C2-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-1-G | T12-C1-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-1-H | T12-C1-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-2-U | T12-C1-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-2-V | T12-C1-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-2-Y | T12-C1-34 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-2-Z | T12-C1-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-2-O | T12-C2-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-2-M | T12-C2-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-2-Q | T12-C2-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-1-J | T12-C1-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-1-R | T12-C1-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-2-S | T12-C1-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-2-T | T12-C3-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-1-L | T12-C3-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-2-L | T12-C3-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-2-W | T12-C3-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-1-E | T12-C3-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-2-R | T12-C3-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-2-X | T12-C3-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-2-I | T12-C3-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-2-N | T12-C2-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-2-P | T12-C2-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-1-M | T12-C2-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-1-C | T12-C2-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-1-O | T12-C2-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-1-P | T12-C2-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-1-Q | T12-C2-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-1-V | T12-C2-15 | 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 | T12-C1-31 | T12-C1-13 | open (OL) | +12 V supply must not touch power ground | |
| 2 | T12-C1-31 | T12-C2-21 | open (OL) | +12 V supply must not touch sensor ground | |
| 3 | T12-C3-26 | T12-C1-13 | open (OL) | +12 V supply must not touch power ground | |
| 4 | T12-C3-26 | T12-C2-21 | open (OL) | +12 V supply must not touch sensor ground | |
| 5 | T12-C1-13 | T12-C2-24 | open (OL) | power ground must not touch 5 V sensor reference | |
| 6 | T12-C1-31 | T12-C2-24 | open (OL) | +12 V supply must not touch 5 V sensor reference | |
| 7 | T12-C2-21 | T12-C2-24 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 8 | T12-C3-26 | T12-C2-24 | open (OL) | +12 V supply must not touch 5 V sensor reference |
If any reading doesn't match, stop and get help before powering up.
Revisions
| Rev | Label | By | Date |
|---|---|---|---|
| No revisions yet. | |||
Schematic
Connectors
OEM-1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Constant +12V | — | W3 | — | 0.85 | T12-C3-26 | — | — | — |
| B | ECU power +14V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| C | Start signal | — | W39 | — | 0.5 | T12-C2-4 | — | — | — |
| D | Data link connector | — | — | — | — | — | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | W32 | — | 0.5 | T12-C3-10 | — | — | — |
| G | Ignition 1 (coils 1+4, wasted spark) | — | W16 | — | 0.5 | T12-C1-10 | — | — | — |
| H | Ignition 2 (coils 2+3, wasted spark) | — | W17 | — | 0.5 | T12-C1-18 | — | — | — |
| I | Powertrain control module (transmission) | — | — | — | — | — | — | — | — |
| J | A/C relay | — | W25 | — | 0.5 | T12-C1-5 | — | — | — |
| L | Coolant fan relay | — | W29 | — | 0.5 | T12-C3-23 | — | — | — |
| M | Vehicle speed | — | W38 | — | 0.5 | T12-C2-2 | — | — | — |
| N | Powertrain control module (transmission) | — | — | — | — | — | — | — | — |
| O | Stop light switch | — | W40 | — | 0.5 | T12-C2-8 | — | — | — |
| P | Power steering pressure switch | — | W41 | — | 0.5 | T12-C2-11 | — | — | — |
| Q | A/C request | — | W42 | — | 0.5 | T12-C2-14 | — | — | — |
| R | Cooling fan relay | — | W26 | — | 0.5 | T12-C1-4 | — | — | — |
| S | Heater control unit | — | — | — | — | — | — | — | — |
| T | Unknown | — | — | — | — | — | — | — | — |
| U | Unknown | — | — | — | — | — | — | — | — |
| V | Neutral/clutch switch | — | W43 | — | 0.5 | T12-C2-15 | — | — | — |
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 | Sensor ground (E2) | — | W8 | — | 0.5 | SP-0V-1 | — | — | — |
| D | Sensor ground (E2) | — | W9 | — | 0.5 | SP-0V-1 | — | — | — |
| E | Crank position (CAS NE) | — | W14 | — | 0.5 | T12-C2-12 | — | — | — |
| F | MAF ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| G | Cam position (CAS G) | — | W15 | — | 0.5 | T12-C2-22 | — | — | — |
| H | Data link connector | — | — | — | — | — | — | — | — |
| I | Tachometer output | — | W35 | — | 0.5 | T12-C3-29 | — | — | — |
| J | EGR function sensor | — | — | — | — | — | — | — | — |
| K | +5V sensor supply | — | W13 | — | 0.5 | T12-C2-24 | — | — | — |
| L | Rear defroster relay | — | W30 | — | 0.5 | T12-C3-24 | — | — | — |
| M | Throttle position (TPS) | — | W23 | — | 0.5 | T12-C2-1 | — | — | — |
| N | O2 sensor | — | W36 | — | 0.5 | T12-C2-5 | — | — | — |
| O | Mass air flow (MAF) | — | W22 | — | 0.5 | T12-C2-10 | — | — | — |
| P | Intake air temperature (IAT) | — | W37 | — | 0.5 | T12-C2-25 | — | — | — |
| Q | Coolant temperature (ECT) | — | W24 | — | 0.5 | T12-C2-7 | — | — | — |
| R | PRC solenoid (fuel pressure regulator) | — | W33 | — | 0.5 | T12-C3-4 | — | — | — |
| S | Condenser fan relay | — | W27 | — | 0.5 | T12-C1-3 | — | — | — |
| T | Fuel pump relay | — | W28 | — | 0.5 | T12-C3-22 | — | — | — |
| U | Injector 1 | — | W18 | — | 0.5 | T12-C1-9 | — | — | — |
| V | Injector 2 | — | W19 | — | 0.5 | T12-C1-17 | — | — | — |
| W | ISC solenoid | — | W31 | — | 0.5 | T12-C3-25 | — | — | — |
| X | Evap purge solenoid | — | W34 | — | 0.5 | T12-C3-28 | — | — | — |
| Y | Injector 3 | — | W20 | — | 0.5 | T12-C1-34 | — | — | — |
| Z | Injector 4 | — | W21 | — | 0.5 | T12-C1-25 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W8 | — | 0.5 | OEM-2-C | — | — | — |
| 1 | — | — | W9 | — | 0.5 | OEM-2-D | — | — | — |
| 1 | — | — | W10 | — | 0.5 | OEM-2-F | — | — | — |
| 1 | — | — | W11 | — | 0.5 | T12-C2-21 | — | — | — |
| 1 | — | — | W12 | — | 0.5 | T12-C2-33 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-1-B | — | — | — |
| 1 | — | — | W2 | — | 0.85 | T12-C1-31 | — | — | — |
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 | T12-C1-13 | — | — | — |
| 1 | — | — | W7 | — | 0.85 | T12-C1-14 | — | — | — |
T12-C1
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Coil 3 | — | — | — | — | — | — | — | — |
| 2 | Coil 11 | — | — | — | — | — | — | — | — |
| 3 | PWM 3 | — | W27 | — | 0.5 | OEM-2-S | — | — | — |
| 4 | PWM 2 | — | W26 | — | 0.5 | OEM-1-R | — | — | — |
| 5 | PWM 1 | — | W25 | — | 0.5 | OEM-1-J | — | — | — |
| 6 | Motor 1 + | — | — | — | — | — | — | — | — |
| 7 | Motor 1 - | — | — | — | — | — | — | — | — |
| 8 | Injector 11 | — | — | — | — | — | — | — | — |
| 9 | Injector 1 | — | W18 | — | 0.5 | OEM-2-U | — | — | — |
| 10 | Coil 1 | — | W16 | — | 0.5 | OEM-1-G | — | — | — |
| 11 | Coil 5 | — | — | — | — | — | — | — | — |
| 12 | Coil 7 | — | — | — | — | — | — | — | — |
| 13 | Power Ground 1 | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | Power Ground 2 | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 15 | Injector 6 | — | — | — | — | — | — | — | — |
| 16 | Injector 5 | — | — | — | — | — | — | — | — |
| 17 | Injector 2 | — | W19 | — | 0.5 | OEM-2-V | — | — | — |
| 18 | Coil 2 | — | W17 | — | 0.5 | OEM-1-H | — | — | — |
| 19 | Coil 8 | — | — | — | — | — | — | — | — |
| 20 | Coil 9 | — | — | — | — | — | — | — | — |
| 21 | Injector 9 | — | — | — | — | — | — | — | — |
| 22 | Injector 10 | — | — | — | — | — | — | — | — |
| 23 | Injector 8 | — | — | — | — | — | — | — | — |
| 24 | Injector 7 | — | — | — | — | — | — | — | — |
| 25 | Injector 4 | — | W21 | — | 0.5 | OEM-2-Z | — | — | — |
| 26 | Coil 4 | — | — | — | — | — | — | — | — |
| 27 | Coil 6 | — | — | — | — | — | — | — | — |
| 28 | Coil 10 | — | — | — | — | — | — | — | — |
| 29 | Motor 2 + | — | — | — | — | — | — | — | — |
| 30 | Motor 2 - | — | — | — | — | — | — | — | — |
| 31 | Ignition 12v In | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 32 | Injector 12 | — | — | — | — | — | — | — | — |
| 33 | Coil 12 | — | — | — | — | — | — | — | — |
| 34 | Injector 3 | — | W20 | — | 0.5 | OEM-2-Y | — | — | — |
T12-C2
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Analogue 2 | — | W23 | — | 0.5 | OEM-2-M | — | — | — |
| 2 | Wheel 1 | — | W38 | — | 0.5 | OEM-1-M | — | — | — |
| 3 | Analogue 10 | — | — | — | — | — | — | — | — |
| 4 | Digital 1 | — | W39 | — | 0.5 | OEM-1-C | — | — | — |
| 5 | Analogue 3 | — | W36 | — | 0.5 | OEM-2-N | — | — | — |
| 6 | Analogue 4 | — | — | — | — | — | — | — | — |
| 7 | Thermistor 1 | — | W24 | — | 0.5 | OEM-2-Q | — | — | — |
| 8 | Digital 2 | — | W40 | — | 0.5 | OEM-1-O | — | — | — |
| 9 | 5v Output | — | — | — | — | — | — | — | — |
| 10 | Analogue 1 | — | W22 | — | 0.5 | OEM-2-O | — | — | — |
| 11 | Digital 3 | — | W41 | — | 0.5 | OEM-1-P | — | — | — |
| 12 | Crank | — | W14 | — | 0.5 | OEM-2-E | — | — | — |
| 13 | Analogue 12 | — | — | — | — | — | — | — | — |
| 14 | Digital 4 | — | W42 | — | 0.5 | OEM-1-Q | — | — | — |
| 15 | Digital 5 | — | W43 | — | 0.5 | OEM-1-V | — | — | — |
| 16 | Analogue 11 | — | — | — | — | — | — | — | — |
| 17 | Thermistor 3 | — | — | — | — | — | — | — | — |
| 18 | Analogue 5 | — | — | — | — | — | — | — | — |
| 19 | Analogue 6 | — | — | — | — | — | — | — | — |
| 20 | Wheel 2 | — | — | — | — | — | — | — | — |
| 21 | Sensor Ground | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 22 | Cam 1 | — | W15 | — | 0.5 | OEM-2-G | — | — | — |
| 23 | Cam 3 | — | — | — | — | — | — | — | — |
| 24 | 5v Output | — | W13 | — | 0.5 | OEM-2-K | — | — | — |
| 25 | Thermistor 2 | — | W37 | — | 0.5 | OEM-2-P | — | — | — |
| 26 | CAN High | — | — | — | — | — | — | — | — |
| 27 | Digital 6 | — | — | — | — | — | — | — | — |
| 28 | CAN Low | — | — | — | — | — | — | — | — |
| 29 | Cam 2 | — | — | — | — | — | — | — | — |
| 30 | Cam 4 | — | — | — | — | — | — | — | — |
| 31 | Wheel 3 | — | — | — | — | — | — | — | — |
| 32 | Wheel 4 | — | — | — | — | — | — | — | — |
| 33 | Sensor Ground | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 34 | Analogue 9 | — | — | — | — | — | — | — | — |
T12-C3
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Lambda 2 Pump Current | — | — | — | — | — | — | — | — |
| 2 | Lambda 2 VGND | — | — | — | — | — | — | — | — |
| 3 | Lambda 2 Heater Negative | — | — | — | — | — | — | — | — |
| 4 | PWM 9 | — | W33 | — | 0.5 | OEM-2-R | — | — | — |
| 5 | Lambda 2 Trim Resistor | — | — | — | — | — | — | — | — |
| 6 | Lambda 2 Nernst Voltage | — | — | — | — | — | — | — | — |
| 7 | Lambda 1 Pump Current | — | — | — | — | — | — | — | — |
| 8 | Lambda 1 VGND | — | — | — | — | — | — | — | — |
| 9 | Lambda 1 Heater Negative | — | — | — | — | — | — | — | — |
| 10 | PWM 8 | — | W32 | — | 0.5 | OEM-1-E | — | — | — |
| 11 | Lambda 1 Trim Resistor | — | — | — | — | — | — | — | — |
| 12 | Lambda 1 Nernst Voltage | — | — | — | — | — | — | — | — |
| 13 | Analogue 13 | — | — | — | — | — | — | — | — |
| 14 | Analogue 14 | — | — | — | — | — | — | — | — |
| 15 | Analogue 15 | — | — | — | — | — | — | — | — |
| 16 | Analogue 16 | — | — | — | — | — | — | — | — |
| 17 | Analogue 7 | — | — | — | — | — | — | — | — |
| 18 | Analogue 8 | — | — | — | — | — | — | — | — |
| 19 | Digital 7 | — | — | — | — | — | — | — | — |
| 20 | Digital 8 | — | — | — | — | — | — | — | — |
| 21 | Digital 9 | — | — | — | — | — | — | — | — |
| 22 | PWM 4 | — | W28 | — | 0.5 | OEM-2-T | — | — | — |
| 23 | PWM 5 | — | W29 | — | 0.5 | OEM-1-L | — | — | — |
| 24 | PWM 6 | — | W30 | — | 0.5 | OEM-2-L | — | — | — |
| 25 | PWM 7 | — | W31 | — | 0.5 | OEM-2-W | — | — | — |
| 26 | Permanent 12v | — | W3 | — | 0.85 | OEM-1-A | — | — | — |
| 27 | Permanent 12v | — | — | — | — | — | — | — | — |
| 28 | PWM 10 | — | W34 | — | 0.5 | OEM-2-X | — | — | — |
| 29 | PWM 11 | — | W35 | — | 0.5 | OEM-2-I | — | — | — |
| 30 | PWM 12 | — | — | — | — | — | — | — | — |
| 31 | Knock 1 | — | — | — | — | — | — | — | — |
| 32 | Knock 2 | — | — | — | — | — | — | — | — |
| 33 | CAN 2 High | — | — | — | — | — | — | — | — |
| 34 | CAN 2 Low | — | — | — | — | — | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-1-A | Constant +12V | power_in | T12-C3-26 | Permanent 12v | power_in | LR | single_source |
| OEM-1-B | ECU power +14V (main relay) | power_in | T12-C1-31 | Ignition 12v In | power_in | WR | single_source |
| OEM-1-C | Start signal | digital_in | T12-C2-4 | Digital 1 | digital_in | V | single_source |
| OEM-1-D | Data link connector | serial | — | — | — | WG | single_source |
| OEM-1-E | Malfunction indicator lamp (MIL) | low_side_out | T12-C3-10 | PWM 8 | low_side_out | YB | single_source |
| OEM-1-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | T12-C1-10 | Coil 1 | ignition_out | BrY | single_source |
| OEM-1-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | T12-C1-18 | Coil 2 | ignition_out | Br | single_source |
| OEM-1-I | Powertrain control module (transmission) | — | — | — | — | LW | single_source |
| OEM-1-J | A/C relay | low_side_out | T12-C1-5 | PWM 1 | low_side_out | single_source | |
| OEM-1-L | Coolant fan relay | low_side_out | T12-C3-23 | PWM 5 | low_side_out | BG | single_source |
| OEM-1-M | Vehicle speed | digital_in | T12-C2-2 | Wheel 1 | digital_in | GR | single_source |
| OEM-1-N | Powertrain control module (transmission) | — | — | — | — | R | single_source |
| OEM-1-O | Stop light switch | digital_in | T12-C2-8 | Digital 2 | digital_in | GB | single_source |
| OEM-1-P | Power steering pressure switch | digital_in | T12-C2-11 | Digital 3 | digital_in | LY | single_source |
| OEM-1-Q | A/C request | digital_in | T12-C2-14 | Digital 4 | digital_in | LgB | single_source |
| OEM-1-R | Cooling fan relay | low_side_out | T12-C1-4 | PWM 2 | low_side_out | YB | single_source |
| OEM-1-S | Heater control unit | — | — | — | — | LOr | single_source |
| OEM-1-T | Unknown | — | — | — | — | YR | single_source |
| OEM-1-U | Unknown | — | — | — | — | RB | single_source |
| OEM-1-V | Neutral/clutch switch | digital_in | T12-C2-15 | Digital 5 | digital_in | BrW | single_source |
| OEM-2-A | Power ground | ground | T12-C1-13 + T12-C1-14 | Power Ground 1 + Power Ground 2 | ground | B | single_source |
| OEM-2-B | Power ground | ground | T12-C1-13 + T12-C1-14 | Power Ground 1 + Power Ground 2 | ground | B | single_source |
| OEM-2-C | Sensor ground (E2) | sensor_ground | T12-C2-21 + T12-C2-33 | Sensor Ground + Sensor Ground | sensor_ground | BLg | corroborated |
| OEM-2-D | Sensor ground (E2) | sensor_ground | T12-C2-21 + T12-C2-33 | Sensor Ground + Sensor Ground | sensor_ground | BL | corroborated |
| OEM-2-E | Crank position (CAS NE) | trigger_in | T12-C2-12 | Crank | trigger_in | W | single_source |
| OEM-2-F | MAF ground | sensor_ground | T12-C2-21 + T12-C2-33 | Sensor Ground + Sensor Ground | sensor_ground | BR | single_source |
| OEM-2-G | Cam position (CAS G) | trigger_in | T12-C2-22 | Cam 1 | trigger_in | YL | single_source |
| OEM-2-H | Data link connector | serial | — | — | — | LgY | single_source |
| OEM-2-I | Tachometer output | tacho_out | T12-C3-29 | PWM 11 | low_side_out | BW | single_source |
| OEM-2-J | EGR function sensor | — | — | — | — | LgR | single_source |
| OEM-2-K | +5V sensor supply | vref | T12-C2-24 | 5v Output | vref | LgW | single_source |
| OEM-2-L | Rear defroster relay | low_side_out | T12-C3-24 | PWM 6 | low_side_out | LR | single_source |
| OEM-2-M | Throttle position (TPS) | analog_in | T12-C2-1 | Analogue 2 | analog_in | RB | single_source |
| OEM-2-N | O2 sensor | lambda_nb_in | T12-C2-5 | Analogue 3 | analog_in | RL | single_source |
| OEM-2-O | Mass air flow (MAF) | analog_in | T12-C2-10 | Analogue 1 | analog_in | R | single_source |
| OEM-2-P | Intake air temperature (IAT) | temp_in | T12-C2-25 | Thermistor 2 | temp_in | RB | single_source |
| OEM-2-Q | Coolant temperature (ECT) | temp_in | T12-C2-7 | Thermistor 1 | temp_in | LW | single_source |
| OEM-2-R | PRC solenoid (fuel pressure regulator) | low_side_out | T12-C3-4 | PWM 9 | low_side_out | YG | single_source |
| OEM-2-S | Condenser fan relay | low_side_out | T12-C1-3 | PWM 3 | low_side_out | LW | single_source |
| OEM-2-T | Fuel pump relay | low_side_out | T12-C3-22 | PWM 4 | low_side_out | Lg | single_source |
| OEM-2-U | Injector 1 | injector_out | T12-C1-9 | Injector 1 | injector_out | Y | single_source |
| OEM-2-V | Injector 2 | injector_out | T12-C1-17 | Injector 2 | injector_out | YB | single_source |
| OEM-2-W | ISC solenoid | low_side_out | T12-C3-25 | PWM 7 | low_side_out | LOr | single_source |
| OEM-2-X | Evap purge solenoid | low_side_out | T12-C3-28 | PWM 10 | low_side_out | YR | single_source |
| OEM-2-Y | Injector 3 | injector_out | T12-C1-34 | Injector 3 | injector_out | GW | single_source |
| OEM-2-Z | Injector 4 | injector_out | T12-C1-25 | Injector 4 | injector_out | G | 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 | T12-C1-31 | 0.85 | no route | Ignition 12v In | — | |
| W3 | OEM-1-A | T12-C3-26 | 0.85 | no route | Constant +12V | — | |
| 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 | SP-GND-1 | T12-C1-13 | 0.85 | no route | Power Ground 1 | — | |
| W7 | SP-GND-1 | T12-C1-14 | 0.85 | no route | Power Ground 2 | — | |
| W8 | OEM-2-C | SP-0V-1 | 0.5 | no route | Sensor ground (E2) | — | |
| W9 | OEM-2-D | SP-0V-1 | 0.5 | no route | Sensor ground (E2) | — | |
| W10 | OEM-2-F | SP-0V-1 | 0.5 | no route | MAF ground | — | |
| W11 | SP-0V-1 | T12-C2-21 | 0.5 | no route | Sensor Ground | — | |
| W12 | SP-0V-1 | T12-C2-33 | 0.5 | no route | Sensor Ground | — | |
| W13 | OEM-2-K | T12-C2-24 | 0.5 | no route | +5V sensor supply | — | |
| W14 | OEM-2-E | T12-C2-12 | 0.5 | no route | Crank position (CAS NE) | — | |
| W15 | OEM-2-G | T12-C2-22 | 0.5 | no route | Cam position (CAS G) | — | |
| W16 | OEM-1-G | T12-C1-10 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W17 | OEM-1-H | T12-C1-18 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W18 | OEM-2-U | T12-C1-9 | 0.5 | no route | Injector 1 | — | |
| W19 | OEM-2-V | T12-C1-17 | 0.5 | no route | Injector 2 | — | |
| W20 | OEM-2-Y | T12-C1-34 | 0.5 | no route | Injector 3 | — | |
| W21 | OEM-2-Z | T12-C1-25 | 0.5 | no route | Injector 4 | — | |
| W22 | OEM-2-O | T12-C2-10 | 0.5 | no route | Mass air flow (MAF) | — | |
| W23 | OEM-2-M | T12-C2-1 | 0.5 | no route | Throttle position (TPS) | — | |
| W24 | OEM-2-Q | T12-C2-7 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W25 | OEM-1-J | T12-C1-5 | 0.5 | no route | A/C relay | — | |
| W26 | OEM-1-R | T12-C1-4 | 0.5 | no route | Cooling fan relay | — | |
| W27 | OEM-2-S | T12-C1-3 | 0.5 | no route | Condenser fan relay | — | |
| W28 | OEM-2-T | T12-C3-22 | 0.5 | no route | Fuel pump relay | — | |
| W29 | OEM-1-L | T12-C3-23 | 0.5 | no route | Coolant fan relay | — | |
| W30 | OEM-2-L | T12-C3-24 | 0.5 | no route | Rear defroster relay | — | |
| W31 | OEM-2-W | T12-C3-25 | 0.5 | no route | ISC solenoid | — | |
| W32 | OEM-1-E | T12-C3-10 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W33 | OEM-2-R | T12-C3-4 | 0.5 | no route | PRC solenoid (fuel pressure regulator) | — | |
| W34 | OEM-2-X | T12-C3-28 | 0.5 | no route | Evap purge solenoid | — | |
| W35 | OEM-2-I | T12-C3-29 | 0.5 | no route | Tachometer output | — | |
| W36 | OEM-2-N | T12-C2-5 | 0.5 | no route | O2 sensor | — | |
| W37 | OEM-2-P | T12-C2-25 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W38 | OEM-1-M | T12-C2-2 | 0.5 | no route | Vehicle speed | — | |
| W39 | OEM-1-C | T12-C2-4 | 0.5 | no route | Start signal | — | |
| W40 | OEM-1-O | T12-C2-8 | 0.5 | no route | Stop light switch | — | |
| W41 | OEM-1-P | T12-C2-11 | 0.5 | no route | Power steering pressure switch | — | |
| W42 | OEM-1-Q | T12-C2-14 | 0.5 | no route | A/C request | — | |
| W43 | OEM-1-V | T12-C2-15 | 0.5 | no route | Neutral/clutch switch | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|---|---|---|---|---|
| connector | 174515-6 | TE | AMP Multilock .040/.070 hybrid 22-pin female harness plug (Miata NA/NB ECU) | 1.000 | ea |
| connector | 174516-6 | TE | AMP Multilock .040/.070 hybrid 26-pin female harness plug (Miata NA/NB ECU) | 1.000 | ea |
| connector | 4-1437290-0 | TE | Superseal 1.0 34-way plug, Key 1 | 3.000 | ea |
| terminal | 3-1447221-4 | TE | Superseal 1.0 socket terminal, 20 AWG (0.5 sq mm) | 37.000 | ea |
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (3)
| Severity | Code | Subject | Message |
|---|---|---|---|
| error | PHYS_REQUIRED_OPEN | T12-C3-27 | T12-C3-27 "Permanent 12v" is required but not wired. |
| info | NET_FAMILY | OEM-2-I ↔ T12-C3-29 | OEM-2-I "Tachometer output" [tacho_out] is wired to T12-C3-29 "PWM 11" [low_side_out]. Tacho as a low-side output: check the tach needs a pull-up. |
| info | UNMAPPED | OEM | 8 optional OEM pins are not mapped: OEM-1-D Data link connector; OEM-1-I Powertrain control module (transmission); OEM-1-N Powertrain control module (transmission); OEM-1-S Heater control unit; OEM-1-T Unknown; OEM-1-U Unknown; OEM-2-H Data link connector; OEM-2-J EGR function sensor |
Accepted (0)
| Code | Subject | Reason | By |
|---|
Notes
Fit check: unconfirmed. Confirm these before building: - Trigger pattern for Mazda BP-ZE not found in the ECU's docs (NA8 not named.) Auto-mapped by auto_map() from the library pin data on 2026-10-11. Review every wire against both manuals before building. Open items: - T12-C3 27: Permanent 12v: required by DTAFast T12 but no stock pin feeds it; wire by hand Not wired: - OEM-1 D: Data link connector: no free k_line on DTAFast T12 - OEM-2 H: Data link connector: no free k_line on DTAFast T12 - OEM-1 I: Powertrain control module (transmission): not classified in the library; wire by hand - OEM-1 N: Powertrain control module (transmission): not classified in the library; wire by hand - OEM-1 S: Heater control unit: not classified in the library; wire by hand - OEM-1 T: Unknown: not classified in the library; wire by hand - OEM-1 U: Unknown: not classified in the library; wire by hand - OEM-2 J: EGR function sensor: not classified in the library; wire by hand
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | vendor_doc | DTAFast T12+ ECU wiring diagram (served for T12 and T12+) | https://cdn.shopify.com/s/files/1/0848/7508/4108/files/T12PLUS_Wiring-Diagram.pdf?v=1728572014 | — | — | — |
| 4 | vendor_doc | Link G4X MX5X install manual (NA 1.6/1.8) | https://linkecu.com/documentation/MX5X.pdf | archive | 2026-10-05 | b7f730de9f6e |
| 2 | expert_report | Justin Barrera — Miata NA/NB wiring corrections | — | — | — | — |
| 2 | community_copy | rusefi wiki: 1994 Mazda Miata 1.8 (NA8) ECU pinout | https://github.com/rusefi/rusefi/wiki/Mazda-Miata-1994 | — | 2026-10-08 | 075801b907f4 |