Two Mk4 ND sheets, the PCM fitted from VIN 100001 and the PCM fitted from VIN 300001. No donor ND plug sits behind either: both are read off the Mazda factory PCM connector figures and checked against the factory terminal tables, and the colours are read from the UK factory wiring diagrams. Confidence is high on both. The full how to read a sheet is on the ECU pinouts hub.
Read this first
Wire colours change between year builds and markets, and the Mk4 colour tables are read from the UK factory wiring diagrams, so treat a colour as a starting point and the cavity map and function as the reference. Ring every pin out on your own car before you cut or crimp.
The Mk4 ND sheets
Tap a sheet for full size. Each has its own PDF for the bench.
Mk4 · ND1
VIN 100001 to 299999
Skyactiv-G 1.5 and 2.0, drive-by-wire, CAN, direct injection. A 140 way and a 60 way connector, 200 terminals.
The early car of the two ND PCMs. Functions come from the Mazda workshop manual PCM inspection table and the plug face is read cell by cell off that same document, and Mazda names no difference between the 1.5 and the 2.0. Colours are read from the UK factory engine control system wiring sheet, all eight pages in both editions, and checked against the Autodata diagrams: Mazda draws 122 PCM pins, the same 122 are coloured here, 120 agree cell for cell, and the nine rows carrying a second colour in brackets are a build number split inside the early band, not two sources disagreeing, because Mazda prints both values on the one wire and footnotes the second against a later VIN.
Still to confirm on car
- Two colours are flagged: 2AD, a sensor shield ground, is black in both Mazda editions where Autodata prints white, so the sheet carries black and names both, and 2AJ agrees at brown with orange but its later build number alternate is brown in one edition and green with yellow in the other. Ring both out.
- Pin 2K, the main relay control, is blue on the Mazda page and Autodata does not draw the pin at all, so that one colour has a single publisher behind it.
- Build numbers 300001 to 649999 have no PCM inspection table on file, and the Mazda wiring for that band prints later PCM pin letters, so a middle car is on the later plug. Read this sheet as 100001 to 299999 only.
Mk4 · ND2
VIN 300001 on
Skyactiv-G 1.5 and 2.0, four ion sensors as well as a knock sensor. A 114 way and a 72 way connector, 186 terminals.
The later PCM, fitted from build number 300001, is a different unit with different connectors and different pin letters, so do not read one sheet against the other: the knock sensor moves from 1D and 1H to 1Y and 1Z, the four ion sensors alongside it. The Mazda wiring for VIN 300001 to 499999 prints PCM pins 2BO and 2BR, which exist only on this 72 way connector, the terminal table this sheet is read from is published on the 650001 carline, and no source we hold gives a calendar year for the changeover, so this sheet gives build numbers, not model years. Functions come from the Mazda workshop manual PCM inspection table and the face off that same document, and the colours from the UK right-hand-drive factory wiring sheets, agreeing with the second source on 103 of the 107 pins.
Still to confirm on car
- Three colours have one source only and are flagged, 2A, 2B and 2F. Pin 2AU came off that list once Mazda was found drawing it on wiring sheet WD827512, where the one wire carries two footnoted colours, white and white with green, and the sheet keeps white with green.
- The build number the later PCM starts at is read from one page of the middle band wiring, and Mazda publishes no PCM inspection table for VIN 300001 to 499999, so the pin letters are sourced for that band but the full terminal list is not.
- Pin 2BM, a shield ground, is drawn white on one automatic variant of the second source where every neighbour is black. We keep black, which is what Mazda and the terminal table both say.
How to read the sheets
- Drawn looking into the PCM header, the same view as the wire side of the harness plug.
- Pin A is ringed red and the letters run down each column from the right-hand end. It is top-right on every sheet bar the ND1 60-way, where the top-right cavity does not exist and 2A sits at the right-hand end of the strip below.
- Find a known pin first, the 12V feed or a ground, to fix left from right.
- The plug in your hand, mating face towards you, is the mirror of what is drawn.
- Each cavity is tinted by what the pin does:
By generation
1989 to 1997Mk1 · NA
Three sheets, the early 1.6, the 1994 to 1995 cars and the OBD-II NA8, confidence high on the 1994 to 1995 sheet and medium on the other two.
1999 to 2005Mk2 · NB
The NB1 and the NB2 VVT sheets, both OBD-II, three connectors each, confidence high on both.
2006 to 2015Mk3 · NC
One sheet, drive-by-wire and CAN, two 60-way connectors and 120 terminals, confidence high.
2015 onThis pageMk4 · ND
Two sheets, one per PCM, split by build number rather than by engine, confidence high on both.