MX-5 Miata NA8 1994-95 (BP-ZE, 1.8, OBD-I) → DTAFast P8 (auto)
MX-5 Miata NA8 1994-95 (BP-ZE, 1.8, OBD-I) — DTAFast — P8
Drawn by Michael Gnankou · Rev 0 · proposal · 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 | proposal · not yet verified: nobody has reported building and running this harness |
|---|---|
| Open errors | none |
| Size of the job | 45 wires · 6 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 | P8-C1-19 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | OEM-2-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-2-B | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | SP-GND-1 | P8-C1-15 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | SP-GND-1 | P8-C1-34 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | SP-GND-1 | P8-C1-55 | 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 | P8-C1-46 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | SP-0V-1 | P8-C1-47 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | SP-0V-1 | P8-C1-49 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | SP-0V-1 | P8-C1-51 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-2-K | P8-C1-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-2-E | P8-C1-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-2-G | P8-C1-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-1-G | P8-C1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-1-H | P8-C1-38 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-2-U | P8-C1-37 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-2-V | P8-C1-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-2-Y | P8-C1-54 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-2-Z | P8-C1-36 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-2-O | P8-C1-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-2-M | P8-C1-48 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-2-Q | P8-C1-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-1-J | P8-C1-41 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-1-R | P8-C1-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-2-S | P8-C1-43 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-2-T | P8-C1-42 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-1-L | P8-C1-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-2-L | P8-C1-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-2-W | P8-C1-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-1-E | P8-C1-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-2-R | P8-C1-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-2-X | P8-C1-35 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-2-I | P8-C1-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-2-N | P8-C1-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-2-P | P8-C1-45 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-1-M | P8-C1-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-1-C | P8-C1-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-1-O | P8-C1-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-1-P | P8-C1-31 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-1-Q | P8-C1-32 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-1-V | P8-C1-33 | 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 | P8-C1-19 | P8-C1-15 | open (OL) | +12 V supply must not touch power ground | |
| 2 | P8-C1-19 | P8-C1-46 | open (OL) | +12 V supply must not touch sensor ground | |
| 3 | P8-C1-15 | P8-C1-10 | open (OL) | power ground must not touch 5 V sensor reference | |
| 4 | P8-C1-19 | P8-C1-10 | open (OL) | +12 V supply must not touch 5 V sensor reference | |
| 5 | P8-C1-46 | P8-C1-10 | open (OL) | sensor ground 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 | — | — | — | — | — | — | — | — |
| B | ECU power +14V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| C | Start signal | — | W41 | — | 0.5 | P8-C1-13 | — | — | — |
| D | Data link connector | — | — | — | — | — | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | W34 | — | 0.5 | P8-C1-6 | — | — | — |
| G | Ignition 1 (coils 1+4, wasted spark) | — | W18 | — | 0.5 | P8-C1-1 | — | — | — |
| H | Ignition 2 (coils 2+3, wasted spark) | — | W19 | — | 0.5 | P8-C1-38 | — | — | — |
| I | Powertrain control module (transmission) | — | — | — | — | — | — | — | — |
| J | A/C relay | — | W27 | — | 0.5 | P8-C1-41 | — | — | — |
| L | Coolant fan relay | — | W31 | — | 0.5 | P8-C1-21 | — | — | — |
| M | Vehicle speed | — | W40 | — | 0.5 | P8-C1-11 | — | — | — |
| N | Powertrain control module (transmission) | — | — | — | — | — | — | — | — |
| O | Stop light switch | — | W42 | — | 0.5 | P8-C1-14 | — | — | — |
| P | Power steering pressure switch | — | W43 | — | 0.5 | P8-C1-31 | — | — | — |
| Q | A/C request | — | W44 | — | 0.5 | P8-C1-32 | — | — | — |
| R | Cooling fan relay | — | W28 | — | 0.5 | P8-C1-5 | — | — | — |
| S | Heater control unit | — | — | — | — | — | — | — | — |
| T | Unknown | — | — | — | — | — | — | — | — |
| U | Unknown | — | — | — | — | — | — | — | — |
| V | Neutral/clutch switch | — | W45 | — | 0.5 | P8-C1-33 | — | — | — |
OEM-2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Power ground | — | W3 | — | 0.85 | SP-GND-1 | — | — | — |
| B | Power ground | — | W4 | — | 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) | — | W16 | — | 0.5 | P8-C1-8 | — | — | — |
| F | MAF ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| G | Cam position (CAS G) | — | W17 | — | 0.5 | P8-C1-27 | — | — | — |
| H | Data link connector | — | — | — | — | — | — | — | — |
| I | Tachometer output | — | W37 | — | 0.5 | P8-C1-24 | — | — | — |
| J | EGR function sensor | — | — | — | — | — | — | — | — |
| K | +5V sensor supply | — | W15 | — | 0.5 | P8-C1-10 | — | — | — |
| L | Rear defroster relay | — | W32 | — | 0.5 | P8-C1-23 | — | — | — |
| M | Throttle position (TPS) | — | W25 | — | 0.5 | P8-C1-48 | — | — | — |
| N | O2 sensor | — | W38 | — | 0.5 | P8-C1-12 | — | — | — |
| O | Mass air flow (MAF) | — | W24 | — | 0.5 | P8-C1-25 | — | — | — |
| P | Intake air temperature (IAT) | — | W39 | — | 0.5 | P8-C1-45 | — | — | — |
| Q | Coolant temperature (ECT) | — | W26 | — | 0.5 | P8-C1-26 | — | — | — |
| R | PRC solenoid (fuel pressure regulator) | — | W35 | — | 0.5 | P8-C1-17 | — | — | — |
| S | Condenser fan relay | — | W29 | — | 0.5 | P8-C1-43 | — | — | — |
| T | Fuel pump relay | — | W30 | — | 0.5 | P8-C1-42 | — | — | — |
| U | Injector 1 | — | W20 | — | 0.5 | P8-C1-37 | — | — | — |
| V | Injector 2 | — | W21 | — | 0.5 | P8-C1-18 | — | — | — |
| W | ISC solenoid | — | W33 | — | 0.5 | P8-C1-4 | — | — | — |
| X | Evap purge solenoid | — | W36 | — | 0.5 | P8-C1-35 | — | — | — |
| Y | Injector 3 | — | W22 | — | 0.5 | P8-C1-54 | — | — | — |
| Z | Injector 4 | — | W23 | — | 0.5 | P8-C1-36 | — | — | — |
P8-C1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Coil 1 | — | W18 | — | 0.5 | OEM-1-G | — | — | — |
| 10 | 5 Volts | — | W15 | — | 0.5 | OEM-2-K | — | — | — |
| 11 | Undriven Wheel (must) | — | W40 | — | 0.5 | OEM-1-M | — | — | — |
| 12 | Lambda Signal | — | W38 | — | 0.5 | OEM-2-N | — | — | — |
| 13 | Map2/ALS/Ana1 On/Off | — | W41 | — | 0.5 | OEM-1-C | — | — | — |
| 14 | Traction Wet/Dry | — | W42 | — | 0.5 | OEM-1-O | — | — | — |
| 15 | Power Ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| 16 | Injector 8 | — | — | — | — | — | — | — | — |
| 17 | Injector 5 | — | W35 | — | 0.5 | OEM-2-R | — | — | — |
| 18 | Injector 2 | — | W21 | — | 0.5 | OEM-2-V | — | — | — |
| 19 | 12 Volts | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 2 | Coil 4 | — | — | — | — | — | — | — | — |
| 20 | Coil 3 | — | — | — | — | — | — | — | — |
| 21 | Turbo Pressure Valve | — | W31 | — | 0.5 | OEM-1-L | — | — | — |
| 22 | Coil 8/or Aux5 | — | — | — | — | — | — | — | — |
| 23 | Turbo ALS Valve | — | W32 | — | 0.5 | OEM-2-L | — | — | — |
| 24 | Tacho | — | W37 | — | 0.5 | OEM-2-I | — | — | — |
| 25 | Analogue Input 1 | — | W24 | — | 0.5 | OEM-2-O | — | — | — |
| 26 | Water Temp | — | W26 | — | 0.5 | OEM-2-Q | — | — | — |
| 27 | Cam Sensor | — | W17 | — | 0.5 | OEM-2-G | — | — | — |
| 28 | 5 Volts | — | — | — | — | — | — | — | — |
| 29 | Left Driven Wheel | — | — | — | — | — | — | — | — |
| 3 | Coil 6 | — | — | — | — | — | — | — | — |
| 30 | Map | — | — | — | — | — | — | — | — |
| 31 | Launch Button | — | W43 | — | 0.5 | OEM-1-P | — | — | — |
| 32 | Traction On/Off | — | W44 | — | 0.5 | OEM-1-Q | — | — | — |
| 33 | Shift Cut | — | W45 | — | 0.5 | OEM-1-V | — | — | — |
| 34 | Power Ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 35 | Injector 6 | — | W36 | — | 0.5 | OEM-2-X | — | — | — |
| 36 | Injector 4 | — | W23 | — | 0.5 | OEM-2-Z | — | — | — |
| 37 | Injector 1 | — | W20 | — | 0.5 | OEM-2-U | — | — | — |
| 38 | Coil 2 | — | W19 | — | 0.5 | OEM-1-H | — | — | — |
| 39 | Coil 5 | — | — | — | — | — | — | — | — |
| 4 | Idle Valve | — | W33 | — | 0.5 | OEM-2-W | — | — | — |
| 40 | Coil 7 | — | — | — | — | — | — | — | — |
| 41 | Fuel Pump Relay | — | W27 | — | 0.5 | OEM-1-J | — | — | — |
| 42 | Cam Phase Valve/Aux Out 4 | — | W30 | — | 0.5 | OEM-2-T | — | — | — |
| 43 | Aux Out 3 | — | W29 | — | 0.5 | OEM-2-S | — | — | — |
| 44 | Analogue Input 3 | — | — | — | — | — | — | — | — |
| 45 | Air Temp | — | W39 | — | 0.5 | OEM-2-P | — | — | — |
| 46 | Signal Ground | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 47 | Signal Ground | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 48 | Throttle Wiper | — | W25 | — | 0.5 | OEM-2-M | — | — | — |
| 49 | Lambda Earth | — | W13 | — | 0.5 | SP-0V-1 | — | — | — |
| 5 | Aux Out 2 | — | W28 | — | 0.5 | OEM-1-R | — | — | — |
| 50 | Undriven Wheel (optional) | — | — | — | — | — | — | — | — |
| 51 | Signal Ground | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| 52 | 5 Volts | — | — | — | — | — | — | — | — |
| 53 | Injector 7 | — | — | — | — | — | — | — | — |
| 54 | Injector 3 | — | W22 | — | 0.5 | OEM-2-Y | — | — | — |
| 55 | Power Ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 6 | Shift Light | — | W34 | — | 0.5 | OEM-1-E | — | — | — |
| 7 | Analogue Input 2 Or Log Switch | — | — | — | — | — | — | — | — |
| 8 | Crank Sensor | — | W16 | — | 0.5 | OEM-2-E | — | — | — |
| 9 | Right Driven Wheel | — | — | — | — | — | — | — | — |
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 | P8-C1-46 | — | — | — |
| 1 | — | — | W12 | — | 0.5 | P8-C1-47 | — | — | — |
| 1 | — | — | W13 | — | 0.5 | P8-C1-49 | — | — | — |
| 1 | — | — | W14 | — | 0.5 | P8-C1-51 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-1-B | — | — | — |
| 1 | — | — | W2 | — | 0.85 | P8-C1-19 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W3 | — | 0.85 | OEM-2-A | — | — | — |
| 1 | — | — | W4 | — | 0.85 | OEM-2-B | — | — | — |
| 1 | — | — | W5 | — | 0.85 | P8-C1-15 | — | — | — |
| 1 | — | — | W6 | — | 0.85 | P8-C1-34 | — | — | — |
| 1 | — | — | W7 | — | 0.85 | P8-C1-55 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-1-A | Constant +12V | power_in | — | — | — | LR | single_source |
| OEM-1-B | ECU power +14V (main relay) | power_in | P8-C1-19 | 12 Volts | power_in | WR | single_source |
| OEM-1-C | Start signal | digital_in | P8-C1-13 | Map2/ALS/Ana1 On/Off | 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 | P8-C1-6 | Shift Light | low_side_out | YB | single_source |
| OEM-1-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | P8-C1-1 | Coil 1 | ignition_out | BrY | single_source |
| OEM-1-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | P8-C1-38 | 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 | P8-C1-41 | Fuel Pump Relay | low_side_out | single_source | |
| OEM-1-L | Coolant fan relay | low_side_out | P8-C1-21 | Turbo Pressure Valve | low_side_out | BG | single_source |
| OEM-1-M | Vehicle speed | digital_in | P8-C1-11 | Undriven Wheel (must) | digital_in | GR | single_source |
| OEM-1-N | Powertrain control module (transmission) | — | — | — | — | R | single_source |
| OEM-1-O | Stop light switch | digital_in | P8-C1-14 | Traction Wet/Dry | digital_in | GB | single_source |
| OEM-1-P | Power steering pressure switch | digital_in | P8-C1-31 | Launch Button | digital_in | LY | single_source |
| OEM-1-Q | A/C request | digital_in | P8-C1-32 | Traction On/Off | digital_in | LgB | single_source |
| OEM-1-R | Cooling fan relay | low_side_out | P8-C1-5 | Aux Out 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 | P8-C1-33 | Shift Cut | digital_in | BrW | single_source |
| OEM-2-A | Power ground | ground | P8-C1-15 + P8-C1-34 + P8-C1-55 | Power Ground + Power Ground + Power Ground | ground | B | single_source |
| OEM-2-B | Power ground | ground | P8-C1-15 + P8-C1-34 + P8-C1-55 | Power Ground + Power Ground + Power Ground | ground | B | single_source |
| OEM-2-C | Sensor ground (E2) | sensor_ground | P8-C1-46 + P8-C1-47 + P8-C1-49 + P8-C1-51 | Signal Ground + Signal Ground + Lambda Earth + Signal Ground | sensor_ground | BLg | corroborated |
| OEM-2-D | Sensor ground (E2) | sensor_ground | P8-C1-46 + P8-C1-47 + P8-C1-49 + P8-C1-51 | Signal Ground + Signal Ground + Lambda Earth + Signal Ground | sensor_ground | BL | corroborated |
| OEM-2-E | Crank position (CAS NE) | trigger_in | P8-C1-8 | Crank Sensor | trigger_in | W | single_source |
| OEM-2-F | MAF ground | sensor_ground | P8-C1-46 + P8-C1-47 + P8-C1-49 + P8-C1-51 | Signal Ground + Signal Ground + Lambda Earth + Signal Ground | sensor_ground | BR | single_source |
| OEM-2-G | Cam position (CAS G) | trigger_in | P8-C1-27 | Cam Sensor | trigger_in | YL | single_source |
| OEM-2-H | Data link connector | serial | — | — | — | LgY | single_source |
| OEM-2-I | Tachometer output | tacho_out | P8-C1-24 | Tacho | tacho_out | BW | single_source |
| OEM-2-J | EGR function sensor | — | — | — | — | LgR | single_source |
| OEM-2-K | +5V sensor supply | vref | P8-C1-10 | 5 Volts | vref | LgW | single_source |
| OEM-2-L | Rear defroster relay | low_side_out | P8-C1-23 | Turbo ALS Valve | low_side_out | LR | single_source |
| OEM-2-M | Throttle position (TPS) | analog_in | P8-C1-48 | Throttle Wiper | analog_in | RB | single_source |
| OEM-2-N | O2 sensor | lambda_nb_in | P8-C1-12 | Lambda Signal | lambda_nb_in | RL | single_source |
| OEM-2-O | Mass air flow (MAF) | analog_in | P8-C1-25 | Analogue Input 1 | analog_in | R | single_source |
| OEM-2-P | Intake air temperature (IAT) | temp_in | P8-C1-45 | Air Temp | temp_in | RB | single_source |
| OEM-2-Q | Coolant temperature (ECT) | temp_in | P8-C1-26 | Water Temp | temp_in | LW | single_source |
| OEM-2-R | PRC solenoid (fuel pressure regulator) | low_side_out | P8-C1-17 | Injector 5 | injector_out | YG | single_source |
| OEM-2-S | Condenser fan relay | low_side_out | P8-C1-43 | Aux Out 3 | low_side_out | LW | single_source |
| OEM-2-T | Fuel pump relay | low_side_out | P8-C1-42 | Cam Phase Valve/Aux Out 4 | low_side_out | Lg | single_source |
| OEM-2-U | Injector 1 | injector_out | P8-C1-37 | Injector 1 | injector_out | Y | single_source |
| OEM-2-V | Injector 2 | injector_out | P8-C1-18 | Injector 2 | injector_out | YB | single_source |
| OEM-2-W | ISC solenoid | low_side_out | P8-C1-4 | Idle Valve | low_side_out | LOr | single_source |
| OEM-2-X | Evap purge solenoid | low_side_out | P8-C1-35 | Injector 6 | injector_out | YR | single_source |
| OEM-2-Y | Injector 3 | injector_out | P8-C1-54 | Injector 3 | injector_out | GW | single_source |
| OEM-2-Z | Injector 4 | injector_out | P8-C1-36 | 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 | P8-C1-19 | 0.85 | no route | 12 Volts | — | |
| W3 | OEM-2-A | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W4 | OEM-2-B | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W5 | SP-GND-1 | P8-C1-15 | 0.85 | no route | Power Ground | — | |
| W6 | SP-GND-1 | P8-C1-34 | 0.85 | no route | Power Ground | — | |
| W7 | SP-GND-1 | P8-C1-55 | 0.85 | no route | Power Ground | — | |
| 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 | P8-C1-46 | 0.5 | no route | Signal Ground | — | |
| W12 | SP-0V-1 | P8-C1-47 | 0.5 | no route | Signal Ground | — | |
| W13 | SP-0V-1 | P8-C1-49 | 0.5 | no route | Lambda Earth | — | |
| W14 | SP-0V-1 | P8-C1-51 | 0.5 | no route | Signal Ground | — | |
| W15 | OEM-2-K | P8-C1-10 | 0.5 | no route | +5V sensor supply | — | |
| W16 | OEM-2-E | P8-C1-8 | 0.5 | no route | Crank position (CAS NE) | — | |
| W17 | OEM-2-G | P8-C1-27 | 0.5 | no route | Cam position (CAS G) | — | |
| W18 | OEM-1-G | P8-C1-1 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W19 | OEM-1-H | P8-C1-38 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W20 | OEM-2-U | P8-C1-37 | 0.5 | no route | Injector 1 | — | |
| W21 | OEM-2-V | P8-C1-18 | 0.5 | no route | Injector 2 | — | |
| W22 | OEM-2-Y | P8-C1-54 | 0.5 | no route | Injector 3 | — | |
| W23 | OEM-2-Z | P8-C1-36 | 0.5 | no route | Injector 4 | — | |
| W24 | OEM-2-O | P8-C1-25 | 0.5 | no route | Mass air flow (MAF) | — | |
| W25 | OEM-2-M | P8-C1-48 | 0.5 | no route | Throttle position (TPS) | — | |
| W26 | OEM-2-Q | P8-C1-26 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W27 | OEM-1-J | P8-C1-41 | 0.5 | no route | A/C relay | — | |
| W28 | OEM-1-R | P8-C1-5 | 0.5 | no route | Cooling fan relay | — | |
| W29 | OEM-2-S | P8-C1-43 | 0.5 | no route | Condenser fan relay | — | |
| W30 | OEM-2-T | P8-C1-42 | 0.5 | no route | Fuel pump relay | — | |
| W31 | OEM-1-L | P8-C1-21 | 0.5 | no route | Coolant fan relay | — | |
| W32 | OEM-2-L | P8-C1-23 | 0.5 | no route | Rear defroster relay | — | |
| W33 | OEM-2-W | P8-C1-4 | 0.5 | no route | ISC solenoid | — | |
| W34 | OEM-1-E | P8-C1-6 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W35 | OEM-2-R | P8-C1-17 | 0.5 | no route | PRC solenoid (fuel pressure regulator) | — | |
| W36 | OEM-2-X | P8-C1-35 | 0.5 | no route | Evap purge solenoid | — | |
| W37 | OEM-2-I | P8-C1-24 | 0.5 | no route | Tachometer output | — | |
| W38 | OEM-2-N | P8-C1-12 | 0.5 | no route | O2 sensor | — | |
| W39 | OEM-2-P | P8-C1-45 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W40 | OEM-1-M | P8-C1-11 | 0.5 | no route | Vehicle speed | — | |
| W41 | OEM-1-C | P8-C1-13 | 0.5 | no route | Start signal | — | |
| W42 | OEM-1-O | P8-C1-14 | 0.5 | no route | Stop light switch | — | |
| W43 | OEM-1-P | P8-C1-31 | 0.5 | no route | Power steering pressure switch | — | |
| W44 | OEM-1-Q | P8-C1-32 | 0.5 | no route | A/C request | — | |
| W45 | OEM-1-V | P8-C1-33 | 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 (8)
| Severity | Code | Subject | Message |
|---|---|---|---|
| warn | LOAD_UNKNOWN | P8-C1-4 | P8-C1-4 "Idle Valve" drives OEM-2-W ISC solenoid (load 1.0 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | P8-C1-41 | P8-C1-41 "Fuel Pump Relay" drives OEM-1-J A/C relay (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | P8-C1-42 | P8-C1-42 "Cam Phase Valve/Aux Out 4" drives OEM-2-T Fuel pump relay (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | P8-C1-43 | P8-C1-43 "Aux Out 3" drives OEM-2-S Condenser fan relay (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | P8-C1-5 | P8-C1-5 "Aux Out 2" drives OEM-1-R Cooling fan relay (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| info | NET_FAMILY | OEM-2-R ↔ P8-C1-17 | OEM-2-R "PRC solenoid (fuel pressure regulator)" [low_side_out] is wired to P8-C1-17 "Injector 5" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-2-X ↔ P8-C1-35 | OEM-2-X "Evap purge solenoid" [low_side_out] is wired to P8-C1-35 "Injector 6" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| 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 (1)
| Code | Subject | Reason | By |
|---|---|---|---|
| REQUIRED_UNMAPPED | OEM-1-A | Battery-constant (memory) feed of the stock ECU: the new ECU has no such input, so it is not needed. | mapping-proposal |
Notes
Auto-mapped by auto_map() from the library pin data on 2026-10-11. Review every wire against both manuals before building. Not wired: - OEM-1 A: Constant +12V: DTAFast P8 has no battery-constant input; not needed - OEM-1 D: Data link connector: no free k_line on DTAFast P8 - OEM-2 H: Data link connector: no free k_line on DTAFast P8 - 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 P8Pro wiring schematic | https://dtafast.co.uk/pages/ecu-wiring-diagrams | — | — | — |
| 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 |