MX-5 Miata NA8 1996-97 (BP-ZE, 1.8, OBD-II) → Emtron KV12 (auto)
MX-5 Miata NA8 1996-97 (BP-ZE, 1.8, OBD-II) — Emtron — KV12
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-12
Before you start
Not confident with automotive wiring? Have a professional harness builder or tuner do it, or check your work before first power-up. A wiring mistake can damage the ECU, the engine or the car, or start a fire.
| Status | draft · not yet verified: nobody has reported building and running this harness |
|---|---|
| Open errors | 1: read the Findings page before cutting any wire |
| Size of the job | 55 wires · 10 connectors · 5 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-4-B | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | SP-14V-1 | KV12-D-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | SP-14V-1 | KV12-D-2 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | SP-14V-1 | KV12-D-20 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-4-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-4-C | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-4-D | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | OEM-4-K | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-GND-1 | KV12-A-19 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | SP-GND-1 | KV12-B-34 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | SP-GND-1 | KV12-B-9 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | SP-GND-1 | KV12-C-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | SP-GND-1 | KV12-C-26 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-3-O | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-4-H | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | SP-0V-1 | KV12-C-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | SP-0V-1 | KV12-C-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-3-I | KV12-D-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-4-E | KV12-D-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | SP-0V-1 | KV12-D-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-4-G | KV12-D-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | SP-0V-1 | KV12-D-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-4-N | KV12-B-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-4-R | KV12-B-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-4-U | KV12-B-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-4-V | KV12-B-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-4-W | KV12-B-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-4-X | KV12-B-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-3-B | KV12-C-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-3-F | KV12-C-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-3-G | KV12-C-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-1-A | KV12-D-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-1-B | KV12-B-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-1-G | KV12-B-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-1-U | KV12-B-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-3-M | KV12-A-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-1-E | KV12-B-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-4-J | KV12-B-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-4-O | KV12-B-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-4-P | KV12-B-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-4-Q | KV12-B-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-4-T | KV12-A-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-3-H | KV12-C-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-3-N | KV12-C-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-3-C | KV12-C-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W46 | OEM-3-D | KV12-C-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W47 | OEM-3-K | KV12-C-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W48 | OEM-3-J | KV12-C-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W49 | OEM-1-M | KV12-C-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W50 | OEM-1-C | KV12-C-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W51 | OEM-1-K | KV12-C-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W52 | OEM-1-L | KV12-C-30 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W53 | OEM-1-Q | KV12-C-31 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W54 | OEM-3-L | KV12-C-32 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W55 | OEM-3-P | KV12-C-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 | KV12-D-21 | KV12-A-19 | open (OL) | 5 V sensor reference must not touch power ground | |
| 2 | KV12-D-21 | KV12-C-17 | open (OL) | 5 V sensor reference must not touch sensor ground | |
| 3 | KV12-A-19 | KV12-D-1 | open (OL) | power ground must not touch +12 V supply | |
| 4 | KV12-C-17 | KV12-D-1 | open (OL) | sensor ground must not touch +12 V supply | |
| 5 | KV12-D-21 | KV12-D-1 | open (OL) | 5 V sensor reference must not touch +12 V supply |
If any reading doesn't match, stop and get help before powering up.
Revisions
| Rev | Label | By | Date |
|---|---|---|---|
| No revisions yet. | |||
Schematic
Connectors
KV12-A
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Injection Channel 9 | — | — | — | — | — | — | — | — |
| 2 | Injection Channel 10 | — | — | — | — | — | — | — | — |
| 3 | Injection Channel 11 | — | — | — | — | — | — | — | — |
| 4 | Injection Channel 12 | — | — | — | — | — | — | — | — |
| 5 | — | — | — | — | — | — | — | — | — |
| 6 | — | — | — | — | — | — | — | — | — |
| 7 | — | — | — | — | — | — | — | — | — |
| 8 | Ignition Channel 9 | — | — | — | — | — | — | — | — |
| 9 | Ignition Channel 10 | — | — | — | — | — | — | — | — |
| 10 | Lambda 1 Heater - | — | W36 | — | 0.5 | OEM-3-M | — | — | — |
| 11 | Lambda 2 Heater - | — | W42 | — | 0.5 | OEM-4-T | — | — | — |
| 12 | — | — | — | — | — | — | — | — | — |
| 13 | — | — | — | — | — | — | — | — | — |
| 14 | Ignition Channel 11 | — | — | — | — | — | — | — | — |
| 15 | Ignition Channel 12 | — | — | — | — | — | — | — | — |
| 16 | Lambda 1 Heater + | — | — | — | — | — | — | — | — |
| 17 | Lambda 2 Heater + | — | — | — | — | — | — | — | — |
| 18 | Lambda 1 Nernst Cell (Vs) | — | — | — | — | — | — | — | — |
| 19 | ECU Ground | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| 20 | Lambda 2 Cal Resistor (CalR) | — | — | — | — | — | — | — | — |
| 21 | Lambda 2 Nernst Cell (Vs) | — | — | — | — | — | — | — | — |
| 22 | Lambda 2 Pump Cell (Ip) | — | — | — | — | — | — | — | — |
| 23 | Lambda 2 Virtual Ground (VGnd) | — | — | — | — | — | — | — | — |
| 24 | Lambda 1 Cal Resistor (CalR) | — | — | — | — | — | — | — | — |
| 25 | Lambda 1 Pump Cell (Ip) | — | — | — | — | — | — | — | — |
| 26 | Lambda 1 Virtual Ground (VGnd) | — | — | — | — | — | — | — | — |
KV12-B
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Injection Channel 1 | — | W25 | — | 0.5 | OEM-4-U | — | — | — |
| 2 | Injection Channel 2 | — | W26 | — | 0.5 | OEM-4-V | — | — | — |
| 3 | Injection Channel 3 | — | W27 | — | 0.5 | OEM-4-W | — | — | — |
| 4 | Injection Channel 4 | — | W28 | — | 0.5 | OEM-4-X | — | — | — |
| 5 | Injection Channel 5 | — | — | — | — | — | — | — | — |
| 6 | Injection Channel 6 | — | — | — | — | — | — | — | — |
| 7 | Injection Channel 7 | — | — | — | — | — | — | — | — |
| 8 | Injection Channel 8 | — | — | — | — | — | — | — | — |
| 9 | ECU Ground | — | W11 | — | 0.85 | SP-GND-1 | — | — | — |
| 10 | Auxiliary Output 1 | — | W38 | — | 0.5 | OEM-4-J | — | — | — |
| 11 | Auxiliary Output 2 | — | W39 | — | 0.5 | OEM-4-O | — | — | — |
| 12 | Auxiliary Output 3 | — | W40 | — | 0.5 | OEM-4-P | — | — | — |
| 13 | Auxiliary Output 4 | — | W41 | — | 0.5 | OEM-4-Q | — | — | — |
| 14 | Auxiliary Output 5 | — | W33 | — | 0.5 | OEM-1-B | — | — | — |
| 15 | Auxiliary Output 6 | — | W34 | — | 0.5 | OEM-1-G | — | — | — |
| 16 | Auxiliary Output 7 | — | W35 | — | 0.5 | OEM-1-U | — | — | — |
| 17 | Auxiliary Output 8 | — | W37 | — | 0.5 | OEM-1-E | — | — | — |
| 18 | Auxiliary Output 9 | — | — | — | — | — | — | — | — |
| 19 | Auxiliary Output 10 | — | — | — | — | — | — | — | — |
| 20 | Auxiliary Output 11 | — | — | — | — | — | — | — | — |
| 21 | Auxiliary Output 12 | — | — | — | — | — | — | — | — |
| 22 | Auxiliary Output 13 | — | — | — | — | — | — | — | — |
| 23 | Auxiliary Output 14 | — | — | — | — | — | — | — | — |
| 24 | Auxiliary Output 15 | — | — | — | — | — | — | — | — |
| 25 | Auxiliary Output 16 | — | — | — | — | — | — | — | — |
| 26 | Ignition Channel 1 | — | W23 | — | 0.5 | OEM-4-N | — | — | — |
| 27 | Ignition Channel 2 | — | W24 | — | 0.5 | OEM-4-R | — | — | — |
| 28 | Ignition Channel 3 | — | — | — | — | — | — | — | — |
| 29 | Ignition Channel 4 | — | — | — | — | — | — | — | — |
| 30 | Ignition Channel 5 | — | — | — | — | — | — | — | — |
| 31 | Ignition Channel 6 | — | — | — | — | — | — | — | — |
| 32 | Ignition Channel 7 | — | — | — | — | — | — | — | — |
| 33 | Ignition Channel 8 | — | — | — | — | — | — | — | — |
| 34 | ECU Ground | — | W10 | — | 0.85 | SP-GND-1 | — | — | — |
KV12-C
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | ECU Ground | — | W12 | — | 0.85 | SP-GND-1 | — | — | — |
| 2 | Analog Input Channel 1 | — | W29 | — | 0.5 | OEM-3-B | — | — | — |
| 3 | Analog Input Channel 2 | — | W30 | — | 0.5 | OEM-3-F | — | — | — |
| 4 | Analog Input Channel 3 | — | W31 | — | 0.5 | OEM-3-G | — | — | — |
| 5 | Analog Input Channel 4 | — | W43 | — | 0.5 | OEM-3-H | — | — | — |
| 6 | Analog Input Channel 5 | — | W44 | — | 0.5 | OEM-3-N | — | — | — |
| 7 | Analog Input Channel 6 | — | W45 | — | 0.5 | OEM-3-C | — | — | — |
| 8 | Analog Input Channel 7 | — | W46 | — | 0.5 | OEM-3-D | — | — | — |
| 9 | Analog Input Channel 8 | — | W47 | — | 0.5 | OEM-3-K | — | — | — |
| 10 | Analog Input Channel 9 | — | W48 | — | 0.5 | OEM-3-J | — | — | — |
| 11 | Analog Input Channel 10 | — | — | — | — | — | — | — | — |
| 12 | Analog Input Channel 11 | — | — | — | — | — | — | — | — |
| 13 | Analog Input Channel 12 | — | — | — | — | — | — | — | — |
| 14 | Analog Input Channel 13 | — | — | — | — | — | — | — | — |
| 15 | Analog Input Channel 14 | — | — | — | — | — | — | — | — |
| 16 | Analog Input Channel 15 | — | — | — | — | — | — | — | — |
| 17 | Analog Sensor 0V Reference | — | W16 | — | 0.5 | SP-0V-1 | — | — | — |
| 18 | Digital Input 9 | — | — | — | — | — | — | — | — |
| 19 | Digital Input 10 | — | — | — | — | — | — | — | — |
| 20 | Digital Input 11 | — | — | — | — | — | — | — | — |
| 21 | Digital Input 12 | — | — | — | — | — | — | — | — |
| 22 | Digital Input 13 | — | — | — | — | — | — | — | — |
| 23 | Digital Input 14 | — | — | — | — | — | — | — | — |
| 24 | Analog Input Channel 16 | — | — | — | — | — | — | — | — |
| 25 | Analog Sensor 0V Reference | — | W17 | — | 0.5 | SP-0V-1 | — | — | — |
| 26 | ECU Ground | — | W13 | — | 0.85 | SP-GND-1 | — | — | — |
| 27 | Digital Input 1 | — | W49 | — | 0.5 | OEM-1-M | — | — | — |
| 28 | Digital Input 2 | — | W50 | — | 0.5 | OEM-1-C | — | — | — |
| 29 | Digital Input 3 | — | W51 | — | 0.5 | OEM-1-K | — | — | — |
| 30 | Digital Input 4 | — | W52 | — | 0.5 | OEM-1-L | — | — | — |
| 31 | Digital Input 5 | — | W53 | — | 0.5 | OEM-1-Q | — | — | — |
| 32 | Digital Input 6 | — | W54 | — | 0.5 | OEM-3-L | — | — | — |
| 33 | Digital Input 7 | — | W55 | — | 0.5 | OEM-3-P | — | — | — |
| 34 | Digital Input 8 | — | — | — | — | — | — | — | — |
KV12-D
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | ECU 14V Supply | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 2 | Auxiliary Output 13-16 14V Supply | — | W3 | — | 0.85 | SP-14V-1 | — | — | — |
| 3 | Sensor Supply 8V | — | — | — | — | — | — | — | — |
| 4 | Crank Index Sensor + | — | W19 | — | 0.5 | OEM-4-E | — | — | — |
| 5 | Crank Index Sensor - | — | W20 | — | 0.5 | SP-0V-1 | — | — | — |
| 6 | Sync Sensor + | — | W21 | — | 0.5 | OEM-4-G | — | — | — |
| 7 | Sync Sensor - | — | W22 | — | 0.5 | SP-0V-1 | — | — | — |
| 8 | CAN 1H | — | — | — | — | — | — | — | — |
| 9 | EFI Relay Output (Low Side 200mA) | — | W32 | — | 0.5 | OEM-1-A | — | — | — |
| 10 | CAN 2H | — | — | — | — | — | — | — | — |
| 11 | Knock 1 + | — | — | — | — | — | — | — | — |
| 12 | Knock 1 - | — | — | — | — | — | — | — | — |
| 13 | Shield (Crank/Cam/ Knock) | — | — | — | — | — | — | — | — |
| 14 | CAN 1L | — | — | — | — | — | — | — | — |
| 15 | Ignition Switch Input | — | — | — | — | — | — | — | — |
| 16 | CAN 2L | — | — | — | — | — | — | — | — |
| 17 | Knock 2 + | — | — | — | — | — | — | — | — |
| 18 | Knock 2 - | — | — | — | — | — | — | — | — |
| 19 | Analog Output (0.0 - 5.0V) | — | — | — | — | — | — | — | — |
| 20 | Auxiliary Output 9-12 14V Supply | — | W4 | — | 0.85 | SP-14V-1 | — | — | — |
| 21 | Sensor Supply Vref1: 5.0V | — | W18 | — | 0.5 | OEM-3-I | — | — | — |
| 22 | Sensor Supply Vref2: 5.0V | — | — | — | — | — | — | — | — |
| 23 | Ethernet Tx + | — | — | — | — | — | — | — | — |
| 24 | Ethernet Tx - | — | — | — | — | — | — | — | — |
| 25 | Ethernet Rx + | — | — | — | — | — | — | — | — |
| 26 | Ethernet Rx - | — | — | — | — | — | — | — | — |
OEM-1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Cooling fan relay (low-side) | — | W32 | — | 0.5 | KV12-D-9 | — | — | — |
| B | A/C condenser fan relay | — | W33 | — | 0.5 | KV12-B-14 | — | — | — |
| C | Starter input (12V while cranking) | — | W50 | — | 0.5 | KV12-C-28 | — | — | — |
| E | Check engine light (MIL) | — | W37 | — | 0.5 | KV12-B-17 | — | — | — |
| G | A/C clutch relay | — | W34 | — | 0.5 | KV12-B-15 | — | — | — |
| K | A/C pressure switch (A/C request) | — | W51 | — | 0.5 | KV12-C-29 | — | — | — |
| L | Clutch switch | — | W52 | — | 0.5 | KV12-C-30 | — | — | — |
| M | Vehicle speed sensor (VSS) | — | W49 | — | 0.5 | KV12-C-27 | — | — | — |
| Q | Brake switch | — | W53 | — | 0.5 | KV12-C-31 | — | — | — |
| U | Fuel pump relay (low-side) | — | W35 | — | 0.5 | KV12-B-16 | — | — | — |
OEM-3
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| B | MAF sensor input | — | W29 | — | 0.5 | KV12-C-2 | — | — | — |
| C | Front O2 sensor input | — | W45 | — | 0.5 | KV12-C-7 | — | — | — |
| D | Rear O2 sensor input | — | W46 | — | 0.5 | KV12-C-8 | — | — | — |
| F | Throttle position (TPS) | — | W30 | — | 0.5 | KV12-C-3 | — | — | — |
| G | Engine coolant temp (CLT) | — | W31 | — | 0.5 | KV12-C-4 | — | — | — |
| H | EGR boost sensor | — | W43 | — | 0.5 | KV12-C-5 | — | — | — |
| I | +5V sensor reference | — | W18 | — | 0.5 | KV12-D-21 | — | — | — |
| J | EGR valve position sensor | — | W48 | — | 0.5 | KV12-C-10 | — | — | — |
| K | Intake air temp (IAT) | — | W47 | — | 0.5 | KV12-C-9 | — | — | — |
| L | Idle switch (closed throttle) | — | W54 | — | 0.5 | KV12-C-32 | — | — | — |
| M | Front O2 heater control | — | W36 | — | 0.5 | KV12-A-10 | — | — | — |
| N | EGR boost sensor (2nd channel) | — | W44 | — | 0.5 | KV12-C-6 | — | — | — |
| O | Sensor ground | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| P | Power steering pressure switch | — | W55 | — | 0.5 | KV12-C-33 | — | — | — |
OEM-4
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Chassis ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| B | ECU power +12V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| C | Chassis ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| D | Chassis ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| E | Crank position (CKP) sensor | — | W19 | — | 0.5 | KV12-D-4 | — | — | — |
| F | CAS SGT (cam trigger) | — | — | — | — | — | — | — | — |
| G | CAS SGC (cam sync) | — | W21 | — | 0.5 | KV12-D-6 | — | — | — |
| H | Crank pickup timing ground (CKP gnd) | — | W15 | — | 0.5 | SP-0V-1 | — | — | — |
| I | Permanent +12V (battery) | — | — | — | — | — | — | — | — |
| J | PRC solenoid (FPR control) | — | W38 | — | 0.5 | KV12-B-10 | — | — | — |
| K | Chassis ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| L | Tachometer output | — | — | — | — | — | — | — | — |
| N | Ignition coil trigger (cyl 1&4) | — | W23 | — | 0.5 | KV12-B-26 | — | — | — |
| O | EGR vent solenoid | — | W39 | — | 0.5 | KV12-B-11 | — | — | — |
| P | EGR vacuum solenoid | — | W40 | — | 0.5 | KV12-B-12 | — | — | — |
| Q | Idle air control (IAC) valve | — | W41 | — | 0.5 | KV12-B-13 | — | — | — |
| R | Ignition coil trigger (cyl 2&3) | — | W24 | — | 0.5 | KV12-B-27 | — | — | — |
| T | EVAP purge solenoid | — | W42 | — | 0.5 | KV12-A-11 | — | — | — |
| U | Injector 1 (cyl 1) | — | W25 | — | 0.5 | KV12-B-1 | — | — | — |
| V | Injector 2 (cyl 2) | — | W26 | — | 0.5 | KV12-B-2 | — | — | — |
| W | Injector 3 (cyl 3) | — | W27 | — | 0.5 | KV12-B-3 | — | — | — |
| X | Injector 4 (cyl 4) | — | W28 | — | 0.5 | KV12-B-4 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W14 | — | 0.5 | OEM-3-O | — | — | — |
| 1 | — | — | W15 | — | 0.5 | OEM-4-H | — | — | — |
| 1 | — | — | W16 | — | 0.5 | KV12-C-17 | — | — | — |
| 1 | — | — | W17 | — | 0.5 | KV12-C-25 | — | — | — |
| 1 | — | — | W20 | — | 0.5 | KV12-D-5 | — | — | — |
| 1 | — | — | W22 | — | 0.5 | KV12-D-7 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-4-B | — | — | — |
| 1 | — | — | W2 | — | 0.85 | KV12-D-1 | — | — | — |
| 1 | — | — | W3 | — | 0.85 | KV12-D-2 | — | — | — |
| 1 | — | — | W4 | — | 0.85 | KV12-D-20 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W5 | — | 0.85 | OEM-4-A | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-4-C | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-4-D | — | — | — |
| 1 | — | — | W8 | — | 0.85 | OEM-4-K | — | — | — |
| 1 | — | — | W9 | — | 0.85 | KV12-A-19 | — | — | — |
| 1 | — | — | W10 | — | 0.85 | KV12-B-34 | — | — | — |
| 1 | — | — | W11 | — | 0.85 | KV12-B-9 | — | — | — |
| 1 | — | — | W12 | — | 0.85 | KV12-C-1 | — | — | — |
| 1 | — | — | W13 | — | 0.85 | KV12-C-26 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-1-A | Cooling fan relay (low-side) | low_side_out | KV12-D-9 | EFI Relay Output (Low Side 200mA) | low_side_out | corroborated | |
| OEM-1-B | A/C condenser fan relay | low_side_out | KV12-B-14 | Auxiliary Output 5 | low_side_out | corroborated | |
| OEM-1-C | Starter input (12V while cranking) | digital_in | KV12-C-28 | Digital Input 2 | digital_in | corroborated | |
| OEM-1-E | Check engine light (MIL) | low_side_out | KV12-B-17 | Auxiliary Output 8 | low_side_out | corroborated | |
| OEM-1-G | A/C clutch relay | low_side_out | KV12-B-15 | Auxiliary Output 6 | low_side_out | corroborated | |
| OEM-1-K | A/C pressure switch (A/C request) | digital_in | KV12-C-29 | Digital Input 3 | digital_in | corroborated | |
| OEM-1-L | Clutch switch | digital_in | KV12-C-30 | Digital Input 4 | digital_in | corroborated | |
| OEM-1-M | Vehicle speed sensor (VSS) | digital_in | KV12-C-27 | Digital Input 1 | digital_in | corroborated | |
| OEM-1-Q | Brake switch | digital_in | KV12-C-31 | Digital Input 5 | digital_in | corroborated | |
| OEM-1-U | Fuel pump relay (low-side) | low_side_out | KV12-B-16 | Auxiliary Output 7 | low_side_out | corroborated | |
| OEM-3-B | MAF sensor input | analog_in | KV12-C-2 | Analog Input Channel 1 | analog_in | corroborated | |
| OEM-3-C | Front O2 sensor input | lambda_nb_in | KV12-C-7 | Analog Input Channel 6 | analog_in | corroborated | |
| OEM-3-D | Rear O2 sensor input | lambda_nb_in | KV12-C-8 | Analog Input Channel 7 | analog_in | corroborated | |
| OEM-3-F | Throttle position (TPS) | analog_in | KV12-C-3 | Analog Input Channel 2 | analog_in | corroborated | |
| OEM-3-G | Engine coolant temp (CLT) | temp_in | KV12-C-4 | Analog Input Channel 3 | analog_in | corroborated | |
| OEM-3-H | EGR boost sensor | analog_in | KV12-C-5 | Analog Input Channel 4 | analog_in | corroborated | |
| OEM-3-I | +5V sensor reference | vref | KV12-D-21 | Sensor Supply Vref1: 5.0V | vref | corroborated | |
| OEM-3-J | EGR valve position sensor | analog_in | KV12-C-10 | Analog Input Channel 9 | analog_in | corroborated | |
| OEM-3-K | Intake air temp (IAT) | temp_in | KV12-C-9 | Analog Input Channel 8 | analog_in | corroborated | |
| OEM-3-L | Idle switch (closed throttle) | digital_in | KV12-C-32 | Digital Input 6 | digital_in | corroborated | |
| OEM-3-M | Front O2 heater control | low_side_out | KV12-A-10 | Lambda 1 Heater - | low_side_out | corroborated | |
| OEM-3-N | EGR boost sensor (2nd channel) | analog_in | KV12-C-6 | Analog Input Channel 5 | analog_in | corroborated | |
| OEM-3-O | Sensor ground | sensor_ground | KV12-C-17 + KV12-C-25 + KV12-D-5 + KV12-D-7 | Analog Sensor 0V Reference + Analog Sensor 0V Reference + Crank Index Sensor - + Sync Sensor - | sensor_ground + trigger_in | corroborated | |
| OEM-3-P | Power steering pressure switch | digital_in | KV12-C-33 | Digital Input 7 | digital_in | corroborated | |
| OEM-4-A | Chassis ground | ground | KV12-A-19 + KV12-B-34 + KV12-B-9 + KV12-C-1 + KV12-C-26 | ECU Ground + ECU Ground + ECU Ground + ECU Ground + ECU Ground | ground | corroborated | |
| OEM-4-B | ECU power +12V (main relay) | power_in | KV12-D-1 + KV12-D-2 + KV12-D-20 | ECU 14V Supply + Auxiliary Output 13-16 14V Supply + Auxiliary Output 9-12 14V Supply | power_in | corroborated | |
| OEM-4-C | Chassis ground | ground | KV12-A-19 + KV12-B-34 + KV12-B-9 + KV12-C-1 + KV12-C-26 | ECU Ground + ECU Ground + ECU Ground + ECU Ground + ECU Ground | ground | corroborated | |
| OEM-4-D | Chassis ground | ground | KV12-A-19 + KV12-B-34 + KV12-B-9 + KV12-C-1 + KV12-C-26 | ECU Ground + ECU Ground + ECU Ground + ECU Ground + ECU Ground | ground | corroborated | |
| OEM-4-E | Crank position (CKP) sensor | trigger_in | KV12-D-4 | Crank Index Sensor + | trigger_in | corroborated | |
| OEM-4-F | CAS SGT (cam trigger) | trigger_in | — | — | — | corroborated | |
| OEM-4-G | CAS SGC (cam sync) | trigger_in | KV12-D-6 | Sync Sensor + | trigger_in | corroborated | |
| OEM-4-H | Crank pickup timing ground (CKP gnd) | sensor_ground | KV12-C-17 + KV12-C-25 + KV12-D-5 + KV12-D-7 | Analog Sensor 0V Reference + Analog Sensor 0V Reference + Crank Index Sensor - + Sync Sensor - | sensor_ground + trigger_in | corroborated | |
| OEM-4-I | Permanent +12V (battery) | power_in | — | — | — | corroborated | |
| OEM-4-J | PRC solenoid (FPR control) | low_side_out | KV12-B-10 | Auxiliary Output 1 | low_side_out | corroborated | |
| OEM-4-K | Chassis ground | ground | KV12-A-19 + KV12-B-34 + KV12-B-9 + KV12-C-1 + KV12-C-26 | ECU Ground + ECU Ground + ECU Ground + ECU Ground + ECU Ground | ground | corroborated | |
| OEM-4-L | Tachometer output | tacho_out | — | — | — | corroborated | |
| OEM-4-N | Ignition coil trigger (cyl 1&4) | ignition_out | KV12-B-26 | Ignition Channel 1 | ignition_out | corroborated | |
| OEM-4-O | EGR vent solenoid | low_side_out | KV12-B-11 | Auxiliary Output 2 | low_side_out | corroborated | |
| OEM-4-P | EGR vacuum solenoid | low_side_out | KV12-B-12 | Auxiliary Output 3 | low_side_out | corroborated | |
| OEM-4-Q | Idle air control (IAC) valve | low_side_out | KV12-B-13 | Auxiliary Output 4 | low_side_out | corroborated | |
| OEM-4-R | Ignition coil trigger (cyl 2&3) | ignition_out | KV12-B-27 | Ignition Channel 2 | ignition_out | corroborated | |
| OEM-4-T | EVAP purge solenoid | low_side_out | KV12-A-11 | Lambda 2 Heater - | low_side_out | corroborated | |
| OEM-4-U | Injector 1 (cyl 1) | injector_out | KV12-B-1 | Injection Channel 1 | injector_out | corroborated | |
| OEM-4-V | Injector 2 (cyl 2) | injector_out | KV12-B-2 | Injection Channel 2 | injector_out | corroborated | |
| OEM-4-W | Injector 3 (cyl 3) | injector_out | KV12-B-3 | Injection Channel 3 | injector_out | corroborated | |
| OEM-4-X | Injector 4 (cyl 4) | injector_out | KV12-B-4 | Injection Channel 4 | injector_out | corroborated |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-4-B | SP-14V-1 | 0.85 | no route | ECU power +12V (main relay) | — | |
| W2 | SP-14V-1 | KV12-D-1 | 0.85 | no route | ECU 14V Supply | — | |
| W3 | SP-14V-1 | KV12-D-2 | 0.85 | no route | Auxiliary Output 13-16 14V Supply | — | |
| W4 | SP-14V-1 | KV12-D-20 | 0.85 | no route | Auxiliary Output 9-12 14V Supply | — | |
| W5 | OEM-4-A | SP-GND-1 | 0.85 | no route | Chassis ground | — | |
| W6 | OEM-4-C | SP-GND-1 | 0.85 | no route | Chassis ground | — | |
| W7 | OEM-4-D | SP-GND-1 | 0.85 | no route | Chassis ground | — | |
| W8 | OEM-4-K | SP-GND-1 | 0.85 | no route | Chassis ground | — | |
| W9 | SP-GND-1 | KV12-A-19 | 0.85 | no route | ECU Ground | — | |
| W10 | SP-GND-1 | KV12-B-34 | 0.85 | no route | ECU Ground | — | |
| W11 | SP-GND-1 | KV12-B-9 | 0.85 | no route | ECU Ground | — | |
| W12 | SP-GND-1 | KV12-C-1 | 0.85 | no route | ECU Ground | — | |
| W13 | SP-GND-1 | KV12-C-26 | 0.85 | no route | ECU Ground | — | |
| W14 | OEM-3-O | SP-0V-1 | 0.5 | no route | Sensor ground | — | |
| W15 | OEM-4-H | SP-0V-1 | 0.5 | no route | Crank pickup timing ground (CKP gnd) | — | |
| W16 | SP-0V-1 | KV12-C-17 | 0.5 | no route | Analog Sensor 0V Reference | — | |
| W17 | SP-0V-1 | KV12-C-25 | 0.5 | no route | Analog Sensor 0V Reference | — | |
| W18 | OEM-3-I | KV12-D-21 | 0.5 | no route | +5V sensor reference | — | |
| W19 | OEM-4-E | KV12-D-4 | 0.5 | no route | Crank position (CKP) sensor | — | |
| W20 | SP-0V-1 | KV12-D-5 | 0.5 | no route | Crank Index Sensor - | — | |
| W21 | OEM-4-G | KV12-D-6 | 0.5 | no route | CAS SGC (cam sync) | — | |
| W22 | SP-0V-1 | KV12-D-7 | 0.5 | no route | Sync Sensor - | — | |
| W23 | OEM-4-N | KV12-B-26 | 0.5 | no route | Ignition coil trigger (cyl 1&4) | — | |
| W24 | OEM-4-R | KV12-B-27 | 0.5 | no route | Ignition coil trigger (cyl 2&3) | — | |
| W25 | OEM-4-U | KV12-B-1 | 0.5 | no route | Injector 1 (cyl 1) | — | |
| W26 | OEM-4-V | KV12-B-2 | 0.5 | no route | Injector 2 (cyl 2) | — | |
| W27 | OEM-4-W | KV12-B-3 | 0.5 | no route | Injector 3 (cyl 3) | — | |
| W28 | OEM-4-X | KV12-B-4 | 0.5 | no route | Injector 4 (cyl 4) | — | |
| W29 | OEM-3-B | KV12-C-2 | 0.5 | no route | MAF sensor input | — | |
| W30 | OEM-3-F | KV12-C-3 | 0.5 | no route | Throttle position (TPS) | — | |
| W31 | OEM-3-G | KV12-C-4 | 0.5 | no route | Engine coolant temp (CLT) | — | |
| W32 | OEM-1-A | KV12-D-9 | 0.5 | no route | Cooling fan relay (low-side) | — | |
| W33 | OEM-1-B | KV12-B-14 | 0.5 | no route | A/C condenser fan relay | — | |
| W34 | OEM-1-G | KV12-B-15 | 0.5 | no route | A/C clutch relay | — | |
| W35 | OEM-1-U | KV12-B-16 | 0.5 | no route | Fuel pump relay (low-side) | — | |
| W36 | OEM-3-M | KV12-A-10 | 0.5 | no route | Front O2 heater control | — | |
| W37 | OEM-1-E | KV12-B-17 | 0.5 | no route | Check engine light (MIL) | — | |
| W38 | OEM-4-J | KV12-B-10 | 0.5 | no route | PRC solenoid (FPR control) | — | |
| W39 | OEM-4-O | KV12-B-11 | 0.5 | no route | EGR vent solenoid | — | |
| W40 | OEM-4-P | KV12-B-12 | 0.5 | no route | EGR vacuum solenoid | — | |
| W41 | OEM-4-Q | KV12-B-13 | 0.5 | no route | Idle air control (IAC) valve | — | |
| W42 | OEM-4-T | KV12-A-11 | 0.5 | no route | EVAP purge solenoid | — | |
| W43 | OEM-3-H | KV12-C-5 | 0.5 | no route | EGR boost sensor | — | |
| W44 | OEM-3-N | KV12-C-6 | 0.5 | no route | EGR boost sensor (2nd channel) | — | |
| W45 | OEM-3-C | KV12-C-7 | 0.5 | no route | Front O2 sensor input | — | |
| W46 | OEM-3-D | KV12-C-8 | 0.5 | no route | Rear O2 sensor input | — | |
| W47 | OEM-3-K | KV12-C-9 | 0.5 | no route | Intake air temp (IAT) | — | |
| W48 | OEM-3-J | KV12-C-10 | 0.5 | no route | EGR valve position sensor | — | |
| W49 | OEM-1-M | KV12-C-27 | 0.5 | no route | Vehicle speed sensor (VSS) | — | |
| W50 | OEM-1-C | KV12-C-28 | 0.5 | no route | Starter input (12V while cranking) | — | |
| W51 | OEM-1-K | KV12-C-29 | 0.5 | no route | A/C pressure switch (A/C request) | — | |
| W52 | OEM-1-L | KV12-C-30 | 0.5 | no route | Clutch switch | — | |
| W53 | OEM-1-Q | KV12-C-31 | 0.5 | no route | Brake switch | — | |
| W54 | OEM-3-L | KV12-C-32 | 0.5 | no route | Idle switch (closed throttle) | — | |
| W55 | OEM-3-P | KV12-C-33 | 0.5 | no route | Power steering pressure switch | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|---|---|---|---|---|
| connector | 3-1437290-7 | TE | Superseal 1.0 26-way plug | 1.000 | ea |
| connector | 3-1437290-8 | TE | Superseal 1.0 26-way plug, Key 2 | 1.000 | ea |
| connector | 4-1437290-0 | TE | Superseal 1.0 34-way plug, Key 1 | 1.000 | ea |
| connector | 4-1437290-1 | TE | Superseal 1.0 34-way plug, Key 2 | 1.000 | ea |
| terminal | 3-1447221-4 | TE | Superseal 1.0 socket terminal, 20 AWG (0.5 sq mm) | 48.000 | 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 | REQUIRED_UNMAPPED | OEM-4-F | Required OEM function "CAS SGT (cam trigger)" (trigger_in) is not connected to the new ECU. |
| warn | DATASET_GAP | KV12 A | 5 of 26 cavities on KV12 A have no pin data (5,6,7,12,13). Anything there is invisible to these checks. |
| info | NET_FAMILY | KV12-C-17 ↔ KV12-D-5 | KV12-C-17 "Analog Sensor 0V Reference" [sensor_ground] is wired to KV12-D-5 "Crank Index Sensor -" [trigger_in]. Trigger return tied to sensor/trigger ground: correct for single-ended trigger inputs. |
| info | NET_FAMILY | OEM-3-G ↔ KV12-C-4 | OEM-3-G "Engine coolant temp (CLT)" [temp_in] is wired to KV12-C-4 "Analog Input Channel 3" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | NET_FAMILY | OEM-3-K ↔ KV12-C-9 | OEM-3-K "Intake air temp (IAT)" [temp_in] is wired to KV12-C-9 "Analog Input Channel 8" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | UNMAPPED | OEM | 1 optional OEM pins are not mapped: OEM-4-L Tachometer output |
Accepted (1)
| Code | Subject | Reason | By |
|---|---|---|---|
| REQUIRED_UNMAPPED | OEM-4-I | 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. Open items: - OEM-4 F: CAS SGT (cam trigger): no free cam_hall/cam_vr/frequency_in input on Emtron KV12 Not wired: - OEM-4 I: Permanent +12V (battery): Emtron KV12 has no battery-constant input; not needed - OEM-4 L: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on Emtron KV12 - KV12-D 15: Ignition Switch Input: not fed (the stock ECU has no ignition-sense pin); feed it from a switched-ignition source
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | vendor_doc | AEM EMS 30-1720 Plug-and-Play adapter manual (1996-97 Miata) | https://static.summitracing.com/global/images/instructions/avm-30-1720.pdf | — | — | — |
| 4 | vendor_doc | Emtron KV12/KV16 Pinout Rev2 | https://github.com/emtron-australia/help | — | 2026-10-05 | 2f3a1b2d2ed4 |
| 3 | community_copy | Mellens.net: 1996 Mazda Miata wiring diagrams (FSM-derived) | http://www.mellens.net/mazda/mazda_miata_extra_manual/1996_wiring.pdf | — | — | — |