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TORQUE SPECIFICATIONS
DIAGNOSIS & TESTING
SELF-DIAGNOSTIC SYSTEM
Trouble Shooting
AIR BAG warning light flashes are used to diagnose air bag system. The number of warning light flashes
depends on the type of fault being detected. Codes are prioritized so that if 2 or more faults are present, the
highest test-priority fault indication will remain until corrected.
Warning Light Does Not Illuminate
Check for blown fuses, burned-out bulb, disconnected diagnostic module, or open circuit between warning light
and diagnostic module.
Warning Light Flashes Or Remains On
Check code output of AIR BAG warning light. See AIR BAG FLASH CODES table.
AIR BAG FLASH CODES
ApplicationFt. Lbs. (N.m)
Air Bag Module Nuts12-15 (16-20)
Steering Wheel Nut29-36 (39-49)
INCH Lbs. (N.m)
Front Impact Sensor Bolts78-113 (9-13)
Rear Safing Sensor Nuts
Miata78-113 (9-13)
RX761-87 (7-10)
WARNING:Follow air bag service precautions to prevent accidentalair bag
deployment and personal injury. See SERVICE PRECAUTIONS.
NOTE: After component replacement, check system to ensure proper operation. See
SYSTEM OPERATION CHECK.
PriorityFlash CodeCause/Diagnosis
1Remains OnFaulty Diagnostic Module
Poor Connection Of Diagnostic
Module Connector (See
DIAGNOSTIC TEST NO. 1)
2Flashes 3 TimesOpen Circuit
Poor Connection Of Power Source
1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Page 160 of 392

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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CHARGING SYSTEM TROUBLE SHOOTING
TROUBLE SHOOTING PRECAUTIONS
Miata
Obtain code number and deactivate audio anti-theft system before disconnecting battery.
All Models
DO NOT reverse battery cable connections. Rectifier will be damaged.
DO NOT use high voltage type testers.
PROBLEM Possible CauseAction
NO START CONDITION
Dead BatteryCheck/Replace Battery
Bad Cable ConnectionsClean/Replace Cables
Ignition Switch/Circuit FaultCheck Switch/Circuit
CHARGING SYSTEM WARNING LIGHT STAYS ON
Loose/Worn Alternator BeltTighten/Replace Belt
Loose Alternator ConnectionsCheck/Repair
Connections
Warning Light WiringCheck/Repair Wiring
Faulty Stator/DiodesTest/Repair Alternator
Faulty Voltage RegulatorTest/Repair Regulator
WARNING LIGHT OFF WITH IGNITION SWITCH ON
Blown FuseCheck/Replace Fuse
Faulty AlternatorTest Alternator
Bad Warning Light BulbTest/Replace Bulb
WARNING LIGHT ON WITH IGNITION SWITCH OFF
Alternator Wiring ShortCheck/Repair Wiring
Faulty Rectifier BridgeTest/Repair Alternator
AMMETER INDICATES DISCHARGE
Loose/Worn Alternator BeltTighten/Replace Belt
Loose Alternator ConnectionsCheck/Repair
Connections
Faulty AmmeterTest/Replace Ammeter
NOISY Defective BatteryReplace Battery
Defective AlternatorTest/Repair Alternator
Defective RegulatorTest/Repair Regulator
NOTE: Observe the following precautions when trouble shooting or testing charging
system:
1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
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Any modification to the exhaust system on turbo models, which reduces exhaust backpressure, will lead to lean
fuel mixtures and excessive spark advance. This could cause serious engine damage.
ELECTROSTATIC DISCHARGE SENSITIVE (ESD) PARTS
ENGINE OIL
FUEL SYSTEM SERVICE
HALOGEN BULBS
Halogen bulbs contain pressurized gas which may explode if overheated. DO NOT touch glass portion of bulb
with bare hands. Eye protection should be worn when handling or working around halogen bulbs.
HEADLIGHT RETRACTOR
RADIATOR CAP
RADIATOR FAN WARNING:Many solid state electrical components can be damaged by static
electricity (ESD). Some will display a warning label, but many will not.
Discharge personal static electricity by touching a metal ground point on
the vehicle prior to servicing any ESD sensitive component.
CAUTION: Never use non-detergent or straight mineral oil.
WARNING:Relieve fuel system pressure prior to servicing any fuel system
component (fuel injection models).
CAUTION: If headlight retractor freezes during cold weather operation, DO NOT
attempt to force mechanism. Headlights should be kept raised at all times
in cold weather. To raise them, use only headlight retractor switch. DO
NOT use headlight switch.
CAUTION: Always disconnect the fan motor when working near the radiator fan. The
fan is temperature controlled and could start at any time even when the
ignition key is in the OFF position. DO NOT loosen or remove radiator cap
when cooling system is hot.
WARNING:Keep hands away from radiator fan. Fan is controlled by a thermostatic
switch which may come on or run for up to 15 minutes even after engine
is turned off.
1991 Mazda MX-5 Miata
FUSES & CIRCUIT BREAKERS Fuses & Circuit Breakers 1990-95 Mazda
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