MX-5 Miata NA8 1994-97 (BP-ZE, 1.8) → Emtron KV12 (auto)
MX-5 Miata NA8 1994-97 (BP-ZE, 1.8) — Emtron — KV12
Drawn by Michael Gnankou · Rev 0 · proposal · 2026-10-08
Before you start
| Status | proposal · not yet verified: nobody has reported building and running this harness |
|---|---|
| Open errors | none |
| Size of the job | 46 wires · 9 connectors · 7 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-1-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-2-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-2-B | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-2-C | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | OEM-2-D | 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-2-F | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | SP-0V-1 | KV12-C-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | SP-0V-1 | KV12-C-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-2-K | KV12-D-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-2-E | KV12-D-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | SP-0V-1 | KV12-D-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-2-G | KV12-D-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | SP-0V-1 | KV12-D-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-1-G | KV12-B-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-1-H | KV12-B-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-2-U | KV12-B-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-2-V | KV12-B-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-2-Y | KV12-B-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-2-Z | KV12-B-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-1-J | KV12-D-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-1-R | KV12-B-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-2-S | KV12-B-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-2-T | KV12-B-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-2-W | KV12-B-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-1-E | KV12-B-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-2-R | KV12-B-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-2-X | KV12-B-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-2-I | KV12-B-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-2-O | KV12-C-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-2-M | KV12-C-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-2-N | KV12-C-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-2-Q | KV12-C-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-2-P | KV12-C-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-1-M | KV12-C-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-1-C | KV12-C-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-1-P | KV12-C-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-1-Q | KV12-C-30 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W46 | OEM-1-V | KV12-C-31 | 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-1 | KV12-A-19 | open (OL) | +12 V supply must not touch power ground | |
| 2 | KV12-D-1 | KV12-C-17 | open (OL) | +12 V supply must not touch sensor ground | |
| 3 | KV12-A-19 | KV12-D-21 | open (OL) | power ground must not touch 5 V sensor reference | |
| 4 | KV12-C-17 | KV12-D-21 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 5 | KV12-D-1 | KV12-D-21 | open (OL) | +12 V supply must not touch 5 V sensor reference |
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 - | — | — | — | — | — | — | — | — |
| 11 | Lambda 2 Heater - | — | — | — | — | — | — | — | — |
| 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 | — | W24 | — | 0.5 | OEM-2-U | — | — | — |
| 2 | Injection Channel 2 | — | W25 | — | 0.5 | OEM-2-V | — | — | — |
| 3 | Injection Channel 3 | — | W26 | — | 0.5 | OEM-2-Y | — | — | — |
| 4 | Injection Channel 4 | — | W27 | — | 0.5 | OEM-2-Z | — | — | — |
| 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 | — | W33 | — | 0.5 | OEM-1-E | — | — | — |
| 11 | Auxiliary Output 2 | — | W34 | — | 0.5 | OEM-2-R | — | — | — |
| 12 | Auxiliary Output 3 | — | W35 | — | 0.5 | OEM-2-X | — | — | — |
| 13 | Auxiliary Output 4 | — | W36 | — | 0.5 | OEM-2-I | — | — | — |
| 14 | Auxiliary Output 5 | — | W29 | — | 0.5 | OEM-1-R | — | — | — |
| 15 | Auxiliary Output 6 | — | W30 | — | 0.5 | OEM-2-S | — | — | — |
| 16 | Auxiliary Output 7 | — | W31 | — | 0.5 | OEM-2-T | — | — | — |
| 17 | Auxiliary Output 8 | — | W32 | — | 0.5 | OEM-2-W | — | — | — |
| 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 | — | W22 | — | 0.5 | OEM-1-G | — | — | — |
| 27 | Ignition Channel 2 | — | W23 | — | 0.5 | OEM-1-H | — | — | — |
| 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 | — | W37 | — | 0.5 | OEM-2-O | — | — | — |
| 3 | Analog Input Channel 2 | — | W38 | — | 0.5 | OEM-2-M | — | — | — |
| 4 | Analog Input Channel 3 | — | W39 | — | 0.5 | OEM-2-N | — | — | — |
| 5 | Analog Input Channel 4 | — | W40 | — | 0.5 | OEM-2-Q | — | — | — |
| 6 | Analog Input Channel 5 | — | W41 | — | 0.5 | OEM-2-P | — | — | — |
| 7 | Analog Input Channel 6 | — | — | — | — | — | — | — | — |
| 8 | Analog Input Channel 7 | — | — | — | — | — | — | — | — |
| 9 | Analog Input Channel 8 | — | — | — | — | — | — | — | — |
| 10 | Analog Input Channel 9 | — | — | — | — | — | — | — | — |
| 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 | — | W15 | — | 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 | — | W16 | — | 0.5 | SP-0V-1 | — | — | — |
| 26 | ECU Ground | — | W13 | — | 0.85 | SP-GND-1 | — | — | — |
| 27 | Digital Input 1 | — | W42 | — | 0.5 | OEM-1-M | — | — | — |
| 28 | Digital Input 2 | — | W43 | — | 0.5 | OEM-1-C | — | — | — |
| 29 | Digital Input 3 | — | W44 | — | 0.5 | OEM-1-P | — | — | — |
| 30 | Digital Input 4 | — | W45 | — | 0.5 | OEM-1-Q | — | — | — |
| 31 | Digital Input 5 | — | W46 | — | 0.5 | OEM-1-V | — | — | — |
| 32 | Digital Input 6 | — | — | — | — | — | — | — | — |
| 33 | Digital Input 7 | — | — | — | — | — | — | — | — |
| 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 + | — | W18 | — | 0.5 | OEM-2-E | — | — | — |
| 5 | Crank Index Sensor - | — | W19 | — | 0.5 | SP-0V-1 | — | — | — |
| 6 | Sync Sensor + | — | W20 | — | 0.5 | OEM-2-G | — | — | — |
| 7 | Sync Sensor - | — | W21 | — | 0.5 | SP-0V-1 | — | — | — |
| 8 | CAN 1H | — | — | — | — | — | — | — | — |
| 9 | EFI Relay Output (Low Side 200mA) | — | W28 | — | 0.5 | OEM-1-J | — | — | — |
| 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 | — | W17 | — | 0.5 | OEM-2-K | — | — | — |
| 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 | Constant +12V | — | — | — | — | — | — | — | — |
| B | ECU power +14V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| C | Start signal | — | W43 | — | 0.5 | KV12-C-28 | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | W33 | — | 0.5 | KV12-B-10 | — | — | — |
| G | Ignition 1 (coils 1+4, wasted spark) | — | W22 | — | 0.5 | KV12-B-26 | — | — | — |
| H | Ignition 2 (coils 2+3, wasted spark) | — | W23 | — | 0.5 | KV12-B-27 | — | — | — |
| J | A/C relay | — | W28 | — | 0.5 | KV12-D-9 | — | — | — |
| M | Vehicle speed | — | W42 | — | 0.5 | KV12-C-27 | — | — | — |
| P | Power steering pressure switch | — | W44 | — | 0.5 | KV12-C-29 | — | — | — |
| Q | A/C request | — | W45 | — | 0.5 | KV12-C-30 | — | — | — |
| R | Cooling fan relay | — | W29 | — | 0.5 | KV12-B-14 | — | — | — |
| V | Neutral/clutch switch | — | W46 | — | 0.5 | KV12-C-31 | — | — | — |
OEM-2
| 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 | — | — | — |
| D | Power ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| E | Crank position (CAS NE) | — | W18 | — | 0.5 | KV12-D-4 | — | — | — |
| F | MAF ground | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| G | Cam position (CAS G) | — | W20 | — | 0.5 | KV12-D-6 | — | — | — |
| I | Tachometer output | — | W36 | — | 0.5 | KV12-B-13 | — | — | — |
| K | +5V sensor supply | — | W17 | — | 0.5 | KV12-D-21 | — | — | — |
| M | Throttle position (TPS) | — | W38 | — | 0.5 | KV12-C-3 | — | — | — |
| N | O2 sensor | — | W39 | — | 0.5 | KV12-C-4 | — | — | — |
| O | Mass air flow (MAF) | — | W37 | — | 0.5 | KV12-C-2 | — | — | — |
| P | Intake air temperature (IAT) | — | W41 | — | 0.5 | KV12-C-6 | — | — | — |
| Q | Coolant temperature (ECT) | — | W40 | — | 0.5 | KV12-C-5 | — | — | — |
| R | PRC solenoid (fuel pressure regulator) | — | W34 | — | 0.5 | KV12-B-11 | — | — | — |
| S | Condenser fan relay | — | W30 | — | 0.5 | KV12-B-15 | — | — | — |
| T | Fuel pump relay | — | W31 | — | 0.5 | KV12-B-16 | — | — | — |
| U | Injector 1 | — | W24 | — | 0.5 | KV12-B-1 | — | — | — |
| V | Injector 2 | — | W25 | — | 0.5 | KV12-B-2 | — | — | — |
| W | ISC solenoid | — | W32 | — | 0.5 | KV12-B-17 | — | — | — |
| X | Evap purge solenoid | — | W35 | — | 0.5 | KV12-B-12 | — | — | — |
| Y | Injector 3 | — | W26 | — | 0.5 | KV12-B-3 | — | — | — |
| Z | Injector 4 | — | W27 | — | 0.5 | KV12-B-4 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W14 | — | 0.5 | OEM-2-F | — | — | — |
| 1 | — | — | W15 | — | 0.5 | KV12-C-17 | — | — | — |
| 1 | — | — | W16 | — | 0.5 | KV12-C-25 | — | — | — |
| 1 | — | — | W19 | — | 0.5 | KV12-D-5 | — | — | — |
| 1 | — | — | W21 | — | 0.5 | KV12-D-7 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-1-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-2-A | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-2-B | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-2-C | — | — | — |
| 1 | — | — | W8 | — | 0.85 | OEM-2-D | — | — | — |
| 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 | Constant +12V | power_in | — | — | — | single_source | |
| OEM-1-B | ECU power +14V (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 | single_source | |
| OEM-1-C | Start signal | digital_in | KV12-C-28 | Digital Input 2 | digital_in | single_source | |
| OEM-1-E | Malfunction indicator lamp (MIL) | low_side_out | KV12-B-10 | Auxiliary Output 1 | low_side_out | single_source | |
| OEM-1-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | KV12-B-26 | Ignition Channel 1 | ignition_out | single_source | |
| OEM-1-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | KV12-B-27 | Ignition Channel 2 | ignition_out | single_source | |
| OEM-1-J | A/C relay | low_side_out | KV12-D-9 | EFI Relay Output (Low Side 200mA) | low_side_out | single_source | |
| OEM-1-M | Vehicle speed | digital_in | KV12-C-27 | Digital Input 1 | digital_in | single_source | |
| OEM-1-P | Power steering pressure switch | digital_in | KV12-C-29 | Digital Input 3 | digital_in | single_source | |
| OEM-1-Q | A/C request | digital_in | KV12-C-30 | Digital Input 4 | digital_in | single_source | |
| OEM-1-R | Cooling fan relay | low_side_out | KV12-B-14 | Auxiliary Output 5 | low_side_out | single_source | |
| OEM-1-V | Neutral/clutch switch | digital_in | KV12-C-31 | Digital Input 5 | digital_in | single_source | |
| OEM-2-A | Power 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 | single_source | |
| OEM-2-B | Power 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 | single_source | |
| OEM-2-C | Power 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 | single_source | |
| OEM-2-D | Power 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 | single_source | |
| OEM-2-E | Crank position (CAS NE) | trigger_in | KV12-D-4 | Crank Index Sensor + | trigger_in | single_source | |
| OEM-2-F | MAF 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 | single_source | |
| OEM-2-G | Cam position (CAS G) | trigger_in | KV12-D-6 | Sync Sensor + | trigger_in | single_source | |
| OEM-2-I | Tachometer output | tacho_out | KV12-B-13 | Auxiliary Output 4 | low_side_out | single_source | |
| OEM-2-K | +5V sensor supply | vref | KV12-D-21 | Sensor Supply Vref1: 5.0V | vref | single_source | |
| OEM-2-M | Throttle position (TPS) | analog_in | KV12-C-3 | Analog Input Channel 2 | analog_in | single_source | |
| OEM-2-N | O2 sensor | lambda_nb_in | KV12-C-4 | Analog Input Channel 3 | analog_in | single_source | |
| OEM-2-O | Mass air flow (MAF) | analog_in | KV12-C-2 | Analog Input Channel 1 | analog_in | single_source | |
| OEM-2-P | Intake air temperature (IAT) | temp_in | KV12-C-6 | Analog Input Channel 5 | analog_in | single_source | |
| OEM-2-Q | Coolant temperature (ECT) | temp_in | KV12-C-5 | Analog Input Channel 4 | analog_in | single_source | |
| OEM-2-R | PRC solenoid (fuel pressure regulator) | low_side_out | KV12-B-11 | Auxiliary Output 2 | low_side_out | single_source | |
| OEM-2-S | Condenser fan relay | low_side_out | KV12-B-15 | Auxiliary Output 6 | low_side_out | single_source | |
| OEM-2-T | Fuel pump relay | low_side_out | KV12-B-16 | Auxiliary Output 7 | low_side_out | single_source | |
| OEM-2-U | Injector 1 | injector_out | KV12-B-1 | Injection Channel 1 | injector_out | single_source | |
| OEM-2-V | Injector 2 | injector_out | KV12-B-2 | Injection Channel 2 | injector_out | single_source | |
| OEM-2-W | ISC solenoid | low_side_out | KV12-B-17 | Auxiliary Output 8 | low_side_out | single_source | |
| OEM-2-X | Evap purge solenoid | low_side_out | KV12-B-12 | Auxiliary Output 3 | low_side_out | single_source | |
| OEM-2-Y | Injector 3 | injector_out | KV12-B-3 | Injection Channel 3 | injector_out | single_source | |
| OEM-2-Z | Injector 4 | injector_out | KV12-B-4 | Injection Channel 4 | injector_out | single_source |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-1-B | SP-14V-1 | 0.85 | no route | ECU power +14V (main relay) | — | |
| W2 | SP-14V-1 | 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-2-A | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W6 | OEM-2-B | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W7 | OEM-2-C | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W8 | OEM-2-D | SP-GND-1 | 0.85 | no route | Power 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-2-F | SP-0V-1 | 0.5 | no route | MAF ground | — | |
| W15 | SP-0V-1 | KV12-C-17 | 0.5 | no route | Analog Sensor 0V Reference | — | |
| W16 | SP-0V-1 | KV12-C-25 | 0.5 | no route | Analog Sensor 0V Reference | — | |
| W17 | OEM-2-K | KV12-D-21 | 0.5 | no route | +5V sensor supply | — | |
| W18 | OEM-2-E | KV12-D-4 | 0.5 | no route | Crank position (CAS NE) | — | |
| W19 | SP-0V-1 | KV12-D-5 | 0.5 | no route | Crank Index Sensor - | — | |
| W20 | OEM-2-G | KV12-D-6 | 0.5 | no route | Cam position (CAS G) | — | |
| W21 | SP-0V-1 | KV12-D-7 | 0.5 | no route | Sync Sensor - | — | |
| W22 | OEM-1-G | KV12-B-26 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W23 | OEM-1-H | KV12-B-27 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W24 | OEM-2-U | KV12-B-1 | 0.5 | no route | Injector 1 | — | |
| W25 | OEM-2-V | KV12-B-2 | 0.5 | no route | Injector 2 | — | |
| W26 | OEM-2-Y | KV12-B-3 | 0.5 | no route | Injector 3 | — | |
| W27 | OEM-2-Z | KV12-B-4 | 0.5 | no route | Injector 4 | — | |
| W28 | OEM-1-J | KV12-D-9 | 0.5 | no route | A/C relay | — | |
| W29 | OEM-1-R | KV12-B-14 | 0.5 | no route | Cooling fan relay | — | |
| W30 | OEM-2-S | KV12-B-15 | 0.5 | no route | Condenser fan relay | — | |
| W31 | OEM-2-T | KV12-B-16 | 0.5 | no route | Fuel pump relay | — | |
| W32 | OEM-2-W | KV12-B-17 | 0.5 | no route | ISC solenoid | — | |
| W33 | OEM-1-E | KV12-B-10 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W34 | OEM-2-R | KV12-B-11 | 0.5 | no route | PRC solenoid (fuel pressure regulator) | — | |
| W35 | OEM-2-X | KV12-B-12 | 0.5 | no route | Evap purge solenoid | — | |
| W36 | OEM-2-I | KV12-B-13 | 0.5 | no route | Tachometer output | — | |
| W37 | OEM-2-O | KV12-C-2 | 0.5 | no route | Mass air flow (MAF) | — | |
| W38 | OEM-2-M | KV12-C-3 | 0.5 | no route | Throttle position (TPS) | — | |
| W39 | OEM-2-N | KV12-C-4 | 0.5 | no route | O2 sensor | — | |
| W40 | OEM-2-Q | KV12-C-5 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W41 | OEM-2-P | KV12-C-6 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W42 | OEM-1-M | KV12-C-27 | 0.5 | no route | Vehicle speed | — | |
| W43 | OEM-1-C | KV12-C-28 | 0.5 | no route | Start signal | — | |
| W44 | OEM-1-P | KV12-C-29 | 0.5 | no route | Power steering pressure switch | — | |
| W45 | OEM-1-Q | KV12-C-30 | 0.5 | no route | A/C request | — | |
| W46 | OEM-1-V | KV12-C-31 | 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 |
| 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) | 40.000 | ea |
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (5)
| Severity | Code | Subject | Message |
|---|---|---|---|
| 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-2-I ↔ KV12-B-13 | OEM-2-I "Tachometer output" [tacho_out] is wired to KV12-B-13 "Auxiliary Output 4" [low_side_out]. Tacho as a low-side output: check the tach needs a pull-up. |
| info | NET_FAMILY | OEM-2-P ↔ KV12-C-6 | OEM-2-P "Intake air temperature (IAT)" [temp_in] is wired to KV12-C-6 "Analog Input Channel 5" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | NET_FAMILY | OEM-2-Q ↔ KV12-C-5 | OEM-2-Q "Coolant temperature (ECT)" [temp_in] is wired to KV12-C-5 "Analog Input Channel 4" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
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 2026-10-06. Review every wire against both manuals before building. Not wired: - OEM-1 A: Constant +12V: Emtron KV12 has no battery-constant input; not needed - 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 | Emtron KV12/KV16 Pinout Rev2 | https://github.com/emtron-australia/help | — | 2026-10-05 | 2f3a1b2d2ed4 |
| 4 | vendor_doc | Link G4X MX5X install manual (NA 1.6/1.8) | https://linkecu.com/documentation/MX5X.pdf | archive | 2026-10-05 | b7f730de9f6e |