VW Golf Mk4 1.8T 20v (AUM, Bosch ME7.5) DBW → AMP EFI MS3Pro Mini (auto)
VW Golf Mk4 1.8T 20v (AUM, Bosch ME7.5) DBW — AMP EFI — MS3Pro Mini
⚠ 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 | 6: read the Findings page before cutting any wire |
| Size of the job | 46 wires · 6 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-T121-121 | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | OEM-T121-21 | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | SP-14V-1 | MS3PROMINI-A-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-T121-1 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-T121-2 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | SP-GND-1 | MS3PROMINI-A-22 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | SP-GND-1 | MS3PROMINI-A-23 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | OEM-T121-108 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | OEM-T121-29 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | OEM-T121-34 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | OEM-T121-36 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-T121-90 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-T121-91 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | SP-0V-1 | MS3PROMINI-A-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-T121-72 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-T121-73 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-T121-83 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-T121-98 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-T121-99 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | SP-5V1-1 | MS3PROMINI-A-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-T121-82 | MS3PROMINI-A-30 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-T121-86 | MS3PROMINI-A-32 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-T121-102 | MS3PROMINI-A-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-T121-95 | MS3PROMINI-A-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-T121-103 | MS3PROMINI-A-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-T121-94 | MS3PROMINI-A-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-T121-96 | MS3PROMINI-A-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-T121-89 | MS3PROMINI-A-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-T121-97 | MS3PROMINI-A-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-T121-88 | MS3PROMINI-A-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-T121-53 | MS3PROMINI-A-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-T121-101 | MS3PROMINI-A-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-T121-33 | MS3PROMINI-A-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-T121-84 | MS3PROMINI-A-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-T121-35 | MS3PROMINI-A-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-T121-93 | MS3PROMINI-A-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-T121-65 | MS3PROMINI-A-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-T121-66 | MS3PROMINI-A-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-T121-5 | MS3PROMINI-A-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-T121-63 | MS3PROMINI-A-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-T121-104 | MS3PROMINI-A-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-T121-105 | MS3PROMINI-A-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-T121-85 | MS3PROMINI-A-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-T121-54 | MS3PROMINI-A-34 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-T121-60 | MS3PROMINI-A-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W46 | OEM-T121-58 | MS3PROMINI-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 | MS3PROMINI-A-1 | MS3PROMINI-A-2 | open (OL) | +12 V supply must not touch 5 V sensor reference | |
| 2 | MS3PROMINI-A-21 | MS3PROMINI-A-1 | open (OL) | sensor ground must not touch +12 V supply | |
| 3 | MS3PROMINI-A-21 | MS3PROMINI-A-2 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 4 | MS3PROMINI-A-22 | MS3PROMINI-A-1 | open (OL) | power ground must not touch +12 V supply | |
| 5 | MS3PROMINI-A-22 | MS3PROMINI-A-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
MS3PROMINI-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 12V+ switched power in | — | W3 | — | 0.85 | SP-14V-1 | — | — | — |
| 10 | Injector out F | — | W27 | — | 0.5 | OEM-T121-96 | — | — | — |
| 11 | Injector out G | — | W28 | — | 0.5 | OEM-T121-89 | — | — | — |
| 12 | Injector out H | — | W29 | — | 0.5 | OEM-T121-97 | — | — | — |
| 13 | Analog in 1 | — | W31 | — | 0.5 | OEM-T121-53 | — | — | — |
| 14 | Analog in 2 | — | W32 | — | 0.5 | OEM-T121-101 | — | — | — |
| 15 | Analog in 3 | — | W34 | — | 0.5 | OEM-T121-84 | — | — | — |
| 16 | Analog in 4 | — | W35 | — | 0.5 | OEM-T121-35 | — | — | — |
| 17 | Spark out A | — | W23 | — | 0.5 | OEM-T121-102 | — | — | — |
| 18 | Spark out B | — | W24 | — | 0.5 | OEM-T121-95 | — | — | — |
| 19 | Spark out C | — | W25 | — | 0.5 | OEM-T121-103 | — | — | — |
| 2 | +5V VREF out | — | W20 | — | 0.5 | SP-5V1-1 | — | — | — |
| 20 | Spark out D | — | W26 | — | 0.5 | OEM-T121-94 | — | — | — |
| 21 | Sensor ground | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| 22 | Power ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 23 | Power ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 24 | CAN Low | — | W46 | — | 0.5 | OEM-T121-58 | — | — | — |
| 25 | CAN High | — | W45 | — | 0.5 | OEM-T121-60 | — | — | — |
| 26 | CLT in | — | W36 | — | 0.5 | OEM-T121-93 | — | — | — |
| 27 | IAT in | — | W43 | — | 0.5 | OEM-T121-85 | — | — | — |
| 28 | TPS in | — | W33 | — | 0.5 | OEM-T121-33 | — | — | — |
| 29 | Digital switched in 1 / Flex fuel | — | — | — | — | — | — | — | — |
| 3 | PWM out 1 / Idle | — | W38 | — | 0.5 | OEM-T121-66 | — | — | — |
| 30 | CKP+ | — | W21 | — | 0.5 | OEM-T121-82 | — | — | — |
| 31 | CKP- | — | — | — | — | — | — | — | — |
| 32 | CMP+ | — | W22 | — | 0.5 | OEM-T121-86 | — | — | — |
| 33 | CMP- | — | — | — | — | — | — | — | — |
| 34 | Digital frequency in 1 (Hall) | — | W44 | — | 0.5 | OEM-T121-54 | — | — | — |
| 35 | Digital frequency in 2 (Hall) | — | — | — | — | — | — | — | — |
| 4 | Fuel pump out | — | W37 | — | 0.5 | OEM-T121-65 | — | — | — |
| 5 | Injector out A | — | W30 | — | 0.5 | OEM-T121-88 | — | — | — |
| 6 | Injector out B | — | W39 | — | 0.5 | OEM-T121-5 | — | — | — |
| 7 | Injector out C | — | W40 | — | 0.5 | OEM-T121-63 | — | — | — |
| 8 | Injector out D | — | W41 | — | 0.5 | OEM-T121-104 | — | — | — |
| 9 | Injector out E | — | W42 | — | 0.5 | OEM-T121-105 | — | — | — |
OEM-T121
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | ECU ground | — | W4 | — | 0.85 | SP-GND-1 | — | — | — |
| 101 | Boost pressure sensor (G31) | — | W32 | — | 0.5 | MS3PROMINI-A-14 | — | — | — |
| 102 | Ignition coil 1 (N127) | — | W23 | — | 0.5 | MS3PROMINI-A-17 | — | — | — |
| 103 | Ignition coil 3 (N158) | — | W25 | — | 0.5 | MS3PROMINI-A-19 | — | — | — |
| 104 | Boost control solenoid (N75) | — | W41 | — | 0.5 | MS3PROMINI-A-8 | — | — | — |
| 105 | Diverter valve (N249) | — | W42 | — | 0.5 | MS3PROMINI-A-9 | — | — | — |
| 106 | Knock sensor 1 (G61) | — | — | — | — | — | — | — | — |
| 107 | Knock sensor 2 (G66) | — | — | — | — | — | — | — | — |
| 108 | Sensor ground | — | W8 | — | 0.5 | SP-0V-1 | — | — | — |
| 115 | VVT camshaft adjustment valve (N205) | — | — | — | — | — | — | — | — |
| 117 | Throttle motor G186 (+) | — | — | — | — | — | — | — | — |
| 118 | Throttle motor G186 (−) | — | — | — | — | — | — | — | — |
| 121 | ECM + coil power (J271 relay feed) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| 2 | ECU ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| 21 | ECM power (J271 relay feed) | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 27 | MAF sensor supply (G70) | — | — | — | — | — | — | — | — |
| 29 | MAF sensor ground (G70) | — | W9 | — | 0.5 | SP-0V-1 | — | — | — |
| 3 | Ignition switch +12V (term 15) | — | — | — | — | — | — | — | — |
| 33 | Accelerator pedal position 1 (G79) | — | W33 | — | 0.5 | MS3PROMINI-A-28 | — | — | — |
| 34 | Accelerator pedal position 1 ground (G79) | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| 35 | Accelerator pedal position 2 (G185) | — | W35 | — | 0.5 | MS3PROMINI-A-16 | — | — | — |
| 36 | Accelerator pedal position 2 ground (G185) | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 37 | Engine speed signal (tacho to cluster) | — | — | — | — | — | — | — | — |
| 43 | K-line diagnostics (OBD pin 7) | — | — | — | — | — | — | — | — |
| 47 | Check engine light (MIL) | — | — | — | — | — | — | — | — |
| 48 | EPC warning light | — | — | — | — | — | — | — | — |
| 5 | Wideband lambda heater (Z19) | — | W39 | — | 0.5 | MS3PROMINI-A-6 | — | — | — |
| 51 | Wideband lambda pump (G39) | — | — | — | — | — | — | — | — |
| 52 | Wideband lambda pump (G39) | — | — | — | — | — | — | — | — |
| 53 | MAF sensor signal (G70) | — | W31 | — | 0.5 | MS3PROMINI-A-13 | — | — | — |
| 54 | Road speed signal (VSS) | — | W44 | — | 0.5 | MS3PROMINI-A-34 | — | — | — |
| 58 | CAN bus low | — | W46 | — | 0.5 | MS3PROMINI-A-24 | — | — | — |
| 60 | CAN bus high | — | W45 | — | 0.5 | MS3PROMINI-A-25 | — | — | — |
| 62 | Battery constant +12V (term 30) | — | — | — | — | — | — | — | — |
| 63 | Post-cat lambda heater (Z29) | — | W40 | — | 0.5 | MS3PROMINI-A-7 | — | — | — |
| 64 | EVAP canister valve (N80) | — | — | — | — | — | — | — | — |
| 65 | Fuel pump relay control | — | W37 | — | 0.5 | MS3PROMINI-A-4 | — | — | — |
| 66 | Secondary-air pump relay (J299) | — | W38 | — | 0.5 | MS3PROMINI-A-3 | — | — | — |
| 68 | Post-cat lambda signal (G130) | — | — | — | — | — | — | — | — |
| 69 | Post-cat lambda signal (G130) | — | — | — | — | — | — | — | — |
| 70 | Wideband lambda Nernst signal (G39) | — | — | — | — | — | — | — | — |
| 71 | Wideband lambda Nernst signal (G39) | — | — | — | — | — | — | — | — |
| 72 | Accelerator pedal position 1 5V supply (G79) | — | W15 | — | 0.5 | SP-5V1-1 | — | — | — |
| 73 | Accelerator pedal position 2 5V supply (G185) | — | W16 | — | 0.5 | SP-5V1-1 | — | — | — |
| 82 | Crank position sensor (G28) | — | W21 | — | 0.5 | MS3PROMINI-A-30 | — | — | — |
| 83 | Throttle position sensor 5V supply (G187/G188) | — | W17 | — | 0.5 | SP-5V1-1 | — | — | — |
| 84 | Throttle position sensor 1 (G187) | — | W34 | — | 0.5 | MS3PROMINI-A-15 | — | — | — |
| 85 | Intake air temperature (G42) | — | W43 | — | 0.5 | MS3PROMINI-A-27 | — | — | — |
| 86 | Camshaft position sensor (G40) | — | W22 | — | 0.5 | MS3PROMINI-A-32 | — | — | — |
| 88 | Injector 4 (N33) | — | W30 | — | 0.5 | MS3PROMINI-A-5 | — | — | — |
| 89 | Injector 2 (N31) | — | W28 | — | 0.5 | MS3PROMINI-A-11 | — | — | — |
| 9 | Secondary-air injection valve (N112) | — | — | — | — | — | — | — | — |
| 90 | Crank position sensor ground (G28) | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 91 | Throttle position sensor ground (G187/G188) | — | W13 | — | 0.5 | SP-0V-1 | — | — | — |
| 92 | Throttle position sensor 2 (G188) | — | — | — | — | — | — | — | — |
| 93 | Engine coolant temperature (G62) | — | W36 | — | 0.5 | MS3PROMINI-A-26 | — | — | — |
| 94 | Ignition coil 4 (N163) | — | W26 | — | 0.5 | MS3PROMINI-A-20 | — | — | — |
| 95 | Ignition coil 2 (N128) | — | W24 | — | 0.5 | MS3PROMINI-A-18 | — | — | — |
| 96 | Injector 1 (N30) | — | W27 | — | 0.5 | MS3PROMINI-A-10 | — | — | — |
| 97 | Injector 3 (N32) | — | W29 | — | 0.5 | MS3PROMINI-A-12 | — | — | — |
| 98 | Cam + boost sensor 5V supply (G40/G31) | — | W18 | — | 0.5 | SP-5V1-1 | — | — | — |
| 99 | Knock sensor 5V supply (G61/G66) | — | W19 | — | 0.5 | SP-5V1-1 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W8 | — | 0.5 | OEM-T121-108 | — | — | — |
| 1 | — | — | W9 | — | 0.5 | OEM-T121-29 | — | — | — |
| 1 | — | — | W10 | — | 0.5 | OEM-T121-34 | — | — | — |
| 1 | — | — | W11 | — | 0.5 | OEM-T121-36 | — | — | — |
| 1 | — | — | W12 | — | 0.5 | OEM-T121-90 | — | — | — |
| 1 | — | — | W13 | — | 0.5 | OEM-T121-91 | — | — | — |
| 1 | — | — | W14 | — | 0.5 | MS3PROMINI-A-21 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-T121-121 | — | — | — |
| 1 | — | — | W2 | — | 0.85 | OEM-T121-21 | — | — | — |
| 1 | — | — | W3 | — | 0.85 | MS3PROMINI-A-1 | — | — | — |
SP-5V1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W15 | — | 0.5 | OEM-T121-72 | — | — | — |
| 1 | — | — | W16 | — | 0.5 | OEM-T121-73 | — | — | — |
| 1 | — | — | W17 | — | 0.5 | OEM-T121-83 | — | — | — |
| 1 | — | — | W18 | — | 0.5 | OEM-T121-98 | — | — | — |
| 1 | — | — | W19 | — | 0.5 | OEM-T121-99 | — | — | — |
| 1 | — | — | W20 | — | 0.5 | MS3PROMINI-A-2 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W4 | — | 0.85 | OEM-T121-1 | — | — | — |
| 1 | — | — | W5 | — | 0.85 | OEM-T121-2 | — | — | — |
| 1 | — | — | W6 | — | 0.85 | MS3PROMINI-A-22 | — | — | — |
| 1 | — | — | W7 | — | 0.85 | MS3PROMINI-A-23 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-T121-1 | ECU ground | ground | MS3PROMINI-A-22 + MS3PROMINI-A-23 | Power ground + Power ground | ground | corroborated | |
| OEM-T121-101 | Boost pressure sensor (G31) | analog_in | MS3PROMINI-A-14 | Analog in 2 | analog_in | corroborated | |
| OEM-T121-102 | Ignition coil 1 (N127) | ignition_out | MS3PROMINI-A-17 | Spark out A | ignition_out | corroborated | |
| OEM-T121-103 | Ignition coil 3 (N158) | ignition_out | MS3PROMINI-A-19 | Spark out C | ignition_out | corroborated | |
| OEM-T121-104 | Boost control solenoid (N75) | low_side_out | MS3PROMINI-A-8 | Injector out D | injector_out | corroborated | |
| OEM-T121-105 | Diverter valve (N249) | low_side_out | MS3PROMINI-A-9 | Injector out E | injector_out | corroborated | |
| OEM-T121-106 | Knock sensor 1 (G61) | knock_in | — | — | — | corroborated | |
| OEM-T121-107 | Knock sensor 2 (G66) | knock_in | — | — | — | corroborated | |
| OEM-T121-108 | Sensor ground | sensor_ground | MS3PROMINI-A-21 | Sensor ground | sensor_ground | corroborated | |
| OEM-T121-115 | VVT camshaft adjustment valve (N205) | low_side_out | — | — | — | corroborated | |
| OEM-T121-117 | Throttle motor G186 (+) | hbridge_out | — | — | — | corroborated | |
| OEM-T121-118 | Throttle motor G186 (−) | hbridge_out | — | — | — | corroborated | |
| OEM-T121-121 | ECM + coil power (J271 relay feed) | power_in | MS3PROMINI-A-1 | 12V+ switched power in | power_in | corroborated | |
| OEM-T121-2 | ECU ground | ground | MS3PROMINI-A-22 + MS3PROMINI-A-23 | Power ground + Power ground | ground | corroborated | |
| OEM-T121-21 | ECM power (J271 relay feed) | power_in | MS3PROMINI-A-1 | 12V+ switched power in | power_in | corroborated | |
| OEM-T121-27 | MAF sensor supply (G70) | power_in | — | — | — | corroborated | |
| OEM-T121-29 | MAF sensor ground (G70) | sensor_ground | MS3PROMINI-A-21 | Sensor ground | sensor_ground | corroborated | |
| OEM-T121-3 | Ignition switch +12V (term 15) | digital_in | — | — | — | corroborated | |
| OEM-T121-33 | Accelerator pedal position 1 (G79) | analog_in | MS3PROMINI-A-28 | TPS in | analog_in | corroborated | |
| OEM-T121-34 | Accelerator pedal position 1 ground (G79) | sensor_ground | MS3PROMINI-A-21 | Sensor ground | sensor_ground | corroborated | |
| OEM-T121-35 | Accelerator pedal position 2 (G185) | analog_in | MS3PROMINI-A-16 | Analog in 4 | analog_in | corroborated | |
| OEM-T121-36 | Accelerator pedal position 2 ground (G185) | sensor_ground | MS3PROMINI-A-21 | Sensor ground | sensor_ground | corroborated | |
| OEM-T121-37 | Engine speed signal (tacho to cluster) | tacho_out | — | — | — | corroborated | |
| OEM-T121-43 | K-line diagnostics (OBD pin 7) | serial | — | — | — | corroborated | |
| OEM-T121-47 | Check engine light (MIL) | low_side_out | — | — | — | corroborated | |
| OEM-T121-48 | EPC warning light | low_side_out | — | — | — | corroborated | |
| OEM-T121-5 | Wideband lambda heater (Z19) | low_side_out | MS3PROMINI-A-6 | Injector out B | injector_out | corroborated | |
| OEM-T121-51 | Wideband lambda pump (G39) | wb_ip | — | — | — | corroborated | |
| OEM-T121-52 | Wideband lambda pump (G39) | wb_ip | — | — | — | corroborated | |
| OEM-T121-53 | MAF sensor signal (G70) | analog_in | MS3PROMINI-A-13 | Analog in 1 | analog_in | corroborated | |
| OEM-T121-54 | Road speed signal (VSS) | digital_in | MS3PROMINI-A-34 | Digital frequency in 1 (Hall) | digital_in | corroborated | |
| OEM-T121-58 | CAN bus low | can_l | MS3PROMINI-A-24 | CAN Low | can_l | corroborated | |
| OEM-T121-60 | CAN bus high | can_h | MS3PROMINI-A-25 | CAN High | can_h | corroborated | |
| OEM-T121-62 | Battery constant +12V (term 30) | power_in | — | — | — | corroborated | |
| OEM-T121-63 | Post-cat lambda heater (Z29) | low_side_out | MS3PROMINI-A-7 | Injector out C | injector_out | corroborated | |
| OEM-T121-64 | EVAP canister valve (N80) | low_side_out | — | — | — | corroborated | |
| OEM-T121-65 | Fuel pump relay control | low_side_out | MS3PROMINI-A-4 | Fuel pump out | low_side_out | corroborated | |
| OEM-T121-66 | Secondary-air pump relay (J299) | low_side_out | MS3PROMINI-A-3 | PWM out 1 / Idle | low_side_out | corroborated | |
| OEM-T121-68 | Post-cat lambda signal (G130) | lambda_nb_in | — | — | — | corroborated | |
| OEM-T121-69 | Post-cat lambda signal (G130) | lambda_nb_in | — | — | — | corroborated | |
| OEM-T121-70 | Wideband lambda Nernst signal (G39) | wb_vs | — | — | — | corroborated | |
| OEM-T121-71 | Wideband lambda Nernst signal (G39) | wb_vs | — | — | — | corroborated | |
| OEM-T121-72 | Accelerator pedal position 1 5V supply (G79) | vref | MS3PROMINI-A-2 | +5V VREF out | vref | corroborated | |
| OEM-T121-73 | Accelerator pedal position 2 5V supply (G185) | vref | MS3PROMINI-A-2 | +5V VREF out | vref | corroborated | |
| OEM-T121-82 | Crank position sensor (G28) | trigger_in | MS3PROMINI-A-30 | CKP+ | trigger_in | corroborated | |
| OEM-T121-83 | Throttle position sensor 5V supply (G187/G188) | vref | MS3PROMINI-A-2 | +5V VREF out | vref | corroborated | |
| OEM-T121-84 | Throttle position sensor 1 (G187) | analog_in | MS3PROMINI-A-15 | Analog in 3 | analog_in | corroborated | |
| OEM-T121-85 | Intake air temperature (G42) | temp_in | MS3PROMINI-A-27 | IAT in | temp_in | corroborated | |
| OEM-T121-86 | Camshaft position sensor (G40) | trigger_in | MS3PROMINI-A-32 | CMP+ | trigger_in | corroborated | |
| OEM-T121-88 | Injector 4 (N33) | injector_out | MS3PROMINI-A-5 | Injector out A | injector_out | corroborated | |
| OEM-T121-89 | Injector 2 (N31) | injector_out | MS3PROMINI-A-11 | Injector out G | injector_out | corroborated | |
| OEM-T121-9 | Secondary-air injection valve (N112) | low_side_out | — | — | — | corroborated | |
| OEM-T121-90 | Crank position sensor ground (G28) | sensor_ground | MS3PROMINI-A-21 | Sensor ground | sensor_ground | corroborated | |
| OEM-T121-91 | Throttle position sensor ground (G187/G188) | sensor_ground | MS3PROMINI-A-21 | Sensor ground | sensor_ground | corroborated | |
| OEM-T121-92 | Throttle position sensor 2 (G188) | analog_in | — | — | — | corroborated | |
| OEM-T121-93 | Engine coolant temperature (G62) | temp_in | MS3PROMINI-A-26 | CLT in | temp_in | corroborated | |
| OEM-T121-94 | Ignition coil 4 (N163) | ignition_out | MS3PROMINI-A-20 | Spark out D | ignition_out | corroborated | |
| OEM-T121-95 | Ignition coil 2 (N128) | ignition_out | MS3PROMINI-A-18 | Spark out B | ignition_out | corroborated | |
| OEM-T121-96 | Injector 1 (N30) | injector_out | MS3PROMINI-A-10 | Injector out F | injector_out | corroborated | |
| OEM-T121-97 | Injector 3 (N32) | injector_out | MS3PROMINI-A-12 | Injector out H | injector_out | corroborated | |
| OEM-T121-98 | Cam + boost sensor 5V supply (G40/G31) | vref | MS3PROMINI-A-2 | +5V VREF out | vref | corroborated | |
| OEM-T121-99 | Knock sensor 5V supply (G61/G66) | vref | MS3PROMINI-A-2 | +5V VREF out | vref | corroborated |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-T121-121 | SP-14V-1 | 0.85 | no route | ECM + coil power (J271 relay feed) | — | |
| W2 | OEM-T121-21 | SP-14V-1 | 0.85 | no route | ECM power (J271 relay feed) | — | |
| W3 | SP-14V-1 | MS3PROMINI-A-1 | 0.85 | no route | 12V+ switched power in | — | |
| W4 | OEM-T121-1 | SP-GND-1 | 0.85 | no route | ECU ground | — | |
| W5 | OEM-T121-2 | SP-GND-1 | 0.85 | no route | ECU ground | — | |
| W6 | SP-GND-1 | MS3PROMINI-A-22 | 0.85 | no route | Power ground | — | |
| W7 | SP-GND-1 | MS3PROMINI-A-23 | 0.85 | no route | Power ground | — | |
| W8 | OEM-T121-108 | SP-0V-1 | 0.5 | no route | Sensor ground | — | |
| W9 | OEM-T121-29 | SP-0V-1 | 0.5 | no route | MAF sensor ground (G70) | — | |
| W10 | OEM-T121-34 | SP-0V-1 | 0.5 | no route | Accelerator pedal position 1 ground (G79) | — | |
| W11 | OEM-T121-36 | SP-0V-1 | 0.5 | no route | Accelerator pedal position 2 ground (G185) | — | |
| W12 | OEM-T121-90 | SP-0V-1 | 0.5 | no route | Crank position sensor ground (G28) | — | |
| W13 | OEM-T121-91 | SP-0V-1 | 0.5 | no route | Throttle position sensor ground (G187/G188) | — | |
| W14 | SP-0V-1 | MS3PROMINI-A-21 | 0.5 | no route | Sensor ground | — | |
| W15 | OEM-T121-72 | SP-5V1-1 | 0.5 | no route | Accelerator pedal position 1 5V supply (G79) | — | |
| W16 | OEM-T121-73 | SP-5V1-1 | 0.5 | no route | Accelerator pedal position 2 5V supply (G185) | — | |
| W17 | OEM-T121-83 | SP-5V1-1 | 0.5 | no route | Throttle position sensor 5V supply (G187/G188) | — | |
| W18 | OEM-T121-98 | SP-5V1-1 | 0.5 | no route | Cam + boost sensor 5V supply (G40/G31) | — | |
| W19 | OEM-T121-99 | SP-5V1-1 | 0.5 | no route | Knock sensor 5V supply (G61/G66) | — | |
| W20 | SP-5V1-1 | MS3PROMINI-A-2 | 0.5 | no route | +5V VREF out | — | |
| W21 | OEM-T121-82 | MS3PROMINI-A-30 | 0.5 | no route | Crank position sensor (G28) | — | |
| W22 | OEM-T121-86 | MS3PROMINI-A-32 | 0.5 | no route | Camshaft position sensor (G40) | — | |
| W23 | OEM-T121-102 | MS3PROMINI-A-17 | 0.5 | no route | Ignition coil 1 (N127) | — | |
| W24 | OEM-T121-95 | MS3PROMINI-A-18 | 0.5 | no route | Ignition coil 2 (N128) | — | |
| W25 | OEM-T121-103 | MS3PROMINI-A-19 | 0.5 | no route | Ignition coil 3 (N158) | — | |
| W26 | OEM-T121-94 | MS3PROMINI-A-20 | 0.5 | no route | Ignition coil 4 (N163) | — | |
| W27 | OEM-T121-96 | MS3PROMINI-A-10 | 0.5 | no route | Injector 1 (N30) | — | |
| W28 | OEM-T121-89 | MS3PROMINI-A-11 | 0.5 | no route | Injector 2 (N31) | — | |
| W29 | OEM-T121-97 | MS3PROMINI-A-12 | 0.5 | no route | Injector 3 (N32) | — | |
| W30 | OEM-T121-88 | MS3PROMINI-A-5 | 0.5 | no route | Injector 4 (N33) | — | |
| W31 | OEM-T121-53 | MS3PROMINI-A-13 | 0.5 | no route | MAF sensor signal (G70) | — | |
| W32 | OEM-T121-101 | MS3PROMINI-A-14 | 0.5 | no route | Boost pressure sensor (G31) | — | |
| W33 | OEM-T121-33 | MS3PROMINI-A-28 | 0.5 | no route | Accelerator pedal position 1 (G79) | — | |
| W34 | OEM-T121-84 | MS3PROMINI-A-15 | 0.5 | no route | Throttle position sensor 1 (G187) | — | |
| W35 | OEM-T121-35 | MS3PROMINI-A-16 | 0.5 | no route | Accelerator pedal position 2 (G185) | — | |
| W36 | OEM-T121-93 | MS3PROMINI-A-26 | 0.5 | no route | Engine coolant temperature (G62) | — | |
| W37 | OEM-T121-65 | MS3PROMINI-A-4 | 0.5 | no route | Fuel pump relay control | — | |
| W38 | OEM-T121-66 | MS3PROMINI-A-3 | 0.5 | no route | Secondary-air pump relay (J299) | — | |
| W39 | OEM-T121-5 | MS3PROMINI-A-6 | 0.5 | no route | Wideband lambda heater (Z19) | — | |
| W40 | OEM-T121-63 | MS3PROMINI-A-7 | 0.5 | no route | Post-cat lambda heater (Z29) | — | |
| W41 | OEM-T121-104 | MS3PROMINI-A-8 | 0.5 | no route | Boost control solenoid (N75) | — | |
| W42 | OEM-T121-105 | MS3PROMINI-A-9 | 0.5 | no route | Diverter valve (N249) | — | |
| W43 | OEM-T121-85 | MS3PROMINI-A-27 | 0.5 | no route | Intake air temperature (G42) | — | |
| W44 | OEM-T121-54 | MS3PROMINI-A-34 | 0.5 | no route | Road speed signal (VSS) | — | |
| W45 | OEM-T121-60 | MS3PROMINI-A-25 | 0.5 | no route | CAN bus high | — | |
| W46 | OEM-T121-58 | MS3PROMINI-A-24 | 0.5 | no route | CAN bus low | — |
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 (13)
| Severity | Code | Subject | Message |
|---|---|---|---|
| error | REQUIRED_UNMAPPED | OEM-T121-106 | Required OEM function "Knock sensor 1 (G61)" (knock_in) is not connected to the new ECU. |
| error | REQUIRED_UNMAPPED | OEM-T121-107 | Required OEM function "Knock sensor 2 (G66)" (knock_in) is not connected to the new ECU. |
| error | REQUIRED_UNMAPPED | OEM-T121-117 | Required OEM function "Throttle motor G186 (+)" (hbridge_out) is not connected to the new ECU. |
| error | REQUIRED_UNMAPPED | OEM-T121-118 | Required OEM function "Throttle motor G186 (−)" (hbridge_out) is not connected to the new ECU. |
| error | REQUIRED_UNMAPPED | OEM-T121-3 | Required OEM function "Ignition switch +12V (term 15)" (digital_in) is not connected to the new ECU. |
| error | REQUIRED_UNMAPPED | OEM-T121-92 | Required OEM function "Throttle position sensor 2 (G188)" (analog_in) is not connected to the new ECU. |
| warn | DBW_SHARED_5V | MS3PROMINI-A-2 + OEM-T121-72 + OEM-T121-73 + OEM-T121-83 + OEM-T121-98 + OEM-T121-99 + SP-5V1-1 | These 5 V supplies are separate in the stock car (OEM-T121-72 [pedal1], OEM-T121-73 [pedal2], OEM-T121-83 [tps], OEM-T121-98 [cam_boost], OEM-T121-99 [knock]) and here share one ECU 5 V (MS3PROMINI-A-2). On a drive-by-wire car the OEM splits them so one short or fault can't corrupt both throttle/pedal tracks at once. MS3Pro Mini has 1 5 V sensor supply pin(s). All are in use, so decide: accept the shared supply (and rely on the ECU's DBW fault checks), or add a separate regulated 5 V for the sub tracks. |
| warn | SUPPLY_GROUP | MS3PROMINI-A-2 + OEM-T121-72 + OEM-T121-73 + OEM-T121-83 + OEM-T121-98 + OEM-T121-99 + SP-5V1-1 | Supplies meant to stay independent share one net: OEM-T121-72 [pedal1], OEM-T121-73 [pedal2], OEM-T121-83 [tps], OEM-T121-98 [cam_boost], OEM-T121-99 [knock]. The new ECU has no free 5 V reference, so they share one: normal on a standalone, but a short on any of these sensors drops them all. |
| info | NET_FAMILY | OEM-T121-104 ↔ MS3PROMINI-A-8 | OEM-T121-104 "Boost control solenoid (N75)" [low_side_out] is wired to MS3PROMINI-A-8 "Injector out D" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-T121-105 ↔ MS3PROMINI-A-9 | OEM-T121-105 "Diverter valve (N249)" [low_side_out] is wired to MS3PROMINI-A-9 "Injector out E" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-T121-5 ↔ MS3PROMINI-A-6 | OEM-T121-5 "Wideband lambda heater (Z19)" [low_side_out] is wired to MS3PROMINI-A-6 "Injector out B" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-T121-63 ↔ MS3PROMINI-A-7 | OEM-T121-63 "Post-cat lambda heater (Z29)" [low_side_out] is wired to MS3PROMINI-A-7 "Injector out C" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | UNMAPPED | OEM | 14 optional OEM pins are not mapped: OEM-T121-115 VVT camshaft adjustment valve (N205); OEM-T121-27 MAF sensor supply (G70); OEM-T121-37 Engine speed signal (tacho to cluster); OEM-T121-43 K-line diagnostics (OBD pin 7); OEM-T121-47 Check engine light (MIL); OEM-T121-48 EPC warning light; OEM-T121-51 Wideband lambda pump (G39); OEM-T121-52 Wideband lambda pump (G39); OEM-T121-64 EVAP canister valve (N80); OEM-T121-68 Post-cat lambda signal (G130); OEM-T121-69 Post-cat lambda signal (G130); OEM-T121-70 Wideband lambda Nernst signal (G39); OEM-T121-71 Wideband lambda Nernst signal (G39); OEM-T121-9 Secondary-air injection valve (N112) |
Accepted (1)
| Code | Subject | Reason | By |
|---|---|---|---|
| REQUIRED_UNMAPPED | OEM-T121-62 | 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: needs add-on. Resolve these before building: - Drive-by-wire only with an add-on: AMP Drive-By-Wire Controller - No knock input; the stock knock sensor would be unused - This car has VW/Audi Immobilizer (delete/bypass for standalone) immobilizer; needs a delete/bypass 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-T121 106: Knock sensor 1 (G61): no free knock input on AMP EFI MS3Pro Mini - OEM-T121 107: Knock sensor 2 (G66): no free knock input on AMP EFI MS3Pro Mini - OEM-T121 117: Throttle motor G186 (+): needs a paired H-bridge on AMP EFI MS3Pro Mini (H-bridge pairing not in the library: set device_pin.bridge_pair from the ECU manual) - OEM-T121 118: Throttle motor G186 (−): needs a paired H-bridge on AMP EFI MS3Pro Mini (H-bridge pairing not in the library: set device_pin.bridge_pair from the ECU manual) - OEM-T121 3: Ignition switch +12V (term 15): key-on 12 V sense — optional in a swap (the main relay is energized from keyed 12 V, not from this pin); AMP EFI MS3Pro Mini has no dedicated key-on input - OEM-T121 92: Throttle position sensor 2 (G188): no free tps/analog_0_5 on AMP EFI MS3Pro Mini Not wired: - OEM-T121 62: Battery constant +12V (term 30): AMP EFI MS3Pro Mini has no battery-constant input; not needed - OEM-T121 115: VVT camshaft adjustment valve (N205): no free low_side/relay_control/heater_low_side/ls_hs/injector on AMP EFI MS3Pro Mini - OEM-T121 47: Check engine light (MIL): no free low_side/relay_control/heater_low_side/ls_hs/injector on AMP EFI MS3Pro Mini - OEM-T121 48: EPC warning light: no free low_side/relay_control/heater_low_side/ls_hs/injector on AMP EFI MS3Pro Mini - OEM-T121 64: EVAP canister valve (N80): no free low_side/relay_control/heater_low_side/ls_hs/injector on AMP EFI MS3Pro Mini - OEM-T121 9: Secondary-air injection valve (N112): no free low_side/relay_control/heater_low_side/ls_hs/injector on AMP EFI MS3Pro Mini - OEM-T121 37: Engine speed signal (tacho to cluster): no free tacho/frequency_out/low_side/ls_hs on AMP EFI MS3Pro Mini - OEM-T121 51: Wideband lambda pump (G39): no free wb_ip on AMP EFI MS3Pro Mini - OEM-T121 52: Wideband lambda pump (G39): no free wb_ip on AMP EFI MS3Pro Mini - OEM-T121 70: Wideband lambda Nernst signal (G39): no free wb_vs on AMP EFI MS3Pro Mini - OEM-T121 71: Wideband lambda Nernst signal (G39): no free wb_vs on AMP EFI MS3Pro Mini - OEM-T121 68: Post-cat lambda signal (G130): no free o2_narrowband/analog_0_5 on AMP EFI MS3Pro Mini - OEM-T121 69: Post-cat lambda signal (G130): no free o2_narrowband/analog_0_5 on AMP EFI MS3Pro Mini - OEM-T121 43: K-line diagnostics (OBD pin 7): no free k_line on AMP EFI MS3Pro Mini - OEM-T121 27: MAF sensor supply (G70): no rule for class sensor_supply_in; wire by hand
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | vendor_doc | AMP EFI: MS3Pro Mini manual (fw 1.6.1) pinout & output ratings | https://cdn.shopify.com/s/files/1/0960/0014/7754/files/MS3Pro_User_Manual_Firmware_1.6.1_Mini.pdf?v=1760643335 | archive | 2026-10-05 | bed7d8ae8408 |
| 3 | community_copy | NefMoto: ME7.5 ECU bench-flashing power/ground pins | http://nefmoto.com/wiki/index.php?title=ECU_Bench_Flashing | — | — | — |
| 3 | community_copy | vwressources: Bosch Motronic ME7.5 (AMK/ARY/AUQ/ARX/AUM) T121 pinout | https://www.vwressources.planethoster.world/me75_pinout.html | — | — | — |