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VW Golf Mk4 1.8T 20v (AUM, Bosch ME7.5) DBW → MaxxECU MaxxECU GEN2 RACE (auto)

VW Golf Mk4 1.8T 20v (AUM, Bosch ME7.5) DBW — MaxxECU — MaxxECU GEN2 RACE
Drawn by Michael Gnankou · Rev 0 · proposal · 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.

Statusproposal · not yet verified: nobody has reported building and running this harness
Open errorsnone
Size of the job66 wires · 10 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-1MAXXECUGEN2R-MX1-250.85☐☐☐☐☐☐☐
W4SP-14V-1MAXXECUGEN2R-MX2-250.85☐☐☐☐☐☐☐
W5OEM-T121-1SP-GND-10.85☐☐☐☐☐☐☐
W6OEM-T121-2SP-GND-10.85☐☐☐☐☐☐☐
W7SP-GND-1MAXXECUGEN2R-MX1-90.85☐☐☐☐☐☐☐
W8SP-GND-1MAXXECUGEN2R-MX2-90.85☐☐☐☐☐☐☐
W9SP-GND-1MAXXECUGEN2R-MX3-90.85☐☐☐☐☐☐☐
W10OEM-T121-108SP-0V-10.5☐☐☐☐☐☐☐
W11OEM-T121-29SP-0V-10.5☐☐☐☐☐☐☐
W12OEM-T121-34SP-0V-10.5☐☐☐☐☐☐☐
W13OEM-T121-36SP-0V-10.5☐☐☐☐☐☐☐
W14OEM-T121-90SP-0V-10.5☐☐☐☐☐☐☐
W15OEM-T121-91SP-0V-10.5☐☐☐☐☐☐☐
W16SP-0V-1MAXXECUGEN2R-MX1-140.5☐☐☐☐☐☐☐
W17OEM-T121-72SP-5V1-10.5☐☐☐☐☐☐☐
W18OEM-T121-98SP-5V1-10.5☐☐☐☐☐☐☐
W19SP-5V1-1MAXXECUGEN2R-MX1-120.5☐☐☐☐☐☐☐
W20OEM-T121-73SP-5V2-10.5☐☐☐☐☐☐☐
W21OEM-T121-99SP-5V2-10.5☐☐☐☐☐☐☐
W22SP-5V2-1MAXXECUGEN2R-MX1-200.5☐☐☐☐☐☐☐
W23OEM-T121-83MAXXECUGEN2R-MX1-220.5☐☐☐☐☐☐☐
W24OEM-T121-82MAXXECUGEN2R-MX1-100.5☐☐☐☐☐☐☐
W25OEM-T121-86MAXXECUGEN2R-MX1-180.5☐☐☐☐☐☐☐
W26OEM-T121-106MAXXECUGEN2R-MX2-280.5☐☐☐☐☐☐☐
W27OEM-T121-107MAXXECUGEN2R-MX2-310.5☐☐☐☐☐☐☐
W28OEM-T121-102MAXXECUGEN2R-MX1-10.5☐☐☐☐☐☐☐
W29OEM-T121-95MAXXECUGEN2R-MX1-20.5☐☐☐☐☐☐☐
W30OEM-T121-103MAXXECUGEN2R-MX1-30.5☐☐☐☐☐☐☐
W31OEM-T121-94MAXXECUGEN2R-MX1-40.5☐☐☐☐☐☐☐
W32OEM-T121-96MAXXECUGEN2R-MX1-310.5☐☐☐☐☐☐☐
W33OEM-T121-89MAXXECUGEN2R-MX1-320.5☐☐☐☐☐☐☐
W34OEM-T121-97MAXXECUGEN2R-MX1-330.5☐☐☐☐☐☐☐
W35OEM-T121-88MAXXECUGEN2R-MX1-340.5☐☐☐☐☐☐☐
W36OEM-T121-118MAXXECUGEN2R-MX2-80.5☐☐☐☐☐☐☐
W37OEM-T121-117MAXXECUGEN2R-MX2-70.5☐☐☐☐☐☐☐
W38OEM-T121-3MAXXECUGEN2R-MX2-240.5☐☐☐☐☐☐☐
W39OEM-T121-53MAXXECUGEN2R-MX1-260.5☐☐☐☐☐☐☐
W40OEM-T121-101MAXXECUGEN2R-MX1-270.5☐☐☐☐☐☐☐
W41OEM-T121-33MAXXECUGEN2R-MX1-280.5☐☐☐☐☐☐☐
W42OEM-T121-84MAXXECUGEN2R-MX1-290.5☐☐☐☐☐☐☐
W43OEM-T121-35MAXXECUGEN2R-MX1-300.5☐☐☐☐☐☐☐
W44OEM-T121-92MAXXECUGEN2R-MX2-40.5☐☐☐☐☐☐☐
W45OEM-T121-93MAXXECUGEN2R-MX2-50.5☐☐☐☐☐☐☐
W46OEM-T121-65MAXXECUGEN2R-MX1-50.5☐☐☐☐☐☐☐
W47OEM-T121-66MAXXECUGEN2R-MX1-60.5☐☐☐☐☐☐☐
W48OEM-T121-5MAXXECUGEN2R-MX2-120.5☐☐☐☐☐☐☐
W49OEM-T121-63MAXXECUGEN2R-MX3-120.5☐☐☐☐☐☐☐
W50OEM-T121-104MAXXECUGEN2R-MX1-70.5☐☐☐☐☐☐☐
W51OEM-T121-105MAXXECUGEN2R-MX1-80.5☐☐☐☐☐☐☐
W52OEM-T121-115MAXXECUGEN2R-MX1-170.5☐☐☐☐☐☐☐
W53OEM-T121-47MAXXECUGEN2R-MX2-30.5☐☐☐☐☐☐☐
W54OEM-T121-48MAXXECUGEN2R-MX2-330.5☐☐☐☐☐☐☐
W55OEM-T121-64MAXXECUGEN2R-MX2-340.5☐☐☐☐☐☐☐
W56OEM-T121-9MAXXECUGEN2R-MX3-290.5☐☐☐☐☐☐☐
W57OEM-T121-51MAXXECUGEN2R-MX2-190.5☐☐☐☐☐☐☐
W58OEM-T121-52MAXXECUGEN2R-MX3-190.5☐☐☐☐☐☐☐
W59OEM-T121-70MAXXECUGEN2R-MX2-100.5☐☐☐☐☐☐☐
W60OEM-T121-71MAXXECUGEN2R-MX3-100.5☐☐☐☐☐☐☐
W61OEM-T121-68MAXXECUGEN2R-MX2-60.5☐☐☐☐☐☐☐
W62OEM-T121-69MAXXECUGEN2R-MX2-130.5☐☐☐☐☐☐☐
W63OEM-T121-85MAXXECUGEN2R-MX2-140.5☐☐☐☐☐☐☐
W64OEM-T121-54MAXXECUGEN2R-MX1-230.5☐☐☐☐☐☐☐
W65OEM-T121-60MAXXECUGEN2R-MX4-300.5☐☐☐☐☐☐☐
W66OEM-T121-58MAXXECUGEN2R-MX4-290.5☐☐☐☐☐☐☐

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
1MAXXECUGEN2R-MX1-14MAXXECUGEN2R-MX1-12open (OL)sensor ground must not touch 5 V sensor reference
2MAXXECUGEN2R-MX1-14MAXXECUGEN2R-MX1-20open (OL)sensor ground must not touch 5 V sensor reference
3MAXXECUGEN2R-MX1-14MAXXECUGEN2R-MX1-22open (OL)sensor ground must not touch 5 V sensor reference
4MAXXECUGEN2R-MX1-14MAXXECUGEN2R-MX1-25open (OL)sensor ground must not touch +12 V supply
5MAXXECUGEN2R-MX1-25MAXXECUGEN2R-MX1-12open (OL)+12 V supply must not touch 5 V sensor reference
6MAXXECUGEN2R-MX1-25MAXXECUGEN2R-MX1-20open (OL)+12 V supply must not touch 5 V sensor reference
7MAXXECUGEN2R-MX1-25MAXXECUGEN2R-MX1-22open (OL)+12 V supply must not touch 5 V sensor reference
8MAXXECUGEN2R-MX1-9MAXXECUGEN2R-MX1-12open (OL)power ground must not touch 5 V sensor reference
9MAXXECUGEN2R-MX1-9MAXXECUGEN2R-MX1-20open (OL)power ground must not touch 5 V sensor reference
10MAXXECUGEN2R-MX1-9MAXXECUGEN2R-MX1-22open (OL)power ground must not touch 5 V sensor reference
11MAXXECUGEN2R-MX1-9MAXXECUGEN2R-MX1-25open (OL)power ground must not touch +12 V supply

If any reading doesn't match, stop and get help before powering up.

Revisions

RevLabelByDate
No revisions yet.

Schematic

MAXXECUGEN2R-MX1MAXXECUGEN2R-MX2MAXXECUGEN2R-MX3MAXXECUGEN2R-MX4OEM-T121SP-0VSP-14VSP-5V1SP-5V2SP-GND

Connectors

MAXXECUGEN2R-MX1

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Ignition 1—W28—0.5OEM-T121-102———
10Digital/VR 1 SIGNAL +—W24—0.5OEM-T121-82———
11Digital/VR 1 SIGNAL -————————
12Digital/VR 1 POWER SUPPLY—W19—0.5SP-5V1-1———
13Digital/VR 1 SHIELD————————
14SENSOR GND—W16—0.5SP-0V-1———
15CAN L————————
16CAN H————————
17GP out 5 (GND)—W52—0.5OEM-T121-115———
18Digital/VR 2 SIGNAL +—W25—0.5OEM-T121-86———
19Digital/VR 2 SIGNAL -————————
2Ignition 2—W29—0.5OEM-T121-95———
20Digital/VR 2 POWER SUPPLY—W22—0.5SP-5V2-1———
21Digital/VR 2 SHIELD————————
225V power supply—W23—0.5OEM-T121-83———
23Digital/VR 3 SIGNAL +—W64—0.5OEM-T121-54———
24Digital/VR 4 SIGNAL +————————
2512V supply 1—W3—0.85SP-14V-1———
26AIN 1—W39—0.5OEM-T121-53———
27AIN 2—W40—0.5OEM-T121-101———
28AIN 3—W41—0.5OEM-T121-33———
29AIN 4—W42—0.5OEM-T121-84———
3Ignition 3—W30—0.5OEM-T121-103———
30AIN 5—W43—0.5OEM-T121-35———
31INJECTOR 1—W32—0.5OEM-T121-96———
32INJECTOR 2—W33—0.5OEM-T121-89———
33INJECTOR 3—W34—0.5OEM-T121-97———
34INJECTOR 4—W35—0.5OEM-T121-88———
4Ignition 4—W31—0.5OEM-T121-94———
5GP out 1 (GND)—W46—0.5OEM-T121-65———
6GP out 2 (GND)—W47—0.5OEM-T121-66———
7GP out 3 (GND)—W50—0.5OEM-T121-104———
8GP out 4 (GND)—W51—0.5OEM-T121-105———
9Engine gnd—W7—0.85SP-GND-1———

MAXXECUGEN2R-MX2

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Ignition 5————————
10WBO2 Sensor 1 VS—W59—0.5OEM-T121-70———
11WBO2 Sensor 1 COM/VREF————————
12GP OUT 7 / WBO2 Sensor 1 H-—W48—0.5OEM-T121-5———
13AIN 9—W62—0.5OEM-T121-69———
14AIN 10—W63—0.5OEM-T121-85———
15AIN 11————————
16AIN 12————————
17AIN 13————————
18WBO2 sensor 1 RCAL————————
19WBO2 sensor 1 IP—W57—0.5OEM-T121-51———
2Ignition 6————————
2012V WBO2 sensor 1 H+————————
21WBO2 sensor 1 SHIELD————————
22AIN 14————————
23AIN 15————————
2412V supply 3—W38—0.5OEM-T121-3———
2512V supply 2—W4—0.85SP-14V-1———
26KNOCK1 SHIELD————————
27KNOCK 1-————————
28KNOCK 1+—W26—0.5OEM-T121-106———
29KNOCK 2 SHIELD————————
3GP out 6 (GND)—W53—0.5OEM-T121-47———
30KNOCK 2-————————
31KNOCK 2+—W27—0.5OEM-T121-107———
32AIN 16————————
33INJECTOR 5—W54—0.5OEM-T121-48———
34INJECTOR 6—W55—0.5OEM-T121-64———
4AIN 6—W44—0.5OEM-T121-92———
5AIN 7—W45—0.5OEM-T121-93———
6AIN 8—W61—0.5OEM-T121-68———
7GP out 13 (H-BRIDGE 1)—W37—0.5OEM-T121-117———
8GP out 14 (H-BRIDGE 1)—W36—0.5OEM-T121-118———
9Engine gnd—W8—0.85SP-GND-1———

MAXXECUGEN2R-MX3

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1GP out 15 (H-BRIDGE 2)————————
10WBO2 sensor 2 VS—W60—0.5OEM-T121-71———
11WBO2 sensor 2 COM/VREF————————
12GP Out 8 (GND) / WBO2 Sensor 2 H-—W49—0.5OEM-T121-63———
13WBO2 sensor 2 SHIELD————————
14GP OUT 9 (12V)————————
15GP OUT 10 (12V)————————
16GP OUT 11 (12V)————————
17GP OUT 12 (12V)————————
18WBO2 sensor 2 RCAL————————
19WBO2 sensor 2 IP—W58—0.5OEM-T121-52———
2GP out 16 (H-BRIDGE 2)————————
2012V WBO2 sensor 2 (H+)————————
21AIN 17————————
22AIN 18————————
23AIN 19————————
24AIN 20————————
25AIN 21————————
26AIN 22————————
27AIN 23————————
28AIN 24————————
29INJECTOR 7—W56—0.5OEM-T121-9———
3Ignition 7————————
30INJECTOR 8————————
31INJECTOR 9————————
32INJECTOR 10————————
33INJECTOR 11————————
34INJECTOR 12————————
4Ignition 8————————
5Ignition 9————————
6Ignition 10————————
7Ignition 11————————
8Ignition 12————————
9Engine gnd—W9—0.85SP-GND-1———

MAXXECUGEN2R-MX4

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Digital/VR 5 SHIELD————————
10EGT 1 +————————
11EGT 2 +————————
12EGT 3 +————————
13EGT 4 +————————
14EGT 5 +————————
15EGT 6 +————————
16EGT 7 +————————
17EGT 8 +————————
18EGT 1 -————————
19EGT 2 -————————
2Digital/VR 5 SIGNAL -————————
20EGT 3 -————————
21EGT 4 -————————
22EGT 5 -————————
23EGT 6 -————————
24EGT 7 -————————
25EGT 8 -————————
26Digital/VR 8 SHIELD————————
27Digital/VR 8 SIGNAL -————————
28Digital/VR 8 SIGNAL +————————
29CAN 2 L—W66—0.5OEM-T121-58———
3Digital/VR 5 SIGNAL +————————
30CAN 2 H—W65—0.5OEM-T121-60———
31INJECTOR 13————————
32INJECTOR 14————————
33INJECTOR 15————————
34INJECTOR 16————————
4Digital/VR 6 SHIELD————————
5Digital/VR 6 SIGNAL -————————
6Digital/VR 6 SIGNAL +————————
7Digital/VR 7 SHIELD————————
8Digital/VR 7 SIGNAL -————————
9Digital/VR 7 SIGNAL +————————

OEM-T121

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1ECU ground—W5—0.85SP-GND-1———
101Boost pressure sensor (G31)—W40—0.5MAXXECUGEN2R-MX1-27———
102Ignition coil 1 (N127)—W28—0.5MAXXECUGEN2R-MX1-1———
103Ignition coil 3 (N158)—W30—0.5MAXXECUGEN2R-MX1-3———
104Boost control solenoid (N75)—W50—0.5MAXXECUGEN2R-MX1-7———
105Diverter valve (N249)—W51—0.5MAXXECUGEN2R-MX1-8———
106Knock sensor 1 (G61)—W26—0.5MAXXECUGEN2R-MX2-28———
107Knock sensor 2 (G66)—W27—0.5MAXXECUGEN2R-MX2-31———
108Sensor ground—W10—0.5SP-0V-1———
115VVT camshaft adjustment valve (N205)—W52—0.5MAXXECUGEN2R-MX1-17———
117Throttle motor G186 (+)—W37—0.5MAXXECUGEN2R-MX2-7———
118Throttle motor G186 (−)—W36—0.5MAXXECUGEN2R-MX2-8———
121ECM + coil power (J271 relay feed)—W1—0.85SP-14V-1———
2ECU ground—W6—0.85SP-GND-1———
21ECM power (J271 relay feed)—W2—0.85SP-14V-1———
27MAF sensor supply (G70)————————
29MAF sensor ground (G70)—W11—0.5SP-0V-1———
3Ignition switch +12V (term 15)—W38—0.5MAXXECUGEN2R-MX2-24———
33Accelerator pedal position 1 (G79)—W41—0.5MAXXECUGEN2R-MX1-28———
34Accelerator pedal position 1 ground (G79)—W12—0.5SP-0V-1———
35Accelerator pedal position 2 (G185)—W43—0.5MAXXECUGEN2R-MX1-30———
36Accelerator pedal position 2 ground (G185)—W13—0.5SP-0V-1———
37Engine speed signal (tacho to cluster)————————
43K-line diagnostics (OBD pin 7)————————
47Check engine light (MIL)—W53—0.5MAXXECUGEN2R-MX2-3———
48EPC warning light—W54—0.5MAXXECUGEN2R-MX2-33———
5Wideband lambda heater (Z19)—W48—0.5MAXXECUGEN2R-MX2-12———
51Wideband lambda pump (G39)—W57—0.5MAXXECUGEN2R-MX2-19———
52Wideband lambda pump (G39)—W58—0.5MAXXECUGEN2R-MX3-19———
53MAF sensor signal (G70)—W39—0.5MAXXECUGEN2R-MX1-26———
54Road speed signal (VSS)—W64—0.5MAXXECUGEN2R-MX1-23———
58CAN bus low—W66—0.5MAXXECUGEN2R-MX4-29———
60CAN bus high—W65—0.5MAXXECUGEN2R-MX4-30———
62Battery constant +12V (term 30)————————
63Post-cat lambda heater (Z29)—W49—0.5MAXXECUGEN2R-MX3-12———
64EVAP canister valve (N80)—W55—0.5MAXXECUGEN2R-MX2-34———
65Fuel pump relay control—W46—0.5MAXXECUGEN2R-MX1-5———
66Secondary-air pump relay (J299)—W47—0.5MAXXECUGEN2R-MX1-6———
68Post-cat lambda signal (G130)—W61—0.5MAXXECUGEN2R-MX2-6———
69Post-cat lambda signal (G130)—W62—0.5MAXXECUGEN2R-MX2-13———
70Wideband lambda Nernst signal (G39)—W59—0.5MAXXECUGEN2R-MX2-10———
71Wideband lambda Nernst signal (G39)—W60—0.5MAXXECUGEN2R-MX3-10———
72Accelerator pedal position 1 5V supply (G79)—W17—0.5SP-5V1-1———
73Accelerator pedal position 2 5V supply (G185)—W20—0.5SP-5V2-1———
82Crank position sensor (G28)—W24—0.5MAXXECUGEN2R-MX1-10———
83Throttle position sensor 5V supply (G187/G188)—W23—0.5MAXXECUGEN2R-MX1-22———
84Throttle position sensor 1 (G187)—W42—0.5MAXXECUGEN2R-MX1-29———
85Intake air temperature (G42)—W63—0.5MAXXECUGEN2R-MX2-14———
86Camshaft position sensor (G40)—W25—0.5MAXXECUGEN2R-MX1-18———
88Injector 4 (N33)—W35—0.5MAXXECUGEN2R-MX1-34———
89Injector 2 (N31)—W33—0.5MAXXECUGEN2R-MX1-32———
9Secondary-air injection valve (N112)—W56—0.5MAXXECUGEN2R-MX3-29———
90Crank position sensor ground (G28)—W14—0.5SP-0V-1———
91Throttle position sensor ground (G187/G188)—W15—0.5SP-0V-1———
92Throttle position sensor 2 (G188)—W44—0.5MAXXECUGEN2R-MX2-4———
93Engine coolant temperature (G62)—W45—0.5MAXXECUGEN2R-MX2-5———
94Ignition coil 4 (N163)—W31—0.5MAXXECUGEN2R-MX1-4———
95Ignition coil 2 (N128)—W29—0.5MAXXECUGEN2R-MX1-2———
96Injector 1 (N30)—W32—0.5MAXXECUGEN2R-MX1-31———
97Injector 3 (N32)—W34—0.5MAXXECUGEN2R-MX1-33———
98Cam + boost sensor 5V supply (G40/G31)—W18—0.5SP-5V1-1———
99Knock sensor 5V supply (G61/G66)—W21—0.5SP-5V2-1———

SP-0V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W10—0.5OEM-T121-108———
1——W11—0.5OEM-T121-29———
1——W12—0.5OEM-T121-34———
1——W13—0.5OEM-T121-36———
1——W14—0.5OEM-T121-90———
1——W15—0.5OEM-T121-91———
1——W16—0.5MAXXECUGEN2R-MX1-14———

SP-14V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W1—0.85OEM-T121-121———
1——W2—0.85OEM-T121-21———
1——W3—0.85MAXXECUGEN2R-MX1-25———
1——W4—0.85MAXXECUGEN2R-MX2-25———

SP-5V1

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W17—0.5OEM-T121-72———
1——W18—0.5OEM-T121-98———
1——W19—0.5MAXXECUGEN2R-MX1-12———

SP-5V2

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W20—0.5OEM-T121-73———
1——W21—0.5OEM-T121-99———
1——W22—0.5MAXXECUGEN2R-MX1-20———

SP-GND

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W5—0.85OEM-T121-1———
1——W6—0.85OEM-T121-2———
1——W7—0.85MAXXECUGEN2R-MX1-9———
1——W8—0.85MAXXECUGEN2R-MX2-9———
1——W9—0.85MAXXECUGEN2R-MX3-9———

Pin map

OEM pointOEM functionOEM familyTarget pointTarget functionTarget familyWire colourEvidence
OEM-T121-1ECU groundgroundMAXXECUGEN2R-MX1-9 + MAXXECUGEN2R-MX2-9 + MAXXECUGEN2R-MX3-9Engine gnd + Engine gnd + Engine gndgroundcorroborated
OEM-T121-101Boost pressure sensor (G31)analog_inMAXXECUGEN2R-MX1-27AIN 2analog_incorroborated
OEM-T121-102Ignition coil 1 (N127)ignition_outMAXXECUGEN2R-MX1-1Ignition 1ignition_outcorroborated
OEM-T121-103Ignition coil 3 (N158)ignition_outMAXXECUGEN2R-MX1-3Ignition 3ignition_outcorroborated
OEM-T121-104Boost control solenoid (N75)low_side_outMAXXECUGEN2R-MX1-7GP out 3 (GND)low_side_outcorroborated
OEM-T121-105Diverter valve (N249)low_side_outMAXXECUGEN2R-MX1-8GP out 4 (GND)low_side_outcorroborated
OEM-T121-106Knock sensor 1 (G61)knock_inMAXXECUGEN2R-MX2-28KNOCK 1+knock_incorroborated
OEM-T121-107Knock sensor 2 (G66)knock_inMAXXECUGEN2R-MX2-31KNOCK 2+knock_incorroborated
OEM-T121-108Sensor groundsensor_groundMAXXECUGEN2R-MX1-14SENSOR GNDsensor_groundcorroborated
OEM-T121-115VVT camshaft adjustment valve (N205)low_side_outMAXXECUGEN2R-MX1-17GP out 5 (GND)low_side_outcorroborated
OEM-T121-117Throttle motor G186 (+)hbridge_outMAXXECUGEN2R-MX2-7GP out 13 (H-BRIDGE 1)hbridge_outcorroborated
OEM-T121-118Throttle motor G186 (−)hbridge_outMAXXECUGEN2R-MX2-8GP out 14 (H-BRIDGE 1)hbridge_outcorroborated
OEM-T121-121ECM + coil power (J271 relay feed)power_inMAXXECUGEN2R-MX1-25 + MAXXECUGEN2R-MX2-2512V supply 1 + 12V supply 2power_incorroborated
OEM-T121-2ECU groundgroundMAXXECUGEN2R-MX1-9 + MAXXECUGEN2R-MX2-9 + MAXXECUGEN2R-MX3-9Engine gnd + Engine gnd + Engine gndgroundcorroborated
OEM-T121-21ECM power (J271 relay feed)power_inMAXXECUGEN2R-MX1-25 + MAXXECUGEN2R-MX2-2512V supply 1 + 12V supply 2power_incorroborated
OEM-T121-27MAF sensor supply (G70)power_in———corroborated
OEM-T121-29MAF sensor ground (G70)sensor_groundMAXXECUGEN2R-MX1-14SENSOR GNDsensor_groundcorroborated
OEM-T121-3Ignition switch +12V (term 15)digital_inMAXXECUGEN2R-MX2-2412V supply 3digital_incorroborated
OEM-T121-33Accelerator pedal position 1 (G79)analog_inMAXXECUGEN2R-MX1-28AIN 3analog_incorroborated
OEM-T121-34Accelerator pedal position 1 ground (G79)sensor_groundMAXXECUGEN2R-MX1-14SENSOR GNDsensor_groundcorroborated
OEM-T121-35Accelerator pedal position 2 (G185)analog_inMAXXECUGEN2R-MX1-30AIN 5analog_incorroborated
OEM-T121-36Accelerator pedal position 2 ground (G185)sensor_groundMAXXECUGEN2R-MX1-14SENSOR 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_outMAXXECUGEN2R-MX2-3GP out 6 (GND)low_side_outcorroborated
OEM-T121-48EPC warning lightlow_side_outMAXXECUGEN2R-MX2-33INJECTOR 5injector_outcorroborated
OEM-T121-5Wideband lambda heater (Z19)low_side_outMAXXECUGEN2R-MX2-12GP OUT 7 / WBO2 Sensor 1 H-low_side_outcorroborated
OEM-T121-51Wideband lambda pump (G39)wb_ipMAXXECUGEN2R-MX2-19WBO2 sensor 1 IPwb_ipcorroborated
OEM-T121-52Wideband lambda pump (G39)wb_ipMAXXECUGEN2R-MX3-19WBO2 sensor 2 IPwb_ipcorroborated
OEM-T121-53MAF sensor signal (G70)analog_inMAXXECUGEN2R-MX1-26AIN 1analog_incorroborated
OEM-T121-54Road speed signal (VSS)digital_inMAXXECUGEN2R-MX1-23Digital/VR 3 SIGNAL +digital_incorroborated
OEM-T121-58CAN bus lowcan_lMAXXECUGEN2R-MX4-29CAN 2 Lcan_lcorroborated
OEM-T121-60CAN bus highcan_hMAXXECUGEN2R-MX4-30CAN 2 Hcan_hcorroborated
OEM-T121-62Battery constant +12V (term 30)power_in———corroborated
OEM-T121-63Post-cat lambda heater (Z29)low_side_outMAXXECUGEN2R-MX3-12GP Out 8 (GND) / WBO2 Sensor 2 H-low_side_outcorroborated
OEM-T121-64EVAP canister valve (N80)low_side_outMAXXECUGEN2R-MX2-34INJECTOR 6injector_outcorroborated
OEM-T121-65Fuel pump relay controllow_side_outMAXXECUGEN2R-MX1-5GP out 1 (GND)low_side_outcorroborated
OEM-T121-66Secondary-air pump relay (J299)low_side_outMAXXECUGEN2R-MX1-6GP out 2 (GND)low_side_outcorroborated
OEM-T121-68Post-cat lambda signal (G130)lambda_nb_inMAXXECUGEN2R-MX2-6AIN 8analog_incorroborated
OEM-T121-69Post-cat lambda signal (G130)lambda_nb_inMAXXECUGEN2R-MX2-13AIN 9analog_incorroborated
OEM-T121-70Wideband lambda Nernst signal (G39)wb_vsMAXXECUGEN2R-MX2-10WBO2 Sensor 1 VSwb_vscorroborated
OEM-T121-71Wideband lambda Nernst signal (G39)wb_vsMAXXECUGEN2R-MX3-10WBO2 sensor 2 VSwb_vscorroborated
OEM-T121-72Accelerator pedal position 1 5V supply (G79)vrefMAXXECUGEN2R-MX1-12Digital/VR 1 POWER SUPPLYvrefcorroborated
OEM-T121-73Accelerator pedal position 2 5V supply (G185)vrefMAXXECUGEN2R-MX1-20Digital/VR 2 POWER SUPPLYvrefcorroborated
OEM-T121-82Crank position sensor (G28)trigger_inMAXXECUGEN2R-MX1-10Digital/VR 1 SIGNAL +trigger_incorroborated
OEM-T121-83Throttle position sensor 5V supply (G187/G188)vrefMAXXECUGEN2R-MX1-225V power supplyvrefcorroborated
OEM-T121-84Throttle position sensor 1 (G187)analog_inMAXXECUGEN2R-MX1-29AIN 4analog_incorroborated
OEM-T121-85Intake air temperature (G42)temp_inMAXXECUGEN2R-MX2-14AIN 10analog_incorroborated
OEM-T121-86Camshaft position sensor (G40)trigger_inMAXXECUGEN2R-MX1-18Digital/VR 2 SIGNAL +trigger_incorroborated
OEM-T121-88Injector 4 (N33)injector_outMAXXECUGEN2R-MX1-34INJECTOR 4injector_outcorroborated
OEM-T121-89Injector 2 (N31)injector_outMAXXECUGEN2R-MX1-32INJECTOR 2injector_outcorroborated
OEM-T121-9Secondary-air injection valve (N112)low_side_outMAXXECUGEN2R-MX3-29INJECTOR 7injector_outcorroborated
OEM-T121-90Crank position sensor ground (G28)sensor_groundMAXXECUGEN2R-MX1-14SENSOR GNDsensor_groundcorroborated
OEM-T121-91Throttle position sensor ground (G187/G188)sensor_groundMAXXECUGEN2R-MX1-14SENSOR GNDsensor_groundcorroborated
OEM-T121-92Throttle position sensor 2 (G188)analog_inMAXXECUGEN2R-MX2-4AIN 6analog_incorroborated
OEM-T121-93Engine coolant temperature (G62)temp_inMAXXECUGEN2R-MX2-5AIN 7analog_incorroborated
OEM-T121-94Ignition coil 4 (N163)ignition_outMAXXECUGEN2R-MX1-4Ignition 4ignition_outcorroborated
OEM-T121-95Ignition coil 2 (N128)ignition_outMAXXECUGEN2R-MX1-2Ignition 2ignition_outcorroborated
OEM-T121-96Injector 1 (N30)injector_outMAXXECUGEN2R-MX1-31INJECTOR 1injector_outcorroborated
OEM-T121-97Injector 3 (N32)injector_outMAXXECUGEN2R-MX1-33INJECTOR 3injector_outcorroborated
OEM-T121-98Cam + boost sensor 5V supply (G40/G31)vrefMAXXECUGEN2R-MX1-12Digital/VR 1 POWER SUPPLYvrefcorroborated
OEM-T121-99Knock sensor 5V supply (G61/G66)vrefMAXXECUGEN2R-MX1-20Digital/VR 2 POWER 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-1MAXXECUGEN2R-MX1-250.85no route12V supply 1—
W4SP-14V-1MAXXECUGEN2R-MX2-250.85no route12V supply 2—
W5OEM-T121-1SP-GND-10.85no routeECU ground—
W6OEM-T121-2SP-GND-10.85no routeECU ground—
W7SP-GND-1MAXXECUGEN2R-MX1-90.85no routeEngine gnd—
W8SP-GND-1MAXXECUGEN2R-MX2-90.85no routeEngine gnd—
W9SP-GND-1MAXXECUGEN2R-MX3-90.85no routeEngine gnd—
W10OEM-T121-108SP-0V-10.5no routeSensor ground—
W11OEM-T121-29SP-0V-10.5no routeMAF sensor ground (G70)—
W12OEM-T121-34SP-0V-10.5no routeAccelerator pedal position 1 ground (G79)—
W13OEM-T121-36SP-0V-10.5no routeAccelerator pedal position 2 ground (G185)—
W14OEM-T121-90SP-0V-10.5no routeCrank position sensor ground (G28)—
W15OEM-T121-91SP-0V-10.5no routeThrottle position sensor ground (G187/G188)—
W16SP-0V-1MAXXECUGEN2R-MX1-140.5no routeSENSOR GND—
W17OEM-T121-72SP-5V1-10.5no routeAccelerator pedal position 1 5V supply (G79)—
W18OEM-T121-98SP-5V1-10.5no routeCam + boost sensor 5V supply (G40/G31)—
W19SP-5V1-1MAXXECUGEN2R-MX1-120.5no routeDigital/VR 1 POWER SUPPLY—
W20OEM-T121-73SP-5V2-10.5no routeAccelerator pedal position 2 5V supply (G185)—
W21OEM-T121-99SP-5V2-10.5no routeKnock sensor 5V supply (G61/G66)—
W22SP-5V2-1MAXXECUGEN2R-MX1-200.5no routeDigital/VR 2 POWER SUPPLY—
W23OEM-T121-83MAXXECUGEN2R-MX1-220.5no routeThrottle position sensor 5V supply (G187/G188)—
W24OEM-T121-82MAXXECUGEN2R-MX1-100.5no routeCrank position sensor (G28)—
W25OEM-T121-86MAXXECUGEN2R-MX1-180.5no routeCamshaft position sensor (G40)—
W26OEM-T121-106MAXXECUGEN2R-MX2-280.5no routeKnock sensor 1 (G61)—
W27OEM-T121-107MAXXECUGEN2R-MX2-310.5no routeKnock sensor 2 (G66)—
W28OEM-T121-102MAXXECUGEN2R-MX1-10.5no routeIgnition coil 1 (N127)—
W29OEM-T121-95MAXXECUGEN2R-MX1-20.5no routeIgnition coil 2 (N128)—
W30OEM-T121-103MAXXECUGEN2R-MX1-30.5no routeIgnition coil 3 (N158)—
W31OEM-T121-94MAXXECUGEN2R-MX1-40.5no routeIgnition coil 4 (N163)—
W32OEM-T121-96MAXXECUGEN2R-MX1-310.5no routeInjector 1 (N30)—
W33OEM-T121-89MAXXECUGEN2R-MX1-320.5no routeInjector 2 (N31)—
W34OEM-T121-97MAXXECUGEN2R-MX1-330.5no routeInjector 3 (N32)—
W35OEM-T121-88MAXXECUGEN2R-MX1-340.5no routeInjector 4 (N33)—
W36OEM-T121-118MAXXECUGEN2R-MX2-80.5no routeThrottle motor G186 (−)—
W37OEM-T121-117MAXXECUGEN2R-MX2-70.5no routeThrottle motor G186 (+)—
W38OEM-T121-3MAXXECUGEN2R-MX2-240.5no routeIgnition switch +12V (term 15)—
W39OEM-T121-53MAXXECUGEN2R-MX1-260.5no routeMAF sensor signal (G70)—
W40OEM-T121-101MAXXECUGEN2R-MX1-270.5no routeBoost pressure sensor (G31)—
W41OEM-T121-33MAXXECUGEN2R-MX1-280.5no routeAccelerator pedal position 1 (G79)—
W42OEM-T121-84MAXXECUGEN2R-MX1-290.5no routeThrottle position sensor 1 (G187)—
W43OEM-T121-35MAXXECUGEN2R-MX1-300.5no routeAccelerator pedal position 2 (G185)—
W44OEM-T121-92MAXXECUGEN2R-MX2-40.5no routeThrottle position sensor 2 (G188)—
W45OEM-T121-93MAXXECUGEN2R-MX2-50.5no routeEngine coolant temperature (G62)—
W46OEM-T121-65MAXXECUGEN2R-MX1-50.5no routeFuel pump relay control—
W47OEM-T121-66MAXXECUGEN2R-MX1-60.5no routeSecondary-air pump relay (J299)—
W48OEM-T121-5MAXXECUGEN2R-MX2-120.5no routeWideband lambda heater (Z19)—
W49OEM-T121-63MAXXECUGEN2R-MX3-120.5no routePost-cat lambda heater (Z29)—
W50OEM-T121-104MAXXECUGEN2R-MX1-70.5no routeBoost control solenoid (N75)—
W51OEM-T121-105MAXXECUGEN2R-MX1-80.5no routeDiverter valve (N249)—
W52OEM-T121-115MAXXECUGEN2R-MX1-170.5no routeVVT camshaft adjustment valve (N205)—
W53OEM-T121-47MAXXECUGEN2R-MX2-30.5no routeCheck engine light (MIL)—
W54OEM-T121-48MAXXECUGEN2R-MX2-330.5no routeEPC warning light—
W55OEM-T121-64MAXXECUGEN2R-MX2-340.5no routeEVAP canister valve (N80)—
W56OEM-T121-9MAXXECUGEN2R-MX3-290.5no routeSecondary-air injection valve (N112)—
W57OEM-T121-51MAXXECUGEN2R-MX2-190.5no routeWideband lambda pump (G39)—
W58OEM-T121-52MAXXECUGEN2R-MX3-190.5no routeWideband lambda pump (G39)—
W59OEM-T121-70MAXXECUGEN2R-MX2-100.5no routeWideband lambda Nernst signal (G39)—
W60OEM-T121-71MAXXECUGEN2R-MX3-100.5no routeWideband lambda Nernst signal (G39)—
W61OEM-T121-68MAXXECUGEN2R-MX2-60.5no routePost-cat lambda signal (G130)—
W62OEM-T121-69MAXXECUGEN2R-MX2-130.5no routePost-cat lambda signal (G130)—
W63OEM-T121-85MAXXECUGEN2R-MX2-140.5no routeIntake air temperature (G42)—
W64OEM-T121-54MAXXECUGEN2R-MX1-230.5no routeRoad speed signal (VSS)—
W65OEM-T121-60MAXXECUGEN2R-MX4-300.5no routeCAN bus high—
W66OEM-T121-58MAXXECUGEN2R-MX4-290.5no routeCAN bus low—

Bill of materials

CategoryPart numberManufacturerDescriptionQtyUnit

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (12)

SeverityCodeSubjectMessage
warnDBW_MOTOR_CURRENTMAXXECUGEN2R-MX2-7Cannot confirm MaxxECU GEN2 RACE can drive the throttle motor: MAXXECUGEN2R-MX2-7 "GP out 13 (H-BRIDGE 1)" is rated 5.0 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_CURRENTMAXXECUGEN2R-MX2-8Cannot confirm MaxxECU GEN2 RACE can drive the throttle motor: MAXXECUGEN2R-MX2-8 "GP out 14 (H-BRIDGE 1)" is rated 5.0 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_5VMAXXECUGEN2R-MX1-12 + OEM-T121-72 + OEM-T121-98 + SP-5V1-1These 5 V supplies are separate in the stock car (OEM-T121-72 [pedal1], OEM-T121-98 [cam_boost]) and here share one ECU 5 V (MAXXECUGEN2R-MX1-12). 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 GEN2 RACE has 3 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.
warnDBW_SHARED_5VMAXXECUGEN2R-MX1-20 + OEM-T121-73 + OEM-T121-99 + SP-5V2-1These 5 V supplies are separate in the stock car (OEM-T121-73 [pedal2], OEM-T121-99 [knock]) and here share one ECU 5 V (MAXXECUGEN2R-MX1-20). 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 GEN2 RACE has 3 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.
warnSUPPLY_GROUPMAXXECUGEN2R-MX1-12 + OEM-T121-72 + OEM-T121-98 + SP-5V1-1Supplies meant to stay independent share one net: OEM-T121-72 [pedal1], OEM-T121-98 [cam_boost]. 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.
warnSUPPLY_GROUPMAXXECUGEN2R-MX1-20 + OEM-T121-73 + OEM-T121-99 + SP-5V2-1Supplies meant to stay independent share one net: OEM-T121-73 [pedal2], 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-T121-48 ↔ MAXXECUGEN2R-MX2-33OEM-T121-48 "EPC warning light" [low_side_out] is wired to MAXXECUGEN2R-MX2-33 "INJECTOR 5" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-T121-64 ↔ MAXXECUGEN2R-MX2-34OEM-T121-64 "EVAP canister valve (N80)" [low_side_out] is wired to MAXXECUGEN2R-MX2-34 "INJECTOR 6" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-T121-85 ↔ MAXXECUGEN2R-MX2-14OEM-T121-85 "Intake air temperature (G42)" [temp_in] is wired to MAXXECUGEN2R-MX2-14 "AIN 10" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one.
infoNET_FAMILYOEM-T121-9 ↔ MAXXECUGEN2R-MX3-29OEM-T121-9 "Secondary-air injection valve (N112)" [low_side_out] is wired to MAXXECUGEN2R-MX3-29 "INJECTOR 7" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-T121-93 ↔ MAXXECUGEN2R-MX2-5OEM-T121-93 "Engine coolant temperature (G62)" [temp_in] is wired to MAXXECUGEN2R-MX2-5 "AIN 7" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one.
infoUNMAPPEDOEM3 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)

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. Not wired: - OEM-T121 62: Battery constant +12V (term 30): MaxxECU MaxxECU GEN2 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 GEN2 RACE - OEM-T121 43: K-line diagnostics (OBD pin 7): no free k_line on MaxxECU MaxxECU GEN2 RACE - OEM-T121 27: MAF sensor supply (G70): no rule for class sensor_supply_in; wire by hand

Sources

ReliabilityKindTitleURLArchiveCapturedSHA-256
4vendor_docMaxxECU GEN2 pinout (RACE MX1–MX4 / TRACK MX1–MX3)http://www.maxxecu.com/webhelp/wirings-maxxecu_gen2_pinout.htmlarchive2026-10-05f689b8b6b08f
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———