[72 pin Connector](OEM-connectors#72-pin) See also [Mazda Miata 2003 alt](Mazda-Miata-2003-alt) For power see [Mazda Miata 2002 - Starting & Power](Mazda-Miata-2002#starting--power) ![Connector Face](Images/NB2 Miata ECU Connectors Drawing.png) ![Connector Face](Images/NB2_Miata_ECU_Connectors_Drawing_rusefi_harness.png) Coil three wire plug: middle wire GND pin closer to the engine is +12v pin further away from the engine signal ## Plug 1 (ECU connector #2) "rusEfi harness" does not mean much - that's just the way I bundle 4-5 wires together on my cars | pos | color | desc | type | rusEfi harness | | --- | ------------ | ------------------- | --------------------------------- | --------------- | | 2A | Yellow/Black | Injector \#1 | | orange Y1 | | 2B | Red/Yellow | Engine radiator fan | | orange B4 | | 2C | Blue/White | AC radiator fan | | | | 2D | Violet/Green | Injector \#2 | | blue Y1 | | 2E | Light Green | EGR Valve \#1 Coil | | | | 2F | White/Green | EGR Valve \#2 Coil | | | | 2G | Yellow/Red | Injector \#3 | | white Y1 | | 2H | Pink/Black | EGR Valve \#3 Coil | | | | 2I | Pink | EGR Valve \#4 Coil | | | | 2J | Yellow/Green | Injector \#4 | | green Y1 | | 2K | | A/C Relay | | | | 2L | | NA | Does not exist | | | 2M | Red/White | Fuel Pump Relay | | red B4 | | 2N | | VTCS Control | | | | 2O | | NC | | | | 2P | Orange | IAC (positive) idle | \+12v wired to main relay via 4AF | red, short wire | | 2Q | Violet/Red | IAC (negative) idle | low-side with diode | blue b4 | | 2R | White/Blue | MIL Control | low-side | white Y1 | ## Plug 2 (ECU Connector #3) | pos | color | desc | type | rusEfi harness | | --- | ------------ | ------------------------- | ----------------------------------- | ------------------------ | | 3A | Black | Injector GND | ground | black Y1 | | 3B | Black/Red | PCM (ECU) GND | ground | black W4, sliced for MAP | | 3C | Green/Yello | Purge Control Solenoid | | | | 3D | | EGR Boost sens. sol. | | | | 3E | | CDCV Control | (Evap canister?) | | | 3F | Brown/White | Coil \#1 | (cylinder 1 & 4) | white B4 | | 3G | | NA | Does not exist | | | 3H | | Main relay control | Low-side output | white or red, R5 | | 3I | Black/Yellow | Coil \#2 | (cylinder 2 & 3) | orange B4 | | 3J | Black/Orange | Front O2 sens. heater GND | Presumably switched to GND in 'run' | | | 3K | | NC | | | | 3L | | NC | | | | 3M | Grey/Red | Alternator field ctrl. | PWM signal to control voltage | orange R5 | | 3N | | NC | | | | 3O | Green/Orange | Tach OUT | Drives tachometer | green B4 | | 3P | White/Black | Rear O2 sens. Signal | | | | 3Q | Green/White | K-Line (serial comm.) | Probably goes to OBDII | | | 3R | | NA | Does not exist | | | 3S | | Immobilizer comm. | | | | 3T | | VSS in | | blue W3 | | 3U | | Alternator warn. light | | | | 3V | | Camshaft Sensor | | blue W3 | | 3W | | NC | | | | 3X | | NC | | | | 3Y | | Crankshaft Sensor | | white W3 | | 3Z | | NC | | | ## Plug 3 (ECU Connector #4) | pos | color | desc | type | rusEfi harness | | --- | ------------- | -------------------------- | --------------------------------------------- | ---------------------- | | 4A | Black/Blue | GND | ground | black W4 | | 4B | | Brake Switch | | | | 4C | | Power Steering Switch | (Presumably used for 'Idle Up') | | | 4D | Yellow | VVT Oil Control Valve pos. | \+12v wired to main relay via 4AF, short wire | | | 4E | | DTM switching | (Diagnostic Terminal?) | | | 4F | | AC Pressure In | | | | 4G | | NA | Does not exist | | | 4H | | Neutral Switch | | | | 4I | | Clutch Switch | | | | 4J | | VTCS ca. switch | | | | 4K | | NC | | | | 4L | Lt GRN / RED | Sensor +5V | | red W3, sliced for MAP | | 4M | | Knock sens. in | | white R5 | | 4N | | IAT Sensor | | green B2 | | 4O | BLK / RED | Sensor GND | ground | black B2 | | 4P | Red/Blue | CLT Sensor | | blue B2 | | 4Q | | NA | Does not esist | | | 4R | Violet/Yellow | VVT Oil Control Valve neg. | low-side driver | white B2 | | 4S | Black/White | \+12V engine fuse 15A | ECU power source, run/start | red B2 | | 4T | | Alternator output voltage | (seems to be feedback from alt.) | | | 4U | | NC | extra main relay for diode | red, short wire | | 4V | Green/Black | TPS Sensor output | | green B2 | | 4W | | Front O2 Sensor Signal | | | | 4X | Pink | MAF Sensor | | orange B2 | | 4Y | | NA | Does not exist | | | 4Z | Pink/Black | ECU - TCM | Communication for A/T | | | 4AA | Red | Rear O2 Sensor | | | | 4AB | | FTP Sensor | Fuel Tank Pressure | | | 4AC | | ECU - TCM | Communication for A/T | | | 4AD | | Fuel Level Sensor | | | | 4AE | | EGR Boost Pressure Sensor | | | | 4AF | white/Red | \+12v from main relay | | red, short wire | | 4AG | Blue/Red | Bat+ (Hot all times) | 12v 10A fuse from battery | | | 4AH | | Evap | | | | desc | type | rusEfi harness | | ---------- | ------ | -------------- | | MAP signal | analog | blue | | AFR signal | analog | white | ![Wiring Diagram](oem_docs/Mazda/2003_Miata/Mazda_miata_2003.png) Individual pages for printing: ![Wiring Diagram](oem_docs/Mazda/2003_Miata/Mazda_miata_2003_page_1.png) ![Wiring Diagram](oem_docs/Mazda/2003_Miata/Mazda_miata_2003_page_1.png) ![Wiring Diagram](oem_docs/Mazda/2003_Miata/Mazda_miata_2003_page_1.png) ## Automatic Transmission see [Mazda Miata 2001 - Automatic Transmission](Mazda-Miata-2001#automatic-transmission) ![Wiring Diagram](oem_docs/Mazda/2003_Miata/Mazda_miata_2003_at.png) ## Immobilizer NALDEC NC87 67 790 MAZDA MX5 EUNOS MK2 MK2.5 BURGLAR ALARM MODULE NC8767790 is not an immobilizer US immobilizer ![Wiring Diagram](Images/2001_miata_immobilizer.png) ## Wiper Motor ![Wiring Diagram](Images/2003_miata_wiper_motor.png) ## Charging ![Wiring Diagram](Images/2003_miata_charging.png) ## Air Conditioning ![Wiring Diagram](Images/2003_miata_ac.png) See also [Mazda Miata 2002](Mazda-Miata-2002) ## Starting & power In start or run ECU is powered from Engine Fuse 15A (behind left side of dash) via 4S. (This is different from 2002 - nothing on 4S in 2002) ECU controls main relay via 3H. (This is different from 2002 - nothing on 3H in 2002) ECU gets +12v from main relay output 4AF which is used as +12v source for VVT (4D) and IAC (2P). Fly-back diode - stripe facing +12 - is needed between VVT 4D (power, stripe side) and VVT control 4R. Fly-back diode - stripe facing +12 - is needed between IAC 2P (power, stripe side) and IAC control 2Q. See http://rusefi.com/forum/viewtopic.php?f=3&t=906&p=25018l#p25018 For ignition key see [Mazda Miata 2002 - Starting & Power](Mazda-Miata-2002#starting--power) ## Misc Two timing marks - the left one is TDC