MX-5 Miata NB2 2001-05 (BP-Z3, VVT; excludes Mazdaspeed) → DTAFast T12 (auto)
MX-5 Miata NB2 2001-05 (BP-Z3, VVT; excludes Mazdaspeed) — DTAFast — T12
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-10
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 4AE) 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. 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 4AE).
Source: Justin Barrera — Miata NA/NB wiring corrections
| 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 | 57 wires · 9 connectors · 2 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-2-P | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | OEM-4-AF | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | OEM-4-D | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | SP-14V-1 | T12-C1-31 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-4-AG | T12-C3-26 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-3-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-3-B | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | OEM-4-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-GND-1 | T12-C1-13 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | SP-GND-1 | T12-C1-14 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | OEM-4-O | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | SP-0V-1 | T12-C2-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | SP-0V-1 | T12-C2-33 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-4-L | T12-C2-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-3-Y | T12-C2-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-3-V | T12-C2-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-4-M | T12-C3-31 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-3-F | T12-C1-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-3-I | T12-C1-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-2-A | T12-C1-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-2-D | T12-C1-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-2-G | T12-C1-34 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-2-J | T12-C1-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-2-B | T12-C1-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-2-C | T12-C1-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-2-K | T12-C1-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-2-M | T12-C3-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-3-H | T12-C3-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-3-J | T12-C3-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-3-P | T12-C3-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-2-Q | T12-C3-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-2-E | T12-C3-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-2-F | T12-C3-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-2-H | T12-C3-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-2-I | T12-C3-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-2-N | T12-C3-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-2-R | T12-C3-30 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-3-E | T12-C1-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-3-M | T12-C1-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-3-U | T12-C1-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-4-R | T12-C1-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-4-X | T12-C2-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-4-AE | T12-C2-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-4-V | T12-C2-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-4-AA | T12-C2-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W46 | OEM-4-W | T12-C2-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W47 | OEM-4-P | T12-C2-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W48 | OEM-4-N | T12-C2-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W49 | OEM-4-AD | T12-C2-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W50 | OEM-3-T | T12-C2-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W51 | OEM-3-S | T12-C2-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W52 | OEM-4-B | T12-C2-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W53 | OEM-4-C | T12-C2-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W54 | OEM-4-F | T12-C2-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W55 | OEM-4-H | T12-C2-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W56 | OEM-4-I | T12-C2-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W57 | OEM-4-J | T12-C3-19 | 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 | 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-C2-24 | T12-C2-21 | open (OL) | 5 V sensor reference must not touch sensor 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-C1-13 | T12-C3-26 | open (OL) | power ground must not touch +12 V supply | |
| 7 | T12-C1-31 | T12-C2-24 | open (OL) | +12 V supply 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-2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Injector 1 | — | W20 | — | 0.5 | T12-C1-9 | — | — | — |
| B | Cooling fan relay | — | W24 | — | 0.5 | T12-C1-5 | — | — | — |
| C | Condenser fan relay | — | W25 | — | 0.5 | T12-C1-4 | — | — | — |
| D | Injector 2 | — | W21 | — | 0.5 | T12-C1-17 | — | — | — |
| E | EGR valve | — | W32 | — | 0.5 | T12-C3-25 | — | — | — |
| F | EGR valve | — | W33 | — | 0.5 | T12-C3-10 | — | — | — |
| G | Injector 3 | — | W22 | — | 0.5 | T12-C1-34 | — | — | — |
| H | EGR valve | — | W34 | — | 0.5 | T12-C3-4 | — | — | — |
| I | EGR valve | — | W35 | — | 0.5 | T12-C3-28 | — | — | — |
| J | Injector 4 | — | W23 | — | 0.5 | T12-C1-25 | — | — | — |
| K | A/C clutch relay | — | W26 | — | 0.5 | T12-C1-3 | — | — | — |
| M | Fuel pump relay | — | W27 | — | 0.5 | T12-C3-22 | — | — | — |
| N | VTCS solenoid (intake butterflies) | — | W36 | — | 0.5 | T12-C3-29 | — | — | — |
| P | ISC valve +14V feed | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| Q | ISC valve low side | — | W31 | — | 0.5 | T12-C3-24 | — | — | — |
| R | Malfunction indicator lamp (MIL) | — | W37 | — | 0.5 | T12-C3-30 | — | — | — |
OEM-3
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Power ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| B | Power ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| D | EGR boost solenoid | — | — | — | — | — | — | — | — |
| E | Charcoal canister purge | — | W38 | — | 0.5 | T12-C1-16 | — | — | — |
| F | Ignition 1 (coils 1+4, wasted spark) | — | W18 | — | 0.5 | T12-C1-10 | — | — | — |
| H | Main relay | — | W28 | — | 0.5 | T12-C3-23 | — | — | — |
| I | Ignition 2 (coils 2+3, wasted spark) | — | W19 | — | 0.5 | T12-C1-18 | — | — | — |
| J | Front O2 heater | — | W29 | — | 0.5 | T12-C3-9 | — | — | — |
| M | Alternator control | — | W39 | — | 0.5 | T12-C1-15 | — | — | — |
| O | Tachometer output | — | — | — | — | — | — | — | — |
| P | Rear O2 heater | — | W30 | — | 0.5 | T12-C3-3 | — | — | — |
| S | Immobiliser | — | W51 | — | 0.5 | T12-C2-4 | — | — | — |
| T | Vehicle speed | — | W50 | — | 0.5 | T12-C2-2 | — | — | — |
| U | Charge lamp | — | W40 | — | 0.5 | T12-C1-24 | — | — | — |
| V | Cam position (CMP) | — | W16 | — | 0.5 | T12-C2-22 | — | — | — |
| Y | Crank position (CKP) | — | W15 | — | 0.5 | T12-C2-12 | — | — | — |
OEM-4
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Power ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| AA | Rear O2 signal | — | W45 | — | 0.5 | T12-C2-6 | — | — | — |
| AD | Fuel level | — | W49 | — | 0.5 | T12-C2-19 | — | — | — |
| AE | Pressure sensor (Mazda: EGR boost sensor) | — | W43 | — | 0.5 | T12-C2-1 | — | — | — |
| AF | ECU power +14V (main relay) | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| AG | Constant +12V | — | W5 | — | 0.85 | T12-C3-26 | — | — | — |
| B | Brake switch | — | W52 | — | 0.5 | T12-C2-8 | — | — | — |
| C | Power steering pressure switch | — | W53 | — | 0.5 | T12-C2-11 | — | — | — |
| D | VVT oil-control solenoid +12V feed | — | W3 | — | 0.85 | SP-14V-1 | — | — | — |
| F | A/C request | — | W54 | — | 0.5 | T12-C2-14 | — | — | — |
| H | Neutral switch | — | W55 | — | 0.5 | T12-C2-15 | — | — | — |
| I | Clutch switch | — | W56 | — | 0.5 | T12-C2-27 | — | — | — |
| J | VTCS vacuum switch | — | W57 | — | 0.5 | T12-C3-19 | — | — | — |
| L | +5V sensor supply | — | W14 | — | 0.5 | T12-C2-24 | — | — | — |
| M | Knock sensor | — | W17 | — | 0.5 | T12-C3-31 | — | — | — |
| N | Intake air temperature (IAT) | — | W48 | — | 0.5 | T12-C2-25 | — | — | — |
| O | Signal ground | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| P | Coolant temperature (ECT) | — | W47 | — | 0.5 | T12-C2-7 | — | — | — |
| R | VVT oil-control solenoid (low-side control) | — | W41 | — | 0.5 | T12-C1-23 | — | — | — |
| V | Throttle position (TPS) | — | W44 | — | 0.5 | T12-C2-5 | — | — | — |
| W | Front O2 signal | — | W46 | — | 0.5 | T12-C2-18 | — | — | — |
| X | Mass air flow (MAF) | — | W42 | — | 0.5 | T12-C2-10 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W11 | — | 0.5 | OEM-4-O | — | — | — |
| 1 | — | — | W12 | — | 0.5 | T12-C2-21 | — | — | — |
| 1 | — | — | W13 | — | 0.5 | T12-C2-33 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-2-P | — | — | — |
| 1 | — | — | W2 | — | 0.85 | OEM-4-AF | — | — | — |
| 1 | — | — | W3 | — | 0.85 | OEM-4-D | — | — | — |
| 1 | — | — | W4 | — | 0.85 | T12-C1-31 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W6 | — | 0.85 | OEM-3-A | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-3-B | — | — | — |
| 1 | — | — | W8 | — | 0.85 | OEM-4-A | — | — | — |
| 1 | — | — | W9 | — | 0.85 | T12-C1-13 | — | — | — |
| 1 | — | — | W10 | — | 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 | — | W26 | — | 0.5 | OEM-2-K | — | — | — |
| 4 | PWM 2 | — | W25 | — | 0.5 | OEM-2-C | — | — | — |
| 5 | PWM 1 | — | W24 | — | 0.5 | OEM-2-B | — | — | — |
| 6 | Motor 1 + | — | — | — | — | — | — | — | — |
| 7 | Motor 1 - | — | — | — | — | — | — | — | — |
| 8 | Injector 11 | — | — | — | — | — | — | — | — |
| 9 | Injector 1 | — | W20 | — | 0.5 | OEM-2-A | — | — | — |
| 10 | Coil 1 | — | W18 | — | 0.5 | OEM-3-F | — | — | — |
| 11 | Coil 5 | — | — | — | — | — | — | — | — |
| 12 | Coil 7 | — | — | — | — | — | — | — | — |
| 13 | Power Ground 1 | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | Power Ground 2 | — | W10 | — | 0.85 | SP-GND-1 | — | — | — |
| 15 | Injector 6 | — | W39 | — | 0.5 | OEM-3-M | — | — | — |
| 16 | Injector 5 | — | W38 | — | 0.5 | OEM-3-E | — | — | — |
| 17 | Injector 2 | — | W21 | — | 0.5 | OEM-2-D | — | — | — |
| 18 | Coil 2 | — | W19 | — | 0.5 | OEM-3-I | — | — | — |
| 19 | Coil 8 | — | — | — | — | — | — | — | — |
| 20 | Coil 9 | — | — | — | — | — | — | — | — |
| 21 | Injector 9 | — | — | — | — | — | — | — | — |
| 22 | Injector 10 | — | — | — | — | — | — | — | — |
| 23 | Injector 8 | — | W41 | — | 0.5 | OEM-4-R | — | — | — |
| 24 | Injector 7 | — | W40 | — | 0.5 | OEM-3-U | — | — | — |
| 25 | Injector 4 | — | W23 | — | 0.5 | OEM-2-J | — | — | — |
| 26 | Coil 4 | — | — | — | — | — | — | — | — |
| 27 | Coil 6 | — | — | — | — | — | — | — | — |
| 28 | Coil 10 | — | — | — | — | — | — | — | — |
| 29 | Motor 2 + | — | — | — | — | — | — | — | — |
| 30 | Motor 2 - | — | — | — | — | — | — | — | — |
| 31 | Ignition 12v In | — | W4 | — | 0.85 | SP-14V-1 | — | — | — |
| 32 | Injector 12 | — | — | — | — | — | — | — | — |
| 33 | Coil 12 | — | — | — | — | — | — | — | — |
| 34 | Injector 3 | — | W22 | — | 0.5 | OEM-2-G | — | — | — |
T12-C2
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Analogue 2 | — | W43 | — | 0.5 | OEM-4-AE | — | — | — |
| 2 | Wheel 1 | — | W50 | — | 0.5 | OEM-3-T | — | — | — |
| 3 | Analogue 10 | — | — | — | — | — | — | — | — |
| 4 | Digital 1 | — | W51 | — | 0.5 | OEM-3-S | — | — | — |
| 5 | Analogue 3 | — | W44 | — | 0.5 | OEM-4-V | — | — | — |
| 6 | Analogue 4 | — | W45 | — | 0.5 | OEM-4-AA | — | — | — |
| 7 | Thermistor 1 | — | W47 | — | 0.5 | OEM-4-P | — | — | — |
| 8 | Digital 2 | — | W52 | — | 0.5 | OEM-4-B | — | — | — |
| 9 | 5v Output | — | — | — | — | — | — | — | — |
| 10 | Analogue 1 | — | W42 | — | 0.5 | OEM-4-X | — | — | — |
| 11 | Digital 3 | — | W53 | — | 0.5 | OEM-4-C | — | — | — |
| 12 | Crank | — | W15 | — | 0.5 | OEM-3-Y | — | — | — |
| 13 | Analogue 12 | — | — | — | — | — | — | — | — |
| 14 | Digital 4 | — | W54 | — | 0.5 | OEM-4-F | — | — | — |
| 15 | Digital 5 | — | W55 | — | 0.5 | OEM-4-H | — | — | — |
| 16 | Analogue 11 | — | — | — | — | — | — | — | — |
| 17 | Thermistor 3 | — | — | — | — | — | — | — | — |
| 18 | Analogue 5 | — | W46 | — | 0.5 | OEM-4-W | — | — | — |
| 19 | Analogue 6 | — | W49 | — | 0.5 | OEM-4-AD | — | — | — |
| 20 | Wheel 2 | — | — | — | — | — | — | — | — |
| 21 | Sensor Ground | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 22 | Cam 1 | — | W16 | — | 0.5 | OEM-3-V | — | — | — |
| 23 | Cam 3 | — | — | — | — | — | — | — | — |
| 24 | 5v Output | — | W14 | — | 0.5 | OEM-4-L | — | — | — |
| 25 | Thermistor 2 | — | W48 | — | 0.5 | OEM-4-N | — | — | — |
| 26 | CAN High | — | — | — | — | — | — | — | — |
| 27 | Digital 6 | — | W56 | — | 0.5 | OEM-4-I | — | — | — |
| 28 | CAN Low | — | — | — | — | — | — | — | — |
| 29 | Cam 2 | — | — | — | — | — | — | — | — |
| 30 | Cam 4 | — | — | — | — | — | — | — | — |
| 31 | Wheel 3 | — | — | — | — | — | — | — | — |
| 32 | Wheel 4 | — | — | — | — | — | — | — | — |
| 33 | Sensor Ground | — | W13 | — | 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 | — | W30 | — | 0.5 | OEM-3-P | — | — | — |
| 4 | PWM 9 | — | W34 | — | 0.5 | OEM-2-H | — | — | — |
| 5 | Lambda 2 Trim Resistor | — | — | — | — | — | — | — | — |
| 6 | Lambda 2 Nernst Voltage | — | — | — | — | — | — | — | — |
| 7 | Lambda 1 Pump Current | — | — | — | — | — | — | — | — |
| 8 | Lambda 1 VGND | — | — | — | — | — | — | — | — |
| 9 | Lambda 1 Heater Negative | — | W29 | — | 0.5 | OEM-3-J | — | — | — |
| 10 | PWM 8 | — | W33 | — | 0.5 | OEM-2-F | — | — | — |
| 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 | — | W57 | — | 0.5 | OEM-4-J | — | — | — |
| 20 | Digital 8 | — | — | — | — | — | — | — | — |
| 21 | Digital 9 | — | — | — | — | — | — | — | — |
| 22 | PWM 4 | — | W27 | — | 0.5 | OEM-2-M | — | — | — |
| 23 | PWM 5 | — | W28 | — | 0.5 | OEM-3-H | — | — | — |
| 24 | PWM 6 | — | W31 | — | 0.5 | OEM-2-Q | — | — | — |
| 25 | PWM 7 | — | W32 | — | 0.5 | OEM-2-E | — | — | — |
| 26 | Permanent 12v | — | W5 | — | 0.85 | OEM-4-AG | — | — | — |
| 27 | Permanent 12v | — | — | — | — | — | — | — | — |
| 28 | PWM 10 | — | W35 | — | 0.5 | OEM-2-I | — | — | — |
| 29 | PWM 11 | — | W36 | — | 0.5 | OEM-2-N | — | — | — |
| 30 | PWM 12 | — | W37 | — | 0.5 | OEM-2-R | — | — | — |
| 31 | Knock 1 | — | W17 | — | 0.5 | OEM-4-M | — | — | — |
| 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-2-A | Injector 1 | injector_out | T12-C1-9 | Injector 1 | injector_out | single_source | |
| OEM-2-B | Cooling fan relay | low_side_out | T12-C1-5 | PWM 1 | low_side_out | single_source | |
| OEM-2-C | Condenser fan relay | low_side_out | T12-C1-4 | PWM 2 | low_side_out | single_source | |
| OEM-2-D | Injector 2 | injector_out | T12-C1-17 | Injector 2 | injector_out | single_source | |
| OEM-2-E | EGR valve | low_side_out | T12-C3-25 | PWM 7 | low_side_out | single_source | |
| OEM-2-F | EGR valve | low_side_out | T12-C3-10 | PWM 8 | low_side_out | single_source | |
| OEM-2-G | Injector 3 | injector_out | T12-C1-34 | Injector 3 | injector_out | single_source | |
| OEM-2-H | EGR valve | low_side_out | T12-C3-4 | PWM 9 | low_side_out | single_source | |
| OEM-2-I | EGR valve | low_side_out | T12-C3-28 | PWM 10 | low_side_out | single_source | |
| OEM-2-J | Injector 4 | injector_out | T12-C1-25 | Injector 4 | injector_out | single_source | |
| OEM-2-K | A/C clutch relay | low_side_out | T12-C1-3 | PWM 3 | low_side_out | single_source | |
| OEM-2-M | Fuel pump relay | low_side_out | T12-C3-22 | PWM 4 | low_side_out | single_source | |
| OEM-2-N | VTCS solenoid (intake butterflies) | low_side_out | T12-C3-29 | PWM 11 | low_side_out | single_source | |
| OEM-2-P | ISC valve +14V feed | power_in | T12-C1-31 | Ignition 12v In | power_in | single_source | |
| OEM-2-Q | ISC valve low side | low_side_out | T12-C3-24 | PWM 6 | low_side_out | single_source | |
| OEM-2-R | Malfunction indicator lamp (MIL) | low_side_out | T12-C3-30 | PWM 12 | low_side_out | single_source | |
| OEM-3-A | Power ground | ground | T12-C1-13 + T12-C1-14 | Power Ground 1 + Power Ground 2 | ground | single_source | |
| OEM-3-B | Power ground | ground | T12-C1-13 + T12-C1-14 | Power Ground 1 + Power Ground 2 | ground | single_source | |
| OEM-3-D | EGR boost solenoid | — | — | — | — | single_source | |
| OEM-3-E | Charcoal canister purge | low_side_out | T12-C1-16 | Injector 5 | injector_out | single_source | |
| OEM-3-F | Ignition 1 (coils 1+4, wasted spark) | ignition_out | T12-C1-10 | Coil 1 | ignition_out | single_source | |
| OEM-3-H | Main relay | low_side_out | T12-C3-23 | PWM 5 | low_side_out | single_source | |
| OEM-3-I | Ignition 2 (coils 2+3, wasted spark) | ignition_out | T12-C1-18 | Coil 2 | ignition_out | single_source | |
| OEM-3-J | Front O2 heater | low_side_out | T12-C3-9 | Lambda 1 Heater Negative | low_side_out | single_source | |
| OEM-3-M | Alternator control | low_side_out | T12-C1-15 | Injector 6 | injector_out | single_source | |
| OEM-3-O | Tachometer output | tacho_out | — | — | — | single_source | |
| OEM-3-P | Rear O2 heater | low_side_out | T12-C3-3 | Lambda 2 Heater Negative | low_side_out | single_source | |
| OEM-3-S | Immobiliser | digital_in | T12-C2-4 | Digital 1 | digital_in | single_source | |
| OEM-3-T | Vehicle speed | digital_in | T12-C2-2 | Wheel 1 | digital_in | single_source | |
| OEM-3-U | Charge lamp | low_side_out | T12-C1-24 | Injector 7 | injector_out | single_source | |
| OEM-3-V | Cam position (CMP) | trigger_in | T12-C2-22 | Cam 1 | trigger_in | single_source | |
| OEM-3-Y | Crank position (CKP) | trigger_in | T12-C2-12 | Crank | trigger_in | single_source | |
| OEM-4-A | Power ground | ground | T12-C1-13 + T12-C1-14 | Power Ground 1 + Power Ground 2 | ground | single_source | |
| OEM-4-AA | Rear O2 signal | lambda_nb_in | T12-C2-6 | Analogue 4 | analog_in | single_source | |
| OEM-4-AD | Fuel level | analog_in | T12-C2-19 | Analogue 6 | analog_in | single_source | |
| OEM-4-AE | Pressure sensor (Mazda: EGR boost sensor) | analog_in | T12-C2-1 | Analogue 2 | analog_in | corroborated | |
| OEM-4-AF | ECU power +14V (main relay) | power_in | T12-C1-31 | Ignition 12v In | power_in | single_source | |
| OEM-4-AG | Constant +12V | power_in | T12-C3-26 | Permanent 12v | power_in | single_source | |
| OEM-4-B | Brake switch | digital_in | T12-C2-8 | Digital 2 | digital_in | single_source | |
| OEM-4-C | Power steering pressure switch | digital_in | T12-C2-11 | Digital 3 | digital_in | single_source | |
| OEM-4-D | VVT oil-control solenoid +12V feed | power_in | T12-C1-31 | Ignition 12v In | power_in | Y | single_source |
| OEM-4-F | A/C request | digital_in | T12-C2-14 | Digital 4 | digital_in | single_source | |
| OEM-4-H | Neutral switch | digital_in | T12-C2-15 | Digital 5 | digital_in | single_source | |
| OEM-4-I | Clutch switch | digital_in | T12-C2-27 | Digital 6 | digital_in | single_source | |
| OEM-4-J | VTCS vacuum switch | digital_in | T12-C3-19 | Digital 7 | digital_in | single_source | |
| OEM-4-L | +5V sensor supply | vref | T12-C2-24 | 5v Output | vref | single_source | |
| OEM-4-M | Knock sensor | knock_in | T12-C3-31 | Knock 1 | knock_in | single_source | |
| OEM-4-N | Intake air temperature (IAT) | temp_in | T12-C2-25 | Thermistor 2 | temp_in | single_source | |
| OEM-4-O | Signal ground | sensor_ground | T12-C2-21 + T12-C2-33 | Sensor Ground + Sensor Ground | sensor_ground | single_source | |
| OEM-4-P | Coolant temperature (ECT) | temp_in | T12-C2-7 | Thermistor 1 | temp_in | single_source | |
| OEM-4-R | VVT oil-control solenoid (low-side control) | low_side_out | T12-C1-23 | Injector 8 | injector_out | VY | corroborated |
| OEM-4-V | Throttle position (TPS) | analog_in | T12-C2-5 | Analogue 3 | analog_in | single_source | |
| OEM-4-W | Front O2 signal | lambda_nb_in | T12-C2-18 | Analogue 5 | analog_in | single_source | |
| OEM-4-X | Mass air flow (MAF) | analog_in | T12-C2-10 | Analogue 1 | analog_in | single_source |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-2-P | SP-14V-1 | 0.85 | no route | ISC valve +14V feed | — | |
| W2 | OEM-4-AF | SP-14V-1 | 0.85 | no route | ECU power +14V (main relay) | — | |
| W3 | OEM-4-D | SP-14V-1 | 0.85 | no route | VVT oil-control solenoid +12V feed | — | |
| W4 | SP-14V-1 | T12-C1-31 | 0.85 | no route | Ignition 12v In | — | |
| W5 | OEM-4-AG | T12-C3-26 | 0.85 | no route | Constant +12V | — | |
| W6 | OEM-3-A | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W7 | OEM-3-B | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W8 | OEM-4-A | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W9 | SP-GND-1 | T12-C1-13 | 0.85 | no route | Power Ground 1 | — | |
| W10 | SP-GND-1 | T12-C1-14 | 0.85 | no route | Power Ground 2 | — | |
| W11 | OEM-4-O | SP-0V-1 | 0.5 | no route | Signal ground | — | |
| W12 | SP-0V-1 | T12-C2-21 | 0.5 | no route | Sensor Ground | — | |
| W13 | SP-0V-1 | T12-C2-33 | 0.5 | no route | Sensor Ground | — | |
| W14 | OEM-4-L | T12-C2-24 | 0.5 | no route | +5V sensor supply | — | |
| W15 | OEM-3-Y | T12-C2-12 | 0.5 | no route | Crank position (CKP) | — | |
| W16 | OEM-3-V | T12-C2-22 | 0.5 | no route | Cam position (CMP) | — | |
| W17 | OEM-4-M | T12-C3-31 | 0.5 | no route | Knock sensor | — | |
| W18 | OEM-3-F | T12-C1-10 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W19 | OEM-3-I | T12-C1-18 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W20 | OEM-2-A | T12-C1-9 | 0.5 | no route | Injector 1 | — | |
| W21 | OEM-2-D | T12-C1-17 | 0.5 | no route | Injector 2 | — | |
| W22 | OEM-2-G | T12-C1-34 | 0.5 | no route | Injector 3 | — | |
| W23 | OEM-2-J | T12-C1-25 | 0.5 | no route | Injector 4 | — | |
| W24 | OEM-2-B | T12-C1-5 | 0.5 | no route | Cooling fan relay | — | |
| W25 | OEM-2-C | T12-C1-4 | 0.5 | no route | Condenser fan relay | — | |
| W26 | OEM-2-K | T12-C1-3 | 0.5 | no route | A/C clutch relay | — | |
| W27 | OEM-2-M | T12-C3-22 | 0.5 | no route | Fuel pump relay | — | |
| W28 | OEM-3-H | T12-C3-23 | 0.5 | no route | Main relay | — | |
| W29 | OEM-3-J | T12-C3-9 | 0.5 | no route | Front O2 heater | — | |
| W30 | OEM-3-P | T12-C3-3 | 0.5 | no route | Rear O2 heater | — | |
| W31 | OEM-2-Q | T12-C3-24 | 0.5 | no route | ISC valve low side | — | |
| W32 | OEM-2-E | T12-C3-25 | 0.5 | no route | EGR valve | — | |
| W33 | OEM-2-F | T12-C3-10 | 0.5 | no route | EGR valve | — | |
| W34 | OEM-2-H | T12-C3-4 | 0.5 | no route | EGR valve | — | |
| W35 | OEM-2-I | T12-C3-28 | 0.5 | no route | EGR valve | — | |
| W36 | OEM-2-N | T12-C3-29 | 0.5 | no route | VTCS solenoid (intake butterflies) | — | |
| W37 | OEM-2-R | T12-C3-30 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W38 | OEM-3-E | T12-C1-16 | 0.5 | no route | Charcoal canister purge | — | |
| W39 | OEM-3-M | T12-C1-15 | 0.5 | no route | Alternator control | — | |
| W40 | OEM-3-U | T12-C1-24 | 0.5 | no route | Charge lamp | — | |
| W41 | OEM-4-R | T12-C1-23 | 0.5 | no route | VVT oil-control solenoid (low-side control) | — | |
| W42 | OEM-4-X | T12-C2-10 | 0.5 | no route | Mass air flow (MAF) | — | |
| W43 | OEM-4-AE | T12-C2-1 | 0.5 | no route | Pressure sensor (Mazda: EGR boost sensor) | — | |
| W44 | OEM-4-V | T12-C2-5 | 0.5 | no route | Throttle position (TPS) | — | |
| W45 | OEM-4-AA | T12-C2-6 | 0.5 | no route | Rear O2 signal | — | |
| W46 | OEM-4-W | T12-C2-18 | 0.5 | no route | Front O2 signal | — | |
| W47 | OEM-4-P | T12-C2-7 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W48 | OEM-4-N | T12-C2-25 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W49 | OEM-4-AD | T12-C2-19 | 0.5 | no route | Fuel level | — | |
| W50 | OEM-3-T | T12-C2-2 | 0.5 | no route | Vehicle speed | — | |
| W51 | OEM-3-S | T12-C2-4 | 0.5 | no route | Immobiliser | — | |
| W52 | OEM-4-B | T12-C2-8 | 0.5 | no route | Brake switch | — | |
| W53 | OEM-4-C | T12-C2-11 | 0.5 | no route | Power steering pressure switch | — | |
| W54 | OEM-4-F | T12-C2-14 | 0.5 | no route | A/C request | — | |
| W55 | OEM-4-H | T12-C2-15 | 0.5 | no route | Neutral switch | — | |
| W56 | OEM-4-I | T12-C2-27 | 0.5 | no route | Clutch switch | — | |
| W57 | OEM-4-J | T12-C3-19 | 0.5 | no route | VTCS vacuum switch | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|---|---|---|---|---|
| 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) | 50.000 | ea |
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (6)
| 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-3-E ↔ T12-C1-16 | OEM-3-E "Charcoal canister purge" [low_side_out] is wired to T12-C1-16 "Injector 5" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-3-M ↔ T12-C1-15 | OEM-3-M "Alternator control" [low_side_out] is wired to T12-C1-15 "Injector 6" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-3-U ↔ T12-C1-24 | OEM-3-U "Charge lamp" [low_side_out] is wired to T12-C1-24 "Injector 7" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-4-R ↔ T12-C1-23 | OEM-4-R "VVT oil-control solenoid (low-side control)" [low_side_out] is wired to T12-C1-23 "Injector 8" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | UNMAPPED | OEM | 2 optional OEM pins are not mapped: OEM-3-D EGR boost solenoid; OEM-3-O 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: - T12-C3 27: Permanent 12v: required by DTAFast T12 but no stock pin feeds it; wire by hand Not wired: - OEM-3 O: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on DTAFast T12 - OEM-3 D: EGR boost solenoid: not classified in the library; wire by hand
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | vendor_doc | Adaptronic eSel039 Select Plugin ECU for Mazda MX5 / Miata NB8B/C (OEM ECU pinout) | https://www.miataturbo.net/attachments/ecus-tuning-54/04-msm-ecu-pinout-104032/nb8bc_oem_ecu_pinouts-224948d1602912806 | — | — | — |
| 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 MX5NB2X install manual (NB2 2001-05) | https://linkecu.com/documentation/MX5XNB2.pdf | archive | 2026-10-05 | 741efdd9f2c8 |
| 4 | oem_manual | Mazda MX-5 NB2 (2003) wiring diagram — engine / starting / charging | https://web.archive.org/web/20191104195207/http://mellens.net/mazda/mazda_miata_extra_manual/2003_wiring.pdf | — | 2026-10-05 | 5ee0777f12c1 |
| 2 | expert_report | Justin Barrera — Miata NA/NB wiring corrections | — | — | — | — |