Mazda MX-5 Miata (1997+). Manual — part 10

Fig. 9: Locating Hydraulic Unit Valve Relay Connector Terminals
Courtesy of MAZDA MOTORS CORP.

ABS WARNING LIGHT

Operational Test

1. Start engine and observe ABS warning light. Light should illuminate for a few seconds. If light does not

illuminate as described, turn ignition off. Disconnect ABS control module connector. Using a jumper
wire, connect terminal AD of ABS control module connector to ground. See Fig. 3 . Turn ignition on.

2. If ABS warning light illuminates, check ABS control module. See ABS CONTROL MODULE. If light

does not illuminate, remove instrument cluster. Remove and check ABS warning light bulb. Replace bulb
as necessary. If bulb is okay, check METER fuse and wiring harness. Repair or replace as necessary. If
METER fuse and wiring harness are okay, go to next step.

3. Using ohmmeter, connect positive lead to terminal 2K (Black/Yellow wire) of instrument cluster and

negative lead to terminal 1K (Blue/Yellow wire) of instrument cluster. See Fig. 10 . If continuity is not
present, replace instrument cluster. If continuity is present, repair wiring harness between instrument
cluster and ABS control module.

1997 Mazda MX-5 Miata

ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock

Fig. 10: Identifying Instrument Cluster Connector Terminals
Courtesy of MAZDA MOTORS CORP.

STOPLIGHT SWITCH

Disconnect stoplight switch connector. Using ohmmeter, check continuity between stoplight switch terminals.
With brake pedal depressed, continuity should exist. With brake pedal released, continuity should not exist. If
continuity is not as specified, replace stoplight switch.

MOTOR RELAY

1. Turn ignition off. Disconnect ABS Control Module (ABS CM) connector. See COMPONENT

LOCATIONS . Connect Adapter Harness (49-F066-002) to ABS CM connector. Turn ignition on. Using
voltmeter, measure voltage between terminals "X" and AB of ABS CM connector. See Fig. 3 . Voltage
should be zero volts. Apply 12 volts to terminal "B" an d ground terminal "G" of ABS CM connector.
Using voltmeter, measure voltage between terminals "X" and AB of ABS CM connector. Voltage should
be 12 volts. If voltage is not as specified, check wiring harness. If wiring harness is okay, go to next step.

2. Remove motor relay from hydraulic unit. See Fig. 14 . Using ohmmeter, check continuity between

terminals "B" and "C" of motor relay. See Fig. 11 . Continuity should exist. Apply 12 volts to terminal
"C" and ground terminal "B". Using ohmmeter, check continuity between terminals "A" and "D" of motor
relay. Continuity should exist. If continuity is not as specified, replace motor relay.

1997 Mazda MX-5 Miata

ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock

Fig. 11: Identifying Motor Relay Terminals
Courtesy of MAZDA MOTORS CORP.

VALVE RELAY

1. Turn ignition off. Disconnect ABS Control Module (ABS CM) connector. See COMPONENT

LOCATIONS . Connect Adapter Harness (49-F066-002) to ABS CM connector. Turn ignition on. Using
voltmeter, measure voltage between terminal AB and terminals "E", "Z", "Y", AG, BA and BB of ABS
CM connector. See Fig. 3 . Voltage on all terminals should be zero volts. If voltage is as specified, go to
next step. If voltage is not as specified, check wiring harness and repair as necessary. If wiring harness is
okay, go to step 3).

2. Apply 12 volts to terminal "B" and ground terminal AK of ABS CM connector. Using voltmeter, measure

voltage between terminal AB and terminals "E", "Z", "Y", AG, BA and BB of ABS CM connector. See
Fig. 3 . Voltage on all terminals should be 12 volts. If voltage is not as specified, check wiring harness. If
wiring harness is okay, go to next step.

3. Remove valve relay from hydraulic unit. See Fig. 14 . Using ohmmeter, check continuity between

terminals "B" and "C" of valve relay. See Fig. 12 . Continuity should exist. Apply 12 volts to terminal
"B" and ground terminal "C". Using ohmmeter, check continuity between terminals "A" and "D" of valve
relay. Continuity should exist. If continuity is not as specified, replace valve relay.

1997 Mazda MX-5 Miata

ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock

Fig. 12: Identifying Valve Relay Terminals
Courtesy of MAZDA MOTORS CORP.

WHEEL SPEED SENSORS

On-Vehicle Inspection

Remove wheel. Inspect wheel speed sensor for looseness and damage. Replace as necessary. Measure clearance
between wheel speed sensor and sensor rotor. See Fig. 13 . Clearance should be .012-.043" (.3-1.1 mm). If
clearance is not as specified, replace wheel speed sensor or sensor rotor.

Resistance Test

Disconnect wheel speed sensor connector. Using ohmmeter, measure resistance between wheel speed sensor
terminals. Resistance should be 800-1200 ohms. If resistance is not as specified, replace wheel speed sensor.

Voltage Test

Ensure vehicle is on level surface. Raise and support vehicle on safety stands. Disconnect wheel speed sensor
connector. Using voltmeter, while rotating wheel one revolution per second, measure voltage between wheel
speed sensor terminals. Voltage should be .25-1.2 volts (AC). If voltage is not as specified, replace wheel speed

1997 Mazda MX-5 Miata

ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock