VW Golf Mk4 1.8T 20v (AUM, Bosch ME7.5) DBW → Emtron SL8 (auto)
VW Golf Mk4 1.8T 20v (AUM, Bosch ME7.5) DBW — Emtron — SL8
⚠ 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 | none |
| Size of the job | 62 wires · 7 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-T121-121 | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | OEM-T121-21 | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | SP-14V-1 | SL8-A-34 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | SP-14V-1 | SL8-B-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-T121-1 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-T121-2 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | SP-GND-1 | SL8-B-18 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | SP-GND-1 | SL8-B-26 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | OEM-T121-108 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | OEM-T121-29 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | OEM-T121-34 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-T121-36 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-T121-90 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-T121-91 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | SP-0V-1 | SL8-B-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-T121-72 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-T121-73 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-T121-83 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-T121-98 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-T121-99 | SP-5V1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | SP-5V1-1 | SL8-B-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-T121-82 | SL8-B-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | SP-0V-1 | SL8-B-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-T121-86 | SL8-B-7 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | SP-0V-1 | SL8-B-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-T121-106 | SL8-B-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-T121-107 | SL8-B-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-T121-102 | SL8-A-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-T121-95 | SL8-A-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-T121-103 | SL8-A-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-T121-94 | SL8-A-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-T121-96 | SL8-A-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-T121-89 | SL8-A-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-T121-97 | SL8-A-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-T121-88 | SL8-A-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-T121-118 | SL8-A-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-T121-117 | SL8-A-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-T121-3 | SL8-B-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-T121-53 | SL8-B-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-T121-101 | SL8-B-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-T121-33 | SL8-B-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-T121-84 | SL8-B-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-T121-35 | SL8-B-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-T121-92 | SL8-B-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-T121-93 | SL8-B-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W46 | OEM-T121-65 | SL8-B-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W47 | OEM-T121-66 | SL8-A-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W48 | OEM-T121-5 | SL8-A-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W49 | OEM-T121-63 | SL8-A-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W50 | OEM-T121-104 | SL8-A-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W51 | OEM-T121-105 | SL8-A-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W52 | OEM-T121-115 | SL8-A-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W53 | OEM-T121-47 | SL8-A-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W54 | OEM-T121-48 | SL8-A-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W55 | OEM-T121-64 | SL8-A-5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W56 | OEM-T121-9 | SL8-A-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W57 | OEM-T121-68 | SL8-B-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W58 | OEM-T121-69 | SL8-B-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W59 | OEM-T121-85 | SL8-B-23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W60 | OEM-T121-54 | SL8-A-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W61 | OEM-T121-60 | SL8-B-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W62 | OEM-T121-58 | SL8-B-28 | 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 | SL8-A-34 | SL8-B-2 | open (OL) | +12 V supply must not touch 5 V sensor reference | |
| 2 | SL8-B-10 | SL8-A-34 | open (OL) | sensor ground must not touch +12 V supply | |
| 3 | SL8-B-10 | SL8-B-2 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 4 | SL8-B-18 | SL8-A-34 | open (OL) | power ground must not touch +12 V supply | |
| 5 | SL8-B-18 | SL8-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-T121
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | ECU ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| 101 | Boost pressure sensor (G31) | — | W40 | — | 0.5 | SL8-B-12 | — | — | — |
| 102 | Ignition coil 1 (N127) | — | W28 | — | 0.5 | SL8-A-26 | — | — | — |
| 103 | Ignition coil 3 (N158) | — | W30 | — | 0.5 | SL8-A-28 | — | — | — |
| 104 | Boost control solenoid (N75) | — | W50 | — | 0.5 | SL8-A-17 | — | — | — |
| 105 | Diverter valve (N249) | — | W51 | — | 0.5 | SL8-A-10 | — | — | — |
| 106 | Knock sensor 1 (G61) | — | W26 | — | 0.5 | SL8-B-16 | — | — | — |
| 107 | Knock sensor 2 (G66) | — | W27 | — | 0.5 | SL8-B-24 | — | — | — |
| 108 | Sensor ground | — | W9 | — | 0.5 | SP-0V-1 | — | — | — |
| 115 | VVT camshaft adjustment valve (N205) | — | W52 | — | 0.5 | SL8-A-11 | — | — | — |
| 117 | Throttle motor G186 (+) | — | W37 | — | 0.5 | SL8-A-18 | — | — | — |
| 118 | Throttle motor G186 (−) | — | W36 | — | 0.5 | SL8-A-19 | — | — | — |
| 121 | ECM + coil power (J271 relay feed) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| 2 | ECU ground | — | W6 | — | 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) | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| 3 | Ignition switch +12V (term 15) | — | W38 | — | 0.5 | SL8-B-4 | — | — | — |
| 33 | Accelerator pedal position 1 (G79) | — | W41 | — | 0.5 | SL8-B-13 | — | — | — |
| 34 | Accelerator pedal position 1 ground (G79) | — | W11 | — | 0.5 | SP-0V-1 | — | — | — |
| 35 | Accelerator pedal position 2 (G185) | — | W43 | — | 0.5 | SL8-B-15 | — | — | — |
| 36 | Accelerator pedal position 2 ground (G185) | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| 37 | Engine speed signal (tacho to cluster) | — | — | — | — | — | — | — | — |
| 43 | K-line diagnostics (OBD pin 7) | — | — | — | — | — | — | — | — |
| 47 | Check engine light (MIL) | — | W53 | — | 0.5 | SL8-A-12 | — | — | — |
| 48 | EPC warning light | — | W54 | — | 0.5 | SL8-A-13 | — | — | — |
| 5 | Wideband lambda heater (Z19) | — | W48 | — | 0.5 | SL8-A-15 | — | — | — |
| 51 | Wideband lambda pump (G39) | — | — | — | — | — | — | — | — |
| 52 | Wideband lambda pump (G39) | — | — | — | — | — | — | — | — |
| 53 | MAF sensor signal (G70) | — | W39 | — | 0.5 | SL8-B-11 | — | — | — |
| 54 | Road speed signal (VSS) | — | W60 | — | 0.5 | SL8-A-20 | — | — | — |
| 58 | CAN bus low | — | W62 | — | 0.5 | SL8-B-28 | — | — | — |
| 60 | CAN bus high | — | W61 | — | 0.5 | SL8-B-27 | — | — | — |
| 62 | Battery constant +12V (term 30) | — | — | — | — | — | — | — | — |
| 63 | Post-cat lambda heater (Z29) | — | W49 | — | 0.5 | SL8-A-16 | — | — | — |
| 64 | EVAP canister valve (N80) | — | W55 | — | 0.5 | SL8-A-5 | — | — | — |
| 65 | Fuel pump relay control | — | W46 | — | 0.5 | SL8-B-3 | — | — | — |
| 66 | Secondary-air pump relay (J299) | — | W47 | — | 0.5 | SL8-A-14 | — | — | — |
| 68 | Post-cat lambda signal (G130) | — | W57 | — | 0.5 | SL8-B-21 | — | — | — |
| 69 | Post-cat lambda signal (G130) | — | W58 | — | 0.5 | SL8-B-22 | — | — | — |
| 70 | Wideband lambda Nernst signal (G39) | — | — | — | — | — | — | — | — |
| 71 | Wideband lambda Nernst signal (G39) | — | — | — | — | — | — | — | — |
| 72 | Accelerator pedal position 1 5V supply (G79) | — | W16 | — | 0.5 | SP-5V1-1 | — | — | — |
| 73 | Accelerator pedal position 2 5V supply (G185) | — | W17 | — | 0.5 | SP-5V1-1 | — | — | — |
| 82 | Crank position sensor (G28) | — | W22 | — | 0.5 | SL8-B-5 | — | — | — |
| 83 | Throttle position sensor 5V supply (G187/G188) | — | W18 | — | 0.5 | SP-5V1-1 | — | — | — |
| 84 | Throttle position sensor 1 (G187) | — | W42 | — | 0.5 | SL8-B-14 | — | — | — |
| 85 | Intake air temperature (G42) | — | W59 | — | 0.5 | SL8-B-23 | — | — | — |
| 86 | Camshaft position sensor (G40) | — | W24 | — | 0.5 | SL8-B-7 | — | — | — |
| 88 | Injector 4 (N33) | — | W35 | — | 0.5 | SL8-A-4 | — | — | — |
| 89 | Injector 2 (N31) | — | W33 | — | 0.5 | SL8-A-2 | — | — | — |
| 9 | Secondary-air injection valve (N112) | — | W56 | — | 0.5 | SL8-A-6 | — | — | — |
| 90 | Crank position sensor ground (G28) | — | W13 | — | 0.5 | SP-0V-1 | — | — | — |
| 91 | Throttle position sensor ground (G187/G188) | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| 92 | Throttle position sensor 2 (G188) | — | W44 | — | 0.5 | SL8-B-19 | — | — | — |
| 93 | Engine coolant temperature (G62) | — | W45 | — | 0.5 | SL8-B-20 | — | — | — |
| 94 | Ignition coil 4 (N163) | — | W31 | — | 0.5 | SL8-A-29 | — | — | — |
| 95 | Ignition coil 2 (N128) | — | W29 | — | 0.5 | SL8-A-27 | — | — | — |
| 96 | Injector 1 (N30) | — | W32 | — | 0.5 | SL8-A-1 | — | — | — |
| 97 | Injector 3 (N32) | — | W34 | — | 0.5 | SL8-A-3 | — | — | — |
| 98 | Cam + boost sensor 5V supply (G40/G31) | — | W19 | — | 0.5 | SP-5V1-1 | — | — | — |
| 99 | Knock sensor 5V supply (G61/G66) | — | W20 | — | 0.5 | SP-5V1-1 | — | — | — |
SL8-A
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Injection channel 1 | — | W32 | — | 0.5 | OEM-T121-96 | — | — | — |
| 2 | Injection channel 2 | — | W33 | — | 0.5 | OEM-T121-89 | — | — | — |
| 3 | Injection channel 3 | — | W34 | — | 0.5 | OEM-T121-97 | — | — | — |
| 4 | Injection channel 4 | — | W35 | — | 0.5 | OEM-T121-88 | — | — | — |
| 5 | Injection channel 5 | — | W55 | — | 0.5 | OEM-T121-64 | — | — | — |
| 6 | Injection channel 6 | — | W56 | — | 0.5 | OEM-T121-9 | — | — | — |
| 7 | Injection channel 7 | — | — | — | — | — | — | — | — |
| 8 | Injection channel 8 | — | — | — | — | — | — | — | — |
| 9 | Sensor supply 8V | — | — | — | — | — | — | — | — |
| 10 | Auxiliary output 1 | — | W51 | — | 0.5 | OEM-T121-105 | — | — | — |
| 11 | Auxiliary output 2 | — | W52 | — | 0.5 | OEM-T121-115 | — | — | — |
| 12 | Auxiliary output 3 | — | W53 | — | 0.5 | OEM-T121-47 | — | — | — |
| 13 | Auxiliary output 4 | — | W54 | — | 0.5 | OEM-T121-48 | — | — | — |
| 14 | Auxiliary output 5 | — | W47 | — | 0.5 | OEM-T121-66 | — | — | — |
| 15 | Auxiliary output 6 | — | W48 | — | 0.5 | OEM-T121-5 | — | — | — |
| 16 | Auxiliary output 7 | — | W49 | — | 0.5 | OEM-T121-63 | — | — | — |
| 17 | Auxiliary output 8 | — | W50 | — | 0.5 | OEM-T121-104 | — | — | — |
| 18 | Auxiliary output 9 | — | W37 | — | 0.5 | OEM-T121-117 | — | — | — |
| 19 | Auxiliary output 10 | — | W36 | — | 0.5 | OEM-T121-118 | — | — | — |
| 20 | Digital input 1 | — | W60 | — | 0.5 | OEM-T121-54 | — | — | — |
| 21 | Digital input 2 | — | — | — | — | — | — | — | — |
| 22 | Digital input 3 | — | — | — | — | — | — | — | — |
| 23 | Digital input 4 | — | — | — | — | — | — | — | — |
| 24 | Digital input 5 | — | — | — | — | — | — | — | — |
| 25 | Digital input 6 | — | — | — | — | — | — | — | — |
| 26 | Ignition channel 1 | — | W28 | — | 0.5 | OEM-T121-102 | — | — | — |
| 27 | Ignition channel 2 | — | W29 | — | 0.5 | OEM-T121-95 | — | — | — |
| 28 | Ignition channel 3 | — | W30 | — | 0.5 | OEM-T121-103 | — | — | — |
| 29 | Ignition channel 4 | — | W31 | — | 0.5 | OEM-T121-94 | — | — | — |
| 30 | Ignition channel 5 | — | — | — | — | — | — | — | — |
| 31 | Ignition channel 6 | — | — | — | — | — | — | — | — |
| 32 | Ignition channel 7 | — | — | — | — | — | — | — | — |
| 33 | Ignition channel 8 | — | — | — | — | — | — | — | — |
| 34 | Aux 9–10 14V supply | — | W3 | — | 0.85 | SP-14V-1 | — | — | — |
SL8-B
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | ECU 14V supply | — | W4 | — | 0.85 | SP-14V-1 | — | — | — |
| 2 | Sensor supply Vref1 5.0V | — | W21 | — | 0.5 | SP-5V1-1 | — | — | — |
| 3 | EFI relay output (low side, 200 mA) | — | W46 | — | 0.5 | OEM-T121-65 | — | — | — |
| 4 | Ignition switch input | — | W38 | — | 0.5 | OEM-T121-3 | — | — | — |
| 5 | Crank index sensor + | — | W22 | — | 0.5 | OEM-T121-82 | — | — | — |
| 6 | Crank index sensor − | — | W23 | — | 0.5 | SP-0V-1 | — | — | — |
| 7 | Sync sensor + | — | W24 | — | 0.5 | OEM-T121-86 | — | — | — |
| 8 | Sync sensor − | — | W25 | — | 0.5 | SP-0V-1 | — | — | — |
| 9 | Shield (crank/sync/knock) | — | — | — | — | — | — | — | — |
| 10 | Analog sensor 0V reference | — | W15 | — | 0.5 | SP-0V-1 | — | — | — |
| 11 | Analog input 1 | — | W39 | — | 0.5 | OEM-T121-53 | — | — | — |
| 12 | Analog input 2 | — | W40 | — | 0.5 | OEM-T121-101 | — | — | — |
| 13 | Analog input 3 | — | W41 | — | 0.5 | OEM-T121-33 | — | — | — |
| 14 | Analog input 4 | — | W42 | — | 0.5 | OEM-T121-84 | — | — | — |
| 15 | Analog input 5 | — | W43 | — | 0.5 | OEM-T121-35 | — | — | — |
| 16 | Knock 1 + | — | W26 | — | 0.5 | OEM-T121-106 | — | — | — |
| 17 | Knock 1 − | — | — | — | — | — | — | — | — |
| 18 | ECU ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 19 | Analog input 6 | — | W44 | — | 0.5 | OEM-T121-92 | — | — | — |
| 20 | Analog input 7 (switchable 1k pull-up) | — | W45 | — | 0.5 | OEM-T121-93 | — | — | — |
| 21 | Analog input 8 (switchable 1k pull-up) | — | W57 | — | 0.5 | OEM-T121-68 | — | — | — |
| 22 | Analog input 9 (switchable 1k pull-up) | — | W58 | — | 0.5 | OEM-T121-69 | — | — | — |
| 23 | Analog input 10 (switchable 1k pull-up) | — | W59 | — | 0.5 | OEM-T121-85 | — | — | — |
| 24 | Knock 2 + | — | W27 | — | 0.5 | OEM-T121-107 | — | — | — |
| 25 | Knock 2 − | — | — | — | — | — | — | — | — |
| 26 | ECU ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| 27 | CAN 1 H | — | W61 | — | 0.5 | OEM-T121-60 | — | — | — |
| 28 | CAN 1 L | — | W62 | — | 0.5 | OEM-T121-58 | — | — | — |
| 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 | — | — | W15 | — | 0.5 | SL8-B-10 | — | — | — |
| 1 | — | — | W9 | — | 0.5 | OEM-T121-108 | — | — | — |
| 1 | — | — | W10 | — | 0.5 | OEM-T121-29 | — | — | — |
| 1 | — | — | W11 | — | 0.5 | OEM-T121-34 | — | — | — |
| 1 | — | — | W12 | — | 0.5 | OEM-T121-36 | — | — | — |
| 1 | — | — | W13 | — | 0.5 | OEM-T121-90 | — | — | — |
| 1 | — | — | W14 | — | 0.5 | OEM-T121-91 | — | — | — |
| 1 | — | — | W23 | — | 0.5 | SL8-B-6 | — | — | — |
| 1 | — | — | W25 | — | 0.5 | SL8-B-8 | — | — | — |
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 | SL8-A-34 | — | — | — |
| 1 | — | — | W4 | — | 0.85 | SL8-B-1 | — | — | — |
SP-5V1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W16 | — | 0.5 | OEM-T121-72 | — | — | — |
| 1 | — | — | W17 | — | 0.5 | OEM-T121-73 | — | — | — |
| 1 | — | — | W18 | — | 0.5 | OEM-T121-83 | — | — | — |
| 1 | — | — | W19 | — | 0.5 | OEM-T121-98 | — | — | — |
| 1 | — | — | W20 | — | 0.5 | OEM-T121-99 | — | — | — |
| 1 | — | — | W21 | — | 0.5 | SL8-B-2 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W5 | — | 0.85 | OEM-T121-1 | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-T121-2 | — | — | — |
| 1 | — | — | W7 | — | 0.85 | SL8-B-18 | — | — | — |
| 1 | — | — | W8 | — | 0.85 | SL8-B-26 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-T121-1 | ECU ground | ground | SL8-B-18 + SL8-B-26 | ECU ground + ECU ground | ground | corroborated | |
| OEM-T121-101 | Boost pressure sensor (G31) | analog_in | SL8-B-12 | Analog input 2 | analog_in | corroborated | |
| OEM-T121-102 | Ignition coil 1 (N127) | ignition_out | SL8-A-26 | Ignition channel 1 | ignition_out | corroborated | |
| OEM-T121-103 | Ignition coil 3 (N158) | ignition_out | SL8-A-28 | Ignition channel 3 | ignition_out | corroborated | |
| OEM-T121-104 | Boost control solenoid (N75) | low_side_out | SL8-A-17 | Auxiliary output 8 | switch_out | corroborated | |
| OEM-T121-105 | Diverter valve (N249) | low_side_out | SL8-A-10 | Auxiliary output 1 | switch_out | corroborated | |
| OEM-T121-106 | Knock sensor 1 (G61) | knock_in | SL8-B-16 | Knock 1 + | knock_in | corroborated | |
| OEM-T121-107 | Knock sensor 2 (G66) | knock_in | SL8-B-24 | Knock 2 + | knock_in | corroborated | |
| OEM-T121-108 | Sensor ground | sensor_ground | SL8-B-10 + SL8-B-6 + SL8-B-8 | Analog sensor 0V reference + Crank index sensor − + Sync sensor − | sensor_ground + trigger_in | corroborated | |
| OEM-T121-115 | VVT camshaft adjustment valve (N205) | low_side_out | SL8-A-11 | Auxiliary output 2 | switch_out | corroborated | |
| OEM-T121-117 | Throttle motor G186 (+) | hbridge_out | SL8-A-18 | Auxiliary output 9 | hbridge_out | corroborated | |
| OEM-T121-118 | Throttle motor G186 (−) | hbridge_out | SL8-A-19 | Auxiliary output 10 | hbridge_out | corroborated | |
| OEM-T121-121 | ECM + coil power (J271 relay feed) | power_in | SL8-A-34 + SL8-B-1 | Aux 9–10 14V supply + ECU 14V supply | power_in | corroborated | |
| OEM-T121-2 | ECU ground | ground | SL8-B-18 + SL8-B-26 | ECU ground + ECU ground | ground | corroborated | |
| OEM-T121-21 | ECM power (J271 relay feed) | power_in | SL8-A-34 + SL8-B-1 | Aux 9–10 14V supply + ECU 14V supply | power_in | corroborated | |
| OEM-T121-27 | MAF sensor supply (G70) | power_in | — | — | — | corroborated | |
| OEM-T121-29 | MAF sensor ground (G70) | sensor_ground | SL8-B-10 + SL8-B-6 + SL8-B-8 | Analog sensor 0V reference + Crank index sensor − + Sync sensor − | sensor_ground + trigger_in | corroborated | |
| OEM-T121-3 | Ignition switch +12V (term 15) | digital_in | SL8-B-4 | Ignition switch input | digital_in | corroborated | |
| OEM-T121-33 | Accelerator pedal position 1 (G79) | analog_in | SL8-B-13 | Analog input 3 | analog_in | corroborated | |
| OEM-T121-34 | Accelerator pedal position 1 ground (G79) | sensor_ground | SL8-B-10 + SL8-B-6 + SL8-B-8 | Analog sensor 0V reference + Crank index sensor − + Sync sensor − | sensor_ground + trigger_in | corroborated | |
| OEM-T121-35 | Accelerator pedal position 2 (G185) | analog_in | SL8-B-15 | Analog input 5 | analog_in | corroborated | |
| OEM-T121-36 | Accelerator pedal position 2 ground (G185) | sensor_ground | SL8-B-10 + SL8-B-6 + SL8-B-8 | Analog sensor 0V reference + Crank index sensor − + Sync sensor − | sensor_ground + trigger_in | 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 | SL8-A-12 | Auxiliary output 3 | switch_out | corroborated | |
| OEM-T121-48 | EPC warning light | low_side_out | SL8-A-13 | Auxiliary output 4 | switch_out | corroborated | |
| OEM-T121-5 | Wideband lambda heater (Z19) | low_side_out | SL8-A-15 | Auxiliary output 6 | switch_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 | SL8-B-11 | Analog input 1 | analog_in | corroborated | |
| OEM-T121-54 | Road speed signal (VSS) | digital_in | SL8-A-20 | Digital input 1 | digital_in | corroborated | |
| OEM-T121-58 | CAN bus low | can_l | SL8-B-28 | CAN 1 L | can_l | corroborated | |
| OEM-T121-60 | CAN bus high | can_h | SL8-B-27 | CAN 1 H | 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 | SL8-A-16 | Auxiliary output 7 | switch_out | corroborated | |
| OEM-T121-64 | EVAP canister valve (N80) | low_side_out | SL8-A-5 | Injection channel 5 | injector_out | corroborated | |
| OEM-T121-65 | Fuel pump relay control | low_side_out | SL8-B-3 | EFI relay output (low side, 200 mA) | low_side_out | corroborated | |
| OEM-T121-66 | Secondary-air pump relay (J299) | low_side_out | SL8-A-14 | Auxiliary output 5 | switch_out | corroborated | |
| OEM-T121-68 | Post-cat lambda signal (G130) | lambda_nb_in | SL8-B-21 | Analog input 8 (switchable 1k pull-up) | analog_in | corroborated | |
| OEM-T121-69 | Post-cat lambda signal (G130) | lambda_nb_in | SL8-B-22 | Analog input 9 (switchable 1k pull-up) | analog_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 | SL8-B-2 | Sensor supply Vref1 5.0V | vref | corroborated | |
| OEM-T121-73 | Accelerator pedal position 2 5V supply (G185) | vref | SL8-B-2 | Sensor supply Vref1 5.0V | vref | corroborated | |
| OEM-T121-82 | Crank position sensor (G28) | trigger_in | SL8-B-5 | Crank index sensor + | trigger_in | corroborated | |
| OEM-T121-83 | Throttle position sensor 5V supply (G187/G188) | vref | SL8-B-2 | Sensor supply Vref1 5.0V | vref | corroborated | |
| OEM-T121-84 | Throttle position sensor 1 (G187) | analog_in | SL8-B-14 | Analog input 4 | analog_in | corroborated | |
| OEM-T121-85 | Intake air temperature (G42) | temp_in | SL8-B-23 | Analog input 10 (switchable 1k pull-up) | analog_in | corroborated | |
| OEM-T121-86 | Camshaft position sensor (G40) | trigger_in | SL8-B-7 | Sync sensor + | trigger_in | corroborated | |
| OEM-T121-88 | Injector 4 (N33) | injector_out | SL8-A-4 | Injection channel 4 | injector_out | corroborated | |
| OEM-T121-89 | Injector 2 (N31) | injector_out | SL8-A-2 | Injection channel 2 | injector_out | corroborated | |
| OEM-T121-9 | Secondary-air injection valve (N112) | low_side_out | SL8-A-6 | Injection channel 6 | injector_out | corroborated | |
| OEM-T121-90 | Crank position sensor ground (G28) | sensor_ground | SL8-B-10 + SL8-B-6 + SL8-B-8 | Analog sensor 0V reference + Crank index sensor − + Sync sensor − | sensor_ground + trigger_in | corroborated | |
| OEM-T121-91 | Throttle position sensor ground (G187/G188) | sensor_ground | SL8-B-10 + SL8-B-6 + SL8-B-8 | Analog sensor 0V reference + Crank index sensor − + Sync sensor − | sensor_ground + trigger_in | corroborated | |
| OEM-T121-92 | Throttle position sensor 2 (G188) | analog_in | SL8-B-19 | Analog input 6 | analog_in | corroborated | |
| OEM-T121-93 | Engine coolant temperature (G62) | temp_in | SL8-B-20 | Analog input 7 (switchable 1k pull-up) | analog_in | corroborated | |
| OEM-T121-94 | Ignition coil 4 (N163) | ignition_out | SL8-A-29 | Ignition channel 4 | ignition_out | corroborated | |
| OEM-T121-95 | Ignition coil 2 (N128) | ignition_out | SL8-A-27 | Ignition channel 2 | ignition_out | corroborated | |
| OEM-T121-96 | Injector 1 (N30) | injector_out | SL8-A-1 | Injection channel 1 | injector_out | corroborated | |
| OEM-T121-97 | Injector 3 (N32) | injector_out | SL8-A-3 | Injection channel 3 | injector_out | corroborated | |
| OEM-T121-98 | Cam + boost sensor 5V supply (G40/G31) | vref | SL8-B-2 | Sensor supply Vref1 5.0V | vref | corroborated | |
| OEM-T121-99 | Knock sensor 5V supply (G61/G66) | vref | SL8-B-2 | Sensor supply Vref1 5.0V | 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 | SL8-A-34 | 0.85 | no route | Aux 9–10 14V supply | — | |
| W4 | SP-14V-1 | SL8-B-1 | 0.85 | no route | ECU 14V supply | — | |
| W5 | OEM-T121-1 | SP-GND-1 | 0.85 | no route | ECU ground | — | |
| W6 | OEM-T121-2 | SP-GND-1 | 0.85 | no route | ECU ground | — | |
| W7 | SP-GND-1 | SL8-B-18 | 0.85 | no route | ECU ground | — | |
| W8 | SP-GND-1 | SL8-B-26 | 0.85 | no route | ECU ground | — | |
| W9 | OEM-T121-108 | SP-0V-1 | 0.5 | no route | Sensor ground | — | |
| W10 | OEM-T121-29 | SP-0V-1 | 0.5 | no route | MAF sensor ground (G70) | — | |
| W11 | OEM-T121-34 | SP-0V-1 | 0.5 | no route | Accelerator pedal position 1 ground (G79) | — | |
| W12 | OEM-T121-36 | SP-0V-1 | 0.5 | no route | Accelerator pedal position 2 ground (G185) | — | |
| W13 | OEM-T121-90 | SP-0V-1 | 0.5 | no route | Crank position sensor ground (G28) | — | |
| W14 | OEM-T121-91 | SP-0V-1 | 0.5 | no route | Throttle position sensor ground (G187/G188) | — | |
| W15 | SP-0V-1 | SL8-B-10 | 0.5 | no route | Analog sensor 0V reference | — | |
| W16 | OEM-T121-72 | SP-5V1-1 | 0.5 | no route | Accelerator pedal position 1 5V supply (G79) | — | |
| W17 | OEM-T121-73 | SP-5V1-1 | 0.5 | no route | Accelerator pedal position 2 5V supply (G185) | — | |
| W18 | OEM-T121-83 | SP-5V1-1 | 0.5 | no route | Throttle position sensor 5V supply (G187/G188) | — | |
| W19 | OEM-T121-98 | SP-5V1-1 | 0.5 | no route | Cam + boost sensor 5V supply (G40/G31) | — | |
| W20 | OEM-T121-99 | SP-5V1-1 | 0.5 | no route | Knock sensor 5V supply (G61/G66) | — | |
| W21 | SP-5V1-1 | SL8-B-2 | 0.5 | no route | Sensor supply Vref1 5.0V | — | |
| W22 | OEM-T121-82 | SL8-B-5 | 0.5 | no route | Crank position sensor (G28) | — | |
| W23 | SP-0V-1 | SL8-B-6 | 0.5 | no route | Crank index sensor − | — | |
| W24 | OEM-T121-86 | SL8-B-7 | 0.5 | no route | Camshaft position sensor (G40) | — | |
| W25 | SP-0V-1 | SL8-B-8 | 0.5 | no route | Sync sensor − | — | |
| W26 | OEM-T121-106 | SL8-B-16 | 0.5 | no route | Knock sensor 1 (G61) | — | |
| W27 | OEM-T121-107 | SL8-B-24 | 0.5 | no route | Knock sensor 2 (G66) | — | |
| W28 | OEM-T121-102 | SL8-A-26 | 0.5 | no route | Ignition coil 1 (N127) | — | |
| W29 | OEM-T121-95 | SL8-A-27 | 0.5 | no route | Ignition coil 2 (N128) | — | |
| W30 | OEM-T121-103 | SL8-A-28 | 0.5 | no route | Ignition coil 3 (N158) | — | |
| W31 | OEM-T121-94 | SL8-A-29 | 0.5 | no route | Ignition coil 4 (N163) | — | |
| W32 | OEM-T121-96 | SL8-A-1 | 0.5 | no route | Injector 1 (N30) | — | |
| W33 | OEM-T121-89 | SL8-A-2 | 0.5 | no route | Injector 2 (N31) | — | |
| W34 | OEM-T121-97 | SL8-A-3 | 0.5 | no route | Injector 3 (N32) | — | |
| W35 | OEM-T121-88 | SL8-A-4 | 0.5 | no route | Injector 4 (N33) | — | |
| W36 | OEM-T121-118 | SL8-A-19 | 0.5 | no route | Throttle motor G186 (−) | — | |
| W37 | OEM-T121-117 | SL8-A-18 | 0.5 | no route | Throttle motor G186 (+) | — | |
| W38 | OEM-T121-3 | SL8-B-4 | 0.5 | no route | Ignition switch +12V (term 15) | — | |
| W39 | OEM-T121-53 | SL8-B-11 | 0.5 | no route | MAF sensor signal (G70) | — | |
| W40 | OEM-T121-101 | SL8-B-12 | 0.5 | no route | Boost pressure sensor (G31) | — | |
| W41 | OEM-T121-33 | SL8-B-13 | 0.5 | no route | Accelerator pedal position 1 (G79) | — | |
| W42 | OEM-T121-84 | SL8-B-14 | 0.5 | no route | Throttle position sensor 1 (G187) | — | |
| W43 | OEM-T121-35 | SL8-B-15 | 0.5 | no route | Accelerator pedal position 2 (G185) | — | |
| W44 | OEM-T121-92 | SL8-B-19 | 0.5 | no route | Throttle position sensor 2 (G188) | — | |
| W45 | OEM-T121-93 | SL8-B-20 | 0.5 | no route | Engine coolant temperature (G62) | — | |
| W46 | OEM-T121-65 | SL8-B-3 | 0.5 | no route | Fuel pump relay control | — | |
| W47 | OEM-T121-66 | SL8-A-14 | 0.5 | no route | Secondary-air pump relay (J299) | — | |
| W48 | OEM-T121-5 | SL8-A-15 | 0.5 | no route | Wideband lambda heater (Z19) | — | |
| W49 | OEM-T121-63 | SL8-A-16 | 0.5 | no route | Post-cat lambda heater (Z29) | — | |
| W50 | OEM-T121-104 | SL8-A-17 | 0.5 | no route | Boost control solenoid (N75) | — | |
| W51 | OEM-T121-105 | SL8-A-10 | 0.5 | no route | Diverter valve (N249) | — | |
| W52 | OEM-T121-115 | SL8-A-11 | 0.5 | no route | VVT camshaft adjustment valve (N205) | — | |
| W53 | OEM-T121-47 | SL8-A-12 | 0.5 | no route | Check engine light (MIL) | — | |
| W54 | OEM-T121-48 | SL8-A-13 | 0.5 | no route | EPC warning light | — | |
| W55 | OEM-T121-64 | SL8-A-5 | 0.5 | no route | EVAP canister valve (N80) | — | |
| W56 | OEM-T121-9 | SL8-A-6 | 0.5 | no route | Secondary-air injection valve (N112) | — | |
| W57 | OEM-T121-68 | SL8-B-21 | 0.5 | no route | Post-cat lambda signal (G130) | — | |
| W58 | OEM-T121-69 | SL8-B-22 | 0.5 | no route | Post-cat lambda signal (G130) | — | |
| W59 | OEM-T121-85 | SL8-B-23 | 0.5 | no route | Intake air temperature (G42) | — | |
| W60 | OEM-T121-54 | SL8-A-20 | 0.5 | no route | Road speed signal (VSS) | — | |
| W61 | OEM-T121-60 | SL8-B-27 | 0.5 | no route | CAN bus high | — | |
| W62 | OEM-T121-58 | SL8-B-28 | 0.5 | no route | CAN bus low | — |
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) | 47.000 | ea |
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (19)
| Severity | Code | Subject | Message |
|---|---|---|---|
| warn | DBW_MOTOR_CURRENT | SL8-A-18 | Cannot confirm SL8 can drive the throttle motor: SL8-A-18 "Auxiliary output 9" is rated 8.0 A peak, but the motor stall current at OEM-T121-117 is unknown. Add the motor's peak current from a source, or measure the motor resistance: peak ≈ 14 V ÷ R (Hondata measured 4.9 A for a Civic Si body, 10.4 A for a ZDX body; holding current is about 1 A). |
| warn | DBW_MOTOR_CURRENT | SL8-A-19 | Cannot confirm SL8 can drive the throttle motor: SL8-A-19 "Auxiliary output 10" is rated 8.0 A peak, but the motor stall current at OEM-T121-118 is unknown. Add the motor's peak current from a source, or measure the motor resistance: peak ≈ 14 V ÷ R (Hondata measured 4.9 A for a Civic Si body, 10.4 A for a ZDX body; holding current is about 1 A). |
| warn | DBW_MOTOR_ISOLATION | SL8-A-34 | SL8-A-34 "Aux 9–10 14V supply" is fed from the same net as the ECU main supply (SL8-B-1). Link's S2000 DBW wiring feeds the throttle-motor supply through a separate isolation relay switched by the ECU, so motor power can be cut on a throttle fault. Add one, or confirm SL8 cuts the H-bridge internally. |
| warn | DBW_SHARED_5V | OEM-T121-72 + OEM-T121-73 + OEM-T121-83 + OEM-T121-98 + OEM-T121-99 + SL8-B-2 + 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 (SL8-B-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. SL8 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 | OEM-T121-72 + OEM-T121-73 + OEM-T121-83 + OEM-T121-98 + OEM-T121-99 + SL8-B-2 + 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 ↔ SL8-A-17 | OEM-T121-104 "Boost control solenoid (N75)" [low_side_out] is wired to SL8-A-17 "Auxiliary output 8" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-T121-105 ↔ SL8-A-10 | OEM-T121-105 "Diverter valve (N249)" [low_side_out] is wired to SL8-A-10 "Auxiliary output 1" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-T121-115 ↔ SL8-A-11 | OEM-T121-115 "VVT camshaft adjustment valve (N205)" [low_side_out] is wired to SL8-A-11 "Auxiliary output 2" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-T121-29 ↔ SL8-B-8 | OEM-T121-29 "MAF sensor ground (G70)" [sensor_ground] is wired to SL8-B-8 "Sync sensor −" [trigger_in]. Trigger return tied to sensor/trigger ground: correct for single-ended trigger inputs. |
| info | NET_FAMILY | OEM-T121-47 ↔ SL8-A-12 | OEM-T121-47 "Check engine light (MIL)" [low_side_out] is wired to SL8-A-12 "Auxiliary output 3" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-T121-48 ↔ SL8-A-13 | OEM-T121-48 "EPC warning light" [low_side_out] is wired to SL8-A-13 "Auxiliary output 4" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-T121-5 ↔ SL8-A-15 | OEM-T121-5 "Wideband lambda heater (Z19)" [low_side_out] is wired to SL8-A-15 "Auxiliary output 6" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-T121-63 ↔ SL8-A-16 | OEM-T121-63 "Post-cat lambda heater (Z29)" [low_side_out] is wired to SL8-A-16 "Auxiliary output 7" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-T121-64 ↔ SL8-A-5 | OEM-T121-64 "EVAP canister valve (N80)" [low_side_out] is wired to SL8-A-5 "Injection channel 5" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-T121-66 ↔ SL8-A-14 | OEM-T121-66 "Secondary-air pump relay (J299)" [low_side_out] is wired to SL8-A-14 "Auxiliary output 5" [switch_out]. Configure this output as low side. |
| info | NET_FAMILY | OEM-T121-85 ↔ SL8-B-23 | OEM-T121-85 "Intake air temperature (G42)" [temp_in] is wired to SL8-B-23 "Analog input 10 (switchable 1k pull-up)" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | NET_FAMILY | OEM-T121-9 ↔ SL8-A-6 | OEM-T121-9 "Secondary-air injection valve (N112)" [low_side_out] is wired to SL8-A-6 "Injection channel 6" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency. |
| info | NET_FAMILY | OEM-T121-93 ↔ SL8-B-20 | OEM-T121-93 "Engine coolant temperature (G62)" [temp_in] is wired to SL8-B-20 "Analog input 7 (switchable 1k pull-up)" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | UNMAPPED | OEM | 7 optional OEM pins are not mapped: 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-T121-51 Wideband lambda pump (G39); OEM-T121-52 Wideband lambda pump (G39); OEM-T121-70 Wideband lambda Nernst signal (G39); OEM-T121-71 Wideband lambda Nernst signal (G39) |
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: unconfirmed. Confirm these before building: - Trigger pattern for VW EA113 not found in the ECU's docs (No VW 1.8T 20v (EA113) decoder.) - 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. Not wired: - OEM-T121 62: Battery constant +12V (term 30): Emtron SL8 has no battery-constant input; not needed - SL8-B 17: Knock 1 − left open: the stock knock sensor has one ECU wire; check the ECU manual for single-wire knock sensors - SL8-B 25: Knock 2 − left open: the stock knock sensor has one ECU wire; check the ECU manual for single-wire knock sensors - OEM-T121 37: Engine speed signal (tacho to cluster): no free tacho/frequency_out/low_side/ls_hs on Emtron SL8 - OEM-T121 51: Wideband lambda pump (G39): no free wb_ip on Emtron SL8 - OEM-T121 52: Wideband lambda pump (G39): no free wb_ip on Emtron SL8 - OEM-T121 70: Wideband lambda Nernst signal (G39): no free wb_vs on Emtron SL8 - OEM-T121 71: Wideband lambda Nernst signal (G39): no free wb_vs on Emtron SL8 - OEM-T121 43: K-line diagnostics (OBD pin 7): no free k_line on Emtron SL8 - 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 | 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 |
| 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 | — | — | — |