MX-5 Miata NB1 1999-00 (BP-4W) → DTAFast T4 (auto)
MX-5 Miata NB1 1999-00 (BP-4W) — 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.
Install modifications
Steps on the car itself, outside the harness. Every harness for this car inherits them.
- Re-route the pressure-sensor vacuum hose to the intake manifoldrequired
Re-route the pressure sensor's (Mazda "EGR boost sensor", pin 3S) vacuum hose directly to the intake manifold, bypassing the EGR boost solenoid. The stock ECU multiplexes baro + MAP through that solenoid: with it off the sensor reads atmosphere, with it energized it reads manifold (2000 FSM P0107/P0108). After re-routing the sensor reads MAP only, so the standalone needs its own barometric source — its onboard baro sensor if fitted, or a separate baro sensor on a spare analog input. (Alternative, not recommended: keep the hose stock and have the ECU energize the solenoid permanently via a low-side output switched with ignition; this costs an output.)
Why: With the solenoid off (its default) the sensor reads atmospheric pressure, not manifold pressure, so a standalone that uses this sensor as its MAP input would read the wrong value.
Where: EGR boost solenoid and the pressure sensor's vacuum hose (sensor signal 3S).
Source: 2000 Mazda MX-5 Miata factory service manual — engine self-diagnostics (DTC P0106/P0107/P0108)
| 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 | 45 wires · 9 connectors · 3 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 | OEM-3-M | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | SP-14V-1 | T4-C1-31 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-1-A | T4-C3-26 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-3-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-3-B | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-3-C | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | SP-GND-1 | T4-C1-13 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-GND-1 | T4-C1-14 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | OEM-3-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-I | T4-C2-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-2-J | T4-C2-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-2-H | T4-C2-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-3-G | T4-C1-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-3-H | T4-C1-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-3-W | T4-C1-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-3-X | T4-C1-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-3-Y | T4-C1-34 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-3-Z | T4-C1-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-1-I | T4-C1-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-1-R | T4-C1-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-1-S | T4-C1-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-3-N | T4-C3-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-1-U | T4-C3-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-3-V | T4-C3-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-3-O | T4-C3-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-1-E | T4-C3-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-1-O | T4-C3-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-2-L | T4-C2-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-3-S | T4-C2-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-3-E | T4-C2-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-2-C | T4-C2-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-3-J | T4-C2-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-2-E | T4-C2-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-2-B | T4-C2-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-2-A | T4-C3-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-3-K | T4-C3-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-2-D | T4-C2-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-1-F | T4-C2-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-1-G | T4-C2-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-1-P | T4-C2-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-1-V | T4-C2-34 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-3-I | T4-C2-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ |
Bench test (before first power-up)
Pre-power install steps (make these cuts/modifications on the car first, then verify the checks below): Re-route the pressure-sensor vacuum hose to the intake manifold.
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-C2-24 | T4-C1-13 | open (OL) | 5 V sensor reference must not touch power ground | |
| 4 | T4-C2-24 | T4-C2-21 | open (OL) | 5 V sensor reference must not touch sensor ground | |
| 5 | T4-C3-26 | T4-C1-13 | open (OL) | +12 V supply must not touch power ground | |
| 6 | T4-C3-26 | T4-C2-21 | open (OL) | +12 V supply must not touch sensor ground | |
| 7 | T4-C1-31 | T4-C2-24 | open (OL) | +12 V supply 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 | — | W4 | — | 0.85 | T4-C3-26 | — | — | — |
| B | ECU power +14V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | W29 | — | 0.5 | T4-C3-25 | — | — | — |
| F | Brake switch | — | W41 | — | 0.5 | T4-C2-4 | — | — | — |
| G | Power steering pressure switch | — | W42 | — | 0.5 | T4-C2-14 | — | — | — |
| I | Condenser fan relay | — | W22 | — | 0.5 | T4-C1-5 | — | — | — |
| O | Alternator control | — | W30 | — | 0.5 | T4-C3-10 | — | — | — |
| P | A/C request | — | W43 | — | 0.5 | T4-C2-15 | — | — | — |
| Q | Charge lamp | — | — | — | — | — | — | — | — |
| R | Cooling fan relay | — | W23 | — | 0.5 | T4-C1-4 | — | — | — |
| S | A/C clutch relay | — | W24 | — | 0.5 | T4-C1-3 | — | — | — |
| U | Front O2 heater | — | W26 | — | 0.5 | T4-C3-9 | — | — | — |
| V | Neutral switch | — | W44 | — | 0.5 | T4-C2-34 | — | — | — |
OEM-2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Fuel tank pressure | — | W38 | — | 0.5 | T4-C3-17 | — | — | — |
| B | Intake air temperature (IAT) | — | W37 | — | 0.5 | T4-C2-25 | — | — | — |
| C | Front O2 signal | — | W34 | — | 0.5 | T4-C2-6 | — | — | — |
| D | Vehicle speed | — | W40 | — | 0.5 | T4-C2-2 | — | — | — |
| E | Coolant temperature (ECT) | — | W36 | — | 0.5 | T4-C2-7 | — | — | — |
| F | Knock sensor | — | — | — | — | — | — | — | — |
| H | Cam position (CMP) | — | W15 | — | 0.5 | T4-C2-22 | — | — | — |
| I | +5V sensor supply | — | W13 | — | 0.5 | T4-C2-24 | — | — | — |
| J | Crank position (CKP) | — | W14 | — | 0.5 | T4-C2-12 | — | — | — |
| K | Tachometer output | — | — | — | — | — | — | — | — |
| L | Mass air flow (MAF) | — | W31 | — | 0.5 | T4-C2-10 | — | — | — |
| M | EGR valve | — | — | — | — | — | — | — | — |
| N | EGR valve | — | — | — | — | — | — | — | — |
| O | EGR valve | — | — | — | — | — | — | — | — |
| P | EGR valve | — | — | — | — | — | — | — | — |
OEM-3
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Power ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| B | Power ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| C | Power ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| E | Throttle position (TPS) | — | W33 | — | 0.5 | T4-C2-5 | — | — | — |
| F | Signal ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| 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 | — | — | — |
| I | Clutch switch | — | W45 | — | 0.5 | T4-C2-3 | — | — | — |
| J | Rear O2 signal | — | W35 | — | 0.5 | T4-C2-19 | — | — | — |
| K | Fuel level | — | W39 | — | 0.5 | T4-C3-18 | — | — | — |
| L | Evap purge solenoid | — | — | — | — | — | — | — | — |
| M | ISC valve +14V feed | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| N | Fuel pump relay | — | W25 | — | 0.5 | T4-C3-22 | — | — | — |
| O | ISC valve low side | — | W28 | — | 0.5 | T4-C3-24 | — | — | — |
| Q | VICS solenoid (intake butterflies) | — | — | — | — | — | — | — | — |
| S | Pressure sensor (Mazda: EGR boost sensor) | — | W32 | — | 0.5 | T4-C2-1 | — | — | — |
| T | EGR boost solenoid | — | — | — | — | — | — | — | — |
| U | Canister drain cut valve (CDCV) | — | — | — | — | — | — | — | — |
| V | Rear O2 heater | — | W27 | — | 0.5 | T4-C3-23 | — | — | — |
| W | Injector 1 | — | W18 | — | 0.5 | T4-C1-9 | — | — | — |
| X | Injector 2 | — | W19 | — | 0.5 | T4-C1-17 | — | — | — |
| 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 | — | — | W10 | — | 0.5 | OEM-3-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 | OEM-3-M | — | — | — |
| 1 | — | — | W3 | — | 0.85 | T4-C1-31 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W5 | — | 0.85 | OEM-3-A | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-3-B | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-3-C | — | — | — |
| 1 | — | — | W8 | — | 0.85 | T4-C1-13 | — | — | — |
| 1 | — | — | W9 | — | 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-3-G | — | — | — |
| 13 | Power Ground 1 | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | Power Ground 2 | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| 17 | Injector 2 | — | W19 | — | 0.5 | OEM-3-X | — | — | — |
| 18 | Coil 2 | — | W17 | — | 0.5 | OEM-3-H | — | — | — |
| 25 | Injector 4 | — | W21 | — | 0.5 | OEM-3-Z | — | — | — |
| 26 | Coil 4 | — | — | — | — | — | — | — | — |
| 3 | PWM 3 | — | W24 | — | 0.5 | OEM-1-S | — | — | — |
| 31 | Ignition 12v In | — | W3 | — | 0.85 | SP-14V-1 | — | — | — |
| 34 | Injector 3 | — | W20 | — | 0.5 | OEM-3-Y | — | — | — |
| 4 | PWM 2 | — | W23 | — | 0.5 | OEM-1-R | — | — | — |
| 5 | PWM 1 | — | W22 | — | 0.5 | OEM-1-I | — | — | — |
| 9 | Injector 1 | — | W18 | — | 0.5 | OEM-3-W | — | — | — |
T4-C2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Analogue 2 | — | W32 | — | 0.5 | OEM-3-S | — | — | — |
| 10 | Analogue 1 | — | W31 | — | 0.5 | OEM-2-L | — | — | — |
| 12 | Crank | — | W14 | — | 0.5 | OEM-2-J | — | — | — |
| 14 | Digital 4 | — | W42 | — | 0.5 | OEM-1-G | — | — | — |
| 15 | Digital 5 | — | W43 | — | 0.5 | OEM-1-P | — | — | — |
| 16 | Analogue 11 | — | — | — | — | — | — | — | — |
| 17 | Thermistor 3 | — | — | — | — | — | — | — | — |
| 19 | Analogue 6 | — | W35 | — | 0.5 | OEM-3-J | — | — | — |
| 2 | Wheel 1 | — | W40 | — | 0.5 | OEM-2-D | — | — | — |
| 21 | Sensor Ground | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 22 | Cam 1 | — | W15 | — | 0.5 | OEM-2-H | — | — | — |
| 24 | 5v Output | — | W13 | — | 0.5 | OEM-2-I | — | — | — |
| 25 | Thermistor 2 | — | W37 | — | 0.5 | OEM-2-B | — | — | — |
| 26 | CAN High | — | — | — | — | — | — | — | — |
| 28 | CAN Low | — | — | — | — | — | — | — | — |
| 3 | Analogue 10 | — | W45 | — | 0.5 | OEM-3-I | — | — | — |
| 33 | Sensor Ground | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 34 | Analogue 9 | — | W44 | — | 0.5 | OEM-1-V | — | — | — |
| 4 | Digital 1 | — | W41 | — | 0.5 | OEM-1-F | — | — | — |
| 5 | Analogue 3 | — | W33 | — | 0.5 | OEM-3-E | — | — | — |
| 6 | Analogue 4 | — | W34 | — | 0.5 | OEM-2-C | — | — | — |
| 7 | Thermistor 1 | — | W36 | — | 0.5 | OEM-2-E | — | — | — |
| 9 | 5v Output | — | — | — | — | — | — | — | — |
T4-C3
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 10 | PWM 8 | — | W30 | — | 0.5 | OEM-1-O | — | — | — |
| 11 | Lambda 1 Trim Resistor | — | — | — | — | — | — | — | — |
| 12 | Lambda 1 Nernst Voltage | — | — | — | — | — | — | — | — |
| 17 | Analogue 7 | — | W38 | — | 0.5 | OEM-2-A | — | — | — |
| 18 | Analogue 8 | — | W39 | — | 0.5 | OEM-3-K | — | — | — |
| 22 | PWM 4 | — | W25 | — | 0.5 | OEM-3-N | — | — | — |
| 23 | PWM 5 | — | W27 | — | 0.5 | OEM-3-V | — | — | — |
| 24 | PWM 6 | — | W28 | — | 0.5 | OEM-3-O | — | — | — |
| 25 | PWM 7 | — | W29 | — | 0.5 | OEM-1-E | — | — | — |
| 26 | Permanent 12v | — | W4 | — | 0.85 | OEM-1-A | — | — | — |
| 27 | Permanent 12v | — | — | — | — | — | — | — | — |
| 7 | Lambda 1 Pump Current | — | — | — | — | — | — | — | — |
| 8 | Lambda 1 VGND | — | — | — | — | — | — | — | — |
| 9 | Lambda 1 Heater Negative | — | W26 | — | 0.5 | OEM-1-U | — | — | — |
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-E | Malfunction indicator lamp (MIL) | low_side_out | T4-C3-25 | PWM 7 | low_side_out | single_source | |
| OEM-1-F | Brake switch | digital_in | T4-C2-4 | Digital 1 | digital_in | single_source | |
| OEM-1-G | Power steering pressure switch | digital_in | T4-C2-14 | Digital 4 | digital_in | single_source | |
| OEM-1-I | Condenser fan relay | low_side_out | T4-C1-5 | PWM 1 | low_side_out | single_source | |
| OEM-1-O | Alternator control | low_side_out | T4-C3-10 | PWM 8 | low_side_out | single_source | |
| OEM-1-P | A/C request | digital_in | T4-C2-15 | Digital 5 | digital_in | single_source | |
| OEM-1-Q | Charge lamp | low_side_out | — | — | — | single_source | |
| OEM-1-R | Cooling fan relay | low_side_out | T4-C1-4 | PWM 2 | low_side_out | single_source | |
| OEM-1-S | A/C clutch relay | low_side_out | T4-C1-3 | PWM 3 | low_side_out | single_source | |
| OEM-1-U | Front O2 heater | low_side_out | T4-C3-9 | Lambda 1 Heater Negative | low_side_out | single_source | |
| OEM-1-V | Neutral switch | digital_in | T4-C2-34 | Analogue 9 | analog_in | single_source | |
| OEM-2-A | Fuel tank pressure | analog_in | T4-C3-17 | Analogue 7 | analog_in | single_source | |
| OEM-2-B | Intake air temperature (IAT) | temp_in | T4-C2-25 | Thermistor 2 | temp_in | single_source | |
| OEM-2-C | Front O2 signal | lambda_nb_in | T4-C2-6 | Analogue 4 | analog_in | single_source | |
| OEM-2-D | Vehicle speed | digital_in | T4-C2-2 | Wheel 1 | digital_in | single_source | |
| OEM-2-E | Coolant temperature (ECT) | temp_in | T4-C2-7 | Thermistor 1 | temp_in | single_source | |
| OEM-2-F | Knock sensor | knock_in | — | — | — | single_source | |
| OEM-2-H | Cam position (CMP) | trigger_in | T4-C2-22 | Cam 1 | trigger_in | single_source | |
| OEM-2-I | +5V sensor supply | vref | T4-C2-24 | 5v Output | vref | single_source | |
| OEM-2-J | Crank position (CKP) | trigger_in | T4-C2-12 | Crank | trigger_in | single_source | |
| OEM-2-K | Tachometer output | tacho_out | — | — | — | single_source | |
| OEM-2-L | Mass air flow (MAF) | analog_in | T4-C2-10 | Analogue 1 | analog_in | single_source | |
| OEM-2-M | EGR valve | low_side_out | — | — | — | single_source | |
| OEM-2-N | EGR valve | low_side_out | — | — | — | single_source | |
| OEM-2-O | EGR valve | low_side_out | — | — | — | single_source | |
| OEM-2-P | EGR valve | low_side_out | — | — | — | single_source | |
| OEM-3-A | Power ground | ground | T4-C1-13 + T4-C1-14 | Power Ground 1 + Power Ground 2 | ground | single_source | |
| OEM-3-B | Power ground | ground | T4-C1-13 + T4-C1-14 | Power Ground 1 + Power Ground 2 | ground | single_source | |
| OEM-3-C | Power ground | ground | T4-C1-13 + T4-C1-14 | Power Ground 1 + Power Ground 2 | ground | single_source | |
| OEM-3-E | Throttle position (TPS) | analog_in | T4-C2-5 | Analogue 3 | analog_in | single_source | |
| OEM-3-F | Signal ground | sensor_ground | T4-C2-21 + T4-C2-33 | Sensor Ground + Sensor Ground | sensor_ground | single_source | |
| OEM-3-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | T4-C1-10 | Coil 1 | ignition_out | single_source | |
| OEM-3-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | T4-C1-18 | Coil 2 | ignition_out | single_source | |
| OEM-3-I | Clutch switch | digital_in | T4-C2-3 | Analogue 10 | analog_in | single_source | |
| OEM-3-J | Rear O2 signal | lambda_nb_in | T4-C2-19 | Analogue 6 | analog_in | single_source | |
| OEM-3-K | Fuel level | analog_in | T4-C3-18 | Analogue 8 | analog_in | single_source | |
| OEM-3-L | Evap purge solenoid | low_side_out | — | — | — | single_source | |
| OEM-3-M | ISC valve +14V feed | power_in | T4-C1-31 | Ignition 12v In | power_in | single_source | |
| OEM-3-N | Fuel pump relay | low_side_out | T4-C3-22 | PWM 4 | low_side_out | single_source | |
| OEM-3-O | ISC valve low side | low_side_out | T4-C3-24 | PWM 6 | low_side_out | single_source | |
| OEM-3-Q | VICS solenoid (intake butterflies) | low_side_out | — | — | — | single_source | |
| OEM-3-S | Pressure sensor (Mazda: EGR boost sensor) | analog_in | T4-C2-1 | Analogue 2 | analog_in | single_source | |
| OEM-3-T | EGR boost solenoid | — | — | — | — | single_source | |
| OEM-3-U | Canister drain cut valve (CDCV) | low_side_out | — | — | — | single_source | |
| OEM-3-V | Rear O2 heater | low_side_out | T4-C3-23 | PWM 5 | low_side_out | single_source | |
| OEM-3-W | Injector 1 | injector_out | T4-C1-9 | Injector 1 | injector_out | single_source | |
| OEM-3-X | Injector 2 | injector_out | T4-C1-17 | Injector 2 | injector_out | single_source | |
| OEM-3-Y | Injector 3 | injector_out | T4-C1-34 | Injector 3 | injector_out | single_source | |
| OEM-3-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 | OEM-3-M | SP-14V-1 | 0.85 | no route | ISC valve +14V feed | — | |
| W3 | SP-14V-1 | T4-C1-31 | 0.85 | no route | Ignition 12v In | — | |
| W4 | OEM-1-A | T4-C3-26 | 0.85 | no route | Constant +12V | — | |
| W5 | OEM-3-A | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W6 | OEM-3-B | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W7 | OEM-3-C | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W8 | SP-GND-1 | T4-C1-13 | 0.85 | no route | Power Ground 1 | — | |
| W9 | SP-GND-1 | T4-C1-14 | 0.85 | no route | Power Ground 2 | — | |
| W10 | OEM-3-F | SP-0V-1 | 0.5 | no route | Signal 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-I | T4-C2-24 | 0.5 | no route | +5V sensor supply | — | |
| W14 | OEM-2-J | T4-C2-12 | 0.5 | no route | Crank position (CKP) | — | |
| W15 | OEM-2-H | T4-C2-22 | 0.5 | no route | Cam position (CMP) | — | |
| W16 | OEM-3-G | T4-C1-10 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W17 | OEM-3-H | T4-C1-18 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W18 | OEM-3-W | T4-C1-9 | 0.5 | no route | Injector 1 | — | |
| W19 | OEM-3-X | T4-C1-17 | 0.5 | no route | Injector 2 | — | |
| W20 | OEM-3-Y | T4-C1-34 | 0.5 | no route | Injector 3 | — | |
| W21 | OEM-3-Z | T4-C1-25 | 0.5 | no route | Injector 4 | — | |
| W22 | OEM-1-I | T4-C1-5 | 0.5 | no route | Condenser fan relay | — | |
| W23 | OEM-1-R | T4-C1-4 | 0.5 | no route | Cooling fan relay | — | |
| W24 | OEM-1-S | T4-C1-3 | 0.5 | no route | A/C clutch relay | — | |
| W25 | OEM-3-N | T4-C3-22 | 0.5 | no route | Fuel pump relay | — | |
| W26 | OEM-1-U | T4-C3-9 | 0.5 | no route | Front O2 heater | — | |
| W27 | OEM-3-V | T4-C3-23 | 0.5 | no route | Rear O2 heater | — | |
| W28 | OEM-3-O | T4-C3-24 | 0.5 | no route | ISC valve low side | — | |
| W29 | OEM-1-E | T4-C3-25 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W30 | OEM-1-O | T4-C3-10 | 0.5 | no route | Alternator control | — | |
| W31 | OEM-2-L | T4-C2-10 | 0.5 | no route | Mass air flow (MAF) | — | |
| W32 | OEM-3-S | T4-C2-1 | 0.5 | no route | Pressure sensor (Mazda: EGR boost sensor) | — | |
| W33 | OEM-3-E | T4-C2-5 | 0.5 | no route | Throttle position (TPS) | — | |
| W34 | OEM-2-C | T4-C2-6 | 0.5 | no route | Front O2 signal | — | |
| W35 | OEM-3-J | T4-C2-19 | 0.5 | no route | Rear O2 signal | — | |
| W36 | OEM-2-E | T4-C2-7 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W37 | OEM-2-B | T4-C2-25 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W38 | OEM-2-A | T4-C3-17 | 0.5 | no route | Fuel tank pressure | — | |
| W39 | OEM-3-K | T4-C3-18 | 0.5 | no route | Fuel level | — | |
| W40 | OEM-2-D | T4-C2-2 | 0.5 | no route | Vehicle speed | — | |
| W41 | OEM-1-F | T4-C2-4 | 0.5 | no route | Brake switch | — | |
| W42 | OEM-1-G | T4-C2-14 | 0.5 | no route | Power steering pressure switch | — | |
| W43 | OEM-1-P | T4-C2-15 | 0.5 | no route | A/C request | — | |
| W44 | OEM-1-V | T4-C2-34 | 0.5 | no route | Neutral switch | — | |
| W45 | OEM-3-I | T4-C2-3 | 0.5 | no route | Clutch switch | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|---|---|---|---|---|
| connector | 174514-6 | TE | AMP Multilock .040/.070 hybrid 16-pin female harness plug (Miata NB1 ECU) | 1.000 | ea |
| 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 (4)
| 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-C2-34 | OEM-1-V "Neutral switch" [digital_in] is wired to T4-C2-34 "Analogue 9" [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. |
| warn | NET_FAMILY | OEM-3-I ↔ T4-C2-3 | OEM-3-I "Clutch switch" [digital_in] is wired to T4-C2-3 "Analogue 10" [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 | 11 optional OEM pins are not mapped: OEM-1-Q Charge lamp; OEM-2-F Knock sensor; OEM-2-K Tachometer output; OEM-2-M EGR valve; OEM-2-N EGR valve; OEM-2-O EGR valve; OEM-2-P EGR valve; OEM-3-L Evap purge solenoid; OEM-3-Q VICS solenoid (intake butterflies); OEM-3-T EGR boost solenoid; OEM-3-U Canister drain cut valve (CDCV) |
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 F: Knock sensor: no free knock input on DTAFast T4 - OEM-1 Q: Charge lamp: no free low_side/ls_hs/injector/hbridge on DTAFast T4 - OEM-2 M: EGR valve: no free low_side/ls_hs/injector/hbridge on DTAFast T4 - OEM-2 N: EGR valve: no free low_side/ls_hs/injector/hbridge on DTAFast T4 - OEM-2 O: EGR valve: no free low_side/ls_hs/injector/hbridge on DTAFast T4 - OEM-2 P: EGR valve: no free low_side/ls_hs/injector/hbridge on DTAFast T4 - OEM-3 L: Evap purge solenoid: no free low_side/ls_hs/injector/hbridge on DTAFast T4 - OEM-3 Q: VICS solenoid (intake butterflies): no free low_side/ls_hs/injector/hbridge on DTAFast T4 - OEM-3 U: Canister drain cut valve (CDCV): no free low_side/ls_hs/injector/hbridge on DTAFast T4 - OEM-2 K: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on DTAFast T4 - OEM-3 T: EGR boost solenoid: not classified in the library; wire by hand
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/T4_Wiring_Diagram.pdf?v=1789413067 | — | — | — |
| 4 | vendor_doc | Link G4X MX5NB1X install manual (NB1 1999-00) | https://linkecu.com/documentation/MX5XNB1.pdf | archive | 2026-10-05 | 2e36c91270cc |
| 2 | expert_report | Justin Barrera — Miata NA/NB wiring corrections | — | — | — | — |