VW Corrado VR6 12v (AAA) Motronic M2.9 OBD1 → Emtron SL4 (auto)
VW Corrado VR6 12v (AAA) Motronic M2.9 OBD1 — Emtron — SL4
⚠ 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 | 2: read the Findings page before cutting any wire |
| Size of the job | 48 wires · 6 connectors · 3 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-A-23 | 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-A-1 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-A-10 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-A-55 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-A-56 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | OEM-A-7 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-GND-1 | SL4-B-18 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | SP-GND-1 | SL4-B-26 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | OEM-A-16 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-A-33 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-A-67 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | SP-0V-1 | SL4-B-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-A-41 | SL4-B-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-A-68 | SL4-B-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | SP-0V-1 | SL4-B-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-A-44 | SL4-B-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | SP-0V-1 | SL4-B-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-A-34 | SL4-B-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-A-8 | SL4-A-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-A-60 | SL4-A-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-A-52 | SL4-A-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-A-24 | SL4-A-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-A-3 | SL4-A-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-A-26 | SL4-A-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-A-4 | SL4-A-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-A-25 | SL4-A-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-A-2 | SL4-A-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-A-38 | SL4-B-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-A-17 | SL4-B-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-A-40 | SL4-B-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-A-14 | SL4-B-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-A-49 | SL4-B-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-A-6 | SL4-A-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-A-9 | SL4-A-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-A-27 | SL4-A-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-A-31 | SL4-A-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-A-5 | SL4-A-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-A-53 | SL4-A-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-A-22 | SL4-A-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-A-51 | SL4-A-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-A-20 | SL4-B-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-A-15 | SL4-B-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-A-36 | SL4-B-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W46 | OEM-A-65 | SL4-A-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W47 | OEM-A-37 | SL4-A-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W48 | OEM-A-39 | SL4-A-22 | 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-2 | open (OL) | +12 V supply must not touch 5 V sensor reference | |
| 2 | SL4-B-10 | SL4-A-34 | open (OL) | sensor ground must not touch +12 V supply | |
| 3 | SL4-B-10 | SL4-B-2 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 4 | SL4-B-18 | SL4-A-34 | open (OL) | power ground must not touch +12 V supply | |
| 5 | SL4-B-18 | SL4-B-2 | open (OL) | power 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-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Ground (E-1) | — | W4 | — | 0.85 | SP-GND-1 | — | — | — |
| 10 | Ground (OBD1 EGR enable) | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | Coolant temperature (CLT) | — | W33 | — | 0.5 | SL4-B-13 | — | — | — |
| 15 | EGR temperature sensor | — | W44 | — | 0.5 | SL4-B-15 | — | — | — |
| 16 | MAF ground | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 17 | MAF signal | — | W31 | — | 0.5 | SL4-B-11 | — | — | — |
| 2 | Injector 6 (cyl 6) | — | W29 | — | 0.5 | SL4-A-2 | — | — | — |
| 20 | O2 sensor 1 (primary) | — | W43 | — | 0.5 | SL4-B-14 | — | — | — |
| 21 | Diagnostic L-line | — | — | — | — | — | — | — | — |
| 22 | Tachometer output | — | W41 | — | 0.5 | SL4-A-12 | — | — | — |
| 23 | ECU main power (from engine-electronics relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| 24 | Injector 1 (cyl 1) | — | W24 | — | 0.5 | SL4-A-1 | — | — | — |
| 25 | Injector 5 (cyl 5) | — | W28 | — | 0.5 | SL4-A-1 | — | — | — |
| 26 | Injector 3 (cyl 3) | — | W26 | — | 0.5 | SL4-A-3 | — | — | — |
| 27 | Idle air control valve | — | W37 | — | 0.5 | SL4-A-16 | — | — | — |
| 3 | Injector 2 (cyl 2) | — | W25 | — | 0.5 | SL4-A-2 | — | — | — |
| 31 | EVAP canister purge valve | — | W38 | — | 0.5 | SL4-A-17 | — | — | — |
| 33 | Sensor ground bus | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 34 | Knock sensor 1 | — | W20 | — | 0.5 | SL4-B-16 | — | — | — |
| 36 | Intake air temperature (IAT) | — | W45 | — | 0.5 | SL4-B-19 | — | — | — |
| 37 | A/C compressor switch | — | W47 | — | 0.5 | SL4-A-21 | — | — | — |
| 38 | Ignition switch (run/start) | — | W30 | — | 0.5 | SL4-B-4 | — | — | — |
| 39 | A/C switch (cabin) | — | W48 | — | 0.5 | SL4-A-22 | — | — | — |
| 4 | Injector 4 (cyl 4) | — | W27 | — | 0.5 | SL4-A-4 | — | — | — |
| 40 | Throttle position sensor 1 | — | W32 | — | 0.5 | SL4-B-12 | — | — | — |
| 41 | TPS power (+5V) | — | W15 | — | 0.5 | SL4-B-2 | — | — | — |
| 43 | Diagnostic K-line | — | — | — | — | — | — | — | — |
| 44 | Camshaft position sensor (G40) | — | W18 | — | 0.5 | SL4-B-7 | — | — | — |
| 49 | Secondary air injection relay control | — | W34 | — | 0.5 | SL4-B-3 | — | — | — |
| 5 | Check engine light (MIL) | — | W39 | — | 0.5 | SL4-A-10 | — | — | — |
| 51 | MFA fuel-consumption signal | — | W42 | — | 0.5 | SL4-A-13 | — | — | — |
| 52 | Ignition coil 4 (coil pack pin 4) | — | W23 | — | 0.5 | SL4-A-28 | — | — | — |
| 53 | Idle air control valve (2nd) | — | W40 | — | 0.5 | SL4-A-11 | — | — | — |
| 54 | Battery constant (+12V) | — | — | — | — | — | — | — | — |
| 55 | Ground (E-3) | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 56 | Ground (E-4) | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 59 | Mass airflow sensor (5th terminal) | — | — | — | — | — | — | — | — |
| 6 | Fuel pump relay control | — | W35 | — | 0.5 | SL4-A-14 | — | — | — |
| 60 | Ignition coil 3 (coil pack pin 3) | — | W22 | — | 0.5 | SL4-A-27 | — | — | — |
| 65 | Vehicle speed sensor (VSS) | — | W46 | — | 0.5 | SL4-A-20 | — | — | — |
| 67 | Crank sensor return (VR-) | — | W13 | — | 0.5 | SP-0V-1 | — | — | — |
| 68 | Crank position sensor (G28, VR+) | — | W16 | — | 0.5 | SL4-B-5 | — | — | — |
| 7 | Ground (E-2) | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| 8 | Ignition coil 2 (coil pack pin 2) | — | W21 | — | 0.5 | SL4-A-26 | — | — | — |
| 9 | Engine electronics relay control | — | W36 | — | 0.5 | SL4-A-15 | — | — | — |
SL4-A
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Injection channel 1 | — | W24 | — | 0.5 | OEM-A-24 | — | — | — |
| 1 | Injection channel 1 | — | W28 | — | 0.5 | OEM-A-25 | — | — | — |
| 2 | Injection channel 2 | — | W29 | — | 0.5 | OEM-A-2 | — | — | — |
| 2 | Injection channel 2 | — | W25 | — | 0.5 | OEM-A-3 | — | — | — |
| 3 | Injection channel 3 | — | W26 | — | 0.5 | OEM-A-26 | — | — | — |
| 4 | Injection channel 4 | — | W27 | — | 0.5 | OEM-A-4 | — | — | — |
| 5 | NC | — | — | — | — | — | — | — | — |
| 6 | NC | — | — | — | — | — | — | — | — |
| 7 | NC | — | — | — | — | — | — | — | — |
| 8 | NC | — | — | — | — | — | — | — | — |
| 9 | Sensor supply 8V | — | — | — | — | — | — | — | — |
| 10 | Auxiliary output 1 | — | W39 | — | 0.5 | OEM-A-5 | — | — | — |
| 11 | Auxiliary output 2 | — | W40 | — | 0.5 | OEM-A-53 | — | — | — |
| 12 | Auxiliary output 3 | — | W41 | — | 0.5 | OEM-A-22 | — | — | — |
| 13 | Auxiliary output 4 | — | W42 | — | 0.5 | OEM-A-51 | — | — | — |
| 14 | Auxiliary output 5 | — | W35 | — | 0.5 | OEM-A-6 | — | — | — |
| 15 | Auxiliary output 6 | — | W36 | — | 0.5 | OEM-A-9 | — | — | — |
| 16 | Auxiliary output 7 | — | W37 | — | 0.5 | OEM-A-27 | — | — | — |
| 17 | Auxiliary output 8 | — | W38 | — | 0.5 | OEM-A-31 | — | — | — |
| 18 | Auxiliary output 9 | — | — | — | — | — | — | — | — |
| 19 | Auxiliary output 10 | — | — | — | — | — | — | — | — |
| 20 | Digital input 1 | — | W46 | — | 0.5 | OEM-A-65 | — | — | — |
| 21 | Digital input 2 | — | W47 | — | 0.5 | OEM-A-37 | — | — | — |
| 22 | Digital input 3 | — | W48 | — | 0.5 | OEM-A-39 | — | — | — |
| 23 | Digital input 4 | — | — | — | — | — | — | — | — |
| 24 | Digital input 5 | — | — | — | — | — | — | — | — |
| 25 | Digital input 6 | — | — | — | — | — | — | — | — |
| 26 | Ignition channel 1 | — | W21 | — | 0.5 | OEM-A-8 | — | — | — |
| 27 | Ignition channel 2 | — | W22 | — | 0.5 | OEM-A-60 | — | — | — |
| 28 | Ignition channel 3 | — | W23 | — | 0.5 | OEM-A-52 | — | — | — |
| 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 | — | W15 | — | 0.5 | OEM-A-41 | — | — | — |
| 3 | EFI relay output (low side, 200 mA) | — | W34 | — | 0.5 | OEM-A-49 | — | — | — |
| 4 | Ignition switch input | — | W30 | — | 0.5 | OEM-A-38 | — | — | — |
| 5 | Crank index sensor + | — | W16 | — | 0.5 | OEM-A-68 | — | — | — |
| 6 | Crank index sensor − | — | W17 | — | 0.5 | SP-0V-1 | — | — | — |
| 7 | Sync sensor + | — | W18 | — | 0.5 | OEM-A-44 | — | — | — |
| 8 | Sync sensor − | — | W19 | — | 0.5 | SP-0V-1 | — | — | — |
| 9 | Shield (crank/sync/knock) | — | — | — | — | — | — | — | — |
| 10 | Analog sensor 0V reference | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| 11 | Analog input 1 | — | W31 | — | 0.5 | OEM-A-17 | — | — | — |
| 12 | Analog input 2 | — | W32 | — | 0.5 | OEM-A-40 | — | — | — |
| 13 | Analog input 3 | — | W33 | — | 0.5 | OEM-A-14 | — | — | — |
| 14 | Analog input 4 | — | W43 | — | 0.5 | OEM-A-20 | — | — | — |
| 15 | Analog input 5 | — | W44 | — | 0.5 | OEM-A-15 | — | — | — |
| 16 | Knock 1 + | — | W20 | — | 0.5 | OEM-A-34 | — | — | — |
| 17 | Knock 1 − | — | — | — | — | — | — | — | — |
| 18 | ECU ground | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| 19 | Analog input 6 | — | W45 | — | 0.5 | OEM-A-36 | — | — | — |
| 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 | — | W10 | — | 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 | — | — | W13 | — | 0.5 | OEM-A-67 | — | — | — |
| 1 | — | — | W11 | — | 0.5 | OEM-A-16 | — | — | — |
| 1 | — | — | W12 | — | 0.5 | OEM-A-33 | — | — | — |
| 1 | — | — | W14 | — | 0.5 | SL4-B-10 | — | — | — |
| 1 | — | — | W17 | — | 0.5 | SL4-B-6 | — | — | — |
| 1 | — | — | W19 | — | 0.5 | SL4-B-8 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-A-23 | — | — | — |
| 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-A-1 | — | — | — |
| 1 | — | — | W5 | — | 0.85 | OEM-A-10 | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-A-55 | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-A-56 | — | — | — |
| 1 | — | — | W8 | — | 0.85 | OEM-A-7 | — | — | — |
| 1 | — | — | W9 | — | 0.85 | SL4-B-18 | — | — | — |
| 1 | — | — | W10 | — | 0.85 | SL4-B-26 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-A-1 | Ground (E-1) | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-A-10 | Ground (OBD1 EGR enable) | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-A-14 | Coolant temperature (CLT) | temp_in | SL4-B-13 | Analog input 3 | analog_in | single_source | |
| OEM-A-15 | EGR temperature sensor | temp_in | SL4-B-15 | Analog input 5 | analog_in | single_source | |
| OEM-A-16 | 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-A-17 | MAF signal | analog_in | SL4-B-11 | Analog input 1 | analog_in | single_source | |
| OEM-A-2 | Injector 6 (cyl 6) | injector_out | SL4-A-2 | Injection channel 2 | injector_out | single_source | |
| OEM-A-20 | O2 sensor 1 (primary) | lambda_nb_in | SL4-B-14 | Analog input 4 | analog_in | single_source | |
| OEM-A-21 | Diagnostic L-line | serial | — | — | — | single_source | |
| OEM-A-22 | Tachometer output | tacho_out | SL4-A-12 | Auxiliary output 3 | switch_out | single_source | |
| OEM-A-23 | ECU main power (from engine-electronics relay) | power_in | SL4-A-34 + SL4-B-1 | Aux 9–10 14V supply + ECU 14V supply | power_in | single_source | |
| OEM-A-24 | Injector 1 (cyl 1) | injector_out | SL4-A-1 | Injection channel 1 | injector_out | single_source | |
| OEM-A-25 | Injector 5 (cyl 5) | injector_out | SL4-A-1 | Injection channel 1 | injector_out | single_source | |
| OEM-A-26 | Injector 3 (cyl 3) | injector_out | SL4-A-3 | Injection channel 3 | injector_out | single_source | |
| OEM-A-27 | Idle air control valve | low_side_out | SL4-A-16 | Auxiliary output 7 | switch_out | single_source | |
| OEM-A-3 | Injector 2 (cyl 2) | injector_out | SL4-A-2 | Injection channel 2 | injector_out | single_source | |
| OEM-A-31 | EVAP canister purge valve | low_side_out | SL4-A-17 | Auxiliary output 8 | switch_out | single_source | |
| OEM-A-33 | Sensor ground bus | 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-A-34 | Knock sensor 1 | knock_in | SL4-B-16 | Knock 1 + | knock_in | single_source | |
| OEM-A-36 | Intake air temperature (IAT) | temp_in | SL4-B-19 | Analog input 6 | analog_in | single_source | |
| OEM-A-37 | A/C compressor switch | digital_in | SL4-A-21 | Digital input 2 | digital_in | single_source | |
| OEM-A-38 | Ignition switch (run/start) | digital_in | SL4-B-4 | Ignition switch input | digital_in | single_source | |
| OEM-A-39 | A/C switch (cabin) | digital_in | SL4-A-22 | Digital input 3 | digital_in | single_source | |
| OEM-A-4 | Injector 4 (cyl 4) | injector_out | SL4-A-4 | Injection channel 4 | injector_out | single_source | |
| OEM-A-40 | Throttle position sensor 1 | analog_in | SL4-B-12 | Analog input 2 | analog_in | single_source | |
| OEM-A-41 | TPS power (+5V) | vref | SL4-B-2 | Sensor supply Vref1 5.0V | vref | single_source | |
| OEM-A-43 | Diagnostic K-line | serial | — | — | — | single_source | |
| OEM-A-44 | Camshaft position sensor (G40) | trigger_in | SL4-B-7 | Sync sensor + | trigger_in | single_source | |
| OEM-A-49 | Secondary air injection relay control | low_side_out | SL4-B-3 | EFI relay output (low side, 200 mA) | low_side_out | single_source | |
| OEM-A-5 | Check engine light (MIL) | low_side_out | SL4-A-10 | Auxiliary output 1 | switch_out | single_source | |
| OEM-A-51 | MFA fuel-consumption signal | tacho_out | SL4-A-13 | Auxiliary output 4 | switch_out | single_source | |
| OEM-A-52 | Ignition coil 4 (coil pack pin 4) | ignition_out | SL4-A-28 | Ignition channel 3 | ignition_out | single_source | |
| OEM-A-53 | Idle air control valve (2nd) | low_side_out | SL4-A-11 | Auxiliary output 2 | switch_out | single_source | |
| OEM-A-54 | Battery constant (+12V) | power_in | — | — | — | single_source | |
| OEM-A-55 | Ground (E-3) | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-A-56 | Ground (E-4) | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-A-59 | Mass airflow sensor (5th terminal) | sensor_out | — | — | — | single_source | |
| OEM-A-6 | Fuel pump relay control | low_side_out | SL4-A-14 | Auxiliary output 5 | switch_out | single_source | |
| OEM-A-60 | Ignition coil 3 (coil pack pin 3) | ignition_out | SL4-A-27 | Ignition channel 2 | ignition_out | single_source | |
| OEM-A-65 | Vehicle speed sensor (VSS) | digital_in | SL4-A-20 | Digital input 1 | digital_in | single_source | |
| OEM-A-67 | Crank sensor return (VR-) | 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-A-68 | Crank position sensor (G28, VR+) | trigger_in | SL4-B-5 | Crank index sensor + | trigger_in | single_source | |
| OEM-A-7 | Ground (E-2) | ground | SL4-B-18 + SL4-B-26 | ECU ground + ECU ground | ground | single_source | |
| OEM-A-8 | Ignition coil 2 (coil pack pin 2) | ignition_out | SL4-A-26 | Ignition channel 1 | ignition_out | single_source | |
| OEM-A-9 | Engine electronics relay control | low_side_out | SL4-A-15 | Auxiliary output 6 | switch_out | single_source |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-A-23 | SP-14V-1 | 0.85 | no route | ECU main power (from engine-electronics 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-A-1 | SP-GND-1 | 0.85 | no route | Ground (E-1) | — | |
| W5 | OEM-A-10 | SP-GND-1 | 0.85 | no route | Ground (OBD1 EGR enable) | — | |
| W6 | OEM-A-55 | SP-GND-1 | 0.85 | no route | Ground (E-3) | — | |
| W7 | OEM-A-56 | SP-GND-1 | 0.85 | no route | Ground (E-4) | — | |
| W8 | OEM-A-7 | SP-GND-1 | 0.85 | no route | Ground (E-2) | — | |
| W9 | SP-GND-1 | SL4-B-18 | 0.85 | no route | ECU ground | — | |
| W10 | SP-GND-1 | SL4-B-26 | 0.85 | no route | ECU ground | — | |
| W11 | OEM-A-16 | SP-0V-1 | 0.5 | no route | MAF ground | — | |
| W12 | OEM-A-33 | SP-0V-1 | 0.5 | no route | Sensor ground bus | — | |
| W13 | OEM-A-67 | SP-0V-1 | 0.5 | no route | Crank sensor return (VR-) | — | |
| W14 | SP-0V-1 | SL4-B-10 | 0.5 | no route | Analog sensor 0V reference | — | |
| W15 | OEM-A-41 | SL4-B-2 | 0.5 | no route | TPS power (+5V) | — | |
| W16 | OEM-A-68 | SL4-B-5 | 0.5 | no route | Crank position sensor (G28, VR+) | — | |
| W17 | SP-0V-1 | SL4-B-6 | 0.5 | no route | Crank index sensor − | — | |
| W18 | OEM-A-44 | SL4-B-7 | 0.5 | no route | Camshaft position sensor (G40) | — | |
| W19 | SP-0V-1 | SL4-B-8 | 0.5 | no route | Sync sensor − | — | |
| W20 | OEM-A-34 | SL4-B-16 | 0.5 | no route | Knock sensor 1 | — | |
| W21 | OEM-A-8 | SL4-A-26 | 0.5 | no route | Ignition coil 2 (coil pack pin 2) | — | |
| W22 | OEM-A-60 | SL4-A-27 | 0.5 | no route | Ignition coil 3 (coil pack pin 3) | — | |
| W23 | OEM-A-52 | SL4-A-28 | 0.5 | no route | Ignition coil 4 (coil pack pin 4) | — | |
| W24 | OEM-A-24 | SL4-A-1 | 0.5 | no route | Injector 1 (cyl 1) | — | |
| W25 | OEM-A-3 | SL4-A-2 | 0.5 | no route | Injector 2 (cyl 2) | — | |
| W26 | OEM-A-26 | SL4-A-3 | 0.5 | no route | Injector 3 (cyl 3) | — | |
| W27 | OEM-A-4 | SL4-A-4 | 0.5 | no route | Injector 4 (cyl 4) | — | |
| W28 | OEM-A-25 | SL4-A-1 | 0.5 | no route | Injector 5 (cyl 5) | — | |
| W29 | OEM-A-2 | SL4-A-2 | 0.5 | no route | Injector 6 (cyl 6) | — | |
| W30 | OEM-A-38 | SL4-B-4 | 0.5 | no route | Ignition switch (run/start) | — | |
| W31 | OEM-A-17 | SL4-B-11 | 0.5 | no route | MAF signal | — | |
| W32 | OEM-A-40 | SL4-B-12 | 0.5 | no route | Throttle position sensor 1 | — | |
| W33 | OEM-A-14 | SL4-B-13 | 0.5 | no route | Coolant temperature (CLT) | — | |
| W34 | OEM-A-49 | SL4-B-3 | 0.5 | no route | Secondary air injection relay control | — | |
| W35 | OEM-A-6 | SL4-A-14 | 0.5 | no route | Fuel pump relay control | — | |
| W36 | OEM-A-9 | SL4-A-15 | 0.5 | no route | Engine electronics relay control | — | |
| W37 | OEM-A-27 | SL4-A-16 | 0.5 | no route | Idle air control valve | — | |
| W38 | OEM-A-31 | SL4-A-17 | 0.5 | no route | EVAP canister purge valve | — | |
| W39 | OEM-A-5 | SL4-A-10 | 0.5 | no route | Check engine light (MIL) | — | |
| W40 | OEM-A-53 | SL4-A-11 | 0.5 | no route | Idle air control valve (2nd) | — | |
| W41 | OEM-A-22 | SL4-A-12 | 0.5 | no route | Tachometer output | — | |
| W42 | OEM-A-51 | SL4-A-13 | 0.5 | no route | MFA fuel-consumption signal | — | |
| W43 | OEM-A-20 | SL4-B-14 | 0.5 | no route | O2 sensor 1 (primary) | — | |
| W44 | OEM-A-15 | SL4-B-15 | 0.5 | no route | EGR temperature sensor | — | |
| W45 | OEM-A-36 | SL4-B-19 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W46 | OEM-A-65 | SL4-A-20 | 0.5 | no route | Vehicle speed sensor (VSS) | — | |
| W47 | OEM-A-37 | SL4-A-21 | 0.5 | no route | A/C compressor switch | — | |
| W48 | OEM-A-39 | SL4-A-22 | 0.5 | no route | A/C switch (cabin) | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|---|---|---|---|---|
| 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) | 37.000 | ea |
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (15)
| Severity | Code | Subject | Message |
|---|---|---|---|
| error | NET_MERGED | OEM-A-2 + OEM-A-3 + SL4-A-2 | 2 different OEM functions share one net: OEM-A-2 Injector 6 (cyl 6); OEM-A-3 Injector 2 (cyl 2) |
| error | NET_MERGED | OEM-A-24 + OEM-A-25 + SL4-A-1 | 2 different OEM functions share one net: OEM-A-24 Injector 1 (cyl 1); OEM-A-25 Injector 5 (cyl 5) |
| info | NET_FAMILY | OEM-A-14 ↔ SL4-B-13 | OEM-A-14 "Coolant temperature (CLT)" [temp_in] is wired to SL4-B-13 "Analog input 3" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | NET_FAMILY | OEM-A-15 ↔ SL4-B-15 | OEM-A-15 "EGR temperature sensor" [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-A-22 ↔ SL4-A-12 | OEM-A-22 "Tachometer output" [tacho_out] is wired to SL4-A-12 "Auxiliary output 3" [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-A-27 ↔ SL4-A-16 | OEM-A-27 "Idle air control valve" [low_side_out] is wired to SL4-A-16 "Auxiliary output 7" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-A-31 ↔ SL4-A-17 | OEM-A-31 "EVAP canister purge valve" [low_side_out] is wired to SL4-A-17 "Auxiliary output 8" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-A-36 ↔ SL4-B-19 | OEM-A-36 "Intake air temperature (IAT)" [temp_in] is wired to SL4-B-19 "Analog input 6" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | NET_FAMILY | OEM-A-5 ↔ SL4-A-10 | OEM-A-5 "Check engine light (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-A-51 ↔ SL4-A-13 | OEM-A-51 "MFA fuel-consumption signal" [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-A-53 ↔ SL4-A-11 | OEM-A-53 "Idle air control valve (2nd)" [low_side_out] is wired to SL4-A-11 "Auxiliary output 2" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-A-6 ↔ SL4-A-14 | OEM-A-6 "Fuel pump relay control" [low_side_out] is wired to SL4-A-14 "Auxiliary output 5" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-A-9 ↔ SL4-A-15 | OEM-A-9 "Engine electronics relay control" [low_side_out] is wired to SL4-A-15 "Auxiliary output 6" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | SL4-B-6 ↔ SL4-B-10 | SL4-B-6 "Crank index 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. |
| info | UNMAPPED | OEM | 3 optional OEM pins are not mapped: OEM-A-21 Diagnostic L-line; OEM-A-43 Diagnostic K-line; OEM-A-59 Mass airflow sensor (5th terminal) |
Accepted (1)
| Code | Subject | Reason | By |
|---|---|---|---|
| REQUIRED_UNMAPPED | OEM-A-54 | Battery-constant (memory) feed of the stock ECU: the new ECU has no such input, so it is not needed. | mapping-proposal |
Notes
Fit check: unconfirmed. Confirm these before building: - Trigger pattern for VW VR6 not found in the ECU's docs (No VR6 decoder.) - Only 4 ignition outputs for 6 cylinders: wasted spark (pair coils per firing order) - Only 4 injector outputs for 6 injectors: batch / semi-sequential injection 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-A 54: Battery constant (+12V): Emtron SL4 has no battery-constant input; not needed - SL4-B 17: Knock 1 − left open: the stock knock sensor has one ECU wire; check the ECU manual for single-wire knock sensors - OEM-A 21: Diagnostic L-line: no free k_line on Emtron SL4 - OEM-A 43: Diagnostic K-line: no free k_line on Emtron SL4 - OEM-A 59: Mass airflow sensor (5th terminal): no rule for class sensor_signal; wire by hand
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 |
| 2 | community_copy | a2resource: VR6/ABA Motronic M2.9 (OBD1) engine control unit pinout | http://www.a2resource.com/electrical/management/motronicvr6aba.html | — | — | — |