MS3 Pro for NA

MS3 Pro PCB V3.5/V4 NA Assembly instructions
MS3 Pro PCB V5 NA Assembly instructions
MS3 Pro PCB V5.1 NA Assembly instructions
MS3 Pro PCB V5.2 NA assembly instructions
MS3 Pro PCB V5.3 NA assembly instructions

I designed this board for the 90-97 MX5 NA, to be used with the DIY Autotune MS3 Pro module.
Usage is very simple, get the MS3 Pro Module, get this PCB and bolt the module to it.  Install inside the oem case, ultimately ending up with a “MSPNP-PRO”.
Final cost is about the same as DIY built to the same level as the ms3pro but it has several advantages:
The difficulty in troubleshooting a non-standard build. Every problem requires an overview of your assembly first.
The robustness of the ms3pro is far better than a diy box.
Future proof HW setup, change the car and only change the harness.

More pictures

You just plug in the MS3 Pro module and install the board inside the stock ecu case.

For clarity, the pcb is made for a standard MS3 Pro module, thus no modifications are necessary to the MS3 Pro or its firmware.

This board fits all NA versions, US, JDM and Euro market.

Board specifications:

  • usb connector
  • pullup resistors for all in- and outputs
  • proto area with gnd, 5V and 12V
  • RS232 to TTL circuit (for internal bluetooth module)
  • 90-93 active fuel pump circuit (with the active fuel pump circuit, there’s no wiring modifications needed under the hood)
  • CAN port
  • map sensor MPX-4250AP
  • 2nd map sensor for baro correction (MPX-4250AP or the MPXH6400A equivalent in SMD footprint)
  • choice between batch and sequential fuel (requires 2 extra wires on 90-93 non-California)
  • choice between batch and sequential spark (requires extra wiring on all engines)
  • Bluetooth or WiFi
  • 1 EGT circuit
  • otional JBperf TinyIxOx module
  • optional accelerometer module
  • 4 simple VR circuits (like ABS to Vss for traction control and launch control)

All unused in- and outputs can be brought out to the mazda connector in case you have extra functions.
All information is on the front and back silk to make it easier to do modifications. It’s just a matter of adding a resistor or a jumper.


V4 pcb only: $35 + $9 shipment


  • basic parts $15 (USB connector, pullup resistors, header pins)
  • oem mazda connector for 90-95 ($29)
  • oem mazda connector for 96-97 ($29)
  • map sensor MPX4250AP ($28)
  • baro sensor (MPX4250AP, 1 resistor, 2 capacitors) ($29)
  • baro sensor SMD (MPXH6400A, 1 resistor , 2 capacitors) ($24)
  • internal Bluetooth module pre-programmed ($24)
  • internal WiFi module pre-programmed ($24)
  • optional for 1.6 cars: active fuel pump circuit (TIP125, 2 resistors, diode) ($7)
  • registered shipping ($8 extra shipping cost)

To order, contact me



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