VW Golf/Jetta Mk2 1.8 8v Digifant II → DTAFast T2i (auto)
VW Golf/Jetta Mk2 1.8 8v Digifant II — DTAFast — T2i
⚠ 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 | 23 wires · 5 connectors · 2 part lines |
| Tools | Crimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink |
| Terminals | 3-1447221-4 |
| Order of work | 1. Check every part against the parts list. 2. Cut and label every wire (labels: Export → Wire labels). 3. Crimp and pin connector by connector, ticking the build checklist. 4. Run the bench test with nothing plugged in and the battery disconnected. 5. Only then connect the ECU and power up. |
Build checklist
Tick each box as you go. Continuity: meter from end to end, expect under 1 Ω.
| Wire | From | To | Gauge | Colour | Cut | Label | Crimp A | Crimp B | Pin A | Pin B | Continuity |
|---|---|---|---|---|---|---|---|---|---|---|---|
| W1 | OEM-A-14 | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | SP-14V-1 | T2I-C1-31 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | OEM-A-13 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-A-19 | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | SP-GND-1 | T2I-C1-13 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | SP-GND-1 | T2I-C1-14 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | OEM-A-5 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | OEM-A-6 | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-0V-1 | T2I-C1-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | SP-0V-1 | T2I-C1-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | OEM-A-17 | T2I-C1-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-A-18 | T2I-C1-12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-A-25 | T2I-C1-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-A-3 | T2I-C1-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-A-21 | T2I-C1-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-A-10 | T2I-C1-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-A-22 | T2I-C1-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-A-23 | T2I-C1-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-A-2 | T2I-C1-22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-A-9 | T2I-C1-32 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-A-1 | T2I-C1-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-A-11 | T2I-C1-30 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-A-16 | T2I-C1-23 | 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 | T2I-C1-27 | T2I-C1-28 | open (OL) | 5 V sensor reference must not touch sensor ground | |
| 2 | T2I-C1-31 | T2I-C1-28 | open (OL) | +12 V supply must not touch sensor ground | |
| 3 | T2I-C1-13 | T2I-C1-27 | open (OL) | power ground must not touch 5 V sensor reference | |
| 4 | T2I-C1-13 | T2I-C1-31 | open (OL) | power ground must not touch +12 V supply | |
| 5 | T2I-C1-31 | T2I-C1-27 | 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
OEM-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Starter signal (term 50) | — | W21 | — | 0.5 | T2I-C1-11 | — | — | — |
| 10 | Coolant temperature sensor | — | W16 | — | 0.5 | T2I-C1-24 | — | — | — |
| 11 | Idle/WOT throttle switch | — | W22 | — | 0.5 | T2I-C1-30 | — | — | — |
| 12 | Injector driver (batch, all 4) | — | — | — | — | — | — | — | — |
| 13 | Ground | — | W3 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | ECU power (control-unit relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| 16 | A/C compressor signal | — | W23 | — | 0.5 | T2I-C1-23 | — | — | — |
| 17 | AFM potentiometer supply | — | W11 | — | 0.5 | T2I-C1-27 | — | — | — |
| 18 | Hall sender signal (engine speed) | — | W12 | — | 0.5 | T2I-C1-12 | — | — | — |
| 19 | Ground | — | W4 | — | 0.85 | SP-GND-1 | — | — | — |
| 2 | Oxygen (lambda) sensor signal | — | W19 | — | 0.5 | T2I-C1-22 | — | — | — |
| 21 | AFM signal | — | W15 | — | 0.5 | T2I-C1-20 | — | — | — |
| 22 | Idle stabilizer valve coil 1 | — | W17 | — | 0.5 | T2I-C1-10 | — | — | — |
| 23 | Idle stabilizer valve coil 2 | — | W18 | — | 0.5 | T2I-C1-18 | — | — | — |
| 25 | Ignition timing signal to TCI | — | W13 | — | 0.5 | T2I-C1-3 | — | — | — |
| 3 | Fuel pump relay control | — | W14 | — | 0.5 | T2I-C1-1 | — | — | — |
| 4 | Knock sensor signal | — | — | — | — | — | — | — | — |
| 5 | Knock sensor return | — | W7 | — | 0.5 | SP-0V-1 | — | — | — |
| 6 | Sensor ground (CTS/Hall/AFM/throttle) | — | W8 | — | 0.5 | SP-0V-1 | — | — | — |
| 7 | Knock sensor shield | — | — | — | — | — | — | — | — |
| 8 | Hall sender supply (distributor) | — | — | — | — | — | — | — | — |
| 9 | Intake air temperature sensor | — | W20 | — | 0.5 | T2I-C1-32 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W8 | — | 0.5 | OEM-A-6 | — | — | — |
| 1 | — | — | W9 | — | 0.5 | T2I-C1-28 | — | — | — |
| 1 | — | — | W7 | — | 0.5 | OEM-A-5 | — | — | — |
| 1 | — | — | W10 | — | 0.5 | T2I-C1-29 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-A-14 | — | — | — |
| 1 | — | — | W2 | — | 0.85 | T2I-C1-31 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W6 | — | 0.85 | T2I-C1-14 | — | — | — |
| 1 | — | — | W3 | — | 0.85 | OEM-A-13 | — | — | — |
| 1 | — | — | W4 | — | 0.85 | OEM-A-19 | — | — | — |
| 1 | — | — | W5 | — | 0.85 | T2I-C1-13 | — | — | — |
T2I-C1
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | PWM 1 | — | W14 | — | 0.5 | OEM-A-3 | — | — | — |
| 2 | Lambda Nernst Voltage | — | — | — | — | — | — | — | — |
| 3 | Coil 1 | — | W13 | — | 0.5 | OEM-A-25 | — | — | — |
| 4 | Lambda VGND | — | — | — | — | — | — | — | — |
| 5 | Lambda Pump Current | — | — | — | — | — | — | — | — |
| 6 | Coil 2 | — | — | — | — | — | — | — | — |
| 7 | Lambda Trim Resistor | — | — | — | — | — | — | — | — |
| 8 | — | — | — | — | — | — | — | — | — |
| 9 | — | — | — | — | — | — | — | — | — |
| 10 | PWM 2 | — | W17 | — | 0.5 | OEM-A-22 | — | — | — |
| 11 | Digital 1 | — | W21 | — | 0.5 | OEM-A-1 | — | — | — |
| 12 | Wheel 1 | — | W12 | — | 0.5 | OEM-A-18 | — | — | — |
| 13 | Power Ground 1 | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | Power Ground 2 | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 15 | Lambda Heater Negative | — | — | — | — | — | — | — | — |
| 16 | CAN High | — | — | — | — | — | — | — | — |
| 17 | CAN Low | — | — | — | — | — | — | — | — |
| 18 | PWM 3 | — | W18 | — | 0.5 | OEM-A-23 | — | — | — |
| 19 | Crank | — | — | — | — | — | — | — | — |
| 20 | Analogue 1 | — | W15 | — | 0.5 | OEM-A-21 | — | — | — |
| 21 | Permanent 12v | — | — | — | — | — | — | — | — |
| 22 | Analogue 2 | — | W19 | — | 0.5 | OEM-A-2 | — | — | — |
| 23 | Analogue 3 | — | W23 | — | 0.5 | OEM-A-16 | — | — | — |
| 24 | Thermistor 1 | — | W16 | — | 0.5 | OEM-A-10 | — | — | — |
| 25 | Analogue 4 | — | — | — | — | — | — | — | — |
| 26 | PWM 4 | — | — | — | — | — | — | — | — |
| 27 | 5v Output | — | W11 | — | 0.5 | OEM-A-17 | — | — | — |
| 28 | Sensor Ground | — | W9 | — | 0.5 | SP-0V-1 | — | — | — |
| 29 | Sensor Ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| 30 | Digital 2 | — | W22 | — | 0.5 | OEM-A-11 | — | — | — |
| 31 | Ignition 12v In | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 32 | Thermistor 2 | — | W20 | — | 0.5 | OEM-A-9 | — | — | — |
| 33 | Analogue 5 | — | — | — | — | — | — | — | — |
| 34 | Analogue 6 | — | — | — | — | — | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-A-1 | Starter signal (term 50) | digital_in | T2I-C1-11 | Digital 1 | digital_in | corroborated | |
| OEM-A-10 | Coolant temperature sensor | temp_in | T2I-C1-24 | Thermistor 1 | temp_in | corroborated | |
| OEM-A-11 | Idle/WOT throttle switch | digital_in | T2I-C1-30 | Digital 2 | digital_in | corroborated | |
| OEM-A-12 | Injector driver (batch, all 4) | injector_out | — | — | — | corroborated | |
| OEM-A-13 | Ground | ground | T2I-C1-13 + T2I-C1-14 | Power Ground 1 + Power Ground 2 | ground | corroborated | |
| OEM-A-14 | ECU power (control-unit relay) | power_in | T2I-C1-31 | Ignition 12v In | power_in | corroborated | |
| OEM-A-16 | A/C compressor signal | digital_in | T2I-C1-23 | Analogue 3 | analog_in | corroborated | |
| OEM-A-17 | AFM potentiometer supply | vref | T2I-C1-27 | 5v Output | vref | corroborated | |
| OEM-A-18 | Hall sender signal (engine speed) | trigger_in | T2I-C1-12 | Wheel 1 | digital_in | corroborated | |
| OEM-A-19 | Ground | ground | T2I-C1-13 + T2I-C1-14 | Power Ground 1 + Power Ground 2 | ground | corroborated | |
| OEM-A-2 | Oxygen (lambda) sensor signal | lambda_nb_in | T2I-C1-22 | Analogue 2 | analog_in | corroborated | |
| OEM-A-21 | AFM signal | analog_in | T2I-C1-20 | Analogue 1 | analog_in | corroborated | |
| OEM-A-22 | Idle stabilizer valve coil 1 | low_side_out | T2I-C1-10 | PWM 2 | low_side_out | corroborated | |
| OEM-A-23 | Idle stabilizer valve coil 2 | low_side_out | T2I-C1-18 | PWM 3 | low_side_out | corroborated | |
| OEM-A-25 | Ignition timing signal to TCI | ignition_out | T2I-C1-3 | Coil 1 | ignition_out | corroborated | |
| OEM-A-3 | Fuel pump relay control | low_side_out | T2I-C1-1 | PWM 1 | low_side_out | corroborated | |
| OEM-A-4 | Knock sensor signal | knock_in | — | — | — | corroborated | |
| OEM-A-5 | Knock sensor return | sensor_ground | T2I-C1-28 + T2I-C1-29 | Sensor Ground + Sensor Ground | sensor_ground | corroborated | |
| OEM-A-6 | Sensor ground (CTS/Hall/AFM/throttle) | sensor_ground | T2I-C1-28 + T2I-C1-29 | Sensor Ground + Sensor Ground | sensor_ground | corroborated | |
| OEM-A-7 | Knock sensor shield | shield | — | — | — | corroborated | |
| OEM-A-8 | Hall sender supply (distributor) | power_in | — | — | — | corroborated | |
| OEM-A-9 | Intake air temperature sensor | temp_in | T2I-C1-32 | Thermistor 2 | temp_in | corroborated |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-A-14 | SP-14V-1 | 0.85 | no route | ECU power (control-unit relay) | — | |
| W2 | SP-14V-1 | T2I-C1-31 | 0.85 | no route | Ignition 12v In | — | |
| W3 | OEM-A-13 | SP-GND-1 | 0.85 | no route | Ground | — | |
| W4 | OEM-A-19 | SP-GND-1 | 0.85 | no route | Ground | — | |
| W5 | SP-GND-1 | T2I-C1-13 | 0.85 | no route | Power Ground 1 | — | |
| W6 | SP-GND-1 | T2I-C1-14 | 0.85 | no route | Power Ground 2 | — | |
| W7 | OEM-A-5 | SP-0V-1 | 0.5 | no route | Knock sensor return | — | |
| W8 | OEM-A-6 | SP-0V-1 | 0.5 | no route | Sensor ground (CTS/Hall/AFM/throttle) | — | |
| W9 | SP-0V-1 | T2I-C1-28 | 0.5 | no route | Sensor Ground | — | |
| W10 | SP-0V-1 | T2I-C1-29 | 0.5 | no route | Sensor Ground | — | |
| W11 | OEM-A-17 | T2I-C1-27 | 0.5 | no route | AFM potentiometer supply | — | |
| W12 | OEM-A-18 | T2I-C1-12 | 0.5 | no route | Hall sender signal (engine speed) | — | |
| W13 | OEM-A-25 | T2I-C1-3 | 0.5 | no route | Ignition timing signal to TCI | — | |
| W14 | OEM-A-3 | T2I-C1-1 | 0.5 | no route | Fuel pump relay control | — | |
| W15 | OEM-A-21 | T2I-C1-20 | 0.5 | no route | AFM signal | — | |
| W16 | OEM-A-10 | T2I-C1-24 | 0.5 | no route | Coolant temperature sensor | — | |
| W17 | OEM-A-22 | T2I-C1-10 | 0.5 | no route | Idle stabilizer valve coil 1 | — | |
| W18 | OEM-A-23 | T2I-C1-18 | 0.5 | no route | Idle stabilizer valve coil 2 | — | |
| W19 | OEM-A-2 | T2I-C1-22 | 0.5 | no route | Oxygen (lambda) sensor signal | — | |
| W20 | OEM-A-9 | T2I-C1-32 | 0.5 | no route | Intake air temperature sensor | — | |
| W21 | OEM-A-1 | T2I-C1-11 | 0.5 | no route | Starter signal (term 50) | — | |
| W22 | OEM-A-11 | T2I-C1-30 | 0.5 | no route | Idle/WOT throttle switch | — | |
| W23 | OEM-A-16 | T2I-C1-23 | 0.5 | no route | A/C compressor signal | — |
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 |
| terminal | 3-1447221-4 | TE | Superseal 1.0 socket terminal, 20 AWG (0.5 sq mm) | 18.000 | ea |
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 | PHYS_REQUIRED_OPEN | T2I-C1-21 | T2I-C1-21 "Permanent 12v" is required but not wired. |
| error | REQUIRED_UNMAPPED | OEM-A-12 | Required OEM function "Injector driver (batch, all 4)" (injector_out) is not connected to the new ECU. |
| error | REQUIRED_UNMAPPED | OEM-A-8 | Required OEM function "Hall sender supply (distributor)" (power_in) is not connected to the new ECU. |
| warn | DATASET_GAP | T2i C1 | 2 of 34 cavities on T2i C1 have no pin data (8,9). Anything there is invisible to these checks. |
| warn | NET_FAMILY | OEM-A-16 ↔ T2I-C1-23 | OEM-A-16 "A/C compressor signal" [digital_in] is wired to T2I-C1-23 "Analogue 3" [analog_in]. Analog and digital on one net. A switch on an analog input works with a pull-up and a threshold; an analog sensor on a digital input loses its value. |
| warn | NET_FAMILY | OEM-A-18 ↔ T2I-C1-12 | OEM-A-18 "Hall sender signal (engine speed)" [trigger_in] is wired to T2I-C1-12 "Wheel 1" [digital_in]. Hall-type cam/speed signals can use a digital input if it handles the frequency; VR signals cannot. |
| info | UNMAPPED | OEM | 2 optional OEM pins are not mapped: OEM-A-4 Knock sensor signal; OEM-A-7 Knock sensor shield |
Accepted (0)
| Code | Subject | Reason | By |
|---|
Notes
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 12: Injector driver (batch, all 4): no free injector output on DTAFast T2i - OEM-A 8: Hall sender supply (distributor): no rule for class sensor_supply_in; wire by hand - T2I-C1 21: Permanent 12v: required by DTAFast T2i but no stock pin feeds it; wire by hand Not wired: - OEM-A 4: Knock sensor signal: no free knock input on DTAFast T2i - OEM-A 7: Knock sensor shield: no shield pin on DTAFast T2i
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | vendor_doc | DTAFast T2i ECU wiring diagram | https://cdn.shopify.com/s/files/1/0848/7508/4108/files/T2i_Wiring-Diagram.pdf?v=1728571341 | — | — | — |
| 2 | community_copy | a2resource: Digifant II engine controller pinout (VW Golf/Jetta Mk2 1.8 8v) | http://www.a2resource.com/electrical/management/digifant2.html | — | — | — |
| 2 | community_copy | drive2.ru: VW Golf Mk2 PF Digifant II ECU pinout | https://www.drive2.ru/l/9886121 | — | — | — |