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MX-5 Miata NB2 2001-05 (BP-Z3, VVT; excludes Mazdaspeed) → ECUMASTER EMU Black (auto)

MX-5 Miata NB2 2001-05 (BP-Z3, VVT; excludes Mazdaspeed) — ECUMASTER — EMU Black
Drawn by Michael Gnankou · Rev 0 · proposal · 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.

Install modifications

Steps on the car itself, outside the harness. Every harness for this car inherits them.

  • Re-route the pressure-sensor vacuum hose to the intake manifoldrequired

    Re-route the pressure sensor's (Mazda "EGR boost sensor", pin 4AE) vacuum hose directly to the intake manifold, bypassing the EGR boost solenoid. The stock ECU multiplexes baro + MAP through that solenoid: with it off the sensor reads atmosphere, with it energized it reads manifold. After re-routing the sensor reads MAP only, so the standalone needs its own barometric source — its onboard baro sensor if fitted, or a separate baro sensor on a spare analog input. (Alternative, not recommended: keep the hose stock and have the ECU energize the solenoid permanently via a low-side output switched with ignition; this costs an output.)

    Why: With the solenoid off (its default) the sensor reads atmospheric pressure, not manifold pressure, so a standalone that uses this sensor as its MAP input would read the wrong value.

    Where: EGR boost solenoid and the pressure sensor's vacuum hose (sensor signal 4AE).

    Source: Justin Barrera — Miata NA/NB wiring corrections

Statusproposal · not yet verified: nobody has reported building and running this harness
Open errorsnone
Size of the job53 wires · 8 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-2-PSP-14V-10.85☐☐☐☐☐☐☐
W2OEM-4-AFSP-14V-10.85☐☐☐☐☐☐☐
W3OEM-4-DSP-14V-10.85☐☐☐☐☐☐☐
W4SP-14V-1EMUBLACK-Black-130.85☐☐☐☐☐☐☐
W5OEM-3-ASP-GND-10.85☐☐☐☐☐☐☐
W6OEM-3-BSP-GND-10.85☐☐☐☐☐☐☐
W7OEM-4-ASP-GND-10.85☐☐☐☐☐☐☐
W8SP-GND-1EMUBLACK-Black-270.85☐☐☐☐☐☐☐
W9SP-GND-1EMUBLACK-Black-280.85☐☐☐☐☐☐☐
W10SP-GND-1EMUBLACK-Grey-170.85☐☐☐☐☐☐☐
W11SP-GND-1EMUBLACK-Grey-240.85☐☐☐☐☐☐☐
W12OEM-4-OSP-0V-10.5☐☐☐☐☐☐☐
W13SP-0V-1EMUBLACK-Black-290.5☐☐☐☐☐☐☐
W14SP-0V-1EMUBLACK-Black-380.5☐☐☐☐☐☐☐
W15SP-0V-1EMUBLACK-Black-390.5☐☐☐☐☐☐☐
W16OEM-4-LEMUBLACK-Black-260.5☐☐☐☐☐☐☐
W17OEM-3-YEMUBLACK-Black-80.5☐☐☐☐☐☐☐
W18OEM-3-VEMUBLACK-Black-210.5☐☐☐☐☐☐☐
W19OEM-4-MEMUBLACK-Black-30.5☐☐☐☐☐☐☐
W20OEM-3-FEMUBLACK-Grey-80.5☐☐☐☐☐☐☐
W21OEM-3-IEMUBLACK-Grey-160.5☐☐☐☐☐☐☐
W22OEM-2-AEMUBLACK-Grey-70.5☐☐☐☐☐☐☐
W23OEM-2-DEMUBLACK-Grey-150.5☐☐☐☐☐☐☐
W24OEM-2-GEMUBLACK-Grey-230.5☐☐☐☐☐☐☐
W25OEM-2-JEMUBLACK-Grey-60.5☐☐☐☐☐☐☐
W26OEM-4-SEMUBLACK-Grey-180.5☐☐☐☐☐☐☐
W27OEM-2-BEMUBLACK-Grey-210.5☐☐☐☐☐☐☐
W28OEM-2-CEMUBLACK-Grey-130.5☐☐☐☐☐☐☐
W29OEM-2-KEMUBLACK-Grey-50.5☐☐☐☐☐☐☐
W30OEM-2-MEMUBLACK-Grey-200.5☐☐☐☐☐☐☐
W31OEM-3-HEMUBLACK-Grey-120.5☐☐☐☐☐☐☐
W32OEM-2-OEMUBLACK-Grey-40.5☐☐☐☐☐☐☐
W33OEM-3-JEMUBLACK-Grey-190.5☐☐☐☐☐☐☐
W34OEM-3-PEMUBLACK-Grey-100.5☐☐☐☐☐☐☐
W35OEM-2-QEMUBLACK-Grey-140.5☐☐☐☐☐☐☐
W36OEM-2-EEMUBLACK-Grey-220.5☐☐☐☐☐☐☐
W37OEM-2-FEMUBLACK-Grey-20.5☐☐☐☐☐☐☐
W38OEM-2-HEMUBLACK-Grey-110.5☐☐☐☐☐☐☐
W39OEM-2-IEMUBLACK-Grey-30.5☐☐☐☐☐☐☐
W40OEM-4-XEMUBLACK-Black-310.5☐☐☐☐☐☐☐
W41OEM-4-AEEMUBLACK-Black-40.5☐☐☐☐☐☐☐
W42OEM-4-VEMUBLACK-Black-180.5☐☐☐☐☐☐☐
W43OEM-4-AAEMUBLACK-Black-170.5☐☐☐☐☐☐☐
W44OEM-4-WEMUBLACK-Black-300.5☐☐☐☐☐☐☐
W45OEM-4-PEMUBLACK-Black-320.5☐☐☐☐☐☐☐
W46OEM-4-NEMUBLACK-Black-50.5☐☐☐☐☐☐☐
W47OEM-4-ADEMUBLACK-Black-90.5☐☐☐☐☐☐☐
W48OEM-3-TEMUBLACK-Black-200.5☐☐☐☐☐☐☐
W49OEM-3-SEMUBLACK-Black-100.5☐☐☐☐☐☐☐
W50OEM-4-BEMUBLACK-Black-230.5☐☐☐☐☐☐☐
W51OEM-4-CEMUBLACK-Black-360.5☐☐☐☐☐☐☐
W52OEM-4-FEMUBLACK-Black-350.5☐☐☐☐☐☐☐
W53OEM-4-HEMUBLACK-Black-370.5☐☐☐☐☐☐☐

Bench test (before first power-up)

Pre-power install steps (make these cuts/modifications on the car first, then verify the checks below): Re-route the pressure-sensor vacuum hose to the intake manifold.

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
1EMUBLACK-Black-13EMUBLACK-Black-27open (OL)+12 V supply must not touch power ground
2EMUBLACK-Black-13EMUBLACK-Black-29open (OL)+12 V supply must not touch sensor ground
3EMUBLACK-Black-26EMUBLACK-Black-29open (OL)5 V sensor reference must not touch sensor ground
4EMUBLACK-Black-13EMUBLACK-Black-26open (OL)+12 V supply must not touch 5 V sensor reference
5EMUBLACK-Black-27EMUBLACK-Black-26open (OL)power ground must not touch 5 V sensor reference

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

Revisions

RevLabelByDate
No revisions yet.

Schematic

EMUBLACK-BlackEMUBLACK-GreyOEM-2OEM-3OEM-4SP-0VSP-14VSP-GND

Connectors

EMUBLACK-Black

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Ignition coil #5————————
10Switch #1 In—W49—0.5OEM-3-S———
11RS232 TXD————————
12CAN H————————
13Battery +12V—W4—0.85SP-14V-1———
14Ignition coil #4————————
15EGT in #2————————
16Knock Sensor in #2————————
17Analog In #3—W43—0.5OEM-4-AA———
18TPS In—W42—0.5OEM-4-V———
19WBO Ip————————
2EGT in #1————————
20VSS In—W48—0.5OEM-3-T———
21Camsync In #1—W18—0.5OEM-3-V———
22WBO Rcal————————
23Switch #2 In—W50—0.5OEM-4-B———
24RS232 RXD————————
25CAN L————————
26+5V supply—W16—0.5OEM-4-L———
27Power Ground—W8—0.85SP-GND-1———
28Ecu Ground—W9—0.85SP-GND-1———
29Sensor Ground—W13—0.5SP-0V-1———
3Knock Sensor in #1—W19—0.5OEM-4-M———
30Analog In #4—W44—0.5OEM-4-W———
31Analog In #1—W40—0.5OEM-4-X———
32IAT In—W45—0.5OEM-4-P———
33WBO VGND————————
34+5V supply————————
35Analog In #5—W52—0.5OEM-4-F———
36Switch #3 In—W51—0.5OEM-4-C———
37Analog In #6—W53—0.5OEM-4-H———
38Sensor Ground—W14—0.5SP-0V-1———
39Sensor Ground—W15—0.5SP-0V-1———
4Analog In #2—W41—0.5OEM-4-AE———
5CLT In—W46—0.5OEM-4-N———
6WBO Vs————————
7Camsync In #2————————
8Primary trigger—W17—0.5OEM-3-Y———
9Flex Fuel In—W47—0.5OEM-4-AD———

EMUBLACK-Grey

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1Ignition coil #6————————
10H-Bridge #1 Winding B—W34—0.5OEM-3-P———
11H-Bridge #2 Winding B—W38—0.5OEM-2-H———
12AUX 5—W31—0.5OEM-3-H———
13AUX 2 / Injector #8—W28—0.5OEM-2-C———
14Injector #5—W35—0.5OEM-2-Q———
15Injector #2—W23—0.5OEM-2-D———
16Ignition coil #2—W21—0.5OEM-3-I———
17Power Ground—W10—0.85SP-GND-1———
18Ignition +12V—W26—0.5OEM-4-S———
19WBO Heater—W33—0.5OEM-3-J———
2H-Bridge #1 Winding A—W37—0.5OEM-2-F———
20AUX 4 / Tacho—W30—0.5OEM-2-M———
21AUX 1 / Injector #7—W27—0.5OEM-2-B———
22Injector #6—W36—0.5OEM-2-E———
23Injector #3—W24—0.5OEM-2-G———
24Power Ground—W11—0.85SP-GND-1———
3H-Bridge #2 Winding A—W39—0.5OEM-2-I———
4AUX 6—W32—0.5OEM-2-O———
5AUX 3—W29—0.5OEM-2-K———
6Injector #4—W25—0.5OEM-2-J———
7Injector #1—W22—0.5OEM-2-A———
8Ignition coil #1—W20—0.5OEM-3-F———
9Ignition coil #3————————

OEM-2

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
AInjector 1—W22—0.5EMUBLACK-Grey-7———
BCooling fan relay—W27—0.5EMUBLACK-Grey-21———
CCondenser fan relay—W28—0.5EMUBLACK-Grey-13———
DInjector 2—W23—0.5EMUBLACK-Grey-15———
EEGR valve—W36—0.5EMUBLACK-Grey-22———
FEGR valve—W37—0.5EMUBLACK-Grey-2———
GInjector 3—W24—0.5EMUBLACK-Grey-23———
HEGR valve—W38—0.5EMUBLACK-Grey-11———
IEGR valve—W39—0.5EMUBLACK-Grey-3———
JInjector 4—W25—0.5EMUBLACK-Grey-6———
KA/C clutch relay—W29—0.5EMUBLACK-Grey-5———
LNC————————
MFuel pump relay—W30—0.5EMUBLACK-Grey-20———
NVTCS solenoid (intake butterflies)————————
OFuel pump relay (non-immobiliser)—W32—0.5EMUBLACK-Grey-4———
PISC valve +14V feed—W1—0.85SP-14V-1———
QISC valve low side—W35—0.5EMUBLACK-Grey-14———
RMalfunction indicator lamp (MIL)————————

OEM-3

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
APower ground—W5—0.85SP-GND-1———
BPower ground—W6—0.85SP-GND-1———
CPurge solenoid valve————————
DEGR boost solenoid————————
ENC————————
FIgnition 1 (coils 1+4, wasted spark)—W20—0.5EMUBLACK-Grey-8———
GNC————————
HMain relay—W31—0.5EMUBLACK-Grey-12———
IIgnition 2 (coils 2+3, wasted spark)—W21—0.5EMUBLACK-Grey-16———
JFront O2 heater—W33—0.5EMUBLACK-Grey-19———
KEVAP leak detection pump————————
LNC————————
MAlternator control————————
NNC————————
OTachometer output————————
PRear O2 heater—W34—0.5EMUBLACK-Grey-10———
QData link connector (K-line)————————
RNC————————
SImmobiliser—W49—0.5EMUBLACK-Black-10———
TVehicle speed—W48—0.5EMUBLACK-Black-20———
UCharge lamp————————
VCam position (CMP)—W18—0.5EMUBLACK-Black-21———
WNC————————
XNC————————
YCrank position (CKP)—W17—0.5EMUBLACK-Black-8———
ZNC————————

OEM-4

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
APower ground—W7—0.85SP-GND-1———
AARear O2 signal—W43—0.5EMUBLACK-Black-17———
ABNC————————
ACTCM (automatic only)————————
ADFuel level—W47—0.5EMUBLACK-Black-9———
AEPressure sensor (Mazda: EGR boost sensor)—W41—0.5EMUBLACK-Black-4———
AFECU power +14V (main relay)—W2—0.85SP-14V-1———
AGConstant +12V————————
AHEVAP leak detection pump solenoid valve————————
BBrake switch—W50—0.5EMUBLACK-Black-23———
CPower steering pressure switch—W51—0.5EMUBLACK-Black-36———
DVVT oil-control solenoid +12V feed—W3—0.85SP-14V-1———
EDiagnostic (DLC TEN) (NA)————————
FA/C request—W52—0.5EMUBLACK-Black-35———
GNC————————
HNeutral switch—W53—0.5EMUBLACK-Black-37———
IClutch switch————————
JVTCS vacuum switch————————
KNC————————
L+5V sensor supply—W16—0.5EMUBLACK-Black-26———
MKnock sensor—W19—0.5EMUBLACK-Black-3———
NIntake air temperature (IAT)—W46—0.5EMUBLACK-Black-5———
OSignal ground—W12—0.5SP-0V-1———
PCoolant temperature (ECT)—W45—0.5EMUBLACK-Black-32———
QNC————————
RVVT oil-control solenoid (low-side control)————————
SIgnition switch (IG1) sense—W26—0.5EMUBLACK-Grey-18———
TGenerator output voltage (terminal P)————————
UNC————————
VThrottle position (TPS)—W42—0.5EMUBLACK-Black-18———
WFront O2 signal—W44—0.5EMUBLACK-Black-30———
XMass air flow (MAF)—W40—0.5EMUBLACK-Black-31———
YNC————————
ZTCM (automatic only)————————

SP-0V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W12—0.5OEM-4-O———
1——W13—0.5EMUBLACK-Black-29———
1——W14—0.5EMUBLACK-Black-38———
1——W15—0.5EMUBLACK-Black-39———

SP-14V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W1—0.85OEM-2-P———
1——W2—0.85OEM-4-AF———
1——W3—0.85OEM-4-D———
1——W4—0.85EMUBLACK-Black-13———

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—0.85EMUBLACK-Black-27———
1——W9—0.85EMUBLACK-Black-28———
1——W10—0.85EMUBLACK-Grey-17———
1——W11—0.85EMUBLACK-Grey-24———

Pin map

OEM pointOEM functionOEM familyTarget pointTarget functionTarget familyWire colourEvidence
OEM-2-AInjector 1injector_outEMUBLACK-Grey-7Injector #1injector_outYBsingle_source
OEM-2-BCooling fan relaylow_side_outEMUBLACK-Grey-21AUX 1 / Injector #7low_side_outRYsingle_source
OEM-2-CCondenser fan relaylow_side_outEMUBLACK-Grey-13AUX 2 / Injector #8low_side_outLWsingle_source
OEM-2-DInjector 2injector_outEMUBLACK-Grey-15Injector #2injector_outVGsingle_source
OEM-2-EEGR valvelow_side_outEMUBLACK-Grey-22Injector #6injector_outLgsingle_source
OEM-2-FEGR valvelow_side_outEMUBLACK-Grey-2H-Bridge #1 Winding Ahbridge_outWGsingle_source
OEM-2-GInjector 3injector_outEMUBLACK-Grey-23Injector #3injector_outYRsingle_source
OEM-2-HEGR valvelow_side_outEMUBLACK-Grey-11H-Bridge #2 Winding Bhbridge_outPBsingle_source
OEM-2-IEGR valvelow_side_outEMUBLACK-Grey-3H-Bridge #2 Winding Ahbridge_outPsingle_source
OEM-2-JInjector 4injector_outEMUBLACK-Grey-6Injector #4injector_outYGsingle_source
OEM-2-KA/C clutch relaylow_side_outEMUBLACK-Grey-5AUX 3low_side_outLBsingle_source
OEM-2-LNC————unverified
OEM-2-MFuel pump relaylow_side_outEMUBLACK-Grey-20AUX 4 / Tacholow_side_outRWsingle_source
OEM-2-NVTCS solenoid (intake butterflies)low_side_out———BWsingle_source
OEM-2-OFuel pump relay (non-immobiliser)low_side_outEMUBLACK-Grey-4AUX 6low_side_outRsingle_source
OEM-2-PISC valve +14V feedpower_inEMUBLACK-Black-13Battery +12Vpower_inOrsingle_source
OEM-2-QISC valve low sidelow_side_outEMUBLACK-Grey-14Injector #5injector_outVRsingle_source
OEM-2-RMalfunction indicator lamp (MIL)low_side_out———WLsingle_source
OEM-3-APower groundgroundEMUBLACK-Black-27 + EMUBLACK-Black-28 + EMUBLACK-Grey-17 + EMUBLACK-Grey-24Power Ground + Ecu Ground + Power Ground + Power GroundgroundBsingle_source
OEM-3-BPower groundgroundEMUBLACK-Black-27 + EMUBLACK-Black-28 + EMUBLACK-Grey-17 + EMUBLACK-Grey-24Power Ground + Ecu Ground + Power Ground + Power GroundgroundBRsingle_source
OEM-3-CPurge solenoid valvelow_side_out———GYsingle_source
OEM-3-DEGR boost solenoid————GyBsingle_source
OEM-3-ENC————unverified
OEM-3-FIgnition 1 (coils 1+4, wasted spark)ignition_outEMUBLACK-Grey-8Ignition coil #1ignition_outBrWsingle_source
OEM-3-GNC————unverified
OEM-3-HMain relaylow_side_outEMUBLACK-Grey-12AUX 5low_side_outLOrsingle_source
OEM-3-IIgnition 2 (coils 2+3, wasted spark)ignition_outEMUBLACK-Grey-16Ignition coil #2ignition_outBYsingle_source
OEM-3-JFront O2 heaterlow_side_outEMUBLACK-Grey-19WBO Heaterlow_side_outBOrsingle_source
OEM-3-KEVAP leak detection pumplow_side_out———YBsingle_source
OEM-3-LNC————unverified
OEM-3-MAlternator controllow_side_out———GyRsingle_source
OEM-3-NNC————unverified
OEM-3-OTachometer outputtacho_out———GOrsingle_source
OEM-3-PRear O2 heaterlow_side_outEMUBLACK-Grey-10H-Bridge #1 Winding Bhbridge_outWBsingle_source
OEM-3-QData link connector (K-line)serial———GWsingle_source
OEM-3-RNC————unverified
OEM-3-SImmobiliserdigital_inEMUBLACK-Black-10Switch #1 Indigital_inRBsingle_source
OEM-3-TVehicle speeddigital_inEMUBLACK-Black-20VSS Indigital_inGRsingle_source
OEM-3-UCharge lamplow_side_out———BrRsingle_source
OEM-3-VCam position (CMP)trigger_inEMUBLACK-Black-21Camsync In #1trigger_inGyLsingle_source
OEM-3-WNC————unverified
OEM-3-XNC————unverified
OEM-3-YCrank position (CKP)trigger_inEMUBLACK-Black-8Primary triggertrigger_inVWsingle_source
OEM-3-ZNC————unverified
OEM-4-APower groundgroundEMUBLACK-Black-27 + EMUBLACK-Black-28 + EMUBLACK-Grey-17 + EMUBLACK-Grey-24Power Ground + Ecu Ground + Power Ground + Power GroundgroundBLsingle_source
OEM-4-AARear O2 signallambda_nb_inEMUBLACK-Black-17Analog In #3analog_inRsingle_source
OEM-4-ABNC————unverified
OEM-4-ACTCM (automatic only)————VGsingle_source
OEM-4-ADFuel levelanalog_inEMUBLACK-Black-9Flex Fuel Inanalog_inBrBsingle_source
OEM-4-AEPressure sensor (Mazda: EGR boost sensor)analog_inEMUBLACK-Black-4Analog In #2analog_inLYcorroborated
OEM-4-AFECU power +14V (main relay)power_inEMUBLACK-Black-13Battery +12Vpower_inWRsingle_source
OEM-4-AGConstant +12Vpower_in———LRsingle_source
OEM-4-AHEVAP leak detection pump solenoid valvelow_side_out———RGsingle_source
OEM-4-BBrake switchdigital_inEMUBLACK-Black-23Switch #2 Indigital_inGsingle_source
OEM-4-CPower steering pressure switchdigital_inEMUBLACK-Black-36Switch #3 Indigital_inBrsingle_source
OEM-4-DVVT oil-control solenoid +12V feedpower_inEMUBLACK-Black-13Battery +12Vpower_inYsingle_source
OEM-4-EDiagnostic (DLC TEN) (NA)serial———LYsingle_source
OEM-4-FA/C requestdigital_inEMUBLACK-Black-35Analog In #5analog_inLgBsingle_source
OEM-4-GNC————unverified
OEM-4-HNeutral switchdigital_inEMUBLACK-Black-37Analog In #6analog_inVsingle_source
OEM-4-IClutch switchdigital_in———WGsingle_source
OEM-4-JVTCS vacuum switchdigital_in———Orsingle_source
OEM-4-KNC————unverified
OEM-4-L+5V sensor supplyvrefEMUBLACK-Black-26+5V supplyvrefLgRsingle_source
OEM-4-MKnock sensorknock_inEMUBLACK-Black-3Knock Sensor in #1knock_inWsingle_source
OEM-4-NIntake air temperature (IAT)temp_inEMUBLACK-Black-5CLT Intemp_inPLsingle_source
OEM-4-OSignal groundsensor_groundEMUBLACK-Black-29 + EMUBLACK-Black-38 + EMUBLACK-Black-39Sensor Ground + Sensor Ground + Sensor Groundsensor_groundBRsingle_source
OEM-4-PCoolant temperature (ECT)temp_inEMUBLACK-Black-32IAT Intemp_inRLsingle_source
OEM-4-QNC————unverified
OEM-4-RVVT oil-control solenoid (low-side control)low_side_out———VYcorroborated
OEM-4-SIgnition switch (IG1) sensedigital_inEMUBLACK-Grey-18Ignition +12Vdigital_inBWsingle_source
OEM-4-TGenerator output voltage (terminal P)————Gysingle_source
OEM-4-UNC————unverified
OEM-4-VThrottle position (TPS)analog_inEMUBLACK-Black-18TPS Inanalog_inGBsingle_source
OEM-4-WFront O2 signallambda_nb_inEMUBLACK-Black-30Analog In #4analog_inLsingle_source
OEM-4-XMass air flow (MAF)analog_inEMUBLACK-Black-31Analog In #1analog_inPsingle_source
OEM-4-YNC————unverified
OEM-4-ZTCM (automatic only)————PBsingle_source

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)—
W3OEM-4-DSP-14V-10.85no routeVVT oil-control solenoid +12V feed—
W4SP-14V-1EMUBLACK-Black-130.85no routeBattery +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-1EMUBLACK-Black-270.85no routePower Ground—
W9SP-GND-1EMUBLACK-Black-280.85no routeEcu Ground—
W10SP-GND-1EMUBLACK-Grey-170.85no routePower Ground—
W11SP-GND-1EMUBLACK-Grey-240.85no routePower Ground—
W12OEM-4-OSP-0V-10.5no routeSignal ground—
W13SP-0V-1EMUBLACK-Black-290.5no routeSensor Ground—
W14SP-0V-1EMUBLACK-Black-380.5no routeSensor Ground—
W15SP-0V-1EMUBLACK-Black-390.5no routeSensor Ground—
W16OEM-4-LEMUBLACK-Black-260.5no route+5V sensor supply—
W17OEM-3-YEMUBLACK-Black-80.5no routeCrank position (CKP)—
W18OEM-3-VEMUBLACK-Black-210.5no routeCam position (CMP)—
W19OEM-4-MEMUBLACK-Black-30.5no routeKnock sensor—
W20OEM-3-FEMUBLACK-Grey-80.5no routeIgnition 1 (coils 1+4, wasted spark)—
W21OEM-3-IEMUBLACK-Grey-160.5no routeIgnition 2 (coils 2+3, wasted spark)—
W22OEM-2-AEMUBLACK-Grey-70.5no routeInjector 1—
W23OEM-2-DEMUBLACK-Grey-150.5no routeInjector 2—
W24OEM-2-GEMUBLACK-Grey-230.5no routeInjector 3—
W25OEM-2-JEMUBLACK-Grey-60.5no routeInjector 4—
W26OEM-4-SEMUBLACK-Grey-180.5no routeIgnition switch (IG1) sense—
W27OEM-2-BEMUBLACK-Grey-210.5no routeCooling fan relay—
W28OEM-2-CEMUBLACK-Grey-130.5no routeCondenser fan relay—
W29OEM-2-KEMUBLACK-Grey-50.5no routeA/C clutch relay—
W30OEM-2-MEMUBLACK-Grey-200.5no routeFuel pump relay—
W31OEM-3-HEMUBLACK-Grey-120.5no routeMain relay—
W32OEM-2-OEMUBLACK-Grey-40.5no routeFuel pump relay (non-immobiliser)—
W33OEM-3-JEMUBLACK-Grey-190.5no routeFront O2 heater—
W34OEM-3-PEMUBLACK-Grey-100.5no routeRear O2 heater—
W35OEM-2-QEMUBLACK-Grey-140.5no routeISC valve low side—
W36OEM-2-EEMUBLACK-Grey-220.5no routeEGR valve—
W37OEM-2-FEMUBLACK-Grey-20.5no routeEGR valve—
W38OEM-2-HEMUBLACK-Grey-110.5no routeEGR valve—
W39OEM-2-IEMUBLACK-Grey-30.5no routeEGR valve—
W40OEM-4-XEMUBLACK-Black-310.5no routeMass air flow (MAF)—
W41OEM-4-AEEMUBLACK-Black-40.5no routePressure sensor (Mazda: EGR boost sensor)—
W42OEM-4-VEMUBLACK-Black-180.5no routeThrottle position (TPS)—
W43OEM-4-AAEMUBLACK-Black-170.5no routeRear O2 signal—
W44OEM-4-WEMUBLACK-Black-300.5no routeFront O2 signal—
W45OEM-4-PEMUBLACK-Black-320.5no routeCoolant temperature (ECT)—
W46OEM-4-NEMUBLACK-Black-50.5no routeIntake air temperature (IAT)—
W47OEM-4-ADEMUBLACK-Black-90.5no routeFuel level—
W48OEM-3-TEMUBLACK-Black-200.5no routeVehicle speed—
W49OEM-3-SEMUBLACK-Black-100.5no routeImmobiliser—
W50OEM-4-BEMUBLACK-Black-230.5no routeBrake switch—
W51OEM-4-CEMUBLACK-Black-360.5no routePower steering pressure switch—
W52OEM-4-FEMUBLACK-Black-350.5no routeA/C request—
W53OEM-4-HEMUBLACK-Black-370.5no routeNeutral switch—

Bill of materials

CategoryPart numberManufacturerDescriptionQtyUnit

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (9)

SeverityCodeSubjectMessage
warnNET_FAMILYOEM-2-F ↔ EMUBLACK-Grey-2OEM-2-F "EGR valve" [low_side_out] is wired to EMUBLACK-Grey-2 "H-Bridge #1 Winding A" [hbridge_out]. A half-bridge can act as a low-side switch only if configured that way.
warnNET_FAMILYOEM-2-H ↔ EMUBLACK-Grey-11OEM-2-H "EGR valve" [low_side_out] is wired to EMUBLACK-Grey-11 "H-Bridge #2 Winding B" [hbridge_out]. A half-bridge can act as a low-side switch only if configured that way.
warnNET_FAMILYOEM-2-I ↔ EMUBLACK-Grey-3OEM-2-I "EGR valve" [low_side_out] is wired to EMUBLACK-Grey-3 "H-Bridge #2 Winding A" [hbridge_out]. A half-bridge can act as a low-side switch only if configured that way.
warnNET_FAMILYOEM-3-P ↔ EMUBLACK-Grey-10OEM-3-P "Rear O2 heater" [low_side_out] is wired to EMUBLACK-Grey-10 "H-Bridge #1 Winding B" [hbridge_out]. A half-bridge can act as a low-side switch only if configured that way.
warnNET_FAMILYOEM-4-F ↔ EMUBLACK-Black-35OEM-4-F "A/C request" [digital_in] is wired to EMUBLACK-Black-35 "Analog In #5" [analog_in]. Analog and digital on one net. A switch on an analog input works with a pull-up and a threshold; an analog sensor on a digital input loses its value.
warnNET_FAMILYOEM-4-H ↔ EMUBLACK-Black-37OEM-4-H "Neutral switch" [digital_in] is wired to EMUBLACK-Black-37 "Analog In #6" [analog_in]. Analog and digital on one net. A switch on an analog input works with a pull-up and a threshold; an analog sensor on a digital input loses its value.
infoNET_FAMILYOEM-2-E ↔ EMUBLACK-Grey-22OEM-2-E "EGR valve" [low_side_out] is wired to EMUBLACK-Grey-22 "Injector #6" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoNET_FAMILYOEM-2-Q ↔ EMUBLACK-Grey-14OEM-2-Q "ISC valve low side" [low_side_out] is wired to EMUBLACK-Grey-14 "Injector #5" [injector_out]. Injector drivers can usually run general low-side loads; check current and PWM frequency.
infoUNMAPPEDOEM17 optional OEM pins are not mapped: OEM-2-N VTCS solenoid (intake butterflies); OEM-2-R Malfunction indicator lamp (MIL); OEM-3-C Purge solenoid valve; OEM-3-D EGR boost solenoid; OEM-3-K EVAP leak detection pump; OEM-3-M Alternator control; OEM-3-O Tachometer output; OEM-3-Q Data link connector (K-line); OEM-3-U Charge lamp; OEM-4-AC TCM (automatic only); OEM-4-AH EVAP leak detection pump solenoid valve; OEM-4-E Diagnostic (DLC TEN) (NA); OEM-4-I Clutch switch; OEM-4-J VTCS vacuum switch; OEM-4-R VVT oil-control solenoid (low-side control); OEM-4-T Generator output voltage (terminal P); OEM-4-Z TCM (automatic only)

Accepted (1)

CodeSubjectReasonBy
REQUIRED_UNMAPPEDOEM-4-AGBattery-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-4 AG: Constant +12V: ECUMASTER EMU Black has no battery-constant input; not needed - OEM-2 N: VTCS solenoid (intake butterflies): no free low_side/ls_hs/injector/hbridge on ECUMASTER EMU Black - OEM-2 R: Malfunction indicator lamp (MIL): no free low_side/ls_hs/injector/hbridge on ECUMASTER EMU Black - OEM-3 C: Purge solenoid valve: no free low_side/ls_hs/injector/hbridge on ECUMASTER EMU Black - OEM-3 K: EVAP leak detection pump: no free low_side/ls_hs/injector/hbridge on ECUMASTER EMU Black - OEM-3 M: Alternator control: no free low_side/ls_hs/injector/hbridge on ECUMASTER EMU Black - OEM-3 U: Charge lamp: no free low_side/ls_hs/injector/hbridge on ECUMASTER EMU Black - OEM-4 AH: EVAP leak detection pump solenoid valve: no free low_side/ls_hs/injector/hbridge on ECUMASTER EMU Black - OEM-4 R: VVT oil-control solenoid (low-side control): no free low_side/ls_hs/injector/hbridge on ECUMASTER EMU Black - OEM-3 O: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on ECUMASTER EMU Black - OEM-4 I: Clutch switch: no free switch_in/frequency_in/analog_0_5 on ECUMASTER EMU Black - OEM-4 J: VTCS vacuum switch: no free switch_in/frequency_in/analog_0_5 on ECUMASTER EMU Black - OEM-3 Q: Data link connector (K-line): no free k_line on ECUMASTER EMU Black - OEM-4 E: Diagnostic (DLC TEN) (NA): no free k_line on ECUMASTER EMU Black - OEM-3 D: EGR boost solenoid: not classified in the library; wire by hand - OEM-4 AC: TCM (automatic only): 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_docECUMASTER EMU Black — pinout (Black 39-pin / Grey 24-pin)https://www.ecumaster.com/wp/wp-content/uploads/2020/05/EMU_Black_pinout.pdfarchive2026-10-05096b2b4df1bd
4vendor_docLink G4X MX5NB2X install manual (NB2 2001-05)https://linkecu.com/documentation/MX5XNB2.pdfarchive2026-10-05741efdd9f2c8
4oem_manualMazda MX-5 NB2 (2003) wiring diagram — engine / starting / charginghttps://web.archive.org/web/20191104195207/http://mellens.net/mazda/mazda_miata_extra_manual/2003_wiring.pdf—2026-10-055ee0777f12c1
2expert_reportJustin Barrera — Miata NA/NB wiring corrections————