MX-5 Miata NA8 1994-97 (BP-ZE, 1.8) → DTAFast T4+ (auto)
MX-5 Miata NA8 1994-95 (BP-ZE, 1.8, OBD-I) — DTAFast — T4+
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-09
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 | 39 wires · 8 connectors · 2 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-1-B | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | SP-14V-1 | T4-C1-31 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | OEM-1-A | T4-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 | T4-C1-13 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | SP-GND-1 | T4-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 | T4-C2-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | SP-0V-1 | T4-C2-33 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-2-K | T4-C2-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-2-E | T4-C2-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-2-G | T4-C2-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-1-G | T4-C1-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-1-H | T4-C1-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-2-U | T4-C1-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-2-V | T4-C1-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-2-Y | T4-C1-34 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-2-Z | T4-C1-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-1-J | T4-C1-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-1-R | T4-C1-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-2-S | T4-C1-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-2-T | T4-C3-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-2-W | T4-C3-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-1-E | T4-C3-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-2-R | T4-C3-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-2-X | T4-C3-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-2-O | T4-C2-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-2-M | T4-C2-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-2-N | T4-C2-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-2-Q | T4-C2-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-2-P | T4-C2-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-1-M | T4-C2-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-1-C | T4-C2-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-1-P | T4-C2-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-1-Q | T4-C2-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-1-V | T4-C2-6 | 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 | T4-C1-31 | T4-C1-13 | open (OL) | +12 V supply must not touch power ground | |
| 2 | T4-C1-31 | T4-C2-21 | open (OL) | +12 V supply must not touch sensor ground | |
| 3 | T4-C3-26 | T4-C1-13 | open (OL) | +12 V supply must not touch power ground | |
| 4 | T4-C3-26 | T4-C2-21 | open (OL) | +12 V supply must not touch sensor ground | |
| 5 | T4-C1-13 | T4-C2-24 | open (OL) | power ground must not touch 5 V sensor reference | |
| 6 | T4-C1-31 | T4-C2-24 | open (OL) | +12 V supply must not touch 5 V sensor reference | |
| 7 | T4-C2-21 | T4-C2-24 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 8 | T4-C3-26 | T4-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 | T4-C3-26 | — | — | — |
| B | ECU power +14V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| C | Start signal | — | W36 | — | 0.5 | T4-C2-4 | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | W27 | — | 0.5 | T4-C3-24 | — | — | — |
| G | Ignition 1 (coils 1+4, wasted spark) | — | W16 | — | 0.5 | T4-C1-10 | — | — | — |
| H | Ignition 2 (coils 2+3, wasted spark) | — | W17 | — | 0.5 | T4-C1-18 | — | — | — |
| J | A/C relay | — | W22 | — | 0.5 | T4-C1-5 | — | — | — |
| M | Vehicle speed | — | W35 | — | 0.5 | T4-C2-2 | — | — | — |
| P | Power steering pressure switch | — | W37 | — | 0.5 | T4-C2-14 | — | — | — |
| Q | A/C request | — | W38 | — | 0.5 | T4-C2-15 | — | — | — |
| R | Cooling fan relay | — | W23 | — | 0.5 | T4-C1-4 | — | — | — |
| V | Neutral/clutch switch | — | W39 | — | 0.5 | T4-C2-6 | — | — | — |
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 | T4-C2-12 | — | — | — |
| F | MAF ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| G | Cam position (CAS G) | — | W15 | — | 0.5 | T4-C2-22 | — | — | — |
| I | Tachometer output | — | — | — | — | — | — | — | — |
| K | +5V sensor supply | — | W13 | — | 0.5 | T4-C2-24 | — | — | — |
| M | Throttle position (TPS) | — | W31 | — | 0.5 | T4-C2-1 | — | — | — |
| N | O2 sensor | — | W32 | — | 0.5 | T4-C2-5 | — | — | — |
| O | Mass air flow (MAF) | — | W30 | — | 0.5 | T4-C2-10 | — | — | — |
| P | Intake air temperature (IAT) | — | W34 | — | 0.5 | T4-C2-25 | — | — | — |
| Q | Coolant temperature (ECT) | — | W33 | — | 0.5 | T4-C2-7 | — | — | — |
| R | PRC solenoid (fuel pressure regulator) | — | W28 | — | 0.5 | T4-C3-25 | — | — | — |
| S | Condenser fan relay | — | W24 | — | 0.5 | T4-C1-3 | — | — | — |
| T | Fuel pump relay | — | W25 | — | 0.5 | T4-C3-22 | — | — | — |
| U | Injector 1 | — | W18 | — | 0.5 | T4-C1-9 | — | — | — |
| V | Injector 2 | — | W19 | — | 0.5 | T4-C1-17 | — | — | — |
| W | ISC solenoid | — | W26 | — | 0.5 | T4-C3-23 | — | — | — |
| X | Evap purge solenoid | — | W29 | — | 0.5 | T4-C3-10 | — | — | — |
| Y | Injector 3 | — | W20 | — | 0.5 | T4-C1-34 | — | — | — |
| Z | Injector 4 | — | W21 | — | 0.5 | T4-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 | T4-C2-21 | — | — | — |
| 1 | — | — | W12 | — | 0.5 | T4-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 | T4-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 | T4-C1-13 | — | — | — |
| 1 | — | — | W7 | — | 0.85 | T4-C1-14 | — | — | — |
T4-C1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Coil 3 | — | — | — | — | — | — | — | — |
| 10 | Coil 1 | — | W16 | — | 0.5 | OEM-1-G | — | — | — |
| 13 | Power Ground 1 | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | Power Ground 2 | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 17 | Injector 2 | — | W19 | — | 0.5 | OEM-2-V | — | — | — |
| 18 | Coil 2 | — | W17 | — | 0.5 | OEM-1-H | — | — | — |
| 25 | Injector 4 | — | W21 | — | 0.5 | OEM-2-Z | — | — | — |
| 26 | Coil 4 | — | — | — | — | — | — | — | — |
| 3 | PWM 3 | — | W24 | — | 0.5 | OEM-2-S | — | — | — |
| 31 | Ignition 12v In | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 34 | Injector 3 | — | W20 | — | 0.5 | OEM-2-Y | — | — | — |
| 4 | PWM 2 | — | W23 | — | 0.5 | OEM-1-R | — | — | — |
| 5 | PWM 1 | — | W22 | — | 0.5 | OEM-1-J | — | — | — |
| 6 | Motor 1 + | — | — | — | — | — | — | — | — |
| 7 | Motor 1 - | — | — | — | — | — | — | — | — |
| 9 | Injector 1 | — | W18 | — | 0.5 | OEM-2-U | — | — | — |
T4-C2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Analogue 2 | — | W31 | — | 0.5 | OEM-2-M | — | — | — |
| 10 | Analogue 1 | — | W30 | — | 0.5 | OEM-2-O | — | — | — |
| 12 | Crank | — | W14 | — | 0.5 | OEM-2-E | — | — | — |
| 14 | Digital 4 | — | W37 | — | 0.5 | OEM-1-P | — | — | — |
| 15 | Digital 5 | — | W38 | — | 0.5 | OEM-1-Q | — | — | — |
| 16 | Analogue 11 | — | — | — | — | — | — | — | — |
| 17 | Thermistor 3 | — | — | — | — | — | — | — | — |
| 19 | Analogue 6 | — | — | — | — | — | — | — | — |
| 2 | Wheel 1 | — | W35 | — | 0.5 | OEM-1-M | — | — | — |
| 21 | Sensor Ground | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 22 | Cam 1 | — | W15 | — | 0.5 | OEM-2-G | — | — | — |
| 24 | 5v Output | — | W13 | — | 0.5 | OEM-2-K | — | — | — |
| 25 | Thermistor 2 | — | W34 | — | 0.5 | OEM-2-P | — | — | — |
| 26 | CAN High | — | — | — | — | — | — | — | — |
| 28 | CAN Low | — | — | — | — | — | — | — | — |
| 3 | Analogue 10 | — | — | — | — | — | — | — | — |
| 33 | Sensor Ground | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 34 | Analogue 9 | — | — | — | — | — | — | — | — |
| 4 | Digital 1 | — | W36 | — | 0.5 | OEM-1-C | — | — | — |
| 5 | Analogue 3 | — | W32 | — | 0.5 | OEM-2-N | — | — | — |
| 6 | Analogue 4 | — | W39 | — | 0.5 | OEM-1-V | — | — | — |
| 7 | Thermistor 1 | — | W33 | — | 0.5 | OEM-2-Q | — | — | — |
| 9 | 5v Output | — | — | — | — | — | — | — | — |
T4-C3
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 10 | PWM 8 | — | W29 | — | 0.5 | OEM-2-X | — | — | — |
| 11 | Lambda 1 Trim Resistor | — | — | — | — | — | — | — | — |
| 12 | Lambda 1 Nernst Voltage | — | — | — | — | — | — | — | — |
| 17 | Analogue 7 | — | — | — | — | — | — | — | — |
| 18 | Analogue 8 | — | — | — | — | — | — | — | — |
| 22 | PWM 4 | — | W25 | — | 0.5 | OEM-2-T | — | — | — |
| 23 | PWM 5 | — | W26 | — | 0.5 | OEM-2-W | — | — | — |
| 24 | PWM 6 | — | W27 | — | 0.5 | OEM-1-E | — | — | — |
| 25 | PWM 7 | — | W28 | — | 0.5 | OEM-2-R | — | — | — |
| 26 | Permanent 12v | — | W3 | — | 0.85 | OEM-1-A | — | — | — |
| 27 | Permanent 12v | — | — | — | — | — | — | — | — |
| 7 | Lambda 1 Pump Current | — | — | — | — | — | — | — | — |
| 8 | Lambda 1 VGND | — | — | — | — | — | — | — | — |
| 9 | Lambda 1 Heater Negative | — | — | — | — | — | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-1-A | Constant +12V | power_in | T4-C3-26 | Permanent 12v | power_in | single_source | |
| OEM-1-B | ECU power +14V (main relay) | power_in | T4-C1-31 | Ignition 12v In | power_in | single_source | |
| OEM-1-C | Start signal | digital_in | T4-C2-4 | Digital 1 | digital_in | single_source | |
| OEM-1-E | Malfunction indicator lamp (MIL) | low_side_out | T4-C3-24 | PWM 6 | low_side_out | single_source | |
| OEM-1-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | T4-C1-10 | Coil 1 | ignition_out | single_source | |
| OEM-1-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | T4-C1-18 | Coil 2 | ignition_out | single_source | |
| OEM-1-J | A/C relay | low_side_out | T4-C1-5 | PWM 1 | low_side_out | single_source | |
| OEM-1-M | Vehicle speed | digital_in | T4-C2-2 | Wheel 1 | digital_in | single_source | |
| OEM-1-P | Power steering pressure switch | digital_in | T4-C2-14 | Digital 4 | digital_in | single_source | |
| OEM-1-Q | A/C request | digital_in | T4-C2-15 | Digital 5 | digital_in | single_source | |
| OEM-1-R | Cooling fan relay | low_side_out | T4-C1-4 | PWM 2 | low_side_out | single_source | |
| OEM-1-V | Neutral/clutch switch | digital_in | T4-C2-6 | Analogue 4 | analog_in | single_source | |
| OEM-2-A | Power ground | ground | T4-C1-13 + T4-C1-14 | Power Ground 1 + Power Ground 2 | ground | single_source | |
| OEM-2-B | Power ground | ground | T4-C1-13 + T4-C1-14 | Power Ground 1 + Power Ground 2 | ground | single_source | |
| OEM-2-C | Sensor ground (E2) | sensor_ground | T4-C2-21 + T4-C2-33 | Sensor Ground + Sensor Ground | sensor_ground | corroborated | |
| OEM-2-D | Sensor ground (E2) | sensor_ground | T4-C2-21 + T4-C2-33 | Sensor Ground + Sensor Ground | sensor_ground | corroborated | |
| OEM-2-E | Crank position (CAS NE) | trigger_in | T4-C2-12 | Crank | trigger_in | single_source | |
| OEM-2-F | MAF ground | sensor_ground | T4-C2-21 + T4-C2-33 | Sensor Ground + Sensor Ground | sensor_ground | single_source | |
| OEM-2-G | Cam position (CAS G) | trigger_in | T4-C2-22 | Cam 1 | trigger_in | single_source | |
| OEM-2-I | Tachometer output | tacho_out | — | — | — | single_source | |
| OEM-2-K | +5V sensor supply | vref | T4-C2-24 | 5v Output | vref | single_source | |
| OEM-2-M | Throttle position (TPS) | analog_in | T4-C2-1 | Analogue 2 | analog_in | single_source | |
| OEM-2-N | O2 sensor | lambda_nb_in | T4-C2-5 | Analogue 3 | analog_in | single_source | |
| OEM-2-O | Mass air flow (MAF) | analog_in | T4-C2-10 | Analogue 1 | analog_in | single_source | |
| OEM-2-P | Intake air temperature (IAT) | temp_in | T4-C2-25 | Thermistor 2 | temp_in | single_source | |
| OEM-2-Q | Coolant temperature (ECT) | temp_in | T4-C2-7 | Thermistor 1 | temp_in | single_source | |
| OEM-2-R | PRC solenoid (fuel pressure regulator) | low_side_out | T4-C3-25 | PWM 7 | low_side_out | single_source | |
| OEM-2-S | Condenser fan relay | low_side_out | T4-C1-3 | PWM 3 | low_side_out | single_source | |
| OEM-2-T | Fuel pump relay | low_side_out | T4-C3-22 | PWM 4 | low_side_out | single_source | |
| OEM-2-U | Injector 1 | injector_out | T4-C1-9 | Injector 1 | injector_out | single_source | |
| OEM-2-V | Injector 2 | injector_out | T4-C1-17 | Injector 2 | injector_out | single_source | |
| OEM-2-W | ISC solenoid | low_side_out | T4-C3-23 | PWM 5 | low_side_out | single_source | |
| OEM-2-X | Evap purge solenoid | low_side_out | T4-C3-10 | PWM 8 | low_side_out | single_source | |
| OEM-2-Y | Injector 3 | injector_out | T4-C1-34 | Injector 3 | injector_out | single_source | |
| OEM-2-Z | Injector 4 | injector_out | T4-C1-25 | 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 | T4-C1-31 | 0.85 | no route | Ignition 12v In | — | |
| W3 | OEM-1-A | T4-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 | T4-C1-13 | 0.85 | no route | Power Ground 1 | — | |
| W7 | SP-GND-1 | T4-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 | T4-C2-21 | 0.5 | no route | Sensor Ground | — | |
| W12 | SP-0V-1 | T4-C2-33 | 0.5 | no route | Sensor Ground | — | |
| W13 | OEM-2-K | T4-C2-24 | 0.5 | no route | +5V sensor supply | — | |
| W14 | OEM-2-E | T4-C2-12 | 0.5 | no route | Crank position (CAS NE) | — | |
| W15 | OEM-2-G | T4-C2-22 | 0.5 | no route | Cam position (CAS G) | — | |
| W16 | OEM-1-G | T4-C1-10 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W17 | OEM-1-H | T4-C1-18 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W18 | OEM-2-U | T4-C1-9 | 0.5 | no route | Injector 1 | — | |
| W19 | OEM-2-V | T4-C1-17 | 0.5 | no route | Injector 2 | — | |
| W20 | OEM-2-Y | T4-C1-34 | 0.5 | no route | Injector 3 | — | |
| W21 | OEM-2-Z | T4-C1-25 | 0.5 | no route | Injector 4 | — | |
| W22 | OEM-1-J | T4-C1-5 | 0.5 | no route | A/C relay | — | |
| W23 | OEM-1-R | T4-C1-4 | 0.5 | no route | Cooling fan relay | — | |
| W24 | OEM-2-S | T4-C1-3 | 0.5 | no route | Condenser fan relay | — | |
| W25 | OEM-2-T | T4-C3-22 | 0.5 | no route | Fuel pump relay | — | |
| W26 | OEM-2-W | T4-C3-23 | 0.5 | no route | ISC solenoid | — | |
| W27 | OEM-1-E | T4-C3-24 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W28 | OEM-2-R | T4-C3-25 | 0.5 | no route | PRC solenoid (fuel pressure regulator) | — | |
| W29 | OEM-2-X | T4-C3-10 | 0.5 | no route | Evap purge solenoid | — | |
| W30 | OEM-2-O | T4-C2-10 | 0.5 | no route | Mass air flow (MAF) | — | |
| W31 | OEM-2-M | T4-C2-1 | 0.5 | no route | Throttle position (TPS) | — | |
| W32 | OEM-2-N | T4-C2-5 | 0.5 | no route | O2 sensor | — | |
| W33 | OEM-2-Q | T4-C2-7 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W34 | OEM-2-P | T4-C2-25 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W35 | OEM-1-M | T4-C2-2 | 0.5 | no route | Vehicle speed | — | |
| W36 | OEM-1-C | T4-C2-4 | 0.5 | no route | Start signal | — | |
| W37 | OEM-1-P | T4-C2-14 | 0.5 | no route | Power steering pressure switch | — | |
| W38 | OEM-1-Q | T4-C2-15 | 0.5 | no route | A/C request | — | |
| W39 | OEM-1-V | T4-C2-6 | 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 |
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 | T4-C3-27 | T4-C3-27 "Permanent 12v" is required but not wired. |
| warn | NET_FAMILY | OEM-1-V ↔ T4-C2-6 | OEM-1-V "Neutral/clutch switch" [digital_in] is wired to T4-C2-6 "Analogue 4" [analog_in]. Analog and digital on one net. A switch on an analog input works with a pull-up and a threshold; an analog sensor on a digital input loses its value. |
| info | UNMAPPED | OEM | 1 optional OEM pins are not mapped: OEM-2-I Tachometer output |
Accepted (0)
| Code | Subject | Reason | By |
|---|
Notes
Auto-mapped by auto_map() from the library pin data on 2026-10-09. Review every wire against both manuals before building. Open items: - T4-C3 27: Permanent 12v: required by DTAFast T4+ but no stock pin feeds it; wire by hand Not wired: - OEM-2 I: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on DTAFast T4+
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | vendor_doc | DTAFast T4+ ECU wiring diagram | https://cdn.shopify.com/s/files/1/0848/7508/4108/files/T4PLUS_Wiring_Diagram.pdf?v=1789412534 | — | — | — |
| 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 |