MX-5 Miata NA8 1994-97 (BP-ZE, 1.8) → Emtron SL4 (auto)
MX-5 Miata NA8 1994-97 (BP-ZE, 1.8) — Emtron — SL4
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 | 41 wires · 7 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-1-B | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | SP-14V-1 | SL4-A-34 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | SP-14V-1 | SL4-B-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-2-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-2-B | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-2-C | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-2-D | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | SP-GND-1 | SL4-B-18 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-GND-1 | SL4-B-26 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | OEM-2-F | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | SP-0V-1 | SL4-B-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-2-K | SL4-B-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-2-E | SL4-B-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | SP-0V-1 | SL4-B-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-2-G | SL4-B-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | SP-0V-1 | SL4-B-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-1-G | SL4-A-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-1-H | SL4-A-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-2-U | SL4-A-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-2-V | SL4-A-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-2-Y | SL4-A-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-2-Z | SL4-A-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-1-J | SL4-B-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-1-R | SL4-A-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-2-S | SL4-A-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-2-T | SL4-A-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-2-W | SL4-A-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-1-E | SL4-A-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-2-R | SL4-A-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-2-X | SL4-A-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-2-I | SL4-A-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-2-O | SL4-B-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-2-M | SL4-B-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-2-N | SL4-B-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-2-Q | SL4-B-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-2-P | SL4-B-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-1-M | SL4-A-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-1-C | SL4-A-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-1-P | SL4-A-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-1-Q | SL4-A-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-1-V | SL4-A-24 | 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 | SL4-A-34 | SL4-B-10 | open (OL) | +12 V supply must not touch sensor ground | |
| 2 | SL4-A-34 | SL4-B-18 | open (OL) | +12 V supply must not touch power ground | |
| 3 | SL4-A-34 | SL4-B-2 | open (OL) | +12 V supply must not touch 5 V sensor reference | |
| 4 | SL4-B-10 | SL4-B-2 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 5 | SL4-B-18 | SL4-B-2 | open (OL) | power ground must not touch 5 V sensor reference |
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 | — | W38 | — | 0.5 | SL4-A-21 | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | W28 | — | 0.5 | SL4-A-10 | — | — | — |
| G | Ignition 1 (coils 1+4, wasted spark) | — | W17 | — | 0.5 | SL4-A-26 | — | — | — |
| H | Ignition 2 (coils 2+3, wasted spark) | — | W18 | — | 0.5 | SL4-A-27 | — | — | — |
| J | A/C relay | — | W23 | — | 0.5 | SL4-B-3 | — | — | — |
| M | Vehicle speed | — | W37 | — | 0.5 | SL4-A-20 | — | — | — |
| P | Power steering pressure switch | — | W39 | — | 0.5 | SL4-A-22 | — | — | — |
| Q | A/C request | — | W40 | — | 0.5 | SL4-A-23 | — | — | — |
| R | Cooling fan relay | — | W24 | — | 0.5 | SL4-A-14 | — | — | — |
| V | Neutral/clutch switch | — | W41 | — | 0.5 | SL4-A-24 | — | — | — |
OEM-2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Power ground | — | W4 | — | 0.85 | SP-GND-1 | — | — | — |
| B | Power ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| C | Power ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| D | Power ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| E | Crank position (CAS NE) | — | W13 | — | 0.5 | SL4-B-5 | — | — | — |
| F | MAF ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| G | Cam position (CAS G) | — | W15 | — | 0.5 | SL4-B-7 | — | — | — |
| I | Tachometer output | — | W31 | — | 0.5 | SL4-A-13 | — | — | — |
| K | +5V sensor supply | — | W12 | — | 0.5 | SL4-B-2 | — | — | — |
| M | Throttle position (TPS) | — | W33 | — | 0.5 | SL4-B-12 | — | — | — |
| N | O2 sensor | — | W34 | — | 0.5 | SL4-B-13 | — | — | — |
| O | Mass air flow (MAF) | — | W32 | — | 0.5 | SL4-B-11 | — | — | — |
| P | Intake air temperature (IAT) | — | W36 | — | 0.5 | SL4-B-15 | — | — | — |
| Q | Coolant temperature (ECT) | — | W35 | — | 0.5 | SL4-B-14 | — | — | — |
| R | PRC solenoid (fuel pressure regulator) | — | W29 | — | 0.5 | SL4-A-11 | — | — | — |
| S | Condenser fan relay | — | W25 | — | 0.5 | SL4-A-15 | — | — | — |
| T | Fuel pump relay | — | W26 | — | 0.5 | SL4-A-16 | — | — | — |
| U | Injector 1 | — | W19 | — | 0.5 | SL4-A-1 | — | — | — |
| V | Injector 2 | — | W20 | — | 0.5 | SL4-A-2 | — | — | — |
| W | ISC solenoid | — | W27 | — | 0.5 | SL4-A-17 | — | — | — |
| X | Evap purge solenoid | — | W30 | — | 0.5 | SL4-A-12 | — | — | — |
| Y | Injector 3 | — | W21 | — | 0.5 | SL4-A-3 | — | — | — |
| Z | Injector 4 | — | W22 | — | 0.5 | SL4-A-4 | — | — | — |
SL4-A
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Injection channel 1 | — | W19 | — | 0.5 | OEM-2-U | — | — | — |
| 2 | Injection channel 2 | — | W20 | — | 0.5 | OEM-2-V | — | — | — |
| 3 | Injection channel 3 | — | W21 | — | 0.5 | OEM-2-Y | — | — | — |
| 4 | Injection channel 4 | — | W22 | — | 0.5 | OEM-2-Z | — | — | — |
| 5 | NC | — | — | — | — | — | — | — | — |
| 6 | NC | — | — | — | — | — | — | — | — |
| 7 | NC | — | — | — | — | — | — | — | — |
| 8 | NC | — | — | — | — | — | — | — | — |
| 9 | Sensor supply 8V | — | — | — | — | — | — | — | — |
| 10 | Auxiliary output 1 | — | W28 | — | 0.5 | OEM-1-E | — | — | — |
| 11 | Auxiliary output 2 | — | W29 | — | 0.5 | OEM-2-R | — | — | — |
| 12 | Auxiliary output 3 | — | W30 | — | 0.5 | OEM-2-X | — | — | — |
| 13 | Auxiliary output 4 | — | W31 | — | 0.5 | OEM-2-I | — | — | — |
| 14 | Auxiliary output 5 | — | W24 | — | 0.5 | OEM-1-R | — | — | — |
| 15 | Auxiliary output 6 | — | W25 | — | 0.5 | OEM-2-S | — | — | — |
| 16 | Auxiliary output 7 | — | W26 | — | 0.5 | OEM-2-T | — | — | — |
| 17 | Auxiliary output 8 | — | W27 | — | 0.5 | OEM-2-W | — | — | — |
| 18 | Auxiliary output 9 | — | — | — | — | — | — | — | — |
| 19 | Auxiliary output 10 | — | — | — | — | — | — | — | — |
| 20 | Digital input 1 | — | W37 | — | 0.5 | OEM-1-M | — | — | — |
| 21 | Digital input 2 | — | W38 | — | 0.5 | OEM-1-C | — | — | — |
| 22 | Digital input 3 | — | W39 | — | 0.5 | OEM-1-P | — | — | — |
| 23 | Digital input 4 | — | W40 | — | 0.5 | OEM-1-Q | — | — | — |
| 24 | Digital input 5 | — | W41 | — | 0.5 | OEM-1-V | — | — | — |
| 25 | Digital input 6 | — | — | — | — | — | — | — | — |
| 26 | Ignition channel 1 | — | W17 | — | 0.5 | OEM-1-G | — | — | — |
| 27 | Ignition channel 2 | — | W18 | — | 0.5 | OEM-1-H | — | — | — |
| 28 | Ignition channel 3 | — | — | — | — | — | — | — | — |
| 29 | Ignition channel 4 | — | — | — | — | — | — | — | — |
| 30 | NC | — | — | — | — | — | — | — | — |
| 31 | NC | — | — | — | — | — | — | — | — |
| 32 | NC | — | — | — | — | — | — | — | — |
| 33 | NC | — | — | — | — | — | — | — | — |
| 34 | Aux 9–10 14V supply | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
SL4-B
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | ECU 14V supply | — | W3 | — | 0.85 | SP-14V-1 | — | — | — |
| 2 | Sensor supply Vref1 5.0V | — | W12 | — | 0.5 | OEM-2-K | — | — | — |
| 3 | EFI relay output (low side, 200 mA) | — | W23 | — | 0.5 | OEM-1-J | — | — | — |
| 4 | Ignition switch input | — | — | — | — | — | — | — | — |
| 5 | Crank index sensor + | — | W13 | — | 0.5 | OEM-2-E | — | — | — |
| 6 | Crank index sensor − | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| 7 | Sync sensor + | — | W15 | — | 0.5 | OEM-2-G | — | — | — |
| 8 | Sync sensor − | — | W16 | — | 0.5 | SP-0V-1 | — | — | — |
| 9 | Shield (crank/sync/knock) | — | — | — | — | — | — | — | — |
| 10 | Analog sensor 0V reference | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 11 | Analog input 1 | — | W32 | — | 0.5 | OEM-2-O | — | — | — |
| 12 | Analog input 2 | — | W33 | — | 0.5 | OEM-2-M | — | — | — |
| 13 | Analog input 3 | — | W34 | — | 0.5 | OEM-2-N | — | — | — |
| 14 | Analog input 4 | — | W35 | — | 0.5 | OEM-2-Q | — | — | — |
| 15 | Analog input 5 | — | W36 | — | 0.5 | OEM-2-P | — | — | — |
| 16 | Knock 1 + | — | — | — | — | — | — | — | — |
| 17 | Knock 1 − | — | — | — | — | — | — | — | — |
| 18 | ECU ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| 19 | Analog input 6 | — | — | — | — | — | — | — | — |
| 20 | Analog input 7 (switchable 1k pull-up) | — | — | — | — | — | — | — | — |
| 21 | Analog input 8 (switchable 1k pull-up) | — | — | — | — | — | — | — | — |
| 22 | Analog input 9 (switchable 1k pull-up) | — | — | — | — | — | — | — | — |
| 23 | Analog input 10 (switchable 1k pull-up) | — | — | — | — | — | — | — | — |
| 24 | Knock 2 + | — | — | — | — | — | — | — | — |
| 25 | Knock 2 − | — | — | — | — | — | — | — | — |
| 26 | ECU ground | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| 27 | CAN 1 H | — | — | — | — | — | — | — | — |
| 28 | CAN 1 L | — | — | — | — | — | — | — | — |
| 29 | NC | — | — | — | — | — | — | — | — |
| 30 | NC | — | — | — | — | — | — | — | — |
| 31 | Ethernet Tx + | — | — | — | — | — | — | — | — |
| 32 | Ethernet Tx − | — | — | — | — | — | — | — | — |
| 33 | Ethernet Rx + | — | — | — | — | — | — | — | — |
| 34 | Ethernet Rx − | — | — | — | — | — | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W10 | — | 0.5 | OEM-2-F | — | — | — |
| 1 | — | — | W11 | — | 0.5 | SL4-B-10 | — | — | — |
| 1 | — | — | W14 | — | 0.5 | SL4-B-6 | — | — | — |
| 1 | — | — | W16 | — | 0.5 | SL4-B-8 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-1-B | — | — | — |
| 1 | — | — | W2 | — | 0.85 | SL4-A-34 | — | — | — |
| 1 | — | — | W3 | — | 0.85 | SL4-B-1 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W4 | — | 0.85 | OEM-2-A | — | — | — |
| 1 | — | — | W5 | — | 0.85 | OEM-2-B | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-2-C | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-2-D | — | — | — |
| 1 | — | — | W8 | — | 0.85 | SL4-B-18 | — | — | — |
| 1 | — | — | W9 | — | 0.85 | SL4-B-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 | SL4-A-34 + SL4-B-1 | Aux 9–10 14V supply + ECU 14V supply | power_in | single_source | |
| OEM-1-C | Start signal | digital_in | SL4-A-21 | Digital input 2 | digital_in | single_source | |
| OEM-1-E | Malfunction indicator lamp (MIL) | low_side_out | SL4-A-10 | Auxiliary output 1 | switch_out | single_source | |
| OEM-1-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | SL4-A-26 | Ignition channel 1 | ignition_out | single_source | |
| OEM-1-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | SL4-A-27 | Ignition channel 2 | ignition_out | single_source | |
| OEM-1-J | A/C relay | low_side_out | SL4-B-3 | EFI relay output (low side, 200 mA) | low_side_out | single_source | |
| OEM-1-M | Vehicle speed | digital_in | SL4-A-20 | Digital input 1 | digital_in | single_source | |
| OEM-1-P | Power steering pressure switch | digital_in | SL4-A-22 | Digital input 3 | digital_in | single_source | |
| OEM-1-Q | A/C request | digital_in | SL4-A-23 | Digital input 4 | digital_in | single_source | |
| OEM-1-R | Cooling fan relay | low_side_out | SL4-A-14 | Auxiliary output 5 | switch_out | single_source | |
| OEM-1-V | Neutral/clutch switch | digital_in | SL4-A-24 | Digital input 5 | digital_in | single_source | |
| OEM-2-A | Power ground | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-2-B | Power ground | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-2-C | Power ground | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-2-D | Power ground | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-2-E | Crank position (CAS NE) | trigger_in | SL4-B-5 | Crank index sensor + | trigger_in | single_source | |
| OEM-2-F | MAF ground | sensor_ground | SL4-B-10 + SL4-B-6 + SL4-B-8 | Analog sensor 0V reference + Crank index sensor − + Sync sensor − | sensor_ground + trigger_in | single_source | |
| OEM-2-G | Cam position (CAS G) | trigger_in | SL4-B-7 | Sync sensor + | trigger_in | single_source | |
| OEM-2-I | Tachometer output | tacho_out | SL4-A-13 | Auxiliary output 4 | switch_out | single_source | |
| OEM-2-K | +5V sensor supply | vref | SL4-B-2 | Sensor supply Vref1 5.0V | vref | single_source | |
| OEM-2-M | Throttle position (TPS) | analog_in | SL4-B-12 | Analog input 2 | analog_in | single_source | |
| OEM-2-N | O2 sensor | lambda_nb_in | SL4-B-13 | Analog input 3 | analog_in | single_source | |
| OEM-2-O | Mass air flow (MAF) | analog_in | SL4-B-11 | Analog input 1 | analog_in | single_source | |
| OEM-2-P | Intake air temperature (IAT) | temp_in | SL4-B-15 | Analog input 5 | analog_in | single_source | |
| OEM-2-Q | Coolant temperature (ECT) | temp_in | SL4-B-14 | Analog input 4 | analog_in | single_source | |
| OEM-2-R | PRC solenoid (fuel pressure regulator) | low_side_out | SL4-A-11 | Auxiliary output 2 | switch_out | single_source | |
| OEM-2-S | Condenser fan relay | low_side_out | SL4-A-15 | Auxiliary output 6 | switch_out | single_source | |
| OEM-2-T | Fuel pump relay | low_side_out | SL4-A-16 | Auxiliary output 7 | switch_out | single_source | |
| OEM-2-U | Injector 1 | injector_out | SL4-A-1 | Injection channel 1 | injector_out | single_source | |
| OEM-2-V | Injector 2 | injector_out | SL4-A-2 | Injection channel 2 | injector_out | single_source | |
| OEM-2-W | ISC solenoid | low_side_out | SL4-A-17 | Auxiliary output 8 | switch_out | single_source | |
| OEM-2-X | Evap purge solenoid | low_side_out | SL4-A-12 | Auxiliary output 3 | switch_out | single_source | |
| OEM-2-Y | Injector 3 | injector_out | SL4-A-3 | Injection channel 3 | injector_out | single_source | |
| OEM-2-Z | Injector 4 | injector_out | SL4-A-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 | SL4-A-34 | 0.85 | no route | Aux 9–10 14V supply | — | |
| W3 | SP-14V-1 | SL4-B-1 | 0.85 | no route | ECU 14V supply | — | |
| W4 | OEM-2-A | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W5 | OEM-2-B | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W6 | OEM-2-C | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W7 | OEM-2-D | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W8 | SP-GND-1 | SL4-B-18 | 0.85 | no route | ECU ground | — | |
| W9 | SP-GND-1 | SL4-B-26 | 0.85 | no route | ECU ground | — | |
| W10 | OEM-2-F | SP-0V-1 | 0.5 | no route | MAF ground | — | |
| W11 | SP-0V-1 | SL4-B-10 | 0.5 | no route | Analog sensor 0V reference | — | |
| W12 | OEM-2-K | SL4-B-2 | 0.5 | no route | +5V sensor supply | — | |
| W13 | OEM-2-E | SL4-B-5 | 0.5 | no route | Crank position (CAS NE) | — | |
| W14 | SP-0V-1 | SL4-B-6 | 0.5 | no route | Crank index sensor − | — | |
| W15 | OEM-2-G | SL4-B-7 | 0.5 | no route | Cam position (CAS G) | — | |
| W16 | SP-0V-1 | SL4-B-8 | 0.5 | no route | Sync sensor − | — | |
| W17 | OEM-1-G | SL4-A-26 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W18 | OEM-1-H | SL4-A-27 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W19 | OEM-2-U | SL4-A-1 | 0.5 | no route | Injector 1 | — | |
| W20 | OEM-2-V | SL4-A-2 | 0.5 | no route | Injector 2 | — | |
| W21 | OEM-2-Y | SL4-A-3 | 0.5 | no route | Injector 3 | — | |
| W22 | OEM-2-Z | SL4-A-4 | 0.5 | no route | Injector 4 | — | |
| W23 | OEM-1-J | SL4-B-3 | 0.5 | no route | A/C relay | — | |
| W24 | OEM-1-R | SL4-A-14 | 0.5 | no route | Cooling fan relay | — | |
| W25 | OEM-2-S | SL4-A-15 | 0.5 | no route | Condenser fan relay | — | |
| W26 | OEM-2-T | SL4-A-16 | 0.5 | no route | Fuel pump relay | — | |
| W27 | OEM-2-W | SL4-A-17 | 0.5 | no route | ISC solenoid | — | |
| W28 | OEM-1-E | SL4-A-10 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W29 | OEM-2-R | SL4-A-11 | 0.5 | no route | PRC solenoid (fuel pressure regulator) | — | |
| W30 | OEM-2-X | SL4-A-12 | 0.5 | no route | Evap purge solenoid | — | |
| W31 | OEM-2-I | SL4-A-13 | 0.5 | no route | Tachometer output | — | |
| W32 | OEM-2-O | SL4-B-11 | 0.5 | no route | Mass air flow (MAF) | — | |
| W33 | OEM-2-M | SL4-B-12 | 0.5 | no route | Throttle position (TPS) | — | |
| W34 | OEM-2-N | SL4-B-13 | 0.5 | no route | O2 sensor | — | |
| W35 | OEM-2-Q | SL4-B-14 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W36 | OEM-2-P | SL4-B-15 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W37 | OEM-1-M | SL4-A-20 | 0.5 | no route | Vehicle speed | — | |
| W38 | OEM-1-C | SL4-A-21 | 0.5 | no route | Start signal | — | |
| W39 | OEM-1-P | SL4-A-22 | 0.5 | no route | Power steering pressure switch | — | |
| W40 | OEM-1-Q | SL4-A-23 | 0.5 | no route | A/C request | — | |
| W41 | OEM-1-V | SL4-A-24 | 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 | 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) | 35.000 | ea |
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (11)
| Severity | Code | Subject | Message |
|---|---|---|---|
| info | NET_FAMILY | OEM-1-E ↔ SL4-A-10 | OEM-1-E "Malfunction indicator lamp (MIL)" [low_side_out] is wired to SL4-A-10 "Auxiliary output 1" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-1-R ↔ SL4-A-14 | OEM-1-R "Cooling fan relay" [low_side_out] is wired to SL4-A-14 "Auxiliary output 5" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-2-I ↔ SL4-A-13 | OEM-2-I "Tachometer output" [tacho_out] is wired to SL4-A-13 "Auxiliary output 4" [switch_out]. Frequency output on a general output: set it up as a tacho/frequency output with the right pull-up. |
| info | NET_FAMILY | OEM-2-P ↔ SL4-B-15 | OEM-2-P "Intake air temperature (IAT)" [temp_in] is wired to SL4-B-15 "Analog input 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 ↔ SL4-B-14 | OEM-2-Q "Coolant temperature (ECT)" [temp_in] is wired to SL4-B-14 "Analog input 4" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | NET_FAMILY | OEM-2-R ↔ SL4-A-11 | OEM-2-R "PRC solenoid (fuel pressure regulator)" [low_side_out] is wired to SL4-A-11 "Auxiliary output 2" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-2-S ↔ SL4-A-15 | OEM-2-S "Condenser fan relay" [low_side_out] is wired to SL4-A-15 "Auxiliary output 6" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-2-T ↔ SL4-A-16 | OEM-2-T "Fuel pump relay" [low_side_out] is wired to SL4-A-16 "Auxiliary output 7" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-2-W ↔ SL4-A-17 | OEM-2-W "ISC solenoid" [low_side_out] is wired to SL4-A-17 "Auxiliary output 8" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-2-X ↔ SL4-A-12 | OEM-2-X "Evap purge solenoid" [low_side_out] is wired to SL4-A-12 "Auxiliary output 3" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | SL4-B-8 ↔ SL4-B-10 | SL4-B-8 "Sync sensor −" [trigger_in] is wired to SL4-B-10 "Analog sensor 0V reference" [sensor_ground]. Trigger return tied to sensor/trigger ground: correct for single-ended trigger inputs. |
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 SL4 has no battery-constant input; not needed - SL4-B 4: 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 SL4/SL6/SL8 ECU datasheets | https://docs.emtronaustralia.com.au/engine-management/datasheets/index.html | archive | 2026-10-05 | 1e22846cec94 |
| 4 | vendor_doc | Emtron SL4/SL6/SL8 pinout pages | https://docs.emtronaustralia.com.au/engine-management/wiring/index.html | archive | 2026-10-05 | e52b3da9996a |
| 4 | vendor_doc | Link G4X MX5X install manual (NA 1.6/1.8) | https://linkecu.com/documentation/MX5X.pdf | archive | 2026-10-05 | b7f730de9f6e |