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VW Golf/Jetta Mk2 1.8 8v Digifant II → Emtron SL4 (auto)

VW Golf/Jetta Mk2 1.8 8v Digifant II — Emtron — SL4
⚠ 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 errors1: read the Findings page before cutting any wire
Size of the job28 wires · 7 connectors · 3 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-1SL4-A-340.85☐☐☐☐☐☐☐
W3SP-14V-1SL4-B-10.85☐☐☐☐☐☐☐
W4OEM-A-13SP-GND-10.85☐☐☐☐☐☐☐
W5OEM-A-19SP-GND-10.85☐☐☐☐☐☐☐
W6SP-GND-1SL4-B-180.85☐☐☐☐☐☐☐
W7SP-GND-1SL4-B-260.85☐☐☐☐☐☐☐
W8OEM-A-5SP-0V-10.5☐☐☐☐☐☐☐
W9OEM-A-6SP-0V-10.5☐☐☐☐☐☐☐
W10SP-0V-1SL4-B-100.5☐☐☐☐☐☐☐
W11OEM-A-17SL4-B-20.5☐☐☐☐☐☐☐
W12OEM-A-18SL4-B-70.5☐☐☐☐☐☐☐
W13SP-0V-1SL4-B-80.5☐☐☐☐☐☐☐
W14OEM-A-4SL4-B-160.5☐☐☐☐☐☐☐
W15OEM-A-25SL4-A-260.5☐☐☐☐☐☐☐
W16OEM-A-12SL4-A-10.5☐☐☐☐☐☐☐
W17OEM-A-7SP-SHD-10.5☐☐☐☐☐☐☐
W18SP-SHD-1SL4-B-90.5☐☐☐☐☐☐☐
W19OEM-A-3SL4-B-30.5☐☐☐☐☐☐☐
W20OEM-A-21SL4-B-110.5☐☐☐☐☐☐☐
W21OEM-A-10SL4-B-120.5☐☐☐☐☐☐☐
W22OEM-A-22SL4-A-140.5☐☐☐☐☐☐☐
W23OEM-A-23SL4-A-150.5☐☐☐☐☐☐☐
W24OEM-A-2SL4-B-130.5☐☐☐☐☐☐☐
W25OEM-A-9SL4-B-140.5☐☐☐☐☐☐☐
W26OEM-A-1SL4-A-200.5☐☐☐☐☐☐☐
W27OEM-A-11SL4-A-210.5☐☐☐☐☐☐☐
W28OEM-A-16SL4-A-220.5☐☐☐☐☐☐☐

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
1SL4-A-34SL4-B-10open (OL)+12 V supply must not touch sensor ground
2SL4-B-2SL4-B-10open (OL)5 V sensor reference must not touch sensor ground
3SL4-A-34SL4-B-2open (OL)+12 V supply must not touch 5 V sensor reference
4SL4-B-18SL4-A-34open (OL)power ground must not touch +12 V supply
5SL4-B-18SL4-B-2open (OL)power ground 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-ASL4-ASL4-BSP-0VSP-14VSP-GNDSP-SHD

Connectors

OEM-A

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Starter signal (term 50)—W26—0.5SL4-A-20———
10Coolant temperature sensor—W21—0.5SL4-B-12———
11Idle/WOT throttle switch—W27—0.5SL4-A-21———
12Injector driver (batch, all 4)—W16—0.5SL4-A-1———
13Ground—W4—0.85SP-GND-1———
14ECU power (control-unit relay)—W1—0.85SP-14V-1———
16A/C compressor signal—W28—0.5SL4-A-22———
17AFM potentiometer supply—W11—0.5SL4-B-2———
18Hall sender signal (engine speed)—W12—0.5SL4-B-7———
19Ground—W5—0.85SP-GND-1———
2Oxygen (lambda) sensor signal—W24—0.5SL4-B-13———
21AFM signal—W20—0.5SL4-B-11———
22Idle stabilizer valve coil 1—W22—0.5SL4-A-14———
23Idle stabilizer valve coil 2—W23—0.5SL4-A-15———
25Ignition timing signal to TCI—W15—0.5SL4-A-26———
3Fuel pump relay control—W19—0.5SL4-B-3———
4Knock sensor signal—W14—0.5SL4-B-16———
5Knock sensor return—W8—0.5SP-0V-1———
6Sensor ground (CTS/Hall/AFM/throttle)—W9—0.5SP-0V-1———
7Knock sensor shield—W17—0.5SP-SHD-1———
8Hall sender supply (distributor)————————
9Intake air temperature sensor—W25—0.5SL4-B-14———

SL4-A

Mating face
SL4-A-1 · Injection channel 11SL4-A-2 · Injection channel 22SL4-A-3 · Injection channel 33SL4-A-4 · Injection channel 44SL4-A-5 · NC5SL4-A-6 · NC6SL4-A-7 · NC7SL4-A-8 · NC8SL4-A-9 · Sensor supply 8V9SL4-A-10 · Auxiliary output 110SL4-A-11 · Auxiliary output 211SL4-A-12 · Auxiliary output 312SL4-A-13 · Auxiliary output 413SL4-A-14 · Auxiliary output 514SL4-A-15 · Auxiliary output 615SL4-A-16 · Auxiliary output 716SL4-A-17 · Auxiliary output 817SL4-A-18 · Auxiliary output 918SL4-A-19 · Auxiliary output 1019SL4-A-20 · Digital input 120SL4-A-21 · Digital input 221SL4-A-22 · Digital input 322SL4-A-23 · Digital input 423SL4-A-24 · Digital input 524SL4-A-25 · Digital input 625SL4-A-26 · Ignition channel 126SL4-A-27 · Ignition channel 227SL4-A-28 · Ignition channel 328SL4-A-29 · Ignition channel 429SL4-A-30 · NC30SL4-A-31 · NC31SL4-A-32 · NC32SL4-A-33 · NC33SL4-A-34 · Aux 9–10 14V supply34
Wire side
SL4-A-1 · Injection channel 11SL4-A-2 · Injection channel 22SL4-A-3 · Injection channel 33SL4-A-4 · Injection channel 44SL4-A-5 · NC5SL4-A-6 · NC6SL4-A-7 · NC7SL4-A-8 · NC8SL4-A-9 · Sensor supply 8V9SL4-A-10 · Auxiliary output 110SL4-A-11 · Auxiliary output 211SL4-A-12 · Auxiliary output 312SL4-A-13 · Auxiliary output 413SL4-A-14 · Auxiliary output 514SL4-A-15 · Auxiliary output 615SL4-A-16 · Auxiliary output 716SL4-A-17 · Auxiliary output 817SL4-A-18 · Auxiliary output 918SL4-A-19 · Auxiliary output 1019SL4-A-20 · Digital input 120SL4-A-21 · Digital input 221SL4-A-22 · Digital input 322SL4-A-23 · Digital input 423SL4-A-24 · Digital input 524SL4-A-25 · Digital input 625SL4-A-26 · Ignition channel 126SL4-A-27 · Ignition channel 227SL4-A-28 · Ignition channel 328SL4-A-29 · Ignition channel 429SL4-A-30 · NC30SL4-A-31 · NC31SL4-A-32 · NC32SL4-A-33 · NC33SL4-A-34 · Aux 9–10 14V supply34
CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Injection channel 1—W16—0.5OEM-A-12———
2Injection channel 2————————
3Injection channel 3————————
4Injection channel 4————————
5NC————————
6NC————————
7NC————————
8NC————————
9Sensor supply 8V————————
10Auxiliary output 1————————
11Auxiliary output 2————————
12Auxiliary output 3————————
13Auxiliary output 4————————
14Auxiliary output 5—W22—0.5OEM-A-22———
15Auxiliary output 6—W23—0.5OEM-A-23———
16Auxiliary output 7————————
17Auxiliary output 8————————
18Auxiliary output 9————————
19Auxiliary output 10————————
20Digital input 1—W26—0.5OEM-A-1———
21Digital input 2—W27—0.5OEM-A-11———
22Digital input 3—W28—0.5OEM-A-16———
23Digital input 4————————
24Digital input 5————————
25Digital input 6————————
26Ignition channel 1—W15—0.5OEM-A-25———
27Ignition channel 2————————
28Ignition channel 3————————
29Ignition channel 4————————
30NC————————
31NC————————
32NC————————
33NC————————
34Aux 9–10 14V supply—W2—0.85SP-14V-1———

SL4-B

Mating face
SL4-B-1 · ECU 14V supply1SL4-B-2 · Sensor supply Vref1 5.0V2SL4-B-3 · EFI relay output (low side, 200 mA)3SL4-B-4 · Ignition switch input4SL4-B-5 · Crank index sensor +5SL4-B-6 · Crank index sensor −6SL4-B-7 · Sync sensor +7SL4-B-8 · Sync sensor −8SL4-B-9 · Shield (crank/sync/knock)9SL4-B-10 · Analog sensor 0V reference10SL4-B-11 · Analog input 111SL4-B-12 · Analog input 212SL4-B-13 · Analog input 313SL4-B-14 · Analog input 414SL4-B-15 · Analog input 515SL4-B-16 · Knock 1 +16SL4-B-17 · Knock 1 −17SL4-B-18 · ECU ground18SL4-B-19 · Analog input 619SL4-B-20 · Analog input 7 (switchable 1k pull-up)20SL4-B-21 · Analog input 8 (switchable 1k pull-up)21SL4-B-22 · Analog input 9 (switchable 1k pull-up)22SL4-B-23 · Analog input 10 (switchable 1k pull-up)23SL4-B-24 · Knock 2 +24SL4-B-25 · Knock 2 −25SL4-B-26 · ECU ground26SL4-B-27 · CAN 1 H27SL4-B-28 · CAN 1 L28SL4-B-29 · NC29SL4-B-30 · NC30SL4-B-31 · Ethernet Tx +31SL4-B-32 · Ethernet Tx −32SL4-B-33 · Ethernet Rx +33SL4-B-34 · Ethernet Rx −34
Wire side
SL4-B-1 · ECU 14V supply1SL4-B-2 · Sensor supply Vref1 5.0V2SL4-B-3 · EFI relay output (low side, 200 mA)3SL4-B-4 · Ignition switch input4SL4-B-5 · Crank index sensor +5SL4-B-6 · Crank index sensor −6SL4-B-7 · Sync sensor +7SL4-B-8 · Sync sensor −8SL4-B-9 · Shield (crank/sync/knock)9SL4-B-10 · Analog sensor 0V reference10SL4-B-11 · Analog input 111SL4-B-12 · Analog input 212SL4-B-13 · Analog input 313SL4-B-14 · Analog input 414SL4-B-15 · Analog input 515SL4-B-16 · Knock 1 +16SL4-B-17 · Knock 1 −17SL4-B-18 · ECU ground18SL4-B-19 · Analog input 619SL4-B-20 · Analog input 7 (switchable 1k pull-up)20SL4-B-21 · Analog input 8 (switchable 1k pull-up)21SL4-B-22 · Analog input 9 (switchable 1k pull-up)22SL4-B-23 · Analog input 10 (switchable 1k pull-up)23SL4-B-24 · Knock 2 +24SL4-B-25 · Knock 2 −25SL4-B-26 · ECU ground26SL4-B-27 · CAN 1 H27SL4-B-28 · CAN 1 L28SL4-B-29 · NC29SL4-B-30 · NC30SL4-B-31 · Ethernet Tx +31SL4-B-32 · Ethernet Tx −32SL4-B-33 · Ethernet Rx +33SL4-B-34 · Ethernet Rx −34
CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1ECU 14V supply—W3—0.85SP-14V-1———
2Sensor supply Vref1 5.0V—W11—0.5OEM-A-17———
3EFI relay output (low side, 200 mA)—W19—0.5OEM-A-3———
4Ignition switch input————————
5Crank index sensor +————————
6Crank index sensor −————————
7Sync sensor +—W12—0.5OEM-A-18———
8Sync sensor −—W13—0.5SP-0V-1———
9Shield (crank/sync/knock)—W18—0.5SP-SHD-1———
10Analog sensor 0V reference—W10—0.5SP-0V-1———
11Analog input 1—W20—0.5OEM-A-21———
12Analog input 2—W21—0.5OEM-A-10———
13Analog input 3—W24—0.5OEM-A-2———
14Analog input 4—W25—0.5OEM-A-9———
15Analog input 5————————
16Knock 1 +—W14—0.5OEM-A-4———
17Knock 1 −————————
18ECU ground—W6—0.85SP-GND-1———
19Analog input 6————————
20Analog input 7 (switchable 1k pull-up)————————
21Analog input 8 (switchable 1k pull-up)————————
22Analog input 9 (switchable 1k pull-up)————————
23Analog input 10 (switchable 1k pull-up)————————
24Knock 2 +————————
25Knock 2 −————————
26ECU ground—W7—0.85SP-GND-1———
27CAN 1 H————————
28CAN 1 L————————
29NC————————
30NC————————
31Ethernet Tx +————————
32Ethernet Tx −————————
33Ethernet Rx +————————
34Ethernet Rx −————————

SP-0V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W13—0.5SL4-B-8———
1——W8—0.5OEM-A-5———
1——W9—0.5OEM-A-6———
1——W10—0.5SL4-B-10———

SP-14V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W1—0.85OEM-A-14———
1——W2—0.85SL4-A-34———
1——W3—0.85SL4-B-1———

SP-GND

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W4—0.85OEM-A-13———
1——W5—0.85OEM-A-19———
1——W6—0.85SL4-B-18———
1——W7—0.85SL4-B-26———

SP-SHD

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W17—0.5OEM-A-7———
1——W18—0.5SL4-B-9———

Pin map

OEM pointOEM functionOEM familyTarget pointTarget functionTarget familyWire colourEvidence
OEM-A-1Starter signal (term 50)digital_inSL4-A-20Digital input 1digital_incorroborated
OEM-A-10Coolant temperature sensortemp_inSL4-B-12Analog input 2analog_incorroborated
OEM-A-11Idle/WOT throttle switchdigital_inSL4-A-21Digital input 2digital_incorroborated
OEM-A-12Injector driver (batch, all 4)injector_outSL4-A-1Injection channel 1injector_outcorroborated
OEM-A-13GroundgroundSL4-B-18 + SL4-B-26ECU ground + ECU groundgroundcorroborated
OEM-A-14ECU power (control-unit relay)power_inSL4-A-34 + SL4-B-1Aux 9–10 14V supply + ECU 14V supplypower_incorroborated
OEM-A-16A/C compressor signaldigital_inSL4-A-22Digital input 3digital_incorroborated
OEM-A-17AFM potentiometer supplyvrefSL4-B-2Sensor supply Vref1 5.0Vvrefcorroborated
OEM-A-18Hall sender signal (engine speed)trigger_inSL4-B-7Sync sensor +trigger_incorroborated
OEM-A-19GroundgroundSL4-B-18 + SL4-B-26ECU ground + ECU groundgroundcorroborated
OEM-A-2Oxygen (lambda) sensor signallambda_nb_inSL4-B-13Analog input 3analog_incorroborated
OEM-A-21AFM signalanalog_inSL4-B-11Analog input 1analog_incorroborated
OEM-A-22Idle stabilizer valve coil 1low_side_outSL4-A-14Auxiliary output 5switch_outcorroborated
OEM-A-23Idle stabilizer valve coil 2low_side_outSL4-A-15Auxiliary output 6switch_outcorroborated
OEM-A-25Ignition timing signal to TCIignition_outSL4-A-26Ignition channel 1ignition_outcorroborated
OEM-A-3Fuel pump relay controllow_side_outSL4-B-3EFI relay output (low side, 200 mA)low_side_outcorroborated
OEM-A-4Knock sensor signalknock_inSL4-B-16Knock 1 +knock_incorroborated
OEM-A-5Knock sensor returnsensor_groundSL4-B-10 + SL4-B-8Analog sensor 0V reference + Sync sensor −sensor_ground + trigger_incorroborated
OEM-A-6Sensor ground (CTS/Hall/AFM/throttle)sensor_groundSL4-B-10 + SL4-B-8Analog sensor 0V reference + Sync sensor −sensor_ground + trigger_incorroborated
OEM-A-7Knock sensor shieldshieldSL4-B-9Shield (crank/sync/knock)shieldcorroborated
OEM-A-8Hall sender supply (distributor)power_in———corroborated
OEM-A-9Intake air temperature sensortemp_inSL4-B-14Analog input 4analog_incorroborated

Cut list

WireFromToGauge (mm²)ColourLengthSignalIdent
W1OEM-A-14SP-14V-10.85no routeECU power (control-unit relay)—
W2SP-14V-1SL4-A-340.85no routeAux 9–10 14V supply—
W3SP-14V-1SL4-B-10.85no routeECU 14V supply—
W4OEM-A-13SP-GND-10.85no routeGround—
W5OEM-A-19SP-GND-10.85no routeGround—
W6SP-GND-1SL4-B-180.85no routeECU ground—
W7SP-GND-1SL4-B-260.85no routeECU ground—
W8OEM-A-5SP-0V-10.5no routeKnock sensor return—
W9OEM-A-6SP-0V-10.5no routeSensor ground (CTS/Hall/AFM/throttle)—
W10SP-0V-1SL4-B-100.5no routeAnalog sensor 0V reference—
W11OEM-A-17SL4-B-20.5no routeAFM potentiometer supply—
W12OEM-A-18SL4-B-70.5no routeHall sender signal (engine speed)—
W13SP-0V-1SL4-B-80.5no routeSync sensor −—
W14OEM-A-4SL4-B-160.5no routeKnock sensor signal—
W15OEM-A-25SL4-A-260.5no routeIgnition timing signal to TCI—
W16OEM-A-12SL4-A-10.5no routeInjector driver (batch, all 4)—
W17OEM-A-7SP-SHD-10.5no routeKnock sensor shield—
W18SP-SHD-1SL4-B-90.5no routeShield (crank/sync/knock)—
W19OEM-A-3SL4-B-30.5no routeFuel pump relay control—
W20OEM-A-21SL4-B-110.5no routeAFM signal—
W21OEM-A-10SL4-B-120.5no routeCoolant temperature sensor—
W22OEM-A-22SL4-A-140.5no routeIdle stabilizer valve coil 1—
W23OEM-A-23SL4-A-150.5no routeIdle stabilizer valve coil 2—
W24OEM-A-2SL4-B-130.5no routeOxygen (lambda) sensor signal—
W25OEM-A-9SL4-B-140.5no routeIntake air temperature sensor—
W26OEM-A-1SL4-A-200.5no routeStarter signal (term 50)—
W27OEM-A-11SL4-A-210.5no routeIdle/WOT throttle switch—
W28OEM-A-16SL4-A-220.5no routeA/C compressor signal—

Bill of materials

CategoryPart numberManufacturerDescriptionQtyUnit
connector4-1437290-0TESuperseal 1.0 34-way plug, Key 11.000ea
connector4-1437290-1TESuperseal 1.0 34-way plug, Key 21.000ea
terminal3-1447221-4TESuperseal 1.0 socket terminal, 20 AWG (0.5 sq mm)22.000ea

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (6)

SeverityCodeSubjectMessage
errorREQUIRED_UNMAPPEDOEM-A-8Required OEM function "Hall sender supply (distributor)" (power_in) is not connected to the new ECU.
infoNET_FAMILYOEM-A-10 ↔ SL4-B-12OEM-A-10 "Coolant temperature sensor" [temp_in] is wired to SL4-B-12 "Analog input 2" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one.
infoNET_FAMILYOEM-A-22 ↔ SL4-A-14OEM-A-22 "Idle stabilizer valve coil 1" [low_side_out] is wired to SL4-A-14 "Auxiliary output 5" [switch_out]. Configure this output as low side.
infoNET_FAMILYOEM-A-23 ↔ SL4-A-15OEM-A-23 "Idle stabilizer valve coil 2" [low_side_out] is wired to SL4-A-15 "Auxiliary output 6" [switch_out]. Configure this output as low side.
infoNET_FAMILYOEM-A-5 ↔ SL4-B-8OEM-A-5 "Knock sensor return" [sensor_ground] is wired to SL4-B-8 "Sync sensor −" [trigger_in]. Trigger return tied to sensor/trigger ground: correct for single-ended trigger inputs.
infoNET_FAMILYOEM-A-9 ↔ SL4-B-14OEM-A-9 "Intake air temperature sensor" [temp_in] is wired to SL4-B-14 "Analog input 4" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one.

Accepted (0)

CodeSubjectReasonBy

Notes

Fit check: unconfirmed. Confirm these before building: - Trigger pattern for VW Digifant not found in the ECU's docs (No VW/Audi decoder anywhere in the mode list.) 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 Not wired: - SL4-B 17: Knock 1 − left open: the stock knock sensor has one ECU wire; check the ECU manual for single-wire knock sensors - SL4-B 4: Ignition switch input: not fed (the stock ECU has no ignition-sense pin); feed it from a switched-ignition source

Sources

ReliabilityKindTitleURLArchiveCapturedSHA-256
4vendor_docEmtron SL4/SL6/SL8 ECU datasheetshttps://docs.emtronaustralia.com.au/engine-management/datasheets/index.htmlarchive2026-10-051e22846cec94
4vendor_docEmtron SL4/SL6/SL8 pinout pageshttps://docs.emtronaustralia.com.au/engine-management/wiring/index.htmlarchive2026-10-05e52b3da9996a
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———