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VW Golf/Jetta Mk2 1.8 8v Digifant II → DTAFast T4+ (auto)

VW Golf/Jetta Mk2 1.8 8v Digifant II — DTAFast — T4+
⚠ 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.

Statusdraft · not yet verified: nobody has reported building and running this harness
Open errors3: read the Findings page before cutting any wire
Size of the job24 wires · 7 connectors · 2 part lines
ToolsCrimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink
Terminals3-1447221-4
Order of work1. 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.

WireFromToGaugeColourCutLabelCrimp ACrimp BPin APin BContinuity
W1OEM-A-14SP-14V-10.85☐☐☐☐☐☐☐
W2SP-14V-1T4-C1-310.85☐☐☐☐☐☐☐
W3OEM-A-13SP-GND-10.85☐☐☐☐☐☐☐
W4OEM-A-19SP-GND-10.85☐☐☐☐☐☐☐
W5SP-GND-1T4-C1-130.85☐☐☐☐☐☐☐
W6SP-GND-1T4-C1-140.85☐☐☐☐☐☐☐
W7OEM-A-5SP-0V-10.5☐☐☐☐☐☐☐
W8OEM-A-6SP-0V-10.5☐☐☐☐☐☐☐
W9SP-0V-1T4-C2-210.5☐☐☐☐☐☐☐
W10SP-0V-1T4-C2-330.5☐☐☐☐☐☐☐
W11OEM-A-17T4-C2-240.5☐☐☐☐☐☐☐
W12OEM-A-18T4-C2-220.5☐☐☐☐☐☐☐
W13OEM-A-25T4-C1-100.5☐☐☐☐☐☐☐
W14OEM-A-12T4-C1-90.5☐☐☐☐☐☐☐
W15OEM-A-3T4-C1-50.5☐☐☐☐☐☐☐
W16OEM-A-21T4-C2-100.5☐☐☐☐☐☐☐
W17OEM-A-10T4-C2-70.5☐☐☐☐☐☐☐
W18OEM-A-22T4-C1-40.5☐☐☐☐☐☐☐
W19OEM-A-23T4-C1-30.5☐☐☐☐☐☐☐
W20OEM-A-2T4-C2-10.5☐☐☐☐☐☐☐
W21OEM-A-9T4-C2-250.5☐☐☐☐☐☐☐
W22OEM-A-1T4-C2-40.5☐☐☐☐☐☐☐
W23OEM-A-11T4-C2-140.5☐☐☐☐☐☐☐
W24OEM-A-16T4-C2-150.5☐☐☐☐☐☐☐

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 AProbe BExpectWhyReading
1T4-C1-31T4-C2-21open (OL)+12 V supply must not touch sensor ground
2T4-C2-24T4-C2-21open (OL)5 V sensor reference must not touch sensor ground
3T4-C1-13T4-C1-31open (OL)power ground must not touch +12 V supply
4T4-C1-13T4-C2-24open (OL)power ground must not touch 5 V sensor reference
5T4-C1-31T4-C2-24open (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

RevLabelByDate
No revisions yet.

Schematic

OEM-ASP-0VSP-14VSP-GNDT4-C1T4-C2T4-C3

Connectors

OEM-A

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Starter signal (term 50)—W22—0.5T4-C2-4———
10Coolant temperature sensor—W17—0.5T4-C2-7———
11Idle/WOT throttle switch—W23—0.5T4-C2-14———
12Injector driver (batch, all 4)—W14—0.5T4-C1-9———
13Ground—W3—0.85SP-GND-1———
14ECU power (control-unit relay)—W1—0.85SP-14V-1———
16A/C compressor signal—W24—0.5T4-C2-15———
17AFM potentiometer supply—W11—0.5T4-C2-24———
18Hall sender signal (engine speed)—W12—0.5T4-C2-22———
19Ground—W4—0.85SP-GND-1———
2Oxygen (lambda) sensor signal—W20—0.5T4-C2-1———
21AFM signal—W16—0.5T4-C2-10———
22Idle stabilizer valve coil 1—W18—0.5T4-C1-4———
23Idle stabilizer valve coil 2—W19—0.5T4-C1-3———
25Ignition timing signal to TCI—W13—0.5T4-C1-10———
3Fuel pump relay control—W15—0.5T4-C1-5———
4Knock sensor signal————————
5Knock sensor return—W7—0.5SP-0V-1———
6Sensor ground (CTS/Hall/AFM/throttle)—W8—0.5SP-0V-1———
7Knock sensor shield————————
8Hall sender supply (distributor)————————
9Intake air temperature sensor—W21—0.5T4-C2-25———

SP-0V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W7—0.5OEM-A-5———
1——W8—0.5OEM-A-6———
1——W9—0.5T4-C2-21———
1——W10—0.5T4-C2-33———

SP-14V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W1—0.85OEM-A-14———
1——W2—0.85T4-C1-31———

SP-GND

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W3—0.85OEM-A-13———
1——W4—0.85OEM-A-19———
1——W5—0.85T4-C1-13———
1——W6—0.85T4-C1-14———

T4-C1

Mating face
T4-C1-1 · Coil 31T4-C1-22T4-C1-3 · PWM 33T4-C1-4 · PWM 24T4-C1-5 · PWM 15T4-C1-6 · Motor 1 +6T4-C1-7 · Motor 1 -7T4-C1-88T4-C1-9 · Injector 19T4-C1-10 · Coil 110T4-C1-1111T4-C1-1212T4-C1-13 · Power Ground 113T4-C1-14 · Power Ground 214T4-C1-1515T4-C1-1616T4-C1-17 · Injector 217T4-C1-18 · Coil 218T4-C1-1919T4-C1-2020T4-C1-2121T4-C1-2222T4-C1-2323T4-C1-2424T4-C1-25 · Injector 425T4-C1-26 · Coil 426T4-C1-2727T4-C1-2828T4-C1-2929T4-C1-3030T4-C1-31 · Ignition 12v In31T4-C1-3232T4-C1-3333T4-C1-34 · Injector 334
Wire side
T4-C1-1 · Coil 31T4-C1-22T4-C1-3 · PWM 33T4-C1-4 · PWM 24T4-C1-5 · PWM 15T4-C1-6 · Motor 1 +6T4-C1-7 · Motor 1 -7T4-C1-88T4-C1-9 · Injector 19T4-C1-10 · Coil 110T4-C1-1111T4-C1-1212T4-C1-13 · Power Ground 113T4-C1-14 · Power Ground 214T4-C1-1515T4-C1-1616T4-C1-17 · Injector 217T4-C1-18 · Coil 218T4-C1-1919T4-C1-2020T4-C1-2121T4-C1-2222T4-C1-2323T4-C1-2424T4-C1-25 · Injector 425T4-C1-26 · Coil 426T4-C1-2727T4-C1-2828T4-C1-2929T4-C1-3030T4-C1-31 · Ignition 12v In31T4-C1-3232T4-C1-3333T4-C1-34 · Injector 334
CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Coil 3————————
2—————————
3PWM 3—W19—0.5OEM-A-23———
4PWM 2—W18—0.5OEM-A-22———
5PWM 1—W15—0.5OEM-A-3———
6Motor 1 +————————
7Motor 1 -————————
8—————————
9Injector 1—W14—0.5OEM-A-12———
10Coil 1—W13—0.5OEM-A-25———
11—————————
12—————————
13Power Ground 1—W5—0.85SP-GND-1———
14Power Ground 2—W6—0.85SP-GND-1———
15—————————
16—————————
17Injector 2————————
18Coil 2————————
19—————————
20—————————
21—————————
22—————————
23—————————
24—————————
25Injector 4————————
26Coil 4————————
27—————————
28—————————
29—————————
30—————————
31Ignition 12v In—W2—0.85SP-14V-1———
32—————————
33—————————
34Injector 3————————

T4-C2

Mating face
T4-C2-1 · Analogue 21T4-C2-2 · Wheel 12T4-C2-3 · Analogue 103T4-C2-4 · Digital 14T4-C2-5 · Analogue 35T4-C2-6 · Analogue 46T4-C2-7 · Thermistor 17T4-C2-88T4-C2-9 · 5v Output9T4-C2-10 · Analogue 110T4-C2-1111T4-C2-12 · Crank12T4-C2-1313T4-C2-14 · Digital 414T4-C2-15 · Digital 515T4-C2-16 · Analogue 1116T4-C2-17 · Thermistor 317T4-C2-1818T4-C2-19 · Analogue 619T4-C2-2020T4-C2-21 · Sensor Ground21T4-C2-22 · Cam 122T4-C2-2323T4-C2-24 · 5v Output24T4-C2-25 · Thermistor 225T4-C2-26 · CAN High26T4-C2-2727T4-C2-28 · CAN Low28T4-C2-2929T4-C2-3030T4-C2-3131T4-C2-3232T4-C2-33 · Sensor Ground33T4-C2-34 · Analogue 934
Wire side
T4-C2-1 · Analogue 21T4-C2-2 · Wheel 12T4-C2-3 · Analogue 103T4-C2-4 · Digital 14T4-C2-5 · Analogue 35T4-C2-6 · Analogue 46T4-C2-7 · Thermistor 17T4-C2-88T4-C2-9 · 5v Output9T4-C2-10 · Analogue 110T4-C2-1111T4-C2-12 · Crank12T4-C2-1313T4-C2-14 · Digital 414T4-C2-15 · Digital 515T4-C2-16 · Analogue 1116T4-C2-17 · Thermistor 317T4-C2-1818T4-C2-19 · Analogue 619T4-C2-2020T4-C2-21 · Sensor Ground21T4-C2-22 · Cam 122T4-C2-2323T4-C2-24 · 5v Output24T4-C2-25 · Thermistor 225T4-C2-26 · CAN High26T4-C2-2727T4-C2-28 · CAN Low28T4-C2-2929T4-C2-3030T4-C2-3131T4-C2-3232T4-C2-33 · Sensor Ground33T4-C2-34 · Analogue 934
CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Analogue 2—W20—0.5OEM-A-2———
2Wheel 1————————
3Analogue 10————————
4Digital 1—W22—0.5OEM-A-1———
5Analogue 3————————
6Analogue 4————————
7Thermistor 1—W17—0.5OEM-A-10———
8—————————
95v Output————————
10Analogue 1—W16—0.5OEM-A-21———
11—————————
12Crank————————
13—————————
14Digital 4—W23—0.5OEM-A-11———
15Digital 5—W24—0.5OEM-A-16———
16Analogue 11————————
17Thermistor 3————————
18—————————
19Analogue 6————————
20—————————
21Sensor Ground—W9—0.5SP-0V-1———
22Cam 1—W12—0.5OEM-A-18———
23—————————
245v Output—W11—0.5OEM-A-17———
25Thermistor 2—W21—0.5OEM-A-9———
26CAN High————————
27—————————
28CAN Low————————
29—————————
30—————————
31—————————
32—————————
33Sensor Ground—W10—0.5SP-0V-1———
34Analogue 9————————

T4-C3

Mating face
T4-C3-11T4-C3-22T4-C3-33T4-C3-44T4-C3-55T4-C3-66T4-C3-7 · Lambda 1 Pump Current7T4-C3-8 · Lambda 1 VGND8T4-C3-9 · Lambda 1 Heater Negative9T4-C3-10 · PWM 810T4-C3-11 · Lambda 1 Trim Resistor11T4-C3-12 · Lambda 1 Nernst Voltage12T4-C3-1313T4-C3-1414T4-C3-1515T4-C3-1616T4-C3-17 · Analogue 717T4-C3-18 · Analogue 818T4-C3-1919T4-C3-2020T4-C3-2121T4-C3-22 · PWM 422T4-C3-23 · PWM 523T4-C3-24 · PWM 624T4-C3-25 · PWM 725T4-C3-26 · Permanent 12v26T4-C3-27 · Permanent 12v27T4-C3-2828T4-C3-2929T4-C3-3030T4-C3-3131T4-C3-3232T4-C3-3333T4-C3-3434
Wire side
T4-C3-11T4-C3-22T4-C3-33T4-C3-44T4-C3-55T4-C3-66T4-C3-7 · Lambda 1 Pump Current7T4-C3-8 · Lambda 1 VGND8T4-C3-9 · Lambda 1 Heater Negative9T4-C3-10 · PWM 810T4-C3-11 · Lambda 1 Trim Resistor11T4-C3-12 · Lambda 1 Nernst Voltage12T4-C3-1313T4-C3-1414T4-C3-1515T4-C3-1616T4-C3-17 · Analogue 717T4-C3-18 · Analogue 818T4-C3-1919T4-C3-2020T4-C3-2121T4-C3-22 · PWM 422T4-C3-23 · PWM 523T4-C3-24 · PWM 624T4-C3-25 · PWM 725T4-C3-26 · Permanent 12v26T4-C3-27 · Permanent 12v27T4-C3-2828T4-C3-2929T4-C3-3030T4-C3-3131T4-C3-3232T4-C3-3333T4-C3-3434
CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1—————————
2—————————
3—————————
4—————————
5—————————
6—————————
7Lambda 1 Pump Current————————
8Lambda 1 VGND————————
9Lambda 1 Heater Negative————————
10PWM 8————————
11Lambda 1 Trim Resistor————————
12Lambda 1 Nernst Voltage————————
13—————————
14—————————
15—————————
16—————————
17Analogue 7————————
18Analogue 8————————
19—————————
20—————————
21—————————
22PWM 4————————
23PWM 5————————
24PWM 6————————
25PWM 7————————
26Permanent 12v————————
27Permanent 12v————————
28—————————
29—————————
30—————————
31—————————
32—————————
33—————————
34—————————

Pin map

OEM pointOEM functionOEM familyTarget pointTarget functionTarget familyWire colourEvidence
OEM-A-1Starter signal (term 50)digital_inT4-C2-4Digital 1digital_incorroborated
OEM-A-10Coolant temperature sensortemp_inT4-C2-7Thermistor 1temp_incorroborated
OEM-A-11Idle/WOT throttle switchdigital_inT4-C2-14Digital 4digital_incorroborated
OEM-A-12Injector driver (batch, all 4)injector_outT4-C1-9Injector 1injector_outcorroborated
OEM-A-13GroundgroundT4-C1-13 + T4-C1-14Power Ground 1 + Power Ground 2groundcorroborated
OEM-A-14ECU power (control-unit relay)power_inT4-C1-31Ignition 12v Inpower_incorroborated
OEM-A-16A/C compressor signaldigital_inT4-C2-15Digital 5digital_incorroborated
OEM-A-17AFM potentiometer supplyvrefT4-C2-245v Outputvrefcorroborated
OEM-A-18Hall sender signal (engine speed)trigger_inT4-C2-22Cam 1trigger_incorroborated
OEM-A-19GroundgroundT4-C1-13 + T4-C1-14Power Ground 1 + Power Ground 2groundcorroborated
OEM-A-2Oxygen (lambda) sensor signallambda_nb_inT4-C2-1Analogue 2analog_incorroborated
OEM-A-21AFM signalanalog_inT4-C2-10Analogue 1analog_incorroborated
OEM-A-22Idle stabilizer valve coil 1low_side_outT4-C1-4PWM 2low_side_outcorroborated
OEM-A-23Idle stabilizer valve coil 2low_side_outT4-C1-3PWM 3low_side_outcorroborated
OEM-A-25Ignition timing signal to TCIignition_outT4-C1-10Coil 1ignition_outcorroborated
OEM-A-3Fuel pump relay controllow_side_outT4-C1-5PWM 1low_side_outcorroborated
OEM-A-4Knock sensor signalknock_in———corroborated
OEM-A-5Knock sensor returnsensor_groundT4-C2-21 + T4-C2-33Sensor Ground + Sensor Groundsensor_groundcorroborated
OEM-A-6Sensor ground (CTS/Hall/AFM/throttle)sensor_groundT4-C2-21 + T4-C2-33Sensor Ground + Sensor Groundsensor_groundcorroborated
OEM-A-7Knock sensor shieldshield———corroborated
OEM-A-8Hall sender supply (distributor)power_in———corroborated
OEM-A-9Intake air temperature sensortemp_inT4-C2-25Thermistor 2temp_incorroborated

Cut list

WireFromToGauge (mm²)ColourLengthSignalIdent
W1OEM-A-14SP-14V-10.85no routeECU power (control-unit relay)—
W2SP-14V-1T4-C1-310.85no routeIgnition 12v In—
W3OEM-A-13SP-GND-10.85no routeGround—
W4OEM-A-19SP-GND-10.85no routeGround—
W5SP-GND-1T4-C1-130.85no routePower Ground 1—
W6SP-GND-1T4-C1-140.85no routePower Ground 2—
W7OEM-A-5SP-0V-10.5no routeKnock sensor return—
W8OEM-A-6SP-0V-10.5no routeSensor ground (CTS/Hall/AFM/throttle)—
W9SP-0V-1T4-C2-210.5no routeSensor Ground—
W10SP-0V-1T4-C2-330.5no routeSensor Ground—
W11OEM-A-17T4-C2-240.5no routeAFM potentiometer supply—
W12OEM-A-18T4-C2-220.5no routeHall sender signal (engine speed)—
W13OEM-A-25T4-C1-100.5no routeIgnition timing signal to TCI—
W14OEM-A-12T4-C1-90.5no routeInjector driver (batch, all 4)—
W15OEM-A-3T4-C1-50.5no routeFuel pump relay control—
W16OEM-A-21T4-C2-100.5no routeAFM signal—
W17OEM-A-10T4-C2-70.5no routeCoolant temperature sensor—
W18OEM-A-22T4-C1-40.5no routeIdle stabilizer valve coil 1—
W19OEM-A-23T4-C1-30.5no routeIdle stabilizer valve coil 2—
W20OEM-A-2T4-C2-10.5no routeOxygen (lambda) sensor signal—
W21OEM-A-9T4-C2-250.5no routeIntake air temperature sensor—
W22OEM-A-1T4-C2-40.5no routeStarter signal (term 50)—
W23OEM-A-11T4-C2-140.5no routeIdle/WOT throttle switch—
W24OEM-A-16T4-C2-150.5no routeA/C compressor signal—

Bill of materials

CategoryPart numberManufacturerDescriptionQtyUnit
connector4-1437290-0TESuperseal 1.0 34-way plug, Key 13.000ea
terminal3-1447221-4TESuperseal 1.0 socket terminal, 20 AWG (0.5 sq mm)19.000ea

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (7)

SeverityCodeSubjectMessage
errorPHYS_REQUIRED_OPENT4-C3-26T4-C3-26 "Permanent 12v" is required but not wired.
errorPHYS_REQUIRED_OPENT4-C3-27T4-C3-27 "Permanent 12v" is required but not wired.
errorREQUIRED_UNMAPPEDOEM-A-8Required OEM function "Hall sender supply (distributor)" (power_in) is not connected to the new ECU.
warnDATASET_GAPT4+ C118 of 34 cavities on T4+ C1 have no pin data (2,8,11,12,15,16,19,20,21,22,23,24,27,28,29,30,32,33). Anything there is invisible to these checks.
warnDATASET_GAPT4+ C211 of 34 cavities on T4+ C2 have no pin data (8,11,13,18,20,23,27,29,30,31,32). Anything there is invisible to these checks.
warnDATASET_GAPT4+ C320 of 34 cavities on T4+ C3 have no pin data (1,2,3,4,5,6,13,14,15,16,19,20,21,28,29,30,31,32,33,34). Anything there is invisible to these checks.
infoUNMAPPEDOEM2 optional OEM pins are not mapped: OEM-A-4 Knock sensor signal; OEM-A-7 Knock sensor shield

Accepted (0)

CodeSubjectReasonBy

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 8: Hall sender supply (distributor): no rule for class sensor_supply_in; wire by hand - T4-C3 26: Permanent 12v: required by DTAFast T4+ but no stock pin feeds it; wire by hand - T4-C3 27: Permanent 12v: required by DTAFast T4+ but no stock pin feeds it; wire by hand Not wired: - OEM-A 4: Knock sensor signal: no free knock input on DTAFast T4+ - OEM-A 7: Knock sensor shield: no shield pin on DTAFast T4+

Sources

ReliabilityKindTitleURLArchiveCapturedSHA-256
4vendor_docDTAFast T4+ ECU wiring diagramhttps://cdn.shopify.com/s/files/1/0848/7508/4108/files/T4PLUS_Wiring_Diagram.pdf?v=1789412534———
2community_copya2resource: Digifant II engine controller pinout (VW Golf/Jetta Mk2 1.8 8v)http://www.a2resource.com/electrical/management/digifant2.html———
2community_copydrive2.ru: VW Golf Mk2 PF Digifant II ECU pinouthttps://www.drive2.ru/l/9886121———