warning MAZDA MIATA 1991 Factory User Guide

Fig. 14: Checking Resistance at Clockspring Terminal
Courtesy of MAZDA MOTORS CORP.
3. If continuity is present, disconnect diagnostic module Black and Gray connectors. See Fig. 10
or Fig. 11.
Check continuity between diagnostic module Black connector Green/White wire and clockspring
connector Red wire. Also check continuity between diagnostic module Black connector Green/Yellow
wire and clockspring connector Green/Yellow wire. If continuity is not present, replace wire harness
assembly.
4. If continuity is present, check continuity between diagnostic module Black connector Green/Yellow wire
and ground. If continuity is present, replace wire harness assembly. If continuity is not present, replace air
bag module.
DIAGNOSTIC TEST NO. 7
Warning Light Flashes 2 Or 8 Times
1. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect diagnostic
module Black and Gray connectors. See Fig. 10
or Fig. 11 . Check continuity between Black connector
Brown/Yellow wire and ground. If continuity is not present, go to step 4). If continuity is present, go to
next step.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Warning Light Flashes 7 Times
1. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect diagnostic
module Black and Gray connectors. See Fig. 10
or Fig. 11 .
2. Check continuity between Black connector Black wire and ground. If continuity is present, replace
diagnostic module. If continuity is not present, replace wire harness.
WIRING DIAGRAMS
Fig. 16: Air Bag System Wiring Diagram (1990 Miata)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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ANTI-LOCK BRAKE SYSTEM
1988-91 BRAKES Mazda Anti-Lock Brake System
DESCRIPTION
The Anti-Lock Brake System (ABS) control unit senses reductions in front and rear wheel speed, and modulates
hydraulic pressure to the brakes to prevent wheel lock-up. The ABS consists of a hydraulic unit, 4 wheel speed
sensors and sensor rotors, valve relay, motor relay, pump motor, and ABS control unit. An ANTI-LOCK
warning light is located on the instrument panel. See Fig. 1
thru Fig. 3 .
Fig. 1: Locating Motor Relay & Valve Relay

Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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OPERATION
Under normal driving conditions, the anti-lock brake system functions as a standard brake system. When
vehicle speed reaches 3.8 MPH, the ABS system will diagnose pump motor by briefly operating motor. Pump
motor operation may be heard inside vehicle.
The Electronic Control Unit (ECU) controls ABS by detecting speed sensor signals and activating solenoid
valve in hydraulic unit. Control unit also controls pump motor and self-diagnostic function. If a problem in the
ABS system is detected, ABS system functions as a conventional brake system. The ANTI-LOCK brake
warning light will also come on.
With detection of wheel lock-up, short pedal pulsations, occurring in rapid succession, will be felt in brake
pedal and steering wheel. Vehicle body may also vibrate slightly. These conditions are normal. Pedal pulsation
will continue until there is no longer a need for anti-lock function or until vehicle is stopped.
ANTI-LOCK BRAKE SAFETY PRECAUTIONS
NEVER open a bleeder valve or loosen a hydraulic line while ABS is pressurized.
NEVER disconnect or reconnect any electrical connectors while ignition is on. Damage to ABS control
unit may result.
DO NOT attempt to bleed hydraulic system without first referring to the appropriate article.
Only use specially designed brake hoses/lines on ABS-equipped vehicles.
DO NOT tap on speed sensor components (sensor, sensor rings). Speed rings must be pressed, NOT
hammered into hubs. Striking these components can cause demagnetization or a loss of polarization,
affecting the accuracy of the speed signal returning to the ABS control unit.
DO NOT mix tire sizes. Increasing the width, as long as tires remain close to the original diameter, is
acceptable. Rolling diameter must be identical for all 4 tires. Some manufacturers recommend tires of the
same brand, style and type. Failure to follow this precaution may cause inaccurate wheel speed readings.
DO NOT contaminate speed sensor components with grease. Only use recommended anti-corrosion
coating.
When speed sensor components have been removed, ALWAYS check sensor-to-ring air gaps when
applicable. These specifications can be found in each appropriate article.
ONLY use recommended brake fluids. DO NOT use silicone brake fluids in an ABS-equipped vehicle.
When installing transmitting devices (CB's, telephones, etc.) on ABS-equipped vehicles, DO NOT locate
the antenna near the ABS control unit (or any control unit).
Disconnect all on-board computers, when using electric welding equipment. CAUTION: See ANTI-LOCK BRAKE SAFETY PRECAUTIONS below.
WARNING:Refer to appropriate Anti-Lock Brakes (ABS) article for description,
operation, depressurizing, testing, system bleeding, trouble shooting and
system service. Failure to depressurize ABS could lead to physical injury.

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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Fig. 7: Locating JC-02 Connector
Courtesy of MAZDA MOTORS CORP.
ANTI-LOCK WARNING LIGHT
Operational Test (Miata)
1. Start engine, and observe ANTI-LOCK light. Light should illuminate for a few seconds. If light does not
illuminate as described, remove instrument cluster. Connect 12 volts to terminal 2k of instrument cluster.
See Fig. 8
. Using a jumper wire, connect terminal 1K of instrument cluster to ground. ANTI-LOCK light
should illuminate. If light does not illuminate, check bulb. If bulb is okay, check meter fuse and wiring
harness.
2. Install instrument cluster, and recheck warning light operation. If light still does not illuminate for a few
seconds, check wiring harness between ANTI-LOCK light and control unit and between ANTI-LOCK
light and hydraulic unit. Check operation of hydraulic unit valve relay.
Operational Test (RX7)

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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1. Start engine, and observe ANTI-LOCK light. Light should illuminate for a few seconds. If light does not
illuminate as described, remove clock and bezel assembly from dashboard. Slide warning and clock unit
from instrument panel. Connect terminal "E" to ground. See Fig. 9
. ANTI-LOCK light should illuminate.
If light does not illuminate, check bulb. If bulb is okay, check meter fuse and wiring harness.
2. Install instrument cluster, and recheck warning light operation. If light still does not illuminate for a few
seconds, check wiring harness between ANTI-LOCK light and control unit, and ANTI-LOCK light and
hydraulic unit. Check operation of hydraulic unit valve relay.
Operational Test (929)
1. Start engine, and observe ANTI-LOCK light. Light should illuminate for a few seconds. If light does not
illuminate as described, remove instrument cluster. Connect 12 volts to terminal "J" of instrument cluster
connector I-06. See Fig. 10
. Using a jumper wire, connect terminal "E" of instrument cluster connector I-
08 to negative ground. ANTI-LOCK light should illuminate. If light does not illuminate, check bulb. If
bulb is okay, check meter fuse and wiring harness.
2. Install instrument cluster, and recheck warning light operation. If light still does not illuminate for a few
seconds, check wiring harness between ANTI-LOCK light and control unit and between ANTI-LOCK
light and hydraulic unit. Check operation of hydraulic unit valve relay.
Fig. 8: Testing ANTI
-LOCK Warning Light (Miata)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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Fig. 9: Testing ANTI-LOCK Warning Light (RX7)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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Fig. 10: Testing ANTI-LOCK Warning Light (929)
Courtesy of MAZDA MOTORS CORP.
STOPLIGHT SWITCH
Continuity Test
Disconnect stoplight switch connector. Using a DVOM, check continuity between Green or Green/White wire
and White/Green wire with brake pedal depressed. Ensure continuity exists. Release pedal, and note reading on
DVOM. Continuity should not be present. If continuity is not as specified, replace switch.
FRONT & REAR VALVES
Resistance Test (Miata)
1. Disconnect hydraulic unit 12-pin connector. Using a DVOM, measure resistance between the following
wires: Yellow/Green wire and Black wire; Brown wire and Black wire; Black/White wire and Black wire.
Resistance should be 1-1.2 ohms in each measurement.
2. If resistance is not as specified, replace hydraulic unit. If resistance is as specified, check wiring harness
between ABS control unit and hydraulic unit.
Resistance Test (RX7 & 929)

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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engagement while rotating adjusting screw to prevent burring screw slots. Ensure adjusting screw rotates
freely.
PARKING BRAKE
B2200 & B2600i
1. Depress brake pedal several times while vehicle is moving in Reverse. Ensure brakes are properly
adjusted. Pull parking brake lever with a force of 44 lbs. (20 kg). If stroke is 7-12 notches, parking brake
is properly adjusted.
2. If stroke is not 7-12 notches, raise and support rear of vehicle. Release parking brake lever. Loosen cable
lock nut at lever end of cable. Rotate adjusting nut until correct stroke is obtained. Operate parking brake
several times and ensure rear wheels rotate freely. Ensure parking brake warning light illuminates when
brake lever is pulled one notch.
Navajo
1. Adjust service brakes before adjusting parking brake cable. Ensure brake drums are cold. Apply parking
brake to fully depressed position. Grip threaded rod to prevent it from spinning.
2. Thread equalizer nut 6 full turns past its original position on threaded rod. See Fig. 4
. Check cable
tension at rear of equalizer assembly using Cable Tension Gauge (021-00018). If tension is not 400-600
lbs. (182-272 k
g), repeat step 2).

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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2. Release parking brake lever. Using a screwdriver, reach through parking brake handle hole in console and
rotate adjusting screw until stroke is 6-8 notches. Ensure rear wheels rotate freely. Ensure parking brake
warning light illuminates when brake lever is pulled one notch.
Miata, MX-6, MPV, Protege, RX7, 323, 626
1. On models with rear disc brakes, depress brake pedal several times. On models with rear drum brakes,
start engine and depress brake pedal several times while vehicle is moving in Reverse. Stop engine.
2. On all models, pull parking brake lever with a force of 22 lbs. (10 kg). If stroke is 5-7 notches, parking
brake is properly adjusted. If stroke is not 5-7 notches, raise and support rear of vehicle. Release parking
brake lever.
3. Rotate cable adjusting nut at lever end of cable (under console cover) until stroke is within specification.
On models equipped with rear disc brakes, ensure clearance between stopper and lever (at each caliper) is
not less than .08" (2 mm) on RX7, or zero on all other models. On all models, ensure parking brake
warning light illuminates when brake lever is pulled one notch.
PARKING BRAKE SHOES
929
Raise and support vehicle. Remove rear wheels. Remove service plug from rotor. Using a screwdriver, rotate
star wheel adjuster toward axle until rotor locks. Rotate adjuster in opposite direction 3-5 notches. Ensure rotors
turn freely and parking brake functions properly. Install service plug and rear wheels.
PEDAL FREE PLAY
Depress pedal a few times to eliminate vacuum. Pedal free play should be .16-.28" (4-7 mm). Adjust play by
loosening push rod lock nut. Turn push rod until correct free play is obtained. Tighten push rod lock nut.
PEDAL HEIGHT & STOPLIGHT SWITCH
1. Released pedal height is measured from carpet surface on vertical portion of firewall to pedal pad center.
Disconnect stoplight switch electrical connector. Loosen lock nut on stoplight switch. Move switch away
from pedal. Loosen push rod lock nut. Turn rod until correct pedal height is obtained. See BRAKE
PEDAL HEIGHT SPECIFICATIONS .
2. Adjust pedal free play. See PEDAL FREE PLAY
under ADJUSTMENTS. Tighten push rod lock nut.
Rotate stoplight switch until it contacts pedal and then rotate an additional 1/2 turn. Tighten stoplight
switch lock nut. Reconnect stoplight switch electrical connector.
3. Applied pedal height is measured from angled portion of firewall (without carpet) to pedal pad center.
Start engine. On B2200, B2600i and MPV, depress brake pedal with 33 lbs. (15 kg) pressure. On all other
models, depress brake pedal with 132 lbs. (60 k
g) pressure. tension should be checked and adjusted.
NOTE: Pedal height and stoplight switch information is not available for Navajo.

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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