← Back

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 · 2026-10-11

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 errors5: read the Findings page before cutting any wire
Size of the job2 wires · 4 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-4-AET12-C2-100.5☐☐☐☐☐☐☐
W2OEM-4-RT12-C2-70.5☐☐☐☐☐☐☐

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
No supply/ground nets found to cross-check.

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

Revisions

RevLabelByDate
No revisions yet.

Schematic

OEM-2OEM-3OEM-4T12-C1T12-C2T12-C3

Connectors

OEM-4

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
ACData link connector (DLC TEN, turbo)————————
AEBARO/MAP sensor (turbo boost pressure)—W1—0.5T12-C2-10———
DBoost control solenoid (turbo)————————
EBoost control solenoid (turbo)————————
RIntake air temperature 2 (IAT2, turbo)—W2—0.5T12-C2-7———

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————————
4PWM 2————————
5PWM 1————————
6Motor 1 +————————
7Motor 1 -————————
8Injector 11————————
9Injector 1————————
10Coil 1————————
11Coil 5————————
12Coil 7————————
13Power Ground 1————————
14Power Ground 2————————
15Injector 6————————
16Injector 5————————
17Injector 2————————
18Coil 2————————
19Coil 8————————
20Coil 9————————
21Injector 9————————
22Injector 10————————
23Injector 8————————
24Injector 7————————
25Injector 4————————
26Coil 4————————
27Coil 6————————
28Coil 10————————
29Motor 2 +————————
30Motor 2 -————————
31Ignition 12v In————————
32Injector 12————————
33Coil 12————————
34Injector 3————————

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————————
2Wheel 1————————
3Analogue 10————————
4Digital 1————————
5Analogue 3————————
6Analogue 4————————
7Thermistor 1—W2—0.5OEM-4-R———
8Digital 2————————
95v Output————————
10Analogue 1—W1—0.5OEM-4-AE———
11Digital 3————————
12Crank————————
13Analogue 12————————
14Digital 4————————
15Digital 5————————
16Analogue 11————————
17Thermistor 3————————
18Analogue 5————————
19Analogue 6————————
20Wheel 2————————
21Sensor Ground————————
22Cam 1————————
23Cam 3————————
245v Output————————
25Thermistor 2————————
26CAN High————————
27Digital 6————————
28CAN Low————————
29Cam 2————————
30Cam 4————————
31Wheel 3————————
32Wheel 4————————
33Sensor Ground————————
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————————
4PWM 9————————
5Lambda 2 Trim Resistor————————
6Lambda 2 Nernst Voltage————————
7Lambda 1 Pump Current————————
8Lambda 1 VGND————————
9Lambda 1 Heater Negative————————
10PWM 8————————
11Lambda 1 Trim Resistor————————
12Lambda 1 Nernst Voltage————————
13Analogue 13————————
14Analogue 14————————
15Analogue 15————————
16Analogue 16————————
17Analogue 7————————
18Analogue 8————————
19Digital 7————————
20Digital 8————————
21Digital 9————————
22PWM 4————————
23PWM 5————————
24PWM 6————————
25PWM 7————————
26Permanent 12v————————
27Permanent 12v————————
28PWM 10————————
29PWM 11————————
30PWM 12————————
31Knock 1————————
32Knock 2————————
33CAN 2 High————————
34CAN 2 Low————————

Pin map

OEM pointOEM functionOEM familyTarget pointTarget functionTarget familyWire colourEvidence
OEM-4-ACData link connector (DLC TEN, turbo)serial———BrYsingle_source
OEM-4-AEBARO/MAP sensor (turbo boost pressure)analog_inT12-C2-10Analogue 1analog_inLYsingle_source
OEM-4-DBoost control solenoid (turbo)high_side_out———Ysingle_source
OEM-4-EBoost control solenoid (turbo)high_side_out———Ysingle_source
OEM-4-RIntake air temperature 2 (IAT2, turbo)temp_inT12-C2-7Thermistor 1temp_inVYsingle_source

Cut list

WireFromToGauge (mm²)ColourLengthSignalIdent
W1OEM-4-AET12-C2-100.5no routeBARO/MAP sensor (turbo boost pressure)—
W2OEM-4-RT12-C2-70.5no routeIntake air temperature 2 (IAT2, turbo)—

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)2.000ea

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (6)

SeverityCodeSubjectMessage
errorPHYS_REQUIRED_OPENT12-C1-13T12-C1-13 "Power Ground 1" is required but not wired.
errorPHYS_REQUIRED_OPENT12-C1-14T12-C1-14 "Power Ground 2" is required but not wired.
errorPHYS_REQUIRED_OPENT12-C1-31T12-C1-31 "Ignition 12v In" is required but not wired.
errorPHYS_REQUIRED_OPENT12-C3-26T12-C3-26 "Permanent 12v" is required but not wired.
errorPHYS_REQUIRED_OPENT12-C3-27T12-C3-27 "Permanent 12v" is required but not wired.
infoUNMAPPEDOEM3 optional OEM pins are not mapped: OEM-4-AC Data link connector (DLC TEN, turbo); OEM-4-D Boost control solenoid (turbo); OEM-4-E Boost control solenoid (turbo)

Accepted (0)

CodeSubjectReasonBy

Notes

Auto-mapped by auto_map() from the library pin data on 2026-10-11. Review every wire against both manuals before building. Open items: - Main-relay feed: no ecu_main_power pin on the stock or the new ECU - T12-C1 13: Power Ground 1: required by DTAFast T12 but no stock pin feeds it; wire by hand - T12-C1 14: Power Ground 2: required by DTAFast T12 but no stock pin feeds it; wire by hand - T12-C1 31: Ignition 12v In: required by DTAFast T12 but no stock pin feeds it; wire by hand - T12-C3 26: Permanent 12v: required by DTAFast T12 but no stock pin feeds it; wire by hand - T12-C3 27: Permanent 12v: required by DTAFast T12 but no stock pin feeds it; wire by hand Not wired: - OEM-4 D: Boost control solenoid (turbo): no free high_side/ls_hs on DTAFast T12 - OEM-4 E: Boost control solenoid (turbo): no free high_side/ls_hs on DTAFast T12 - OEM-4 AC: Data link connector (DLC TEN, turbo): no free k_line on DTAFast T12

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_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———