I have a 2002 NBFL with an ABS light on, i have cleaned all 4 sensors & rotors and checked all the wiring connections but to no use. I already have a VS550 diagnostic reader but it only does engine faults not ABS. I am now torn between taking the car to a garage for them to carry out a diagnostic check or buying an ABS fault code reader and doing the check myself. Does anyone know of or have a reasonably priced ABS fault code reader they could recommend please?
You can read ABS codes using a jumper wire in the diagnostic port under the bonnet. Look in the Downloads section, I think the procedure is in there.
Sorry, I’ve just checked the Downloads section and it’s not there, do a search on here, I’ve certainly outlined the procedure in the past. It’s been covered in a past STHT if you have old back issues.
I can’t find a cheap reader for ABS codes and it seems it is not needed. Unlike some cars, the MX5 resets its ABS and airbag errors automatically when the problem is solved.
The following posts indicate, that like the engine error codes, ABS error codes can be retrieved by accessing the diagnostic box situated under the bonnet up near the scuttle on the right hand side.
Thanks Guys, i’m half way through welding up the rear sills at the moment so will give the diagnostic bridging a go when i have the vehicle back on it’s wheels, many thanks, much appreciated.
I have PM’d one person that replied but not sure i have done it correctly so apologies to that person if it’s duplicated. I have checked the Diagnosis plug under the bonnet but there are no markings on the various terminals as per the attached photo, can anybody help with the location of the ABS and the GND pins to bridge please?
Thanks Rhino666. I don’t have a key to the diagnostic port but, having read the web page from your link, if i understand you correctly i need to bridge the FEN and the +B then read the number of flashes at the ABS light on the dashboard once i switch the ignition on. Assuming i’m correct, if you take a look at my diagnostic socket there isn’t a connector in the FEN slot, any ideas please?
I see your car is a MK2.5. Wasn’t aware of differences in the diagnostic box but clearly there are.
B+ is just a battery 12volt positive but it’s absence worries me as does the fact I cannot find any info on using the MK2 facelift diagnostic box.
In the absence of additional info, I would risk a simple battery positive feed to replace b+ but hopefully someone who has interrogated this box on the facelift can confirm.
Hi all. Just an update for those who may be interested. After much appreciated help, i managed to bridge the correct terminals in the Diagnostics plug under the bonnet and got two readings of
(12 - Left Front Wheel Speed Sensor Open circuit or Short to power supply) and also a reading of
(41 - Right Front Wheel Speed Sensor Rotor Short to ground or Disagreement with other sensors is detected).
I don’t quite understand the second fault code exactly but i disconnected both front ABS sensor wires from the main loom and put a test for continuity through the terminals of each in turn and got nothing so i have two new front sensor units on their way to me by the end of the week, i am hoping this will clear my faults once fitted so i’ll let you know how i get on. Thanks again for all your help, much appreciated. Kind regards Geoff
Hi Gra, i did a clearing of the codes using the 10 brake pedal applications in less than 10 seconds method and then a short run after but both codes still remained so, assuming i did the cleardown correctly, i still have the faults, i’ll see when i’ve fitted the two new sensors.
Hi mate, yes i did thanks. I bridged the TBS and the GND terminals which gave me he test flashing light sequence with the ABS light on the dashboard. I have 2 fault codes 12 & 41 as above.
Great stuff - good to have it confirmed that this actually works on the MK2.5. The pic you sent seemed to have quite a few of the usual connectors missing but glad you got to the bottom of that.
It’s usually the nearside sensor that goes so a bit unfortunate that your tests indicate the offside gone as well. That error code kind of sounded like it may have been generated by the nearside sensor problem.
Hopefully they will come out nice and easy for you.