VW Corrado VR6 12v (AAA) Motronic M2.9 OBD1 → Link G4X AtomX 111-4000 (auto)
VW Corrado VR6 12v (AAA) Motronic M2.9 OBD1 — Link — G4X AtomX
⚠ 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 | 3: read the Findings page before cutting any wire |
| Size of the job | 37 wires · 5 connectors · 0 part lines |
| Tools | Crimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink |
| Order of work | 1. Check every part against the parts list. 2. Cut and label every wire (labels: Export → Wire labels). 3. Crimp and pin connector by connector, ticking the build checklist. 4. Run the bench test with nothing plugged in and the battery disconnected. 5. Only then connect the ECU and power up. |
Build checklist
Tick each box as you go. Continuity: meter from end to end, expect under 1 Ω.
| Wire | From | To | Gauge | Colour | Cut | Label | Crimp A | Crimp B | Pin A | Pin B | Continuity |
|---|---|---|---|---|---|---|---|---|---|---|---|
| W1 | OEM-A-23 | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | SP-14V-1 | G4XATOMX-A-A5 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | OEM-A-1 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-A-10 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-A-55 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-A-56 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-A-7 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | SP-GND-1 | G4XATOMX-A-A25 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-GND-1 | G4XATOMX-A-A34 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | OEM-A-16 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | OEM-A-33 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-A-67 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | SP-0V-1 | G4XATOMX-A-A24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-A-41 | G4XATOMX-A-A32 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-A-68 | G4XATOMX-A-A8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-A-44 | G4XATOMX-A-A9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-A-34 | G4XATOMX-A-A6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-A-8 | G4XATOMX-A-A13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-A-60 | G4XATOMX-A-A12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-A-52 | G4XATOMX-A-A11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-A-24 | G4XATOMX-A-A4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-A-3 | G4XATOMX-A-A3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-A-26 | G4XATOMX-A-A2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-A-4 | G4XATOMX-A-A1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-A-25 | G4XATOMX-A-A4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-A-2 | G4XATOMX-A-A3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-A-17 | G4XATOMX-A-A17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-A-40 | G4XATOMX-A-A22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-A-14 | G4XATOMX-A-A15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-A-49 | G4XATOMX-A-A21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-A-6 | G4XATOMX-A-A20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-A-9 | G4XATOMX-A-A19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-A-27 | G4XATOMX-A-A18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-A-20 | G4XATOMX-A-A33 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-A-15 | G4XATOMX-A-A16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-A-65 | G4XATOMX-A-A30 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-A-37 | G4XATOMX-A-A31 | 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 | G4XATOMX-A-A24 | G4XATOMX-A-A32 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 2 | G4XATOMX-A-A24 | G4XATOMX-A-A5 | open (OL) | sensor ground must not touch +12 V supply | |
| 3 | G4XATOMX-A-A25 | G4XATOMX-A-A32 | open (OL) | power ground must not touch 5 V sensor reference | |
| 4 | G4XATOMX-A-A25 | G4XATOMX-A-A5 | open (OL) | power ground must not touch +12 V supply | |
| 5 | G4XATOMX-A-A5 | G4XATOMX-A-A32 | open (OL) | +12 V supply 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
G4XATOMX-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A1 | Injector 4 | — | W24 | — | 0.5 | OEM-A-4 | — | — | — |
| A10 | Ignition 4 | — | — | — | — | — | — | — | — |
| A11 | Ignition 3 | — | W20 | — | 0.5 | OEM-A-52 | — | — | — |
| A12 | Ignition 2 | — | W19 | — | 0.5 | OEM-A-60 | — | — | — |
| A13 | Ignition 1 | — | W18 | — | 0.5 | OEM-A-8 | — | — | — |
| A15 | Analog Temp 1 | — | W29 | — | 0.5 | OEM-A-14 | — | — | — |
| A16 | Analog Temp 2 | — | W35 | — | 0.5 | OEM-A-15 | — | — | — |
| A17 | Analog Volt 1 | — | W27 | — | 0.5 | OEM-A-17 | — | — | — |
| A18 | Aux 4 | — | W33 | — | 0.5 | OEM-A-27 | — | — | — |
| A19 | Aux 3 | — | W32 | — | 0.5 | OEM-A-9 | — | — | — |
| A2 | Injector 3 | — | W23 | — | 0.5 | OEM-A-26 | — | — | — |
| A20 | Aux 2 | — | W31 | — | 0.5 | OEM-A-6 | — | — | — |
| A21 | Aux 1 | — | W30 | — | 0.5 | OEM-A-49 | — | — | — |
| A22 | Analog Volt 2 | — | W28 | — | 0.5 | OEM-A-40 | — | — | — |
| A24 | Sensor Ground | — | W13 | — | 0.5 | SP-0V-1 | — | — | — |
| A25 | System Ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| A28 | CAN H | — | — | — | — | — | — | — | — |
| A29 | CAN L | — | — | — | — | — | — | — | — |
| A3 | Injector 2 | — | W22 | — | 0.5 | OEM-A-3 | — | — | — |
| A3 | Injector 2 | — | W26 | — | 0.5 | OEM-A-2 | — | — | — |
| A30 | Digital Input 1 | — | W36 | — | 0.5 | OEM-A-65 | — | — | — |
| A31 | Digital Input 2 | — | W37 | — | 0.5 | OEM-A-37 | — | — | — |
| A32 | +5V Out | — | W14 | — | 0.5 | OEM-A-41 | — | — | — |
| A33 | Analog Volt 3 | — | W34 | — | 0.5 | OEM-A-20 | — | — | — |
| A34 | System Ground | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| A4 | Injector 1 | — | W21 | — | 0.5 | OEM-A-24 | — | — | — |
| A4 | Injector 1 | — | W25 | — | 0.5 | OEM-A-25 | — | — | — |
| A5 | +14V ECU Power | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| A6 | Knock 1 | — | W17 | — | 0.5 | OEM-A-34 | — | — | — |
| A7 | Shield Ground | — | — | — | — | — | — | — | — |
| A8 | Trigger 1 | — | W15 | — | 0.5 | OEM-A-68 | — | — | — |
| A9 | Trigger 2 | — | W16 | — | 0.5 | OEM-A-44 | — | — | — |
OEM-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Ground (E-1) | — | W3 | — | 0.85 | SP-GND-1 | — | — | — |
| 10 | Ground (OBD1 EGR enable) | — | W4 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | Coolant temperature (CLT) | — | W29 | — | 0.5 | G4XATOMX-A-A15 | — | — | — |
| 15 | EGR temperature sensor | — | W35 | — | 0.5 | G4XATOMX-A-A16 | — | — | — |
| 16 | MAF ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| 17 | MAF signal | — | W27 | — | 0.5 | G4XATOMX-A-A17 | — | — | — |
| 2 | Injector 6 (cyl 6) | — | W26 | — | 0.5 | G4XATOMX-A-A3 | — | — | — |
| 20 | O2 sensor 1 (primary) | — | W34 | — | 0.5 | G4XATOMX-A-A33 | — | — | — |
| 21 | Diagnostic L-line | — | — | — | — | — | — | — | — |
| 22 | Tachometer output | — | — | — | — | — | — | — | — |
| 23 | ECU main power (from engine-electronics relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| 24 | Injector 1 (cyl 1) | — | W21 | — | 0.5 | G4XATOMX-A-A4 | — | — | — |
| 25 | Injector 5 (cyl 5) | — | W25 | — | 0.5 | G4XATOMX-A-A4 | — | — | — |
| 26 | Injector 3 (cyl 3) | — | W23 | — | 0.5 | G4XATOMX-A-A2 | — | — | — |
| 27 | Idle air control valve | — | W33 | — | 0.5 | G4XATOMX-A-A18 | — | — | — |
| 3 | Injector 2 (cyl 2) | — | W22 | — | 0.5 | G4XATOMX-A-A3 | — | — | — |
| 31 | EVAP canister purge valve | — | — | — | — | — | — | — | — |
| 33 | Sensor ground bus | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 34 | Knock sensor 1 | — | W17 | — | 0.5 | G4XATOMX-A-A6 | — | — | — |
| 36 | Intake air temperature (IAT) | — | — | — | — | — | — | — | — |
| 37 | A/C compressor switch | — | W37 | — | 0.5 | G4XATOMX-A-A31 | — | — | — |
| 38 | Ignition switch (run/start) | — | — | — | — | — | — | — | — |
| 39 | A/C switch (cabin) | — | — | — | — | — | — | — | — |
| 4 | Injector 4 (cyl 4) | — | W24 | — | 0.5 | G4XATOMX-A-A1 | — | — | — |
| 40 | Throttle position sensor 1 | — | W28 | — | 0.5 | G4XATOMX-A-A22 | — | — | — |
| 41 | TPS power (+5V) | — | W14 | — | 0.5 | G4XATOMX-A-A32 | — | — | — |
| 43 | Diagnostic K-line | — | — | — | — | — | — | — | — |
| 44 | Camshaft position sensor (G40) | — | W16 | — | 0.5 | G4XATOMX-A-A9 | — | — | — |
| 49 | Secondary air injection relay control | — | W30 | — | 0.5 | G4XATOMX-A-A21 | — | — | — |
| 5 | Check engine light (MIL) | — | — | — | — | — | — | — | — |
| 51 | MFA fuel-consumption signal | — | — | — | — | — | — | — | — |
| 52 | Ignition coil 4 (coil pack pin 4) | — | W20 | — | 0.5 | G4XATOMX-A-A11 | — | — | — |
| 53 | Idle air control valve (2nd) | — | — | — | — | — | — | — | — |
| 54 | Battery constant (+12V) | — | — | — | — | — | — | — | — |
| 55 | Ground (E-3) | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| 56 | Ground (E-4) | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 59 | Mass airflow sensor (5th terminal) | — | — | — | — | — | — | — | — |
| 6 | Fuel pump relay control | — | W31 | — | 0.5 | G4XATOMX-A-A20 | — | — | — |
| 60 | Ignition coil 3 (coil pack pin 3) | — | W19 | — | 0.5 | G4XATOMX-A-A12 | — | — | — |
| 65 | Vehicle speed sensor (VSS) | — | W36 | — | 0.5 | G4XATOMX-A-A30 | — | — | — |
| 67 | Crank sensor return (VR-) | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 68 | Crank position sensor (G28, VR+) | — | W15 | — | 0.5 | G4XATOMX-A-A8 | — | — | — |
| 7 | Ground (E-2) | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 8 | Ignition coil 2 (coil pack pin 2) | — | W18 | — | 0.5 | G4XATOMX-A-A13 | — | — | — |
| 9 | Engine electronics relay control | — | W32 | — | 0.5 | G4XATOMX-A-A19 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W10 | — | 0.5 | OEM-A-16 | — | — | — |
| 1 | — | — | W11 | — | 0.5 | OEM-A-33 | — | — | — |
| 1 | — | — | W12 | — | 0.5 | OEM-A-67 | — | — | — |
| 1 | — | — | W13 | — | 0.5 | G4XATOMX-A-A24 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-A-23 | — | — | — |
| 1 | — | — | W2 | — | 0.85 | G4XATOMX-A-A5 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W3 | — | 0.85 | OEM-A-1 | — | — | — |
| 1 | — | — | W4 | — | 0.85 | OEM-A-10 | — | — | — |
| 1 | — | — | W5 | — | 0.85 | OEM-A-55 | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-A-56 | — | — | — |
| 1 | — | — | W7 | — | 0.85 | OEM-A-7 | — | — | — |
| 1 | — | — | W8 | — | 0.85 | G4XATOMX-A-A25 | — | — | — |
| 1 | — | — | W9 | — | 0.85 | G4XATOMX-A-A34 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-A-1 | Ground (E-1) | ground | G4XATOMX-A-A25 + G4XATOMX-A-A34 | System Ground + System Ground | ground | single_source | |
| OEM-A-10 | Ground (OBD1 EGR enable) | ground | G4XATOMX-A-A25 + G4XATOMX-A-A34 | System Ground + System Ground | ground | single_source | |
| OEM-A-14 | Coolant temperature (CLT) | temp_in | G4XATOMX-A-A15 | Analog Temp 1 | temp_in | single_source | |
| OEM-A-15 | EGR temperature sensor | temp_in | G4XATOMX-A-A16 | Analog Temp 2 | temp_in | single_source | |
| OEM-A-16 | MAF ground | sensor_ground | G4XATOMX-A-A24 | Sensor Ground | sensor_ground | single_source | |
| OEM-A-17 | MAF signal | analog_in | G4XATOMX-A-A17 | Analog Volt 1 | analog_in | single_source | |
| OEM-A-2 | Injector 6 (cyl 6) | injector_out | G4XATOMX-A-A3 | Injector 2 | injector_out | single_source | |
| OEM-A-20 | O2 sensor 1 (primary) | lambda_nb_in | G4XATOMX-A-A33 | Analog Volt 3 | analog_in | single_source | |
| OEM-A-21 | Diagnostic L-line | serial | — | — | — | single_source | |
| OEM-A-22 | Tachometer output | tacho_out | — | — | — | single_source | |
| OEM-A-23 | ECU main power (from engine-electronics relay) | power_in | G4XATOMX-A-A5 | +14V ECU Power | power_in | single_source | |
| OEM-A-24 | Injector 1 (cyl 1) | injector_out | G4XATOMX-A-A4 | Injector 1 | injector_out | single_source | |
| OEM-A-25 | Injector 5 (cyl 5) | injector_out | G4XATOMX-A-A4 | Injector 1 | injector_out | single_source | |
| OEM-A-26 | Injector 3 (cyl 3) | injector_out | G4XATOMX-A-A2 | Injector 3 | injector_out | single_source | |
| OEM-A-27 | Idle air control valve | low_side_out | G4XATOMX-A-A18 | Aux 4 | low_side_out | single_source | |
| OEM-A-3 | Injector 2 (cyl 2) | injector_out | G4XATOMX-A-A3 | Injector 2 | injector_out | single_source | |
| OEM-A-31 | EVAP canister purge valve | low_side_out | — | — | — | single_source | |
| OEM-A-33 | Sensor ground bus | sensor_ground | G4XATOMX-A-A24 | Sensor Ground | sensor_ground | single_source | |
| OEM-A-34 | Knock sensor 1 | knock_in | G4XATOMX-A-A6 | Knock 1 | knock_in | single_source | |
| OEM-A-36 | Intake air temperature (IAT) | temp_in | — | — | — | single_source | |
| OEM-A-37 | A/C compressor switch | digital_in | G4XATOMX-A-A31 | Digital Input 2 | digital_in | single_source | |
| OEM-A-38 | Ignition switch (run/start) | digital_in | — | — | — | single_source | |
| OEM-A-39 | A/C switch (cabin) | digital_in | — | — | — | single_source | |
| OEM-A-4 | Injector 4 (cyl 4) | injector_out | G4XATOMX-A-A1 | Injector 4 | injector_out | single_source | |
| OEM-A-40 | Throttle position sensor 1 | analog_in | G4XATOMX-A-A22 | Analog Volt 2 | analog_in | single_source | |
| OEM-A-41 | TPS power (+5V) | vref | G4XATOMX-A-A32 | +5V Out | vref | single_source | |
| OEM-A-43 | Diagnostic K-line | serial | — | — | — | single_source | |
| OEM-A-44 | Camshaft position sensor (G40) | trigger_in | G4XATOMX-A-A9 | Trigger 2 | trigger_in | single_source | |
| OEM-A-49 | Secondary air injection relay control | low_side_out | G4XATOMX-A-A21 | Aux 1 | low_side_out | single_source | |
| OEM-A-5 | Check engine light (MIL) | low_side_out | — | — | — | single_source | |
| OEM-A-51 | MFA fuel-consumption signal | tacho_out | — | — | — | single_source | |
| OEM-A-52 | Ignition coil 4 (coil pack pin 4) | ignition_out | G4XATOMX-A-A11 | Ignition 3 | ignition_out | single_source | |
| OEM-A-53 | Idle air control valve (2nd) | low_side_out | — | — | — | single_source | |
| OEM-A-54 | Battery constant (+12V) | power_in | — | — | — | single_source | |
| OEM-A-55 | Ground (E-3) | ground | G4XATOMX-A-A25 + G4XATOMX-A-A34 | System Ground + System Ground | ground | single_source | |
| OEM-A-56 | Ground (E-4) | ground | G4XATOMX-A-A25 + G4XATOMX-A-A34 | System Ground + System 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 | G4XATOMX-A-A20 | Aux 2 | low_side_out | single_source | |
| OEM-A-60 | Ignition coil 3 (coil pack pin 3) | ignition_out | G4XATOMX-A-A12 | Ignition 2 | ignition_out | single_source | |
| OEM-A-65 | Vehicle speed sensor (VSS) | digital_in | G4XATOMX-A-A30 | Digital Input 1 | digital_in | single_source | |
| OEM-A-67 | Crank sensor return (VR-) | sensor_ground | G4XATOMX-A-A24 | Sensor Ground | sensor_ground | single_source | |
| OEM-A-68 | Crank position sensor (G28, VR+) | trigger_in | G4XATOMX-A-A8 | Trigger 1 | trigger_in | single_source | |
| OEM-A-7 | Ground (E-2) | ground | G4XATOMX-A-A25 + G4XATOMX-A-A34 | System Ground + System Ground | ground | single_source | |
| OEM-A-8 | Ignition coil 2 (coil pack pin 2) | ignition_out | G4XATOMX-A-A13 | Ignition 1 | ignition_out | single_source | |
| OEM-A-9 | Engine electronics relay control | low_side_out | G4XATOMX-A-A19 | Aux 3 | low_side_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 | G4XATOMX-A-A5 | 0.85 | no route | +14V ECU Power | — | |
| W3 | OEM-A-1 | SP-GND-1 | 0.85 | no route | Ground (E-1) | — | |
| W4 | OEM-A-10 | SP-GND-1 | 0.85 | no route | Ground (OBD1 EGR enable) | — | |
| W5 | OEM-A-55 | SP-GND-1 | 0.85 | no route | Ground (E-3) | — | |
| W6 | OEM-A-56 | SP-GND-1 | 0.85 | no route | Ground (E-4) | — | |
| W7 | OEM-A-7 | SP-GND-1 | 0.85 | no route | Ground (E-2) | — | |
| W8 | SP-GND-1 | G4XATOMX-A-A25 | 0.85 | no route | System Ground | — | |
| W9 | SP-GND-1 | G4XATOMX-A-A34 | 0.85 | no route | System Ground | — | |
| W10 | OEM-A-16 | SP-0V-1 | 0.5 | no route | MAF ground | — | |
| W11 | OEM-A-33 | SP-0V-1 | 0.5 | no route | Sensor ground bus | — | |
| W12 | OEM-A-67 | SP-0V-1 | 0.5 | no route | Crank sensor return (VR-) | — | |
| W13 | SP-0V-1 | G4XATOMX-A-A24 | 0.5 | no route | Sensor Ground | — | |
| W14 | OEM-A-41 | G4XATOMX-A-A32 | 0.5 | no route | TPS power (+5V) | — | |
| W15 | OEM-A-68 | G4XATOMX-A-A8 | 0.5 | no route | Crank position sensor (G28, VR+) | — | |
| W16 | OEM-A-44 | G4XATOMX-A-A9 | 0.5 | no route | Camshaft position sensor (G40) | — | |
| W17 | OEM-A-34 | G4XATOMX-A-A6 | 0.5 | no route | Knock sensor 1 | — | |
| W18 | OEM-A-8 | G4XATOMX-A-A13 | 0.5 | no route | Ignition coil 2 (coil pack pin 2) | — | |
| W19 | OEM-A-60 | G4XATOMX-A-A12 | 0.5 | no route | Ignition coil 3 (coil pack pin 3) | — | |
| W20 | OEM-A-52 | G4XATOMX-A-A11 | 0.5 | no route | Ignition coil 4 (coil pack pin 4) | — | |
| W21 | OEM-A-24 | G4XATOMX-A-A4 | 0.5 | no route | Injector 1 (cyl 1) | — | |
| W22 | OEM-A-3 | G4XATOMX-A-A3 | 0.5 | no route | Injector 2 (cyl 2) | — | |
| W23 | OEM-A-26 | G4XATOMX-A-A2 | 0.5 | no route | Injector 3 (cyl 3) | — | |
| W24 | OEM-A-4 | G4XATOMX-A-A1 | 0.5 | no route | Injector 4 (cyl 4) | — | |
| W25 | OEM-A-25 | G4XATOMX-A-A4 | 0.5 | no route | Injector 5 (cyl 5) | — | |
| W26 | OEM-A-2 | G4XATOMX-A-A3 | 0.5 | no route | Injector 6 (cyl 6) | — | |
| W27 | OEM-A-17 | G4XATOMX-A-A17 | 0.5 | no route | MAF signal | — | |
| W28 | OEM-A-40 | G4XATOMX-A-A22 | 0.5 | no route | Throttle position sensor 1 | — | |
| W29 | OEM-A-14 | G4XATOMX-A-A15 | 0.5 | no route | Coolant temperature (CLT) | — | |
| W30 | OEM-A-49 | G4XATOMX-A-A21 | 0.5 | no route | Secondary air injection relay control | — | |
| W31 | OEM-A-6 | G4XATOMX-A-A20 | 0.5 | no route | Fuel pump relay control | — | |
| W32 | OEM-A-9 | G4XATOMX-A-A19 | 0.5 | no route | Engine electronics relay control | — | |
| W33 | OEM-A-27 | G4XATOMX-A-A18 | 0.5 | no route | Idle air control valve | — | |
| W34 | OEM-A-20 | G4XATOMX-A-A33 | 0.5 | no route | O2 sensor 1 (primary) | — | |
| W35 | OEM-A-15 | G4XATOMX-A-A16 | 0.5 | no route | EGR temperature sensor | — | |
| W36 | OEM-A-65 | G4XATOMX-A-A30 | 0.5 | no route | Vehicle speed sensor (VSS) | — | |
| W37 | OEM-A-37 | G4XATOMX-A-A31 | 0.5 | no route | A/C compressor switch | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (7)
| Severity | Code | Subject | Message |
|---|---|---|---|
| error | NET_MERGED | G4XATOMX-A-A3 + OEM-A-2 + OEM-A-3 | 2 different OEM functions share one net: OEM-A-2 Injector 6 (cyl 6); OEM-A-3 Injector 2 (cyl 2) |
| error | NET_MERGED | G4XATOMX-A-A4 + OEM-A-24 + OEM-A-25 | 2 different OEM functions share one net: OEM-A-24 Injector 1 (cyl 1); OEM-A-25 Injector 5 (cyl 5) |
| error | REQUIRED_UNMAPPED | OEM-A-38 | Required OEM function "Ignition switch (run/start)" (digital_in) is not connected to the new ECU. |
| warn | LOAD_UNKNOWN | G4XATOMX-A-A19 | G4XATOMX-A-A19 "Aux 3" drives OEM-A-9 Engine electronics relay control (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | G4XATOMX-A-A20 | G4XATOMX-A-A20 "Aux 2" drives OEM-A-6 Fuel pump relay control (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | G4XATOMX-A-A21 | G4XATOMX-A-A21 "Aux 1" drives OEM-A-49 Secondary air injection relay control (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| info | UNMAPPED | OEM | 10 optional OEM pins are not mapped: OEM-A-21 Diagnostic L-line; OEM-A-22 Tachometer output; OEM-A-31 EVAP canister purge valve; OEM-A-36 Intake air temperature (IAT); OEM-A-39 A/C switch (cabin); OEM-A-43 Diagnostic K-line; OEM-A-5 Check engine light (MIL); OEM-A-51 MFA fuel-consumption signal; OEM-A-53 Idle air control valve (2nd); 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 (Link's trigger-mode list is only inside PCLink, not online) - 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. Open items: - OEM-A 38: Ignition switch (run/start): key-on 12 V sense — optional in a swap (the main relay is energized from keyed 12 V, not from this pin); Link G4X AtomX has no dedicated key-on input Not wired: - OEM-A 54: Battery constant (+12V): Link G4X AtomX has no battery-constant input; not needed - OEM-A 31: EVAP canister purge valve: no free low_side/relay_control/heater_low_side/ls_hs/injector on Link G4X AtomX - OEM-A 5: Check engine light (MIL): no free low_side/relay_control/heater_low_side/ls_hs/injector on Link G4X AtomX - OEM-A 53: Idle air control valve (2nd): no free low_side/relay_control/heater_low_side/ls_hs/injector on Link G4X AtomX - OEM-A 22: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on Link G4X AtomX - OEM-A 51: MFA fuel-consumption signal: no free tacho/frequency_out/low_side/ls_hs on Link G4X AtomX - OEM-A 36: Intake air temperature (IAT): no free thermistor/analog_0_5 on Link G4X AtomX - OEM-A 39: A/C switch (cabin): no free switch_in/frequency_in/analog_0_5 on Link G4X AtomX - OEM-A 21: Diagnostic L-line: no free k_line on Link G4X AtomX - OEM-A 43: Diagnostic K-line: no free k_line on Link G4X AtomX - 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 | Link: G4X AtomX quickstart | https://linkecu.com/documentation/AtomXQuickstartGuide.pdf | archive | 2026-10-05 | 5fa903ea7bdf |
| 3 | community_copy | YourSpec: Link G4X AtomX ECU flying-lead harness wiring list | https://wpm.yourspec.com/projects/view/1462 | — | — | — |
| 2 | community_copy | a2resource: VR6/ABA Motronic M2.9 (OBD1) engine control unit pinout | http://www.a2resource.com/electrical/management/motronicvr6aba.html | — | — | — |