1994 MAZDA MX-5 Workshop Manual

P ANTILOCK BRAKE SYSTEM (AM) 6C. SOLENOID TEST AND IS IT SPINNING? CHECK HYDRAULICS I 1 J PRESS: -OR - I I 1 [STAT TEST DYNAM~ PRESS: 1 TESTER WILL TEST~R WILL RETURN TO 5A RETURN TO 6A 1 YES LOCKED? NO HASTHE WHEEL STOPPEO SPINNING AND LOCKED IN PLACE? 'RESS: i +I BRAKE PRESS: '->I THEN I I PRESS: + TESTER WILL RETURN TO SA TESTER WILL RETURN TO 6A I c IMPORTANT-CONTINUE TO RETURN TO 6A UNTIL ALL FWR WHEELS HAVE BEEN ESTED. Gartner Banana

ANTILOCK BRAKE SYSTEM (ABS) P Inspection of ABS system Check system ground Caution To prevent damage to the terminals, create a probe by wrapping a thin wire around the tester lead before inserting. Check for an open circuit in (B) wire from terminals 1 Dl 1 S, and 2F of the control unit connector and ground. Check antilock warning light 1. Remove the instrument cluster. 2. Connect 12V to terminal 2K (C-Ol), and ground to termi- nal 1 K ((2-01). 3. Verify that the ABS warning light illuminates. 4. If there is no illumination, check the meter fuse, bulb, and wiring harness. 5. If OK, check the wiring harness (Warning light - Control unit - Hydraulic unit) and repair or replace as necessary. Check ABS diode 1. Check the meter fuse, bulb, and wiring harness. 2. Check the wiring harness (Warning light - Control unit - Hydraulic unit). 3. Disconnect the hydraulic unit 12-pin connector. 4. Using an ohmmeter, check for continuity of the terminals. 5. If continuity is not as specified, replace the hydraulic unit. Check front and rear valves 1. Disconnect the hydraulic unit 12-pin connector. 2. Using an ohmmeter, check for resistance of the termi- nals. -- 3. If resistance is not as specified, replace the hydraulic unit. 4. If resistance is as spe'cified, check the wiring harness (Hydraulic unit - ABS control unit). E (YIG) - H (B) (Rear Valve) C (BR) - H (B) (Right Front Valve) A (B/W) - H (B) (Left Front Valve) Check brake light switch 1. Disconnect the brake light switch connector. 2. Check for continuity between the terminals of the switch. Resistance (n) Approx. 1 .O-1.2 Approx. 1.0-1.2 Approx. 1 .+I .2 M : Indicates continuity Depressed brake pedal 3. If the continuity is not as specified, check the STOP fuse and wiring harness (Brake light switch - Control unit). 0 I 0 Released brake pedal Gartner Banana

P ANTILOCK BRAKE SYSTEM (ABS) MOTOR RELAY I I VALVE RELAY / I Check motor relay 1. Disconnect the negative battery cable. 2. Remove the motor relay. 3. Connect an ohmmeter and check for continuity at the .,i relay terminals. 4. If continuity is not as specified, replace the motor relay. 5. If OK, check the wiring harness (Motor relay - Control unit main fuse [ABS 60A1). Check pump motor Disconnect the control unit 2-pin connector and check for continuity between terminal a (FIN) wire and ground. If there is no continuity, replace the hydraulic unit. d 0 Check valve relay 1. Disconnect the negative battery cable. 2. Release the valve relay locks from the hydraulic unit and remove the valve relay. 3. Using an ohmmeter, check continuity of the relay termi- nals. M: Indicates continuity Connect to a 0 12V - c I b d 0 I I C++3: lndicates continuity Ground - b 4. If continuity is not as specified, replace the valve relay. b 0 e Connect to 12V I Ground c 0 a b c d Gartner Banana

ANTILOCK BRAKE SYSTEM (ABS) P ABS CONTROL UNIT 35-PIN CONNECTOR OHMMETER 15UOPX-OI Check rotor Check the rotor for missing or damaged teeth and replace as necessary. Check alternator Refer to section G. Check wheel-speed sensor Caution To prevent damage to the terminals, create a probe by wrapping a thin wire around the tester lead before inserting. 1. Using an ohmmeter, check for continuity at the control unit connector terminals. 0----0: Indicates continuity Right front Left rear Right rear 2. If the continuity is not as specified, check the wiring har- ness (Wheel-speed sensor - Control unit). 3. If the continuity is OK, check voltage between 1K and 1 G, 10 and 1 Q, 1 U and 1 F, and 1 L and 1 P while rotating the wheel one rotation per second by hand. 4. If voltage is not approximately 50 mV--60 mV, the wheel-speed sensor is faulty. 5. If voltage is approximately 50 mV-60 mV, the control unit is faulty. 1L Check hydraulics Verify that all brake fluid connections are tight and that no fluid is leaking. IP 1Q Left front 0--0 Check hydraulic unit wiring 1. Verify that the hydraulic unit connectors are properly secured. 2. Verify that the valve relay and motor relay are properly secured. IG 1K 0-4 1U 10 S-0 IF 0-4 Gartner Banana

-01 ABS CONTHOL UNIT (Fa) 10-02 ABS HYDRAULIC UNIT (F) , WlRlNQ DIAQRAM -03 ABS HYDRAULIC UNIT 10-04 ABS WHEEL SPEED SENSOR LF(F) 10-05 ABS MEL SPEEO SENSOR W(F) 0 -06 ABS WHEEL SPEEO =ANTILOCK BRAKE SYSTEM SENSOR LR (R) 10-07 ABS WHEEL SPEED SENSOR RR(R) I I Gartner Banana

ANTILOCK BRAKE SYSTEM (ABS) P HYDRAULIC UNIT Removal 1 lnstallation 1. Disconnect the negative battery cable. - 2. Remove in the order shown in the figure, referring to Removal Note. 3. The only serviceable parts of the hydraulic unit are the valve relay and the motor relay. If there is a failure of any other part, replace the hydraulic unit assembly. 4. Install in the reverse order of removal, referring to Installation Note. 5. Add brake fluid, bleed the air, and check for fluid leakage. 1. Connectors 3. Nut bolts 2. Brake pipes 4. Hydraulic unit Removal / lnstallation Note . . . . page P-55 Gartner Banana

P ANTILOCK BRAKE SYSTEM (ABS) Disassembly 1 Assembly 1. Disassemble in the order shown in the figure. 2. Assemble in the reverse order of disassembly, referring to Assembly Note. 2.2-2.6 Nm [22-27 kgfcm, 2&29 [2--3,14--22) 6.9-9.8 Nm (70-1 00 kgfcm, 81-47 Inlbf) 1 15--25 11 S-2.5,11-18) 19-25 [1.92.6,14--19) t4.m [kgfm, Wlbf) 25uopx-o: 1. Nut, washer . 2. ABS bracket 3. Connector bolt 4. Gasket 5. Pipe joint 6. Bolt 7. Clip Installation Note 8. Cover 9. Motor relay ................... Inspection page P-56 10. Valve relay ................... Inspection page P-57 11. Casing 12. Mount 13. Stud ................. below 14. Nut, washer 15. Ground wire 16. Hydraulic unit Assembly note A SECTION A-A Clip Secure only the larger part of the wiring harness in the clips. The 2-pin connector part of the harness should re- main outside the clips. Gartner Banana

ANTILOCK BRAKE SYSTEM (ABS) P Removal I Installation note Brake pipes Caution Brake fluid will damage painted surfaces. If brake fluid does get on a painted surface, wipe it off im- mediately. Loosenltighten the brake pipes fromlto the hydraulic unit with the SST. 15UOPX-058 ABS CONTROL UNIT Removal I Installation 1. Disconnect the negative battery cable. 2. Roll back the carpet. 3. Remove in the order shown in the figure. 4. Install in the reverse order of removal. 1. Protecter 15UOPX-059 3. ABS control unit 2. Connector Gartner Banana