1994 MAZDA MX-5 Workshop Manual

T SRS AIR BAG SYSTEM SRS AIR BAG SYSTEM PREPARATION SST 46UOTX-812 STRUCTURAL VIEW 49 H066 002 Deployment tool 1. Driver-side air bag module Removal I Installation ...... page T-206 Disposal procedure ........ page T-215 2. Passenger-side air bag module Removal I Installation ...... page T-207 Disposal procedure ........ page T-215 3. Clock spring Removal I Installation ...... page T- 19 Inspection ................ page T-209 For deployment of air bag module 4. Diagnostic module Removal / Installation ...... page T-208 5. Crush sensor (D-sensor) Removal / Installation ...... page T-210 Inspection ................ page T-212 6. Crash sensor (S-sensor) Removal I Installation ...... page T-213 Inspection ................ page T-214 Gartner Banana

SRS AIR BAG SYSTEM T COMPONENT DESCRIPTION Component Air bag module Function Air bag system warning light Deploys air bag when current flows to integrated igniter Light illuminates or flashes if malfunction occurs in air bag system I EE with S-sensor, completes Circuit Clock spring I Ensures uninterrupted electrical connec- tion to air bag module while allowing turning of steering wheel Activated(closed) when crash impact de- Crash sensor Diagnostic module to infktor Activated(closed) when crash impact de- S-sensor 1 Monitors com~onents and harnesses in tected Acting with D-sensor, completes circuit to inflator Remark Located in instrument cluster Location: Driver side . . . . . . . . in steering wheel hub Passenger side . . . above the glove compartment Part of combination switch Located in front part of vehicle(left, right, and center) Located behind heater unit in passenger compartment Contains back-up battery air bag system Indicates system malfunction by flashing or illuminating air bag system warning light If warning light is bunt, sounds warning buzzer Detects short circuit between air bag module and ground or crash sensor rnal- function and melts system fuse to pre- vent unintended air bag deployment Gartner Banana

SRS AIR BAG SYSTEM SYSTEM DIAGRAM PASSENGER-SIDE S-SENSOR AIR BAG MODULE I IG1 B+ HORN RELAY CLOCK SPRING BACK-UP BATTERY I AIR BAG SYSTEM WARNING LIGHT SENSOR -7 System Operation During collision When either of the D-sensors and the S-sensor are activated (closed) simultaneously by shock of a colli- sion, the circuit to the inflator is completed. The inflator creates nitrogen gas and the air bag is deployed. The air bag vents the nitrogen gas from the vent hole on the back side of the bag to reduce shock to the driver and to allow easier exit from the vehicle. During normal condition and malfunction The diagnostic module constantly monitors the components and wiring of the air bag system for malfunc- tion, open circuits, and short circuits. .J If a malfunction is detected, the diagnostic module illuminates or flashes the warning light. In the case of a short circuit in the sensors or sensor harnesses, the diagnostic module activates the warning light and shuts down the system to prevent accidental deployment of the air bag. Gartner Banana

SRS AIR BAG SYSTEM SERVICE WARNINGS Component Disassembly Disassembling and reassembling the components of the air bag system can render the system inopera- tive, which may result in serious injury or death in the event of an accident. Do not disassemble any air bag system components. Wiring Harness Repair Incorrectly repairing an air bag system wiring har- ness can accidently deploy the air bag, which can cause serious injury. If a problem is found in the sys- tem wiring, replace the wiring harness. Do not try to repair it. Air Bag Module Inspection Inspecting the air bag module with an ohmmeter can deploy the air bag, which can cause serious injury. Do not use an ohmmeter to inspect the air bag mod- ule. Air Bag Module Handling A live (undeployed) air bag may accidently deploy when it is handled and cause serious injury. When carrying a live air bag module, point the trim cover away from your body to lessen the chance of injury in case it deploys. A live air bag placed face down on a surface is dan- gerous. If the air bag deploys, the motion of the mod- ule can cause serious injury. Always face the trim cover up to reduce the motion of the module in case it accidently deploys. Gartner Banana

T SRS AIR BAG SYSTEM GENERALPROCEDURES Before Servicing 1. Deactivate the audio antitheft system, if installed. (Refer to page T-120.) 2. Disconnect the negative battery cable. 3. Remove the lower panel. 4. Disconnect the orange and blue clock spring connec- tors. 5. Remove the glove compartment. 6. Disconnect the orange and blue passenger-side air bag module connectors. I , 46UOTXd21 TROUBLESHOOTING Troubleshootinn Procedure The air bag diagnostic module has a self-diagnosis function that flashes or illuminates the AIR BAG sys- tem warning light to indicate trouble in the air bag system. The trouble can be determined by the warning light illumination or flashing pattern. If the light does not illuminate but the system still has trouble, a warn- ing buzzer will sound 5 cycles of 5 times each. . . Flowchart I START Troubleshoot warning light circuit Does AIR BAG system warning light illuminate for 4-8 secs and I I Yes t Refer to service code table and troubleshoot system Press horn switch while turning steering wheel. Does horn sound? I I I Yes Reconnect connectors Are air bag module and horn switch connectors properly con- nected to clock spring connec- tor? Yes I I I I Troubleshooting horn circuit - Gartner Banana

SRS AIR BAG SYSTEM T Circuit Diagram Gartner Banana

T SRS AIR BAG SYSTEM Connector Locations Gartner Banana

SRS AIR BAG SYSTEM T Service Code Table (With passenger-side air bag) Possible cause Flowchart No. Poor connection of diagnostic module priority connector Open circuit or poor connection of power source circuit code Output signal (Air bag system warning light) Remains ON Damaged D-sensor (D-sensor ON) 2 Poor installation of S-sensor Damaged S-sensor (S-sensor ON) 12 5 22 OFF OFF Open connection in S-sensor feed circuit S-sensor diagnosis circuit open High resistance or open circuit in driver- 8 32 OFF side air bag module circuit High resistance or open circuit in pas- senger-side air bag module circuit Low resistance in driver-side air bag module circuit I 11 1 35 ION- OFF b Low resistance in passenger-side air bag module circuit Open circuit between diagnostic module 10 and D-sensor - Poor installation of right D-sensor 113 144 ION- OFF 34 OFF Poor installation of center D-sensor 14 I 15 1 46 ION- OFF Poor installation of left D-sensor 45 System-down fuse burnt OFF 1 17 1 52 ( ON ml flk OFF Damaged back-up battery Damaged diagnostic module I 18 I 53 IoNm[~ OFF Poor connection of all D-sensor 19 I I I w Note If two or more troubles exist in the air bag system, the warning light indicates the cause of the trouble with the highest priority. T-163 99 Flashes quickly and continuously Gartner Banana