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MX-5 Miata Mazdaspeed 2004-05 (BP-ZET turbo, no VVT) → DTAFast T12 (auto)

MX-5 Miata Mazdaspeed 2004-05 (BP-ZET turbo, no VVT) — DTAFast — T12
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-17

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 job67 wires · 11 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-2-PSP-14V-10.85☐☐☐☐☐☐☐
W2OEM-4-AFSP-14V-10.85☐☐☐☐☐☐☐
W3SP-14V-1T12-C1-310.85☐☐☐☐☐☐☐
W4OEM-4-AGT12-C3-260.85☐☐☐☐☐☐☐
W5OEM-3-ASP-GND-10.85☐☐☐☐☐☐☐
W6OEM-3-BSP-GND-10.85☐☐☐☐☐☐☐
W7OEM-4-ASP-GND-10.85☐☐☐☐☐☐☐
W8SP-GND-1T12-C1-130.85☐☐☐☐☐☐☐
W9SP-GND-1T12-C1-140.85☐☐☐☐☐☐☐
W10OEM-4-OSP-0V-10.5☐☐☐☐☐☐☐
W11SP-0V-1T12-C2-210.5☐☐☐☐☐☐☐
W12SP-0V-1T12-C2-330.5☐☐☐☐☐☐☐
W13OEM-4-LT12-C2-240.5☐☐☐☐☐☐☐
W14OEM-3-YT12-C2-120.5☐☐☐☐☐☐☐
W15OEM-3-VT12-C2-220.5☐☐☐☐☐☐☐
W16OEM-4-MT12-C3-310.5☐☐☐☐☐☐☐
W17OEM-3-FT12-C1-100.5☐☐☐☐☐☐☐
W18OEM-3-IT12-C1-180.5☐☐☐☐☐☐☐
W19OEM-2-AT12-C1-90.5☐☐☐☐☐☐☐
W20OEM-2-DT12-C1-170.5☐☐☐☐☐☐☐
W21OEM-2-GT12-C1-340.5☐☐☐☐☐☐☐
W22OEM-2-JT12-C1-250.5☐☐☐☐☐☐☐
W23OEM-4-XT12-C2-100.5☐☐☐☐☐☐☐
W24OEM-4-VT12-C2-10.5☐☐☐☐☐☐☐
W25OEM-4-PT12-C2-70.5☐☐☐☐☐☐☐
W26OEM-2-BT12-C1-50.5☐☐☐☐☐☐☐
W27OEM-2-CT12-C1-40.5☐☐☐☐☐☐☐
W28OEM-2-KT12-C1-30.5☐☐☐☐☐☐☐
W29OEM-2-MT12-C3-220.5☐☐☐☐☐☐☐
W30OEM-3-HT12-C3-230.5☐☐☐☐☐☐☐
W31OEM-2-OT12-C3-240.5☐☐☐☐☐☐☐
W32OEM-4-DRLY1-R-OUT0.5☐☐☐☐☐☐☐
W33SP-14V-1RLY1-R-IN0.5☐☐☐☐☐☐☐
W34SP-14V-1RLY1-R-COIL+0.5☐☐☐☐☐☐☐
W35RLY1-R-COIL-T12-C3-250.5☐☐☐☐☐☐☐
W36OEM-4-ERLY2-R-OUT0.5☐☐☐☐☐☐☐
W37SP-14V-1RLY2-R-IN0.5☐☐☐☐☐☐☐
W38SP-14V-1RLY2-R-COIL+0.5☐☐☐☐☐☐☐
W39RLY2-R-COIL-T12-C3-100.5☐☐☐☐☐☐☐
W40OEM-3-JT12-C3-90.5☐☐☐☐☐☐☐
W41OEM-3-PT12-C3-30.5☐☐☐☐☐☐☐
W42OEM-2-QT12-C3-40.5☐☐☐☐☐☐☐
W43OEM-2-ET12-C3-280.5☐☐☐☐☐☐☐
W44OEM-2-FT12-C3-290.5☐☐☐☐☐☐☐
W45OEM-2-HT12-C3-300.5☐☐☐☐☐☐☐
W46OEM-2-IT12-C1-160.5☐☐☐☐☐☐☐
W47OEM-2-NT12-C1-150.5☐☐☐☐☐☐☐
W48OEM-2-RT12-C1-240.5☐☐☐☐☐☐☐
W49OEM-3-CT12-C1-230.5☐☐☐☐☐☐☐
W50OEM-3-KT12-C1-210.5☐☐☐☐☐☐☐
W51OEM-3-MT12-C1-220.5☐☐☐☐☐☐☐
W52OEM-3-UT12-C1-80.5☐☐☐☐☐☐☐
W53OEM-4-AHT12-C1-320.5☐☐☐☐☐☐☐
W54OEM-4-AET12-C2-50.5☐☐☐☐☐☐☐
W55OEM-4-AAT12-C2-60.5☐☐☐☐☐☐☐
W56OEM-4-WT12-C2-180.5☐☐☐☐☐☐☐
W57OEM-4-RT12-C2-250.5☐☐☐☐☐☐☐
W58OEM-4-NT12-C2-170.5☐☐☐☐☐☐☐
W59OEM-4-ADT12-C2-190.5☐☐☐☐☐☐☐
W60OEM-3-TT12-C2-20.5☐☐☐☐☐☐☐
W61OEM-3-ST12-C2-40.5☐☐☐☐☐☐☐
W62OEM-4-BT12-C2-80.5☐☐☐☐☐☐☐
W63OEM-4-CT12-C2-110.5☐☐☐☐☐☐☐
W64OEM-4-FT12-C2-140.5☐☐☐☐☐☐☐
W65OEM-4-HT12-C2-150.5☐☐☐☐☐☐☐
W66OEM-4-IT12-C2-270.5☐☐☐☐☐☐☐
W67OEM-4-JT12-C3-190.5☐☐☐☐☐☐☐

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
1RLY1-R-COIL+T12-C1-13open (OL)+12 V supply must not touch power ground
2RLY1-R-COIL+T12-C2-21open (OL)+12 V supply must not touch sensor ground
3RLY1-R-OUTT12-C2-21open (OL)+12 V supply must not touch sensor ground
4RLY2-R-OUTT12-C2-21open (OL)+12 V supply must not touch sensor ground
5T12-C2-24T12-C2-21open (OL)5 V sensor reference must not touch sensor ground
6T12-C3-26T12-C2-21open (OL)+12 V supply must not touch sensor ground
7RLY1-R-COIL+T12-C2-24open (OL)+12 V supply must not touch 5 V sensor reference
8RLY1-R-OUTT12-C2-24open (OL)+12 V supply must not touch 5 V sensor reference
9RLY2-R-OUTT12-C2-24open (OL)+12 V supply must not touch 5 V sensor reference
10T12-C1-13RLY1-R-OUTopen (OL)power ground must not touch +12 V supply
11T12-C1-13RLY2-R-OUTopen (OL)power ground must not touch +12 V supply
12T12-C1-13T12-C2-24open (OL)power ground must not touch 5 V sensor reference
13T12-C1-13T12-C3-26open (OL)power ground must not touch +12 V supply
14T12-C3-26T12-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-2OEM-3OEM-4RLY1-RRLY2-RSP-0VSP-14VSP-GNDT12-C1T12-C2T12-C3

Connectors

OEM-2

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
AInjector 1—W19—0.5T12-C1-9———
BCooling fan relay—W26—0.5T12-C1-5———
CCondenser fan relay—W27—0.5T12-C1-4———
DInjector 2—W20—0.5T12-C1-17———
EEGR valve—W43—0.5T12-C3-28———
FEGR valve—W44—0.5T12-C3-29———
GInjector 3—W21—0.5T12-C1-34———
HEGR valve—W45—0.5T12-C3-30———
IEGR valve—W46—0.5T12-C1-16———
JInjector 4—W22—0.5T12-C1-25———
KA/C clutch relay—W28—0.5T12-C1-3———
LNC————————
MFuel pump relay—W29—0.5T12-C3-22———
NVTCS solenoid (intake butterflies)—W47—0.5T12-C1-15———
OFuel pump relay (non-immobiliser)—W31—0.5T12-C3-24———
PISC valve +14V feed—W1—0.85SP-14V-1———
QISC valve low side—W42—0.5T12-C3-4———
RMalfunction indicator lamp (MIL)—W48—0.5T12-C1-24———

OEM-3

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
APower ground—W5—0.85SP-GND-1———
BPower ground—W6—0.85SP-GND-1———
CPurge solenoid valve—W49—0.5T12-C1-23———
DEGR boost solenoid————————
ENC————————
FIgnition 1 (coils 1+4, wasted spark)—W17—0.5T12-C1-10———
GNC————————
HMain relay—W30—0.5T12-C3-23———
IIgnition 2 (coils 2+3, wasted spark)—W18—0.5T12-C1-18———
JFront O2 heater—W40—0.5T12-C3-9———
KEVAP leak detection pump—W50—0.5T12-C1-21———
LNC————————
MAlternator control—W51—0.5T12-C1-22———
NNC————————
OTachometer output————————
PRear O2 heater—W41—0.5T12-C3-3———
QData link connector (K-line)————————
RNC————————
SImmobiliser—W61—0.5T12-C2-4———
TVehicle speed—W60—0.5T12-C2-2———
UCharge lamp—W52—0.5T12-C1-8———
VCam position (CMP)—W15—0.5T12-C2-22———
WNC————————
XNC————————
YCrank position (CKP)—W14—0.5T12-C2-12———
ZNC————————

OEM-4

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
APower ground—W7—0.85SP-GND-1———
AARear O2 signal—W55—0.5T12-C2-6———
ABNC————————
ACData link connector (DLC TEN, turbo)————————
ADFuel level—W59—0.5T12-C2-19———
AEBARO/MAP sensor (turbo boost pressure)—W54—0.5T12-C2-5———
AFECU power +14V (main relay)—W2—0.85SP-14V-1———
AGConstant +12V—W4—0.85T12-C3-26———
AHEVAP leak detection pump solenoid valve—W53—0.5T12-C1-32———
BBrake switch—W62—0.5T12-C2-8———
CPower steering pressure switch—W63—0.5T12-C2-11———
DBoost control solenoid (turbo)—W32—0.5RLY1-R-OUT———
EBoost control solenoid (turbo)—W36—0.5RLY2-R-OUT———
FA/C request—W64—0.5T12-C2-14———
GNC————————
HNeutral switch—W65—0.5T12-C2-15———
IClutch switch—W66—0.5T12-C2-27———
JVTCS vacuum switch—W67—0.5T12-C3-19———
KNC————————
L+5V sensor supply—W13—0.5T12-C2-24———
MKnock sensor—W16—0.5T12-C3-31———
NIntake air temperature (IAT)—W58—0.5T12-C2-17———
OSignal ground—W10—0.5SP-0V-1———
PCoolant temperature (ECT)—W25—0.5T12-C2-7———
QNC————————
RIntake air temperature 2 (IAT2, turbo)—W57—0.5T12-C2-25———
SIgnition switch (IG1) sense————————
TGenerator output voltage (terminal P)————————
UNC————————
VThrottle position (TPS)—W24—0.5T12-C2-1———
WFront O2 signal—W56—0.5T12-C2-18———
XMass air flow (MAF)—W23—0.5T12-C2-10———
YNC————————
ZTCM (automatic only)————————

RLY1-R

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
COIL+Relay coil positive (switched +12 V)—W34—0.5SP-14V-1———
COIL-Relay coil negative (ECU low-side driver)—W35—0.5T12-C3-25———
INRelay contact input (switched +12 V)—W33—0.5SP-14V-1———
OUTRelay contact output (switched +12 V to load)—W32—0.5OEM-4-D———

RLY2-R

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
COIL+Relay coil positive (switched +12 V)—W38—0.5SP-14V-1———
COIL-Relay coil negative (ECU low-side driver)—W39—0.5T12-C3-10———
INRelay contact input (switched +12 V)—W37—0.5SP-14V-1———
OUTRelay contact output (switched +12 V to load)—W36—0.5OEM-4-E———

SP-0V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W10—0.5OEM-4-O———
1——W11—0.5T12-C2-21———
1——W12—0.5T12-C2-33———

SP-14V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W1—0.85OEM-2-P———
1——W2—0.85OEM-4-AF———
1——W3—0.85T12-C1-31———
1——W33—0.5RLY1-R-IN———
1——W34—0.5RLY1-R-COIL+———
1——W37—0.5RLY2-R-IN———
1——W38—0.5RLY2-R-COIL+———

SP-GND

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W5—0.85OEM-3-A———
1——W6—0.85OEM-3-B———
1——W7—0.85OEM-4-A———
1——W8—0.85T12-C1-13———
1——W9—0.85T12-C1-14———

T12-C1

Mating face
T12-C1-1 · Coil 31T12-C1-2 · Coil 112T12-C1-3 · PWM 33T12-C1-4 · PWM 24T12-C1-5 · PWM 15T12-C1-6 · Motor 1 +6T12-C1-7 · Motor 1 -7T12-C1-8 · Injector 118T12-C1-9 · Injector 19T12-C1-10 · Coil 110T12-C1-11 · Coil 511T12-C1-12 · Coil 712T12-C1-13 · Power Ground 113T12-C1-14 · Power Ground 214T12-C1-15 · Injector 615T12-C1-16 · Injector 516T12-C1-17 · Injector 217T12-C1-18 · Coil 218T12-C1-19 · Coil 819T12-C1-20 · Coil 920T12-C1-21 · Injector 921T12-C1-22 · Injector 1022T12-C1-23 · Injector 823T12-C1-24 · Injector 724T12-C1-25 · Injector 425T12-C1-26 · Coil 426T12-C1-27 · Coil 627T12-C1-28 · Coil 1028T12-C1-29 · Motor 2 +29T12-C1-30 · Motor 2 -30T12-C1-31 · Ignition 12v In31T12-C1-32 · Injector 1232T12-C1-33 · Coil 1233T12-C1-34 · Injector 334
Wire side
T12-C1-1 · Coil 31T12-C1-2 · Coil 112T12-C1-3 · PWM 33T12-C1-4 · PWM 24T12-C1-5 · PWM 15T12-C1-6 · Motor 1 +6T12-C1-7 · Motor 1 -7T12-C1-8 · Injector 118T12-C1-9 · Injector 19T12-C1-10 · Coil 110T12-C1-11 · Coil 511T12-C1-12 · Coil 712T12-C1-13 · Power Ground 113T12-C1-14 · Power Ground 214T12-C1-15 · Injector 615T12-C1-16 · Injector 516T12-C1-17 · Injector 217T12-C1-18 · Coil 218T12-C1-19 · Coil 819T12-C1-20 · Coil 920T12-C1-21 · Injector 921T12-C1-22 · Injector 1022T12-C1-23 · Injector 823T12-C1-24 · Injector 724T12-C1-25 · Injector 425T12-C1-26 · Coil 426T12-C1-27 · Coil 627T12-C1-28 · Coil 1028T12-C1-29 · Motor 2 +29T12-C1-30 · Motor 2 -30T12-C1-31 · Ignition 12v In31T12-C1-32 · Injector 1232T12-C1-33 · Coil 1233T12-C1-34 · Injector 334
CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Coil 3————————
2Coil 11————————
3PWM 3—W28—0.5OEM-2-K———
4PWM 2—W27—0.5OEM-2-C———
5PWM 1—W26—0.5OEM-2-B———
6Motor 1 +————————
7Motor 1 -————————
8Injector 11—W52—0.5OEM-3-U———
9Injector 1—W19—0.5OEM-2-A———
10Coil 1—W17—0.5OEM-3-F———
11Coil 5————————
12Coil 7————————
13Power Ground 1—W8—0.85SP-GND-1———
14Power Ground 2—W9—0.85SP-GND-1———
15Injector 6—W47—0.5OEM-2-N———
16Injector 5—W46—0.5OEM-2-I———
17Injector 2—W20—0.5OEM-2-D———
18Coil 2—W18—0.5OEM-3-I———
19Coil 8————————
20Coil 9————————
21Injector 9—W50—0.5OEM-3-K———
22Injector 10—W51—0.5OEM-3-M———
23Injector 8—W49—0.5OEM-3-C———
24Injector 7—W48—0.5OEM-2-R———
25Injector 4—W22—0.5OEM-2-J———
26Coil 4————————
27Coil 6————————
28Coil 10————————
29Motor 2 +————————
30Motor 2 -————————
31Ignition 12v In—W3—0.85SP-14V-1———
32Injector 12—W53—0.5OEM-4-AH———
33Coil 12————————
34Injector 3—W21—0.5OEM-2-G———

T12-C2

Mating face
T12-C2-1 · Analogue 21T12-C2-2 · Wheel 12T12-C2-3 · Analogue 103T12-C2-4 · Digital 14T12-C2-5 · Analogue 35T12-C2-6 · Analogue 46T12-C2-7 · Thermistor 17T12-C2-8 · Digital 28T12-C2-9 · 5v Output9T12-C2-10 · Analogue 110T12-C2-11 · Digital 311T12-C2-12 · Crank12T12-C2-13 · Analogue 1213T12-C2-14 · Digital 414T12-C2-15 · Digital 515T12-C2-16 · Analogue 1116T12-C2-17 · Thermistor 317T12-C2-18 · Analogue 518T12-C2-19 · Analogue 619T12-C2-20 · Wheel 220T12-C2-21 · Sensor Ground21T12-C2-22 · Cam 122T12-C2-23 · Cam 323T12-C2-24 · 5v Output24T12-C2-25 · Thermistor 225T12-C2-26 · CAN High26T12-C2-27 · Digital 627T12-C2-28 · CAN Low28T12-C2-29 · Cam 229T12-C2-30 · Cam 430T12-C2-31 · Wheel 331T12-C2-32 · Wheel 432T12-C2-33 · Sensor Ground33T12-C2-34 · Analogue 934
Wire side
T12-C2-1 · Analogue 21T12-C2-2 · Wheel 12T12-C2-3 · Analogue 103T12-C2-4 · Digital 14T12-C2-5 · Analogue 35T12-C2-6 · Analogue 46T12-C2-7 · Thermistor 17T12-C2-8 · Digital 28T12-C2-9 · 5v Output9T12-C2-10 · Analogue 110T12-C2-11 · Digital 311T12-C2-12 · Crank12T12-C2-13 · Analogue 1213T12-C2-14 · Digital 414T12-C2-15 · Digital 515T12-C2-16 · Analogue 1116T12-C2-17 · Thermistor 317T12-C2-18 · Analogue 518T12-C2-19 · Analogue 619T12-C2-20 · Wheel 220T12-C2-21 · Sensor Ground21T12-C2-22 · Cam 122T12-C2-23 · Cam 323T12-C2-24 · 5v Output24T12-C2-25 · Thermistor 225T12-C2-26 · CAN High26T12-C2-27 · Digital 627T12-C2-28 · CAN Low28T12-C2-29 · Cam 229T12-C2-30 · Cam 430T12-C2-31 · Wheel 331T12-C2-32 · Wheel 432T12-C2-33 · Sensor Ground33T12-C2-34 · Analogue 934
CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Analogue 2—W24—0.5OEM-4-V———
2Wheel 1—W60—0.5OEM-3-T———
3Analogue 10————————
4Digital 1—W61—0.5OEM-3-S———
5Analogue 3—W54—0.5OEM-4-AE———
6Analogue 4—W55—0.5OEM-4-AA———
7Thermistor 1—W25—0.5OEM-4-P———
8Digital 2—W62—0.5OEM-4-B———
95v Output————————
10Analogue 1—W23—0.5OEM-4-X———
11Digital 3—W63—0.5OEM-4-C———
12Crank—W14—0.5OEM-3-Y———
13Analogue 12————————
14Digital 4—W64—0.5OEM-4-F———
15Digital 5—W65—0.5OEM-4-H———
16Analogue 11————————
17Thermistor 3—W58—0.5OEM-4-N———
18Analogue 5—W56—0.5OEM-4-W———
19Analogue 6—W59—0.5OEM-4-AD———
20Wheel 2————————
21Sensor Ground—W11—0.5SP-0V-1———
22Cam 1—W15—0.5OEM-3-V———
23Cam 3————————
245v Output—W13—0.5OEM-4-L———
25Thermistor 2—W57—0.5OEM-4-R———
26CAN High————————
27Digital 6—W66—0.5OEM-4-I———
28CAN Low————————
29Cam 2————————
30Cam 4————————
31Wheel 3————————
32Wheel 4————————
33Sensor Ground—W12—0.5SP-0V-1———
34Analogue 9————————

T12-C3

Mating face
T12-C3-1 · Lambda 2 Pump Current1T12-C3-2 · Lambda 2 VGND2T12-C3-3 · Lambda 2 Heater Negative3T12-C3-4 · PWM 94T12-C3-5 · Lambda 2 Trim Resistor5T12-C3-6 · Lambda 2 Nernst Voltage6T12-C3-7 · Lambda 1 Pump Current7T12-C3-8 · Lambda 1 VGND8T12-C3-9 · Lambda 1 Heater Negative9T12-C3-10 · PWM 810T12-C3-11 · Lambda 1 Trim Resistor11T12-C3-12 · Lambda 1 Nernst Voltage12T12-C3-13 · Analogue 1313T12-C3-14 · Analogue 1414T12-C3-15 · Analogue 1515T12-C3-16 · Analogue 1616T12-C3-17 · Analogue 717T12-C3-18 · Analogue 818T12-C3-19 · Digital 719T12-C3-20 · Digital 820T12-C3-21 · Digital 921T12-C3-22 · PWM 422T12-C3-23 · PWM 523T12-C3-24 · PWM 624T12-C3-25 · PWM 725T12-C3-26 · Permanent 12v26T12-C3-27 · Permanent 12v27T12-C3-28 · PWM 1028T12-C3-29 · PWM 1129T12-C3-30 · PWM 1230T12-C3-31 · Knock 131T12-C3-32 · Knock 232T12-C3-33 · CAN 2 High33T12-C3-34 · CAN 2 Low34
Wire side
T12-C3-1 · Lambda 2 Pump Current1T12-C3-2 · Lambda 2 VGND2T12-C3-3 · Lambda 2 Heater Negative3T12-C3-4 · PWM 94T12-C3-5 · Lambda 2 Trim Resistor5T12-C3-6 · Lambda 2 Nernst Voltage6T12-C3-7 · Lambda 1 Pump Current7T12-C3-8 · Lambda 1 VGND8T12-C3-9 · Lambda 1 Heater Negative9T12-C3-10 · PWM 810T12-C3-11 · Lambda 1 Trim Resistor11T12-C3-12 · Lambda 1 Nernst Voltage12T12-C3-13 · Analogue 1313T12-C3-14 · Analogue 1414T12-C3-15 · Analogue 1515T12-C3-16 · Analogue 1616T12-C3-17 · Analogue 717T12-C3-18 · Analogue 818T12-C3-19 · Digital 719T12-C3-20 · Digital 820T12-C3-21 · Digital 921T12-C3-22 · PWM 422T12-C3-23 · PWM 523T12-C3-24 · PWM 624T12-C3-25 · PWM 725T12-C3-26 · Permanent 12v26T12-C3-27 · Permanent 12v27T12-C3-28 · PWM 1028T12-C3-29 · PWM 1129T12-C3-30 · PWM 1230T12-C3-31 · Knock 131T12-C3-32 · Knock 232T12-C3-33 · CAN 2 High33T12-C3-34 · CAN 2 Low34
CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Lambda 2 Pump Current————————
2Lambda 2 VGND————————
3Lambda 2 Heater Negative—W41—0.5OEM-3-P———
4PWM 9—W42—0.5OEM-2-Q———
5Lambda 2 Trim Resistor————————
6Lambda 2 Nernst Voltage————————
7Lambda 1 Pump Current————————
8Lambda 1 VGND————————
9Lambda 1 Heater Negative—W40—0.5OEM-3-J———
10PWM 8—W39—0.5RLY2-R-COIL-———
11Lambda 1 Trim Resistor————————
12Lambda 1 Nernst Voltage————————
13Analogue 13————————
14Analogue 14————————
15Analogue 15————————
16Analogue 16————————
17Analogue 7————————
18Analogue 8————————
19Digital 7—W67—0.5OEM-4-J———
20Digital 8————————
21Digital 9————————
22PWM 4—W29—0.5OEM-2-M———
23PWM 5—W30—0.5OEM-3-H———
24PWM 6—W31—0.5OEM-2-O———
25PWM 7—W35—0.5RLY1-R-COIL-———
26Permanent 12v—W4—0.85OEM-4-AG———
27Permanent 12v————————
28PWM 10—W43—0.5OEM-2-E———
29PWM 11—W44—0.5OEM-2-F———
30PWM 12—W45—0.5OEM-2-H———
31Knock 1—W16—0.5OEM-4-M———
32Knock 2————————
33CAN 2 High————————
34CAN 2 Low————————

Pin map

OEM pointOEM functionOEM familyTarget pointTarget functionTarget familyWire colourEvidence
OEM-2-AInjector 1injector_outT12-C1-9Injector 1injector_outcorroborated
OEM-2-BCooling fan relaylow_side_outT12-C1-5PWM 1low_side_outcorroborated
OEM-2-CCondenser fan relaylow_side_outT12-C1-4PWM 2low_side_outcorroborated
OEM-2-DInjector 2injector_outT12-C1-17Injector 2injector_outcorroborated
OEM-2-EEGR valvelow_side_outT12-C3-28PWM 10low_side_outcorroborated
OEM-2-FEGR valvelow_side_outT12-C3-29PWM 11low_side_outcorroborated
OEM-2-GInjector 3injector_outT12-C1-34Injector 3injector_outcorroborated
OEM-2-HEGR valvelow_side_outT12-C3-30PWM 12low_side_outcorroborated
OEM-2-IEGR valvelow_side_outT12-C1-16Injector 5injector_outcorroborated
OEM-2-JInjector 4injector_outT12-C1-25Injector 4injector_outcorroborated
OEM-2-KA/C clutch relaylow_side_outT12-C1-3PWM 3low_side_outcorroborated
OEM-2-LNC————single_source
OEM-2-MFuel pump relaylow_side_outT12-C3-22PWM 4low_side_outcorroborated
OEM-2-NVTCS solenoid (intake butterflies)low_side_outT12-C1-15Injector 6injector_outcorroborated
OEM-2-OFuel pump relay (non-immobiliser)low_side_outT12-C3-24PWM 6low_side_outcorroborated
OEM-2-PISC valve +14V feedpower_inRLY1-R-COIL+ + RLY1-R-IN + RLY2-R-COIL+ + RLY2-R-IN + T12-C1-31Relay coil positive (switched +12 V) + Relay contact input (switched +12 V) + Relay coil positive (switched +12 V) + Relay contact input (switched +12 V) + Ignition 12v Inpower_in + power_outcorroborated
OEM-2-QISC valve low sidelow_side_outT12-C3-4PWM 9low_side_outcorroborated
OEM-2-RMalfunction indicator lamp (MIL)low_side_outT12-C1-24Injector 7injector_outcorroborated
OEM-3-APower groundgroundT12-C1-13 + T12-C1-14Power Ground 1 + Power Ground 2groundcorroborated
OEM-3-BPower groundgroundT12-C1-13 + T12-C1-14Power Ground 1 + Power Ground 2groundcorroborated
OEM-3-CPurge solenoid valvelow_side_outT12-C1-23Injector 8injector_outcorroborated
OEM-3-DEGR boost solenoid————conflict
OEM-3-ENC————single_source
OEM-3-FIgnition 1 (coils 1+4, wasted spark)ignition_outT12-C1-10Coil 1ignition_outcorroborated
OEM-3-GNC————single_source
OEM-3-HMain relaylow_side_outT12-C3-23PWM 5low_side_outcorroborated
OEM-3-IIgnition 2 (coils 2+3, wasted spark)ignition_outT12-C1-18Coil 2ignition_outcorroborated
OEM-3-JFront O2 heaterlow_side_outT12-C3-9Lambda 1 Heater Negativelow_side_outcorroborated
OEM-3-KEVAP leak detection pumplow_side_outT12-C1-21Injector 9injector_outcorroborated
OEM-3-LNC————single_source
OEM-3-MAlternator controllow_side_outT12-C1-22Injector 10injector_outcorroborated
OEM-3-NNC————single_source
OEM-3-OTachometer outputtacho_out———corroborated
OEM-3-PRear O2 heaterlow_side_outT12-C3-3Lambda 2 Heater Negativelow_side_outcorroborated
OEM-3-QData link connector (K-line)serial———corroborated
OEM-3-RNC————single_source
OEM-3-SImmobiliserdigital_inT12-C2-4Digital 1digital_incorroborated
OEM-3-TVehicle speeddigital_inT12-C2-2Wheel 1digital_incorroborated
OEM-3-UCharge lamplow_side_outT12-C1-8Injector 11injector_outcorroborated
OEM-3-VCam position (CMP)trigger_inT12-C2-22Cam 1trigger_incorroborated
OEM-3-WNC————single_source
OEM-3-XNC————single_source
OEM-3-YCrank position (CKP)trigger_inT12-C2-12Cranktrigger_incorroborated
OEM-3-ZNC————single_source
OEM-4-APower groundgroundT12-C1-13 + T12-C1-14Power Ground 1 + Power Ground 2groundcorroborated
OEM-4-AARear O2 signallambda_nb_inT12-C2-6Analogue 4analog_incorroborated
OEM-4-ABNC————single_source
OEM-4-ACData link connector (DLC TEN, turbo)serial———BrYsingle_source
OEM-4-ADFuel levelanalog_inT12-C2-19Analogue 6analog_incorroborated
OEM-4-AEBARO/MAP sensor (turbo boost pressure)analog_inT12-C2-5Analogue 3analog_inLYsingle_source
OEM-4-AFECU power +14V (main relay)power_inRLY1-R-COIL+ + RLY1-R-IN + RLY2-R-COIL+ + RLY2-R-IN + T12-C1-31Relay coil positive (switched +12 V) + Relay contact input (switched +12 V) + Relay coil positive (switched +12 V) + Relay contact input (switched +12 V) + Ignition 12v Inpower_in + power_outcorroborated
OEM-4-AGConstant +12Vpower_inT12-C3-26Permanent 12vpower_incorroborated
OEM-4-AHEVAP leak detection pump solenoid valvelow_side_outT12-C1-32Injector 12injector_outcorroborated
OEM-4-BBrake switchdigital_inT12-C2-8Digital 2digital_incorroborated
OEM-4-CPower steering pressure switchdigital_inT12-C2-11Digital 3digital_incorroborated
OEM-4-DBoost control solenoid (turbo)high_side_outRLY1-R-OUTRelay contact output (switched +12 V to load)power_outYsingle_source
OEM-4-EBoost control solenoid (turbo)high_side_outRLY2-R-OUTRelay contact output (switched +12 V to load)power_outYsingle_source
OEM-4-FA/C requestdigital_inT12-C2-14Digital 4digital_incorroborated
OEM-4-GNC————single_source
OEM-4-HNeutral switchdigital_inT12-C2-15Digital 5digital_incorroborated
OEM-4-IClutch switchdigital_inT12-C2-27Digital 6digital_incorroborated
OEM-4-JVTCS vacuum switchdigital_inT12-C3-19Digital 7digital_incorroborated
OEM-4-KNC————single_source
OEM-4-L+5V sensor supplyvrefT12-C2-245v Outputvrefcorroborated
OEM-4-MKnock sensorknock_inT12-C3-31Knock 1knock_incorroborated
OEM-4-NIntake air temperature (IAT)temp_inT12-C2-17Thermistor 3temp_incorroborated
OEM-4-OSignal groundsensor_groundT12-C2-21 + T12-C2-33Sensor Ground + Sensor Groundsensor_groundcorroborated
OEM-4-PCoolant temperature (ECT)temp_inT12-C2-7Thermistor 1temp_incorroborated
OEM-4-QNC————single_source
OEM-4-RIntake air temperature 2 (IAT2, turbo)temp_inT12-C2-25Thermistor 2temp_inVYsingle_source
OEM-4-SIgnition switch (IG1) sensedigital_in———corroborated
OEM-4-TGenerator output voltage (terminal P)————corroborated
OEM-4-UNC————single_source
OEM-4-VThrottle position (TPS)analog_inT12-C2-1Analogue 2analog_incorroborated
OEM-4-WFront O2 signallambda_nb_inT12-C2-18Analogue 5analog_incorroborated
OEM-4-XMass air flow (MAF)analog_inT12-C2-10Analogue 1analog_incorroborated
OEM-4-YNC————single_source
OEM-4-ZTCM (automatic only)————corroborated

Cut list

WireFromToGauge (mm²)ColourLengthSignalIdent
W1OEM-2-PSP-14V-10.85no routeISC valve +14V feed—
W2OEM-4-AFSP-14V-10.85no routeECU power +14V (main relay)—
W3SP-14V-1T12-C1-310.85no routeIgnition 12v In—
W4OEM-4-AGT12-C3-260.85no routeConstant +12V—
W5OEM-3-ASP-GND-10.85no routePower ground—
W6OEM-3-BSP-GND-10.85no routePower ground—
W7OEM-4-ASP-GND-10.85no routePower ground—
W8SP-GND-1T12-C1-130.85no routePower Ground 1—
W9SP-GND-1T12-C1-140.85no routePower Ground 2—
W10OEM-4-OSP-0V-10.5no routeSignal ground—
W11SP-0V-1T12-C2-210.5no routeSensor Ground—
W12SP-0V-1T12-C2-330.5no routeSensor Ground—
W13OEM-4-LT12-C2-240.5no route+5V sensor supply—
W14OEM-3-YT12-C2-120.5no routeCrank position (CKP)—
W15OEM-3-VT12-C2-220.5no routeCam position (CMP)—
W16OEM-4-MT12-C3-310.5no routeKnock sensor—
W17OEM-3-FT12-C1-100.5no routeIgnition 1 (coils 1+4, wasted spark)—
W18OEM-3-IT12-C1-180.5no routeIgnition 2 (coils 2+3, wasted spark)—
W19OEM-2-AT12-C1-90.5no routeInjector 1—
W20OEM-2-DT12-C1-170.5no routeInjector 2—
W21OEM-2-GT12-C1-340.5no routeInjector 3—
W22OEM-2-JT12-C1-250.5no routeInjector 4—
W23OEM-4-XT12-C2-100.5no routeMass air flow (MAF)—
W24OEM-4-VT12-C2-10.5no routeThrottle position (TPS)—
W25OEM-4-PT12-C2-70.5no routeCoolant temperature (ECT)—
W26OEM-2-BT12-C1-50.5no routeCooling fan relay—
W27OEM-2-CT12-C1-40.5no routeCondenser fan relay—
W28OEM-2-KT12-C1-30.5no routeA/C clutch relay—
W29OEM-2-MT12-C3-220.5no routeFuel pump relay—
W30OEM-3-HT12-C3-230.5no routeMain relay—
W31OEM-2-OT12-C3-240.5no routeFuel pump relay (non-immobiliser)—
W32OEM-4-DRLY1-R-OUT0.5no routeBoost control solenoid (turbo)—
W33SP-14V-1RLY1-R-IN0.5no routeRelay contact input (switched +12 V)—
W34SP-14V-1RLY1-R-COIL+0.5no routeRelay coil positive (switched +12 V)—
W35RLY1-R-COIL-T12-C3-250.5no routeRelay coil negative (ECU low-side driver)—
W36OEM-4-ERLY2-R-OUT0.5no routeBoost control solenoid (turbo)—
W37SP-14V-1RLY2-R-IN0.5no routeRelay contact input (switched +12 V)—
W38SP-14V-1RLY2-R-COIL+0.5no routeRelay coil positive (switched +12 V)—
W39RLY2-R-COIL-T12-C3-100.5no routeRelay coil negative (ECU low-side driver)—
W40OEM-3-JT12-C3-90.5no routeFront O2 heater—
W41OEM-3-PT12-C3-30.5no routeRear O2 heater—
W42OEM-2-QT12-C3-40.5no routeISC valve low side—
W43OEM-2-ET12-C3-280.5no routeEGR valve—
W44OEM-2-FT12-C3-290.5no routeEGR valve—
W45OEM-2-HT12-C3-300.5no routeEGR valve—
W46OEM-2-IT12-C1-160.5no routeEGR valve—
W47OEM-2-NT12-C1-150.5no routeVTCS solenoid (intake butterflies)—
W48OEM-2-RT12-C1-240.5no routeMalfunction indicator lamp (MIL)—
W49OEM-3-CT12-C1-230.5no routePurge solenoid valve—
W50OEM-3-KT12-C1-210.5no routeEVAP leak detection pump—
W51OEM-3-MT12-C1-220.5no routeAlternator control—
W52OEM-3-UT12-C1-80.5no routeCharge lamp—
W53OEM-4-AHT12-C1-320.5no routeEVAP leak detection pump solenoid valve—
W54OEM-4-AET12-C2-50.5no routeBARO/MAP sensor (turbo boost pressure)—
W55OEM-4-AAT12-C2-60.5no routeRear O2 signal—
W56OEM-4-WT12-C2-180.5no routeFront O2 signal—
W57OEM-4-RT12-C2-250.5no routeIntake air temperature 2 (IAT2, turbo)—
W58OEM-4-NT12-C2-170.5no routeIntake air temperature (IAT)—
W59OEM-4-ADT12-C2-190.5no routeFuel level—
W60OEM-3-TT12-C2-20.5no routeVehicle speed—
W61OEM-3-ST12-C2-40.5no routeImmobiliser—
W62OEM-4-BT12-C2-80.5no routeBrake switch—
W63OEM-4-CT12-C2-110.5no routePower steering pressure switch—
W64OEM-4-FT12-C2-140.5no routeA/C request—
W65OEM-4-HT12-C2-150.5no routeNeutral switch—
W66OEM-4-IT12-C2-270.5no routeClutch switch—
W67OEM-4-JT12-C3-190.5no routeVTCS vacuum switch—

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)55.000ea

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (10)

SeverityCodeSubjectMessage
errorPHYS_REQUIRED_OPENT12-C3-27T12-C3-27 "Permanent 12v" is required but not wired.
infoNET_FAMILYOEM-2-I ↔ T12-C1-16OEM-2-I "EGR valve" [low_side_out] is wired to T12-C1-16 "Injector 5" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-2-N ↔ T12-C1-15OEM-2-N "VTCS solenoid (intake butterflies)" [low_side_out] is wired to T12-C1-15 "Injector 6" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-2-R ↔ T12-C1-24OEM-2-R "Malfunction indicator lamp (MIL)" [low_side_out] is wired to T12-C1-24 "Injector 7" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-3-C ↔ T12-C1-23OEM-3-C "Purge solenoid valve" [low_side_out] is wired to T12-C1-23 "Injector 8" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-3-K ↔ T12-C1-21OEM-3-K "EVAP leak detection pump" [low_side_out] is wired to T12-C1-21 "Injector 9" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-3-M ↔ T12-C1-22OEM-3-M "Alternator control" [low_side_out] is wired to T12-C1-22 "Injector 10" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-3-U ↔ T12-C1-8OEM-3-U "Charge lamp" [low_side_out] is wired to T12-C1-8 "Injector 11" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-4-AH ↔ T12-C1-32OEM-4-AH "EVAP leak detection pump solenoid valve" [low_side_out] is wired to T12-C1-32 "Injector 12" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoUNMAPPEDOEM7 optional OEM pins are not mapped: OEM-3-D EGR boost solenoid; OEM-3-O Tachometer output; OEM-3-Q Data link connector (K-line); OEM-4-AC Data link connector (DLC TEN, turbo); OEM-4-S Ignition switch (IG1) sense; OEM-4-T Generator output voltage (terminal P); OEM-4-Z TCM (automatic only)

Accepted (0)

CodeSubjectReasonBy

Notes

Auto-mapped by auto_map() from the library pin data on 2026-10-17. Review every wire against both manuals before building. Open items: - T12-C3 27: Permanent 12v: required by DTAFast T12 but no stock pin feeds it; wire by hand Not wired: - OEM-4 S: Ignition switch (IG1) sense: key-on 12 V sense — optional in a swap (the main relay is energized from keyed 12 V, not from this pin); DTAFast T12 has no dedicated key-on input - OEM-3 O: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on DTAFast T12 - OEM-3 Q: Data link connector (K-line): no free k_line on DTAFast T12 - OEM-4 AC: Data link connector (DLC TEN, turbo): no free k_line on DTAFast T12 - OEM-3 D: EGR boost solenoid: not classified in the library; wire by hand - OEM-4 T: Generator output voltage (terminal P): not classified in the library; wire by hand - OEM-4 Z: TCM (automatic only): not classified in the library; wire by hand

Sources

ReliabilityKindTitleURLArchiveCapturedSHA-256
4oem_manual2005 Mazda MX-5 Miata Engine Performance Control System (PCM terminal voltage reference, BP and BP WITH TC)https://trull.org/alex/pubmirror/www.mellens.net/mazda/Mazda-Miata-2005/engine_control_system.pdf———
4vendor_docAdaptronic eSel039 Select Plugin ECU for Mazda MX5 / Miata NB8B/C (OEM ECU pinout)https://www.miataturbo.net/attachments/ecus-tuning-54/04-msm-ecu-pinout-104032/nb8bc_oem_ecu_pinouts-224948d1602912806———
4vendor_docBosch relay catalogue (mini ISO relays)https://www.bosch-ibusiness.com/media/downloads/kataloge/relay/2025_10_bosch_relay_catalogue.pdfarchive2026-10-0520344cff1ef3
4vendor_docDTAFast T12+ ECU wiring diagram (served for T12 and T12+)https://cdn.shopify.com/s/files/1/0848/7508/4108/files/T12PLUS_Wiring-Diagram.pdf?v=1728572014———
4community_copyHonda S2000 Service Manual 2000–2008, Fuel and Emissions Systemshttps://www.s2000.wiki/view/images/7/7f/Service_Manual_2000-2008.pdfarchive2026-10-05a470cfc928e9
4vendor_docLink G4X MX5NB2X install manual (NB2 2001-05)https://linkecu.com/documentation/MX5XNB2.pdfarchive2026-10-05741efdd9f2c8
4vendor_docOmron G8V-RH-1C7T-R-DC12 high-current micro 280 automotive relay datasheethttps://www.alldatasheet.com/datasheet-pdf/pdf/333797/OMRON/G8V-RH-1C7T-R-DC12.html—2026-10-05764a0505a941