To check for DTC on the ABS system on MX-5 turn ignition switch to off, bridge the TBS and GND terminals in the DIAGNOSTIC socket under the bonnet, turn the igniton switch to on and count the groups of flashes on the ABS lamp. Long flashes count tens, short flashes count units. To clear DTC, allow all codes to be output (flash codes repeat) then with ignition switch still on, press and release the brake pedal 10 times at less than 1 second intervals.
Diagnostic Trouble Codes are as follows
05 - Brake Switch open circuit
11 - Right Front Wheel Speed Sensor Open circuit or Short to power supply
12 - Left Front Wheel Speed Sensor Open circuit or Short to power supply
13 - Right Rear Wheel Speed Sensor Open circuit or Short to power supply
14 - Left Rear Wheel Speed Sensor Open circuit or Short to power supply
15 - Wheel Speed Sensor, Sensor Rotor
22 - Front Right Solenoid Valve Signal (AV)
23 - Front Right Solenoid Valve Signal (EV)
24 - Front Left Solenoid Valve Signal (AV)
25 - Front Left Solenoid Valve Signal (EV)
26 - Rear Solenoid Valve Signal (AV)
27 - Rear Solenoid Valve Signal (EV)
41 - Right Front Wheel Speed Sensor Rotor Short to ground or Disagreement with other sensors is detected
42 - Left Front Wheel Speed Sensor Rotor Short to ground or Disagreement with other sensors is detected
43 - Right Rear Wheel Speed Sensor Rotor Short to ground or Disagreement with other sensors is detected
44 - Left Rear Wheel Speed Sensor Rotor Short to ground or Disagreement with other sensors is detected
51 - Valve Relay fault
53 - Motor monitor fault
61 - ABS Control Module fault
63 - ABS Module Power Supply Malfunction