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VW Golf Mk4 1.8T 20v (AUM, Bosch ME7.5) DBW → MaxxECU MaxxECU RACE REV9+ (auto)

VW Golf Mk4 1.8T 20v (AUM, Bosch ME7.5) DBW — MaxxECU — MaxxECU RACE
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-11

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 job60 wires · 7 connectors · 0 part lines
ToolsCrimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink
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-T121-121SP-14V-10.85☐☐☐☐☐☐☐
W2OEM-T121-21SP-14V-10.85☐☐☐☐☐☐☐
W3SP-14V-1MAXXECURACE-C1-M40.85☐☐☐☐☐☐☐
W4OEM-T121-1SP-GND-10.85☐☐☐☐☐☐☐
W5OEM-T121-2SP-GND-10.85☐☐☐☐☐☐☐
W6SP-GND-1MAXXECURACE-C1-L40.85☐☐☐☐☐☐☐
W7SP-GND-1MAXXECURACE-C2-G40.85☐☐☐☐☐☐☐
W8OEM-T121-108SP-0V-10.5☐☐☐☐☐☐☐
W9OEM-T121-29SP-0V-10.5☐☐☐☐☐☐☐
W10OEM-T121-34SP-0V-10.5☐☐☐☐☐☐☐
W11OEM-T121-36SP-0V-10.5☐☐☐☐☐☐☐
W12OEM-T121-90SP-0V-10.5☐☐☐☐☐☐☐
W13OEM-T121-91SP-0V-10.5☐☐☐☐☐☐☐
W14SP-0V-1MAXXECURACE-C1-H10.5☐☐☐☐☐☐☐
W15SP-0V-1MAXXECURACE-C1-H20.5☐☐☐☐☐☐☐
W16OEM-T121-72SP-5V1-10.5☐☐☐☐☐☐☐
W17OEM-T121-73SP-5V1-10.5☐☐☐☐☐☐☐
W18OEM-T121-83SP-5V1-10.5☐☐☐☐☐☐☐
W19OEM-T121-98SP-5V1-10.5☐☐☐☐☐☐☐
W20OEM-T121-99SP-5V1-10.5☐☐☐☐☐☐☐
W21SP-5V1-1MAXXECURACE-C1-G10.5☐☐☐☐☐☐☐
W22OEM-T121-82MAXXECURACE-C1-H30.5☐☐☐☐☐☐☐
W23OEM-T121-86MAXXECURACE-C1-H40.5☐☐☐☐☐☐☐
W24OEM-T121-106MAXXECURACE-C2-E20.5☐☐☐☐☐☐☐
W25OEM-T121-107MAXXECURACE-C2-E30.5☐☐☐☐☐☐☐
W26OEM-T121-102MAXXECURACE-C1-A20.5☐☐☐☐☐☐☐
W27OEM-T121-95MAXXECURACE-C1-A30.5☐☐☐☐☐☐☐
W28OEM-T121-103MAXXECURACE-C1-B20.5☐☐☐☐☐☐☐
W29OEM-T121-94MAXXECURACE-C1-B30.5☐☐☐☐☐☐☐
W30OEM-T121-96MAXXECURACE-C1-K10.5☐☐☐☐☐☐☐
W31OEM-T121-89MAXXECURACE-C1-K20.5☐☐☐☐☐☐☐
W32OEM-T121-97MAXXECURACE-C1-M10.5☐☐☐☐☐☐☐
W33OEM-T121-88MAXXECURACE-C1-M20.5☐☐☐☐☐☐☐
W34OEM-T121-118MAXXECURACE-C2-H40.5☐☐☐☐☐☐☐
W35OEM-T121-117MAXXECURACE-C2-H20.5☐☐☐☐☐☐☐
W36OEM-T121-53MAXXECURACE-C1-J30.5☐☐☐☐☐☐☐
W37OEM-T121-101MAXXECURACE-C1-J40.5☐☐☐☐☐☐☐
W38OEM-T121-33MAXXECURACE-C1-G20.5☐☐☐☐☐☐☐
W39OEM-T121-84MAXXECURACE-C2-G30.5☐☐☐☐☐☐☐
W40OEM-T121-35MAXXECURACE-C2-E40.5☐☐☐☐☐☐☐
W41OEM-T121-92MAXXECURACE-C2-F10.5☐☐☐☐☐☐☐
W42OEM-T121-93MAXXECURACE-C1-F10.5☐☐☐☐☐☐☐
W43OEM-T121-65MAXXECURACE-C1-B40.5☐☐☐☐☐☐☐
W44OEM-T121-66MAXXECURACE-C1-C40.5☐☐☐☐☐☐☐
W45OEM-T121-5MAXXECURACE-C1-D10.5☐☐☐☐☐☐☐
W46OEM-T121-63MAXXECURACE-C1-D40.5☐☐☐☐☐☐☐
W47OEM-T121-104MAXXECURACE-C1-E40.5☐☐☐☐☐☐☐
W48OEM-T121-105MAXXECURACE-C1-A10.5☐☐☐☐☐☐☐
W49OEM-T121-115MAXXECURACE-C1-B10.5☐☐☐☐☐☐☐
W50OEM-T121-47MAXXECURACE-C1-C10.5☐☐☐☐☐☐☐
W51OEM-T121-48MAXXECURACE-C1-A40.5☐☐☐☐☐☐☐
W52OEM-T121-64MAXXECURACE-C1-M30.5☐☐☐☐☐☐☐
W53OEM-T121-9MAXXECURACE-C1-L30.5☐☐☐☐☐☐☐
W54OEM-T121-51MAXXECURACE-C1-G30.5☐☐☐☐☐☐☐
W55OEM-T121-70MAXXECURACE-C1-F40.5☐☐☐☐☐☐☐
W56OEM-T121-68MAXXECURACE-C2-F20.5☐☐☐☐☐☐☐
W57OEM-T121-85MAXXECURACE-C1-F20.5☐☐☐☐☐☐☐
W58OEM-T121-54MAXXECURACE-C1-K30.5☐☐☐☐☐☐☐
W59OEM-T121-60MAXXECURACE-C1-E10.5☐☐☐☐☐☐☐
W60OEM-T121-58MAXXECURACE-C1-E20.5☐☐☐☐☐☐☐

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
1MAXXECURACE-C1-H1MAXXECURACE-C1-G1open (OL)sensor ground must not touch 5 V sensor reference
2MAXXECURACE-C1-H1MAXXECURACE-C1-M4open (OL)sensor ground must not touch +12 V supply
3MAXXECURACE-C1-L4MAXXECURACE-C1-G1open (OL)power ground must not touch 5 V sensor reference
4MAXXECURACE-C1-L4MAXXECURACE-C1-M4open (OL)power ground must not touch +12 V supply
5MAXXECURACE-C1-M4MAXXECURACE-C1-G1open (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

MAXXECURACE-C1MAXXECURACE-C2OEM-T121SP-0VSP-14VSP-5V1SP-GND

Connectors

MAXXECURACE-C1

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
A1GPO 5—W48—0.5OEM-T121-105———
A2IGN 1—W26—0.5OEM-T121-102———
A3IGN 2—W27—0.5OEM-T121-95———
A4GPO 8/TACHO—W51—0.5OEM-T121-48———
B1GPO 6—W49—0.5OEM-T121-115———
B2IGN 3—W28—0.5OEM-T121-103———
B3IGN 4—W29—0.5OEM-T121-94———
B4GPO 1—W43—0.5OEM-T121-65———
C1GPO 7—W50—0.5OEM-T121-47———
C2IGN 5————————
C3IGN 6————————
C4GPO 2—W44—0.5OEM-T121-66———
D1WBO2 Heater-—W45—0.5OEM-T121-5———
D2IGN 7————————
D3IGN 8————————
D4GPO 3—W46—0.5OEM-T121-63———
E1CAN H—W59—0.5OEM-T121-60———
E2CAN L—W60—0.5OEM-T121-58———
E3GND Shield————————
E4GPO 4—W47—0.5OEM-T121-104———
F1CLT—W42—0.5OEM-T121-93———
F2IAT—W57—0.5OEM-T121-85———
F3WBO2 VREF————————
F4WBO2 VS—W55—0.5OEM-T121-70———
G1+5V sensor supply—W21—0.5SP-5V1-1———
G2TPS/AIN—W38—0.5OEM-T121-33———
G3WBO2 IP—W54—0.5OEM-T121-51———
G4WBO2 RCAL————————
H1Sensor GND—W14—0.5SP-0V-1———
H2Trigger GND—W15—0.5SP-0V-1———
H3TRIGGER—W22—0.5OEM-T121-82———
H4HOME—W23—0.5OEM-T121-86———
J1AIN 1 (temperature)————————
J2AIN 2 (temperature)————————
J3AIN 3 (0-5V)—W36—0.5OEM-T121-53———
J4AIN 4 (0-5V)—W37—0.5OEM-T121-101———
K1INJ 1—W30—0.5OEM-T121-96———
K2INJ 2—W31—0.5OEM-T121-89———
K3DIN/VR 1—W58—0.5OEM-T121-54———
K4DIN/VR 2————————
L1INJ 8————————
L2INJ 7————————
L3INJ 6—W53—0.5OEM-T121-9———
L4Engine GND—W6—0.85SP-GND-1———
M1INJ 3—W32—0.5OEM-T121-97———
M2INJ 4—W33—0.5OEM-T121-88———
M3INJ 5—W52—0.5OEM-T121-64———
M4+12V ECU power supply—W3—0.85SP-14V-1———

MAXXECURACE-C2

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
A1EGT 5+————————
A2EGT 6+————————
A3EGT 7+————————
A4EGT 8+————————
B1EGT 5-————————
B2EGT 6-————————
B3EGT 7-————————
B4EGT 8-————————
C1EGT 1+————————
C2EGT 2+————————
C3EGT 3+————————
C4EGT 4+————————
D1EGT 1-————————
D2EGT 2-————————
D3EGT 3-————————
D4EGT 4-————————
E1KNOCK GND————————
E2Knock 1—W24—0.5OEM-T121-106———
E3Knock 2—W25—0.5OEM-T121-107———
E4AIN 6 (0-5V)—W40—0.5OEM-T121-35———
F1AIN 7 (0-5V)—W41—0.5OEM-T121-92———
F2AIN 8 (0-5V)—W56—0.5OEM-T121-68———
F3DIN/VR 4————————
F4DIN/VR 5————————
G1GPO 15 (+12V)————————
G2GPO 16 (+12V)————————
G3AIN 5 (0-5V)—W39—0.5OEM-T121-84———
G4ENGINE GROUND—W7—0.85SP-GND-1———
H1MOTOR 2+————————
H2MOTOR 1-—W35—0.5OEM-T121-117———
H3MOTOR 2-————————
H4MOTOR 1+—W34—0.5OEM-T121-118———

OEM-T121

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1ECU ground—W4—0.85SP-GND-1———
101Boost pressure sensor (G31)—W37—0.5MAXXECURACE-C1-J4———
102Ignition coil 1 (N127)—W26—0.5MAXXECURACE-C1-A2———
103Ignition coil 3 (N158)—W28—0.5MAXXECURACE-C1-B2———
104Boost control solenoid (N75)—W47—0.5MAXXECURACE-C1-E4———
105Diverter valve (N249)—W48—0.5MAXXECURACE-C1-A1———
106Knock sensor 1 (G61)—W24—0.5MAXXECURACE-C2-E2———
107Knock sensor 2 (G66)—W25—0.5MAXXECURACE-C2-E3———
108Sensor ground—W8—0.5SP-0V-1———
115VVT camshaft adjustment valve (N205)—W49—0.5MAXXECURACE-C1-B1———
117Throttle motor G186 (+)—W35—0.5MAXXECURACE-C2-H2———
118Throttle motor G186 (−)—W34—0.5MAXXECURACE-C2-H4———
121ECM + coil power (J271 relay feed)—W1—0.85SP-14V-1———
2ECU ground—W5—0.85SP-GND-1———
21ECM power (J271 relay feed)—W2—0.85SP-14V-1———
27MAF sensor supply (G70)————————
29MAF sensor ground (G70)—W9—0.5SP-0V-1———
3Ignition switch +12V (term 15)————————
33Accelerator pedal position 1 (G79)—W38—0.5MAXXECURACE-C1-G2———
34Accelerator pedal position 1 ground (G79)—W10—0.5SP-0V-1———
35Accelerator pedal position 2 (G185)—W40—0.5MAXXECURACE-C2-E4———
36Accelerator pedal position 2 ground (G185)—W11—0.5SP-0V-1———
37Engine speed signal (tacho to cluster)————————
43K-line diagnostics (OBD pin 7)————————
47Check engine light (MIL)—W50—0.5MAXXECURACE-C1-C1———
48EPC warning light—W51—0.5MAXXECURACE-C1-A4———
5Wideband lambda heater (Z19)—W45—0.5MAXXECURACE-C1-D1———
51Wideband lambda pump (G39)—W54—0.5MAXXECURACE-C1-G3———
52Wideband lambda pump (G39)————————
53MAF sensor signal (G70)—W36—0.5MAXXECURACE-C1-J3———
54Road speed signal (VSS)—W58—0.5MAXXECURACE-C1-K3———
58CAN bus low—W60—0.5MAXXECURACE-C1-E2———
60CAN bus high—W59—0.5MAXXECURACE-C1-E1———
62Battery constant +12V (term 30)————————
63Post-cat lambda heater (Z29)—W46—0.5MAXXECURACE-C1-D4———
64EVAP canister valve (N80)—W52—0.5MAXXECURACE-C1-M3———
65Fuel pump relay control—W43—0.5MAXXECURACE-C1-B4———
66Secondary-air pump relay (J299)—W44—0.5MAXXECURACE-C1-C4———
68Post-cat lambda signal (G130)—W56—0.5MAXXECURACE-C2-F2———
69Post-cat lambda signal (G130)————————
70Wideband lambda Nernst signal (G39)—W55—0.5MAXXECURACE-C1-F4———
71Wideband lambda Nernst signal (G39)————————
72Accelerator pedal position 1 5V supply (G79)—W16—0.5SP-5V1-1———
73Accelerator pedal position 2 5V supply (G185)—W17—0.5SP-5V1-1———
82Crank position sensor (G28)—W22—0.5MAXXECURACE-C1-H3———
83Throttle position sensor 5V supply (G187/G188)—W18—0.5SP-5V1-1———
84Throttle position sensor 1 (G187)—W39—0.5MAXXECURACE-C2-G3———
85Intake air temperature (G42)—W57—0.5MAXXECURACE-C1-F2———
86Camshaft position sensor (G40)—W23—0.5MAXXECURACE-C1-H4———
88Injector 4 (N33)—W33—0.5MAXXECURACE-C1-M2———
89Injector 2 (N31)—W31—0.5MAXXECURACE-C1-K2———
9Secondary-air injection valve (N112)—W53—0.5MAXXECURACE-C1-L3———
90Crank position sensor ground (G28)—W12—0.5SP-0V-1———
91Throttle position sensor ground (G187/G188)—W13—0.5SP-0V-1———
92Throttle position sensor 2 (G188)—W41—0.5MAXXECURACE-C2-F1———
93Engine coolant temperature (G62)—W42—0.5MAXXECURACE-C1-F1———
94Ignition coil 4 (N163)—W29—0.5MAXXECURACE-C1-B3———
95Ignition coil 2 (N128)—W27—0.5MAXXECURACE-C1-A3———
96Injector 1 (N30)—W30—0.5MAXXECURACE-C1-K1———
97Injector 3 (N32)—W32—0.5MAXXECURACE-C1-M1———
98Cam + boost sensor 5V supply (G40/G31)—W19—0.5SP-5V1-1———
99Knock sensor 5V supply (G61/G66)—W20—0.5SP-5V1-1———

SP-0V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W8—0.5OEM-T121-108———
1——W9—0.5OEM-T121-29———
1——W10—0.5OEM-T121-34———
1——W11—0.5OEM-T121-36———
1——W12—0.5OEM-T121-90———
1——W13—0.5OEM-T121-91———
1——W14—0.5MAXXECURACE-C1-H1———
1——W15—0.5MAXXECURACE-C1-H2———

SP-14V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W1—0.85OEM-T121-121———
1——W2—0.85OEM-T121-21———
1——W3—0.85MAXXECURACE-C1-M4———

SP-5V1

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W16—0.5OEM-T121-72———
1——W17—0.5OEM-T121-73———
1——W18—0.5OEM-T121-83———
1——W19—0.5OEM-T121-98———
1——W20—0.5OEM-T121-99———
1——W21—0.5MAXXECURACE-C1-G1———

SP-GND

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W4—0.85OEM-T121-1———
1——W5—0.85OEM-T121-2———
1——W6—0.85MAXXECURACE-C1-L4———
1——W7—0.85MAXXECURACE-C2-G4———

Pin map

OEM pointOEM functionOEM familyTarget pointTarget functionTarget familyWire colourEvidence
OEM-T121-1ECU groundgroundMAXXECURACE-C1-L4 + MAXXECURACE-C2-G4Engine GND + ENGINE GROUNDgroundcorroborated
OEM-T121-101Boost pressure sensor (G31)analog_inMAXXECURACE-C1-J4AIN 4 (0-5V)analog_incorroborated
OEM-T121-102Ignition coil 1 (N127)ignition_outMAXXECURACE-C1-A2IGN 1ignition_outcorroborated
OEM-T121-103Ignition coil 3 (N158)ignition_outMAXXECURACE-C1-B2IGN 3ignition_outcorroborated
OEM-T121-104Boost control solenoid (N75)low_side_outMAXXECURACE-C1-E4GPO 4low_side_outcorroborated
OEM-T121-105Diverter valve (N249)low_side_outMAXXECURACE-C1-A1GPO 5low_side_outcorroborated
OEM-T121-106Knock sensor 1 (G61)knock_inMAXXECURACE-C2-E2Knock 1knock_incorroborated
OEM-T121-107Knock sensor 2 (G66)knock_inMAXXECURACE-C2-E3Knock 2knock_incorroborated
OEM-T121-108Sensor groundsensor_groundMAXXECURACE-C1-H1 + MAXXECURACE-C1-H2Sensor GND + Trigger GNDsensor_groundcorroborated
OEM-T121-115VVT camshaft adjustment valve (N205)low_side_outMAXXECURACE-C1-B1GPO 6low_side_outcorroborated
OEM-T121-117Throttle motor G186 (+)hbridge_outMAXXECURACE-C2-H2MOTOR 1-hbridge_outcorroborated
OEM-T121-118Throttle motor G186 (−)hbridge_outMAXXECURACE-C2-H4MOTOR 1+hbridge_outcorroborated
OEM-T121-121ECM + coil power (J271 relay feed)power_inMAXXECURACE-C1-M4+12V ECU power supplypower_incorroborated
OEM-T121-2ECU groundgroundMAXXECURACE-C1-L4 + MAXXECURACE-C2-G4Engine GND + ENGINE GROUNDgroundcorroborated
OEM-T121-21ECM power (J271 relay feed)power_inMAXXECURACE-C1-M4+12V ECU power supplypower_incorroborated
OEM-T121-27MAF sensor supply (G70)power_in———corroborated
OEM-T121-29MAF sensor ground (G70)sensor_groundMAXXECURACE-C1-H1 + MAXXECURACE-C1-H2Sensor GND + Trigger GNDsensor_groundcorroborated
OEM-T121-3Ignition switch +12V (term 15)digital_in———corroborated
OEM-T121-33Accelerator pedal position 1 (G79)analog_inMAXXECURACE-C1-G2TPS/AINanalog_incorroborated
OEM-T121-34Accelerator pedal position 1 ground (G79)sensor_groundMAXXECURACE-C1-H1 + MAXXECURACE-C1-H2Sensor GND + Trigger GNDsensor_groundcorroborated
OEM-T121-35Accelerator pedal position 2 (G185)analog_inMAXXECURACE-C2-E4AIN 6 (0-5V)analog_incorroborated
OEM-T121-36Accelerator pedal position 2 ground (G185)sensor_groundMAXXECURACE-C1-H1 + MAXXECURACE-C1-H2Sensor GND + Trigger GNDsensor_groundcorroborated
OEM-T121-37Engine speed signal (tacho to cluster)tacho_out———corroborated
OEM-T121-43K-line diagnostics (OBD pin 7)serial———corroborated
OEM-T121-47Check engine light (MIL)low_side_outMAXXECURACE-C1-C1GPO 7low_side_outcorroborated
OEM-T121-48EPC warning lightlow_side_outMAXXECURACE-C1-A4GPO 8/TACHOlow_side_outcorroborated
OEM-T121-5Wideband lambda heater (Z19)low_side_outMAXXECURACE-C1-D1WBO2 Heater-low_side_outcorroborated
OEM-T121-51Wideband lambda pump (G39)wb_ipMAXXECURACE-C1-G3WBO2 IPwb_ipcorroborated
OEM-T121-52Wideband lambda pump (G39)wb_ip———corroborated
OEM-T121-53MAF sensor signal (G70)analog_inMAXXECURACE-C1-J3AIN 3 (0-5V)analog_incorroborated
OEM-T121-54Road speed signal (VSS)digital_inMAXXECURACE-C1-K3DIN/VR 1digital_incorroborated
OEM-T121-58CAN bus lowcan_lMAXXECURACE-C1-E2CAN Lcan_lcorroborated
OEM-T121-60CAN bus highcan_hMAXXECURACE-C1-E1CAN Hcan_hcorroborated
OEM-T121-62Battery constant +12V (term 30)power_in———corroborated
OEM-T121-63Post-cat lambda heater (Z29)low_side_outMAXXECURACE-C1-D4GPO 3low_side_outcorroborated
OEM-T121-64EVAP canister valve (N80)low_side_outMAXXECURACE-C1-M3INJ 5injector_outcorroborated
OEM-T121-65Fuel pump relay controllow_side_outMAXXECURACE-C1-B4GPO 1low_side_outcorroborated
OEM-T121-66Secondary-air pump relay (J299)low_side_outMAXXECURACE-C1-C4GPO 2low_side_outcorroborated
OEM-T121-68Post-cat lambda signal (G130)lambda_nb_inMAXXECURACE-C2-F2AIN 8 (0-5V)analog_incorroborated
OEM-T121-69Post-cat lambda signal (G130)lambda_nb_in———corroborated
OEM-T121-70Wideband lambda Nernst signal (G39)wb_vsMAXXECURACE-C1-F4WBO2 VSwb_vscorroborated
OEM-T121-71Wideband lambda Nernst signal (G39)wb_vs———corroborated
OEM-T121-72Accelerator pedal position 1 5V supply (G79)vrefMAXXECURACE-C1-G1+5V sensor supplyvrefcorroborated
OEM-T121-73Accelerator pedal position 2 5V supply (G185)vrefMAXXECURACE-C1-G1+5V sensor supplyvrefcorroborated
OEM-T121-82Crank position sensor (G28)trigger_inMAXXECURACE-C1-H3TRIGGERtrigger_incorroborated
OEM-T121-83Throttle position sensor 5V supply (G187/G188)vrefMAXXECURACE-C1-G1+5V sensor supplyvrefcorroborated
OEM-T121-84Throttle position sensor 1 (G187)analog_inMAXXECURACE-C2-G3AIN 5 (0-5V)analog_incorroborated
OEM-T121-85Intake air temperature (G42)temp_inMAXXECURACE-C1-F2IATtemp_incorroborated
OEM-T121-86Camshaft position sensor (G40)trigger_inMAXXECURACE-C1-H4HOMEtrigger_incorroborated
OEM-T121-88Injector 4 (N33)injector_outMAXXECURACE-C1-M2INJ 4injector_outcorroborated
OEM-T121-89Injector 2 (N31)injector_outMAXXECURACE-C1-K2INJ 2injector_outcorroborated
OEM-T121-9Secondary-air injection valve (N112)low_side_outMAXXECURACE-C1-L3INJ 6injector_outcorroborated
OEM-T121-90Crank position sensor ground (G28)sensor_groundMAXXECURACE-C1-H1 + MAXXECURACE-C1-H2Sensor GND + Trigger GNDsensor_groundcorroborated
OEM-T121-91Throttle position sensor ground (G187/G188)sensor_groundMAXXECURACE-C1-H1 + MAXXECURACE-C1-H2Sensor GND + Trigger GNDsensor_groundcorroborated
OEM-T121-92Throttle position sensor 2 (G188)analog_inMAXXECURACE-C2-F1AIN 7 (0-5V)analog_incorroborated
OEM-T121-93Engine coolant temperature (G62)temp_inMAXXECURACE-C1-F1CLTtemp_incorroborated
OEM-T121-94Ignition coil 4 (N163)ignition_outMAXXECURACE-C1-B3IGN 4ignition_outcorroborated
OEM-T121-95Ignition coil 2 (N128)ignition_outMAXXECURACE-C1-A3IGN 2ignition_outcorroborated
OEM-T121-96Injector 1 (N30)injector_outMAXXECURACE-C1-K1INJ 1injector_outcorroborated
OEM-T121-97Injector 3 (N32)injector_outMAXXECURACE-C1-M1INJ 3injector_outcorroborated
OEM-T121-98Cam + boost sensor 5V supply (G40/G31)vrefMAXXECURACE-C1-G1+5V sensor supplyvrefcorroborated
OEM-T121-99Knock sensor 5V supply (G61/G66)vrefMAXXECURACE-C1-G1+5V sensor supplyvrefcorroborated

Cut list

WireFromToGauge (mm²)ColourLengthSignalIdent
W1OEM-T121-121SP-14V-10.85no routeECM + coil power (J271 relay feed)—
W2OEM-T121-21SP-14V-10.85no routeECM power (J271 relay feed)—
W3SP-14V-1MAXXECURACE-C1-M40.85no route+12V ECU power supply—
W4OEM-T121-1SP-GND-10.85no routeECU ground—
W5OEM-T121-2SP-GND-10.85no routeECU ground—
W6SP-GND-1MAXXECURACE-C1-L40.85no routeEngine GND—
W7SP-GND-1MAXXECURACE-C2-G40.85no routeENGINE GROUND—
W8OEM-T121-108SP-0V-10.5no routeSensor ground—
W9OEM-T121-29SP-0V-10.5no routeMAF sensor ground (G70)—
W10OEM-T121-34SP-0V-10.5no routeAccelerator pedal position 1 ground (G79)—
W11OEM-T121-36SP-0V-10.5no routeAccelerator pedal position 2 ground (G185)—
W12OEM-T121-90SP-0V-10.5no routeCrank position sensor ground (G28)—
W13OEM-T121-91SP-0V-10.5no routeThrottle position sensor ground (G187/G188)—
W14SP-0V-1MAXXECURACE-C1-H10.5no routeSensor GND—
W15SP-0V-1MAXXECURACE-C1-H20.5no routeTrigger GND—
W16OEM-T121-72SP-5V1-10.5no routeAccelerator pedal position 1 5V supply (G79)—
W17OEM-T121-73SP-5V1-10.5no routeAccelerator pedal position 2 5V supply (G185)—
W18OEM-T121-83SP-5V1-10.5no routeThrottle position sensor 5V supply (G187/G188)—
W19OEM-T121-98SP-5V1-10.5no routeCam + boost sensor 5V supply (G40/G31)—
W20OEM-T121-99SP-5V1-10.5no routeKnock sensor 5V supply (G61/G66)—
W21SP-5V1-1MAXXECURACE-C1-G10.5no route+5V sensor supply—
W22OEM-T121-82MAXXECURACE-C1-H30.5no routeCrank position sensor (G28)—
W23OEM-T121-86MAXXECURACE-C1-H40.5no routeCamshaft position sensor (G40)—
W24OEM-T121-106MAXXECURACE-C2-E20.5no routeKnock sensor 1 (G61)—
W25OEM-T121-107MAXXECURACE-C2-E30.5no routeKnock sensor 2 (G66)—
W26OEM-T121-102MAXXECURACE-C1-A20.5no routeIgnition coil 1 (N127)—
W27OEM-T121-95MAXXECURACE-C1-A30.5no routeIgnition coil 2 (N128)—
W28OEM-T121-103MAXXECURACE-C1-B20.5no routeIgnition coil 3 (N158)—
W29OEM-T121-94MAXXECURACE-C1-B30.5no routeIgnition coil 4 (N163)—
W30OEM-T121-96MAXXECURACE-C1-K10.5no routeInjector 1 (N30)—
W31OEM-T121-89MAXXECURACE-C1-K20.5no routeInjector 2 (N31)—
W32OEM-T121-97MAXXECURACE-C1-M10.5no routeInjector 3 (N32)—
W33OEM-T121-88MAXXECURACE-C1-M20.5no routeInjector 4 (N33)—
W34OEM-T121-118MAXXECURACE-C2-H40.5no routeThrottle motor G186 (−)—
W35OEM-T121-117MAXXECURACE-C2-H20.5no routeThrottle motor G186 (+)—
W36OEM-T121-53MAXXECURACE-C1-J30.5no routeMAF sensor signal (G70)—
W37OEM-T121-101MAXXECURACE-C1-J40.5no routeBoost pressure sensor (G31)—
W38OEM-T121-33MAXXECURACE-C1-G20.5no routeAccelerator pedal position 1 (G79)—
W39OEM-T121-84MAXXECURACE-C2-G30.5no routeThrottle position sensor 1 (G187)—
W40OEM-T121-35MAXXECURACE-C2-E40.5no routeAccelerator pedal position 2 (G185)—
W41OEM-T121-92MAXXECURACE-C2-F10.5no routeThrottle position sensor 2 (G188)—
W42OEM-T121-93MAXXECURACE-C1-F10.5no routeEngine coolant temperature (G62)—
W43OEM-T121-65MAXXECURACE-C1-B40.5no routeFuel pump relay control—
W44OEM-T121-66MAXXECURACE-C1-C40.5no routeSecondary-air pump relay (J299)—
W45OEM-T121-5MAXXECURACE-C1-D10.5no routeWideband lambda heater (Z19)—
W46OEM-T121-63MAXXECURACE-C1-D40.5no routePost-cat lambda heater (Z29)—
W47OEM-T121-104MAXXECURACE-C1-E40.5no routeBoost control solenoid (N75)—
W48OEM-T121-105MAXXECURACE-C1-A10.5no routeDiverter valve (N249)—
W49OEM-T121-115MAXXECURACE-C1-B10.5no routeVVT camshaft adjustment valve (N205)—
W50OEM-T121-47MAXXECURACE-C1-C10.5no routeCheck engine light (MIL)—
W51OEM-T121-48MAXXECURACE-C1-A40.5no routeEPC warning light—
W52OEM-T121-64MAXXECURACE-C1-M30.5no routeEVAP canister valve (N80)—
W53OEM-T121-9MAXXECURACE-C1-L30.5no routeSecondary-air injection valve (N112)—
W54OEM-T121-51MAXXECURACE-C1-G30.5no routeWideband lambda pump (G39)—
W55OEM-T121-70MAXXECURACE-C1-F40.5no routeWideband lambda Nernst signal (G39)—
W56OEM-T121-68MAXXECURACE-C2-F20.5no routePost-cat lambda signal (G130)—
W57OEM-T121-85MAXXECURACE-C1-F20.5no routeIntake air temperature (G42)—
W58OEM-T121-54MAXXECURACE-C1-K30.5no routeRoad speed signal (VSS)—
W59OEM-T121-60MAXXECURACE-C1-E10.5no routeCAN bus high—
W60OEM-T121-58MAXXECURACE-C1-E20.5no routeCAN bus low—

Bill of materials

CategoryPart numberManufacturerDescriptionQtyUnit

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (10)

SeverityCodeSubjectMessage
errorREQUIRED_UNMAPPEDOEM-T121-3Required OEM function "Ignition switch +12V (term 15)" (digital_in) is not connected to the new ECU.
warnDBW_MOTOR_CURRENTMAXXECURACE-C2-H2Cannot confirm MaxxECU RACE can drive the throttle motor: MAXXECURACE-C2-H2 "MOTOR 1-" is rated 2.0 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).
warnDBW_MOTOR_CURRENTMAXXECURACE-C2-H4Cannot confirm MaxxECU RACE can drive the throttle motor: MAXXECURACE-C2-H4 "MOTOR 1+" is rated 2.0 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).
warnDBW_SHARED_5VMAXXECURACE-C1-G1 + OEM-T121-72 + OEM-T121-73 + OEM-T121-83 + OEM-T121-98 + OEM-T121-99 + SP-5V1-1These 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 (MAXXECURACE-C1-G1). On a drive-by-wire car the OEM splits them so one short or fault can't corrupt both throttle/pedal tracks at once. MaxxECU RACE 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.
warnLOAD_UNKNOWNMAXXECURACE-C1-B4MAXXECURACE-C1-B4 "GPO 1" drives OEM-T121-65 Fuel pump relay control (load 0.2 A) but its current rating is unknown. Check the ECU manual.
warnLOAD_UNKNOWNMAXXECURACE-C1-C4MAXXECURACE-C1-C4 "GPO 2" drives OEM-T121-66 Secondary-air pump relay (J299) (load 0.2 A) but its current rating is unknown. Check the ECU manual.
warnSUPPLY_GROUPMAXXECURACE-C1-G1 + OEM-T121-72 + OEM-T121-73 + OEM-T121-83 + OEM-T121-98 + OEM-T121-99 + SP-5V1-1Supplies 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.
infoNET_FAMILYOEM-T121-64 ↔ MAXXECURACE-C1-M3OEM-T121-64 "EVAP canister valve (N80)" [low_side_out] is wired to MAXXECURACE-C1-M3 "INJ 5" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-T121-9 ↔ MAXXECURACE-C1-L3OEM-T121-9 "Secondary-air injection valve (N112)" [low_side_out] is wired to MAXXECURACE-C1-L3 "INJ 6" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoUNMAPPEDOEM6 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-T121-52 Wideband lambda pump (G39); OEM-T121-69 Post-cat lambda signal (G130); OEM-T121-71 Wideband lambda Nernst signal (G39)

Accepted (1)

CodeSubjectReasonBy
REQUIRED_UNMAPPEDOEM-T121-62Battery-constant (memory) feed of the stock ECU: the new ECU has no such input, so it is not needed.mapping-proposal

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-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); MaxxECU MaxxECU RACE has no dedicated key-on input Not wired: - OEM-T121 62: Battery constant +12V (term 30): MaxxECU MaxxECU RACE has no battery-constant input; not needed - OEM-T121 37: Engine speed signal (tacho to cluster): no free tacho/frequency_out/low_side/ls_hs on MaxxECU MaxxECU RACE - OEM-T121 52: Wideband lambda pump (G39): no free wb_ip on MaxxECU MaxxECU RACE - OEM-T121 71: Wideband lambda Nernst signal (G39): no free wb_vs on MaxxECU MaxxECU RACE - OEM-T121 69: Post-cat lambda signal (G130): no free o2_narrowband/analog_0_5 on MaxxECU MaxxECU RACE - OEM-T121 43: K-line diagnostics (OBD pin 7): no free k_line on MaxxECU MaxxECU RACE - OEM-T121 27: MAF sensor supply (G70): no rule for class sensor_supply_in; wire by hand

Sources

ReliabilityKindTitleURLArchiveCapturedSHA-256
4vendor_docMaxxECU GEN1 pinout (MINI / STREET / SPORT / V1 / RACE / PRO)http://www.maxxecu.com/webhelp/wirings-maxxecu_pinout.htmlarchive2026-10-052e37b6814690
3community_copyNefMoto: ME7.5 ECU bench-flashing power/ground pinshttp://nefmoto.com/wiki/index.php?title=ECU_Bench_Flashing———
3community_copyvwressources: Bosch Motronic ME7.5 (AMK/ARY/AUQ/ARX/AUM) T121 pinouthttps://www.vwressources.planethoster.world/me75_pinout.html———