Robert, I’ve made some progress…after nearly throwing the towel in!!
Took your advice and pushed a small flat screwdriver into the connector to lift the tab and with a bit of a pull, it came apart. Set my multimeter to the 2000 mark (in the ohms range - see pic) and trying a good few times, including switching the +ve and -ve probes around, got no reading. Suggesting this sensor has failed, yes?
Went straight onto the offside front and did same test and got a reading of around 1600, so looks to be working ok
Will do same test for both rear wheels and see what I get. After that I think it would be worth doing the fault codes procedure (that you have kindly explained in your last post), do you? Should hopefully confirm my findings…
Robin
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Hi there
My ABS light came on… mechanic came round and foxes had chewed the cable at rear!!
If you havent already, might be worth looking underneath and inspecting all wires? easy fix to solder and insulate again.
Thanks
KP
Yes that seems correct, open circuit in the left front wheel speed sensor. If you can get to the rear ones to check those then probably worth it although those ones tend to be more reliable.
I’d carry out the fault code read as you have said, worth getting familiar with it to check and clear codes once any repair has been carried out.
Interested to hear how you get on.
That seems to be the nature of working on cars, Robin 
Lots of tricky little connectors that seem determined not to cooperate.
I’ve been working my way through another “working on the car” challenge this weekend, and I think the “John Cleese hit the car with a tree branch” moment urge always hits us just before we succeed. So hang on in there!
Happy New year!
Yes…that’s easier said than done. Just got the nearside rear jacked up and straight away it is obvious that the set-up and cable routing is very different to the front. The sensor is double-bolted to the hub and points directly at the toothed ‘wheel’. As per my pics, the cable twists and turns and goes into the body of the car (forward of the boot) and all you can see is a big black grommet. All I can do at the moment is twist this around. I assume a connector (like the front) will be behind this.
Do I just have to prise this grommet out or could I potentially gain access to the connector from the boot?? Would have to remove all the lining etc I guess. It’s never easy
Yes, you gain access to those connections from inside the boot. Don’t be tempted to prise the plastic grommet out as you’ll probably break one of the locating tags on the top of it.
I’ve removed the boot lining and the aluminium shield (in front of the fuel in and breather tubes) and located both the black plastic tubing (containing the wires) coming through the grommet and, further towards the front of the car, the white connector - how on earth are you meant to reach that, let alone disconnect it??! It looks well-nigh impossible.
Would you strongly dissuade me from cutting the wires from within the wheel arch and if so, why? In this thread, Binkman said
Too destructive to cut the wires in my opinion especially if the sensor is not faulty. They my be aluminum wire too which you can’t solder.
If you really can’t get to the connector to disconnect and test it, I’d read the fault codes rather than cut any wires.
ok, understood. That said, the feel of the incoming black and white wires from front nearside sensor does suggest multi-strand copper, but I guess you can’t be certain.
Yes, I will bridge the appropriate terminals (TBS and GND) on the diagnostic plug and see what I get on the fault codes.
Just checking - do you go in the GND (to the left of FAT) and not the one between IG- and TFA? It’s just that there are two GND terminals showing on the diagram. Only one TBS, so that’s ok
Either will do, I tend to use the one next to FAT.
Hi again Robert,
Just carried out the fault codes procedure and…it outputted just the one code! One long and two short flashes meaning DTC 12 which states ‘Left front wheel speed sensor open circuit or short to power supply’ This confirms my resistance testing result and that I don’t (hopefully!) need to have any concerns about the two rear sensors - would you agree?
Clearly I need to replace this failed one. Would you have any suggestions as to where I could obtain it and indeed would an aftermarket one do the job rather than a genuine Mazda part?
I’m not sure I fancy tackling the removal of old as there are a few (very rusty!) bolts to wrestle with, particularly the one that secures the sensor to the hub. Might get my local garage to do this job…
Equally, could I do the brake pedal pushing step and see if the light goes out and if yes (and it stays out when driving), then just forget about it?
Your diagnosis sounds correct to me. My go to place for parts would be mx5parts.co.uk there is a link below to the wheel speed sensor options available from there. I have no experience of the aftermarket part but for the price difference it’s probably worth a punt.
Mazda Miata MX5 Mk2 ABS Parts - MX5 Parts
I tend to agree with your decision to take it to a garage to replace the sensor, it will fight you all the way!
You could try clearing the code, I’d try it anyway, but I’m pretty confident that with an open circuit the light will come back on immediately.
Good morning, hope you are well.
Just a quick update. Had the car in with my local, reputable garage a week or so ago and they managed to successfully replace the near-side front sensor, but not without a struggle!! All told, three bolts sheared and had to be drilled out and re-threaded. ABS light gone out now. I knew all along, but there was no way I could have done that.
Following that bit of ‘good news’ came some bad…car was in for MOT last Thursday and it failed. Same old story with MX5’s I guess - a lot of well-established rust (and holes!) on offside front floor area, where it meets the sill and a small (couple of inches) hole in inner sill (nearside rear). That looks pretty minor and an easy fix. Front offside is the serious one. Ah well, off to some body shops to get a few quotes to get it sorted.
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Good luck with the rust repairs. Don’t look too unkindly on any garages that say they can’t quote until they’ve done some cutting out. If you get one quote that’s way lower and you go with it, expect them to come back to you with a different quote after they’ve done the initial cutting out.
I guess you could also get all quotes in writing and hold your chosen garage to their quote. I think they’re only allowed to vary by 10%.
Morning. Thank you for the heads-up on this. Much appreciated!
Glad you got your abs sensor sorted, touch would mine have okay to date. Mine is currently having 3 new wings, the rear was showing a one inch blob of rust on the arch but as with the o/s I had done two years ago it has rusted all the way round from the inside out, having the front two wings done so will use this opportunity for a complete respray so that when finished she will be just the one shade of red instead of the hitherto 50 shades. Nice to see someone else keeping faith with their 2.5 
Worth drilling extra and bigger holes in the bottom of the front wings and regularly checking they’re clear. That way you’ll avoid this particular piece of Mazda’s Planned Obsolescence Program where rainwater drains from the scuttle to the bottom of the wing and can’t escape. Clever of them! Not as clever as the double-skinned chassis rails on Mk2 though.
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Yes my man Steve is aware of that little trick and made bigger holes 