technicians reference booklet - ludicrous-speed€¦ · integrity. there are two (2) air bag...

© Copyright 2001Subaru of America, Inc.

All rights reserved. This book may not bereproduced in whole or in part without theexpress permission of Subaru of America, Inc.

Subaru of America, Inc. reserves the right atany time to make changes or modifications tosystems, procedures, descriptions, andillustrations contained in this book withoutnecessarily updating this document. Informationcontained herein is considered current as ofMarch 2001.

Table of Contents

SRS Supplemental Restraint System (1992 SVX) -------------------------- 4SRS System Precautions ---------------------------------------------------------- 4Component Overview --------------------------------------------------------------- 5Component Operation -------------------------------------------------------------- 7Roll Connector Phasing ------------------------------------------------------------ 8Connector Double Lock Sensors------------------------------------------------- 9Air Bag Module --------------------------------------------------------------------- 10Inflator Igniter ------------------------------------------------------------------------ 11Air Bag -------------------------------------------------------------------------------- 11Air Bag Warning Lamps ---------------------------------------------------------- 11Air Bag Deployment --------------------------------------------------------------- 12Diagnostics and Servicing ------------------------------------------------------- 12SRS System Servicing------------------------------------------------------------ 13

1995 Model Legacy ---------------------------------------------------------------- 141996 Model Legacy and Outback ---------------------------------------------- 141998 Model Forester -------------------------------------------------------------- 152000 Model Legacy and Outback ---------------------------------------------- 172001 Model Legacy ---------------------------------------------------------------- 192002 Model Impreza WRX ------------------------------------------------------- 20

Supplemental Restraint System (SRS)

4SRS (3/2001)

SRS SUPPLEMENTALRESTRAINT SYSTEMSVX System OverviewThe SRS Air Bag System is a safety devicedesigned to function in conjunction with a kneebolster, seat belts and shoulder belts. Similarto other manufacturers, it deploys in frontalcollisions only. It is an electrically operatedsystem which uses a chemical deploymentdevice.

The SRS System features built-in SelfDiagnostics and a redundant Saftey Designwith back-ups built into all of the circuits.The system safeguards include double lockingconnectors with diagnostic sensors, a self-shorting inflator SRS air bag module connectorto prevent accidental deployment duringservicing, and a steering roll connector. Acapacitor supplies back-up power.Finally, for redundancy, there are two frontinertia sensors and two safeing sensor circuits.

NOTE: THE SRS AIR BAG SYSTEM ISNOTE: THE SRS AIR BAG SYSTEM ISNOTE: THE SRS AIR BAG SYSTEM ISNOTE: THE SRS AIR BAG SYSTEM ISNOTE: THE SRS AIR BAG SYSTEM ISTHOROUGHLY DESIGNED TOTHOROUGHLY DESIGNED TOTHOROUGHLY DESIGNED TOTHOROUGHLY DESIGNED TOTHOROUGHLY DESIGNED TOPREVENT ACCIDENTAL DEPLOYMENT,PREVENT ACCIDENTAL DEPLOYMENT,PREVENT ACCIDENTAL DEPLOYMENT,PREVENT ACCIDENTAL DEPLOYMENT,PREVENT ACCIDENTAL DEPLOYMENT,HOWEVER, CAUTION SHOULDHOWEVER, CAUTION SHOULDHOWEVER, CAUTION SHOULDHOWEVER, CAUTION SHOULDHOWEVER, CAUTION SHOULDALWAYS BE USED WHEN SERVICINGALWAYS BE USED WHEN SERVICINGALWAYS BE USED WHEN SERVICINGALWAYS BE USED WHEN SERVICINGALWAYS BE USED WHEN SERVICINGOR DIAGNOSING THE SYSTEM. THEOR DIAGNOSING THE SYSTEM. THEOR DIAGNOSING THE SYSTEM. THEOR DIAGNOSING THE SYSTEM. THEOR DIAGNOSING THE SYSTEM. THESRS SYSTEM, WHEN HANDLEDSRS SYSTEM, WHEN HANDLEDSRS SYSTEM, WHEN HANDLEDSRS SYSTEM, WHEN HANDLEDSRS SYSTEM, WHEN HANDLEDPROPERLY, IS LESS HAZARDOUS TOPROPERLY, IS LESS HAZARDOUS TOPROPERLY, IS LESS HAZARDOUS TOPROPERLY, IS LESS HAZARDOUS TOPROPERLY, IS LESS HAZARDOUS TOSERVICE THAN A CAR BATTERY ORSERVICE THAN A CAR BATTERY ORSERVICE THAN A CAR BATTERY ORSERVICE THAN A CAR BATTERY ORSERVICE THAN A CAR BATTERY ORFUEL SYSTEM.FUEL SYSTEM.FUEL SYSTEM.FUEL SYSTEM.FUEL SYSTEM.

SRS SYSTEM PRECAUTIONS1. Whenever serving the SRS System

disconnect the battery and wait at least 10minutes before proceeding.

2. Always store the SRS Air Bag Module(steering wheel pad) facing up.

3. All of the SRS components are sealed -DO NOT DISASSEMBLE.

4. All of the SRS wiring is enclosed in ayellow housing for quick identification. Usecare whenever working near a yellowhousing. These wires may not be repairedif they are damaged. They MUST bereplaced.

5. Do not drop any of the components. Thiscould alter their sensitivity.

6. The SRS Module must avoid extreme heatexposure (200 degrees F. or greater).

NOTE: EXPOSURE TONOTE: EXPOSURE TONOTE: EXPOSURE TONOTE: EXPOSURE TONOTE: EXPOSURE TOTEMPERATURES OF 300 DEGREES F.TEMPERATURES OF 300 DEGREES F.TEMPERATURES OF 300 DEGREES F.TEMPERATURES OF 300 DEGREES F.TEMPERATURES OF 300 DEGREES F.OR GREATER WILL CAUSEOR GREATER WILL CAUSEOR GREATER WILL CAUSEOR GREATER WILL CAUSEOR GREATER WILL CAUSEDEPLOYMENT.DEPLOYMENT.DEPLOYMENT.DEPLOYMENT.DEPLOYMENT.

7. Wear protective clothing when handlingdeployed air bag components. Always usegloves and eye protection. Althoughthe residue is NOT toxic, it may causeminor eye and skin irritation.

8. Never place yourself or test equipmentbetween the Air Bag Module andseat when serving the air bag system.

NOTE: REVIEW ALL CAUTIONSNOTE: REVIEW ALL CAUTIONSNOTE: REVIEW ALL CAUTIONSNOTE: REVIEW ALL CAUTIONSNOTE: REVIEW ALL CAUTIONSOUTLINED IN THE SERVICE MANUALOUTLINED IN THE SERVICE MANUALOUTLINED IN THE SERVICE MANUALOUTLINED IN THE SERVICE MANUALOUTLINED IN THE SERVICE MANUALREGARDING SKIN AND EYEREGARDING SKIN AND EYEREGARDING SKIN AND EYEREGARDING SKIN AND EYEREGARDING SKIN AND EYEEXPOSURE TO DEPLOYED AIR BAGEXPOSURE TO DEPLOYED AIR BAGEXPOSURE TO DEPLOYED AIR BAGEXPOSURE TO DEPLOYED AIR BAGEXPOSURE TO DEPLOYED AIR BAGRESIDUES.RESIDUES.RESIDUES.RESIDUES.RESIDUES.

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5SRS (3/2001)

Supplemental Restraint System (SRS)COMPONENT OVERVIEWThe Air Bag and Inflator Module is attached tothe steering wheel and covered by the steeringwheel pad. It contains the deployment module,air bag and cover pad.

There are two (2) front sensors located insidethe front fenders behind each inner fenderliner. In addition, there are two Safeing sensorslocated inside the ECU.

The steering roll connector is mountedbetween the steering wheel and thecombination switch. It is an integral part of thecombination switch assembly. The design ofthis assembly allows for steering wheelrotation. It also provides the hard wireconnection between the air bag module andthe SRS system harness.

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All SRS connectors are equipped with doublelocks and sensors. The sensors are used toindicate that the connector is not double-locked. For identification purposes, they aregreen in color.

The ECU is located under the center console.It receives sensor input signals in the event ofa frontal impact. It then sends a signal to triggerair bag deployment. The ECU features a self-diagnostic capability incorporating long termmemory.

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6SRS (3/2001)

The ECU sends a continuous low voltagesignal to monitor the sensors, the harness, thedeployment module and to check for connectorintegrity.

There are two (2) air bag warning lampslocated in the combination meter. For safetypurposes, there are also two (2) independentdrive circuits. Both lights and circuits illuminateonly one light position in the combinationmeter.

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7SRS (3/2001)

Supplemental Restraint System (SRS)COMPONENT OPERATIONThe ECU controls the SRS Air Bag Systemby constantly monitoring the input signals fromthe front sensors, the safeing sensors and thedouble lock circuit. It also generates outputsignals to the warning lamps and to the inflatormodule.

Among other things, the ECU contains twosafeing sensors which provide input signals,and two capacitors which supplement lowbattery voltage.The capacitors also provide back-up voltagein the event of a total loss of battery voltage.They are triggered by an internal voltageregulator.

NOTE: THE CAPACITORS CANNOTE: THE CAPACITORS CANNOTE: THE CAPACITORS CANNOTE: THE CAPACITORS CANNOTE: THE CAPACITORS CANACTIVATE THE SRS AIR BAG UP TO 10ACTIVATE THE SRS AIR BAG UP TO 10ACTIVATE THE SRS AIR BAG UP TO 10ACTIVATE THE SRS AIR BAG UP TO 10ACTIVATE THE SRS AIR BAG UP TO 10MINUTES AFTER A TOTAL LOSS OFMINUTES AFTER A TOTAL LOSS OFMINUTES AFTER A TOTAL LOSS OFMINUTES AFTER A TOTAL LOSS OFMINUTES AFTER A TOTAL LOSS OFBATTERY VOLTAGE. THE REGULATORBATTERY VOLTAGE. THE REGULATORBATTERY VOLTAGE. THE REGULATORBATTERY VOLTAGE. THE REGULATORBATTERY VOLTAGE. THE REGULATORMONITORS BATTERY VOLTAGE ANDMONITORS BATTERY VOLTAGE ANDMONITORS BATTERY VOLTAGE ANDMONITORS BATTERY VOLTAGE ANDMONITORS BATTERY VOLTAGE ANDCAN SUPPLEMENT BATTERY VOLTAGECAN SUPPLEMENT BATTERY VOLTAGECAN SUPPLEMENT BATTERY VOLTAGECAN SUPPLEMENT BATTERY VOLTAGECAN SUPPLEMENT BATTERY VOLTAGEAS NEEDED IN THE EVENT OF AAS NEEDED IN THE EVENT OF AAS NEEDED IN THE EVENT OF AAS NEEDED IN THE EVENT OF AAS NEEDED IN THE EVENT OF ACOLLISION.COLLISION.COLLISION.COLLISION.COLLISION.

Redundancy is provided by the front left handand right hand sensors. The hollow rollerdesign provides a movable mass. The rolleris mounted on a flat surface and held in placeby a flat roller spring. The roller spring allowsforward roller movement during frontal impactsof 12.5 MPH or greater. In this case, the rollerand spring assembly makes contact with thecircuit terminal.When the roller makes contact with the circuitterminal, it sends a collision signal to the ECU.This completes the sensor circuit and providesa ground circuit to the inflator.The metal housing of the front sensors aresurrounded by resin and filled with inert gasto prevent moisture damage.

CAUTION: DO NOT OPEN THECAUTION: DO NOT OPEN THECAUTION: DO NOT OPEN THECAUTION: DO NOT OPEN THECAUTION: DO NOT OPEN THESENSOR HOUSING. THE INTERNALSENSOR HOUSING. THE INTERNALSENSOR HOUSING. THE INTERNALSENSOR HOUSING. THE INTERNALSENSOR HOUSING. THE INTERNALCOMPONENTS ARE NOTCOMPONENTS ARE NOTCOMPONENTS ARE NOTCOMPONENTS ARE NOTCOMPONENTS ARE NOTSERVICEABLE.SERVICEABLE.SERVICEABLE.SERVICEABLE.SERVICEABLE.

The continuous sensor harness is moldeddirectly into the sensor body. The harness hasonly one sensor connector, which is locatedat the ECU. This provides a one-piece circuitpath to the ECU. A damaged harness orsensor must be replaced as an assembly.

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8SRS (3/2001)

Two safing sensors located inside the ECUprovide redundancy and safety. They operatesimilar to the front sensors in that they providea B+ circuit to the inflator. Although they aresimilar in construction and operation to thefront sensors, the safeing sensors are moresensitive.Weight added to the center of the roller makesit heavier, which in turn, makes the sensormore sensitive to impact. The ECU must bereplaced if one of the safeing sensors fail.The steering roll connector is a continuous flatribbon-type cable. The cable coils around thehub which allows 2.65 turns (either direction)from the center steering position. This providesa direct hard wire connection between the SRSair bag module and the ECU harness. It alsoincludes the horn circuit. This eliminates thepotential circuit interruption inherent to slidingcontact-type connectors, which also preventsfalse trouble codes.

Two guide pins are used to align the rollconnector with the steering wheel.

ROLL CONNECTOR PHASINGThe roll connector MUST be phased to thesteering system. With the front wheelscentered, aline the inner "center" indicatorlocated behind the window in the rollconnector, with the "center" indicator locatedon the rotating cover next to the window. Thereis also an alignment arrow on the connectorcase.

If the inner indicator shows "1R" in the window,rotate the cover one full rotation to the right. Ifthe inner indicator shows "2R" in the window,rotate the cover two full rotations to the right.

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9SRS (3/2001)

Supplemental Restraint System (SRS)Similarly, if the indicator shows either "1L" or"2L", rotate the cover one or two left handrotations.

NOTE: TO MAINTAIN PROPERNOTE: TO MAINTAIN PROPERNOTE: TO MAINTAIN PROPERNOTE: TO MAINTAIN PROPERNOTE: TO MAINTAIN PROPERSTEERING WHEEL ALIGNMENT,STEERING WHEEL ALIGNMENT,STEERING WHEEL ALIGNMENT,STEERING WHEEL ALIGNMENT,STEERING WHEEL ALIGNMENT,CENTER THE FRONT WHEELS ANDCENTER THE FRONT WHEELS ANDCENTER THE FRONT WHEELS ANDCENTER THE FRONT WHEELS ANDCENTER THE FRONT WHEELS ANDSCRIBE AN ALIGNMENT MARKSCRIBE AN ALIGNMENT MARKSCRIBE AN ALIGNMENT MARKSCRIBE AN ALIGNMENT MARKSCRIBE AN ALIGNMENT MARKBETWEEN THE STEERING WHEEL HUBBETWEEN THE STEERING WHEEL HUBBETWEEN THE STEERING WHEEL HUBBETWEEN THE STEERING WHEEL HUBBETWEEN THE STEERING WHEEL HUBAND THE SHAFT, PRIOR TOAND THE SHAFT, PRIOR TOAND THE SHAFT, PRIOR TOAND THE SHAFT, PRIOR TOAND THE SHAFT, PRIOR TODISASSEMBLY.DISASSEMBLY.DISASSEMBLY.DISASSEMBLY.DISASSEMBLY.

CONNECTOR DOUBLE LOCKSENSORSDouble lock sensor mechanisms are identifiedby a green color. They are used on all SRSelectrical connectors. The system uses four (4)double lock sensors between:

1. The system power supply andthe warning light (Connector B58 to AB1)

2. The main ECU connection #1(Connectors AB4, 5, & 6 to ECU)

3. The ECU harness and the rollconnector # at the combination switch(Connector AB2 to AB7)

4. The roll connector and the air bagmodule #3 located behind the steeringwheel pad (Connector AB7 to AB8)

These sensors connect the double lockdetecting circuit to the negative side of theigniter circuit. This provides a ground signalcircuit for the warning light system.If any green double-lock lever is not properlylatched, the SRS warning lamp will beilluminated and a Trouble Code will bedisplayed (Code 14).The double lock (#1) at the ECU secures themain harness connector as well as the twofront sensor harness connectors.

Double lock sensor terminals make contactwhen they are unlocked and they separatewhen they are locked. The green tabsmechanically prevent the connector frombeing removed. The double lock will not latchunless the connectors are completely inserted.

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10SRS (3/2001)

In order to release double lock #1, use a smallscrew driver. Press in on the metal loop andsimultaneously raise the green latch. Then toremove the individual connectors, press downon the primary connector locks.

Secure the double lock by pressing the greenlatch down until a click is heard.

The procedure for locks #2 and #3 are similarto sensor #1 except that they are released atthe primary lock in two steps. First, press downonce on the spring-loaded green latch and itwill pop out. Then press it down a second timein order to remove the connector. To securethe double lock, push in the green latch until aclick is heard.

AIR BAG MODULEThe air bag module comes as a one pieceassembly with the horn buttons. It is mountedto the steering wheel with four #30 tamper-proof torx bolts.

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11SRS (3/2001)

Supplemental Restraint System (SRS)The air bag module consists of three sub-components:

1. Inflator2. Air Bag3. Inflator harness with connector

NOTE: THE AIR BAG MODULE ISNOTE: THE AIR BAG MODULE ISNOTE: THE AIR BAG MODULE ISNOTE: THE AIR BAG MODULE ISNOTE: THE AIR BAG MODULE ISSERVICED ONLY AS AN ASSEMBLY.SERVICED ONLY AS AN ASSEMBLY.SERVICED ONLY AS AN ASSEMBLY.SERVICED ONLY AS AN ASSEMBLY.SERVICED ONLY AS AN ASSEMBLY.DO NOT ATTEMPT TO DISASSEMBLEDO NOT ATTEMPT TO DISASSEMBLEDO NOT ATTEMPT TO DISASSEMBLEDO NOT ATTEMPT TO DISASSEMBLEDO NOT ATTEMPT TO DISASSEMBLEOR REPACK THE AIR BAG.OR REPACK THE AIR BAG.OR REPACK THE AIR BAG.OR REPACK THE AIR BAG.OR REPACK THE AIR BAG.

INFLATOR IGNITERThe inflator igniter is designed to ignite a squibafter it receives an input from the ECU. Theigniter is an electrically heater device withgenerates temperatures in excess of 300degrees F. to ignite the squib.

The squib consists of fire transmissive materialused to ignite nitrogen pellets. The nitrogenpellets generate nitrogen gas (N2) duringcombustion. This creates rapid gas expansionwith, in turn, inflates the air bag.The built-in screen cools and removes hotcinders from the N2 before the N2 enters theair bag.

NOTE: FOR MORE SPECIFICNOTE: FOR MORE SPECIFICNOTE: FOR MORE SPECIFICNOTE: FOR MORE SPECIFICNOTE: FOR MORE SPECIFICCHEMICAL CONTENT, PLEASE REFERCHEMICAL CONTENT, PLEASE REFERCHEMICAL CONTENT, PLEASE REFERCHEMICAL CONTENT, PLEASE REFERCHEMICAL CONTENT, PLEASE REFERTO THE SUBARU SVX SERVICETO THE SUBARU SVX SERVICETO THE SUBARU SVX SERVICETO THE SUBARU SVX SERVICETO THE SUBARU SVX SERVICEMANUAL.MANUAL.MANUAL.MANUAL.MANUAL.

AIR BAGThe air bag itself is located behind the steeringwheel center pad. It is made out of nylonmaterial which expands to a diameter ofapproximately 30 inches(762mm) wheninflated.The bag is coated on the inside with siliconeand is coated on the outside with talcumpowder or cornstarch. This provideslubrication for deployment. These inner andouter coating produce the majority of theresidue found after deployment.

AIR BAG DEPLOYMENTIn order to activate the system, a frontal forceof 12.5 MPH or greater is required. This forceovercomes the inertia and the tension of theroller springs of the rollers in the front sensorsand the safeing sensors. The rollers then makecontact with the circuit terminals. The frontsensors provide a ground circuit while thesafeing sensors provide a positive circuit.In order for the ECU to activate the inflator, itmust receive at least one collision signal fromthe front sensors and at least one collisionsignal from the safeing sensors.After receiving a signal from the ECU, theigniter instantly heats up to 300 degrees F.,igniting the squib which burns the nitrogenpellets to create nitrogen gas. The generatedN2 goes through the screen into the air bag.The outer skin (steering wheel pad) of theinflator air bag module then ruptures as the airbag deploys. The Drivers forward movementis absorbed by the air bag as it vents the N2through two 1.58 inch(40mm) holes.The Operational Time Sequence is almostinstantaneous:

1. Collision: Zero seconds2. Operation of the inflator: 3/100 second3. Discharge of the N2: About 6/100 second4. Completion: About 110/1000 second

NOTE: A VEHICLE WITH A DEPLOYEDNOTE: A VEHICLE WITH A DEPLOYEDNOTE: A VEHICLE WITH A DEPLOYEDNOTE: A VEHICLE WITH A DEPLOYEDNOTE: A VEHICLE WITH A DEPLOYEDAIR BAG MUST BE TOWED TO THEAIR BAG MUST BE TOWED TO THEAIR BAG MUST BE TOWED TO THEAIR BAG MUST BE TOWED TO THEAIR BAG MUST BE TOWED TO THEDEALER FOR SERVICE.DEALER FOR SERVICE.DEALER FOR SERVICE.DEALER FOR SERVICE.DEALER FOR SERVICE.

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12SRS (3/2001)

AIR BAG WARNING LAMPSTwo (2) air bag warning lamps are located onthe lower right-hand corner of the combinationmeter. Two bulbs are used with independentdrive circuits for redundancy. The assemblyis replaced as one unit.

The lamp illuminates for 8 seconds after thekey is turned to the "ON" position. Itcommunicates to the operator when serviceis required and it communicates trouble codesto the technician.

DIAGNOSTICS AND SERVICINGThe self-diagnostic system employs threemodes similar to the fuel system self-diagnostics:

1. U-Check (User Check)2. D-Check (Dealer Check)3. Read Memory

The U-Check Mode warns the driver of asystem fault by illumination of the "AIR BAG"light on the dash. The light will turn off if thetrouble source corrects itself.Trouble codes are stored in long term memoryand displayed similar to the fuel system codes.They are indicated by the "AIR BAG" light withthe following values:

1. 1.2 Second (Long) Flash = 102. 0.3 Second (Short) Flash = 13. Continuous 0.6 Second Flashes = no trouble

There is also an additional factory long-termmemory which can only be accessed by thefactory. The purpose of this is for the ECU tomaintain a vehicle trouble code history. Thelong term memory cannot be cleared in thefield.

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13SRS (3/2001)

Supplemental Restraint System (SRS)NOTE: THE DIAGNOSTICNOTE: THE DIAGNOSTICNOTE: THE DIAGNOSTICNOTE: THE DIAGNOSTICNOTE: THE DIAGNOSTIC

PROCEDURES ARE FOUND IN THEPROCEDURES ARE FOUND IN THEPROCEDURES ARE FOUND IN THEPROCEDURES ARE FOUND IN THEPROCEDURES ARE FOUND IN THESVX SERVICE MANUAL, SECTION 5-5.SVX SERVICE MANUAL, SECTION 5-5.SVX SERVICE MANUAL, SECTION 5-5.SVX SERVICE MANUAL, SECTION 5-5.SVX SERVICE MANUAL, SECTION 5-5.

CAUTION: DO NOT UNLOCK "DOUBLECAUTION: DO NOT UNLOCK "DOUBLECAUTION: DO NOT UNLOCK "DOUBLECAUTION: DO NOT UNLOCK "DOUBLECAUTION: DO NOT UNLOCK "DOUBLELOCK" CONNECTORS ORLOCK" CONNECTORS ORLOCK" CONNECTORS ORLOCK" CONNECTORS ORLOCK" CONNECTORS ORDISCONNECT SYSTEM CONNECTORSDISCONNECT SYSTEM CONNECTORSDISCONNECT SYSTEM CONNECTORSDISCONNECT SYSTEM CONNECTORSDISCONNECT SYSTEM CONNECTORSWITH THE IGNITION "ON". THE ECUWITH THE IGNITION "ON". THE ECUWITH THE IGNITION "ON". THE ECUWITH THE IGNITION "ON". THE ECUWITH THE IGNITION "ON". THE ECUWILL SET A TROUBLE CODEWILL SET A TROUBLE CODEWILL SET A TROUBLE CODEWILL SET A TROUBLE CODEWILL SET A TROUBLE CODEIMMEDIATELY. THESE CODES WILLIMMEDIATELY. THESE CODES WILLIMMEDIATELY. THESE CODES WILLIMMEDIATELY. THESE CODES WILLIMMEDIATELY. THESE CODES WILLALSO BE SET IN HIDDEN MEMORYALSO BE SET IN HIDDEN MEMORYALSO BE SET IN HIDDEN MEMORYALSO BE SET IN HIDDEN MEMORYALSO BE SET IN HIDDEN MEMORYAND CANNOT BE CLEARED FROM THEAND CANNOT BE CLEARED FROM THEAND CANNOT BE CLEARED FROM THEAND CANNOT BE CLEARED FROM THEAND CANNOT BE CLEARED FROM THEHIDDEN MEMORY.HIDDEN MEMORY.HIDDEN MEMORY.HIDDEN MEMORY.HIDDEN MEMORY.

SRS SYSTEM SERVICINGAn SRS inspection is required every ten (10)years. Perform the Self-Diagnostic Checks andverify that the air bag warning lights arefunctioning. Also verify that there are no codesin memory and no current codes existing.

NOTE: REFER TO THE SUBARU SVXNOTE: REFER TO THE SUBARU SVXNOTE: REFER TO THE SUBARU SVXNOTE: REFER TO THE SUBARU SVXNOTE: REFER TO THE SUBARU SVXSERVICE MANUAL, SECTION 1-5, ANDSERVICE MANUAL, SECTION 1-5, ANDSERVICE MANUAL, SECTION 1-5, ANDSERVICE MANUAL, SECTION 1-5, ANDSERVICE MANUAL, SECTION 1-5, ANDREVIEW THE TEN YEAR SERVICEREVIEW THE TEN YEAR SERVICEREVIEW THE TEN YEAR SERVICEREVIEW THE TEN YEAR SERVICEREVIEW THE TEN YEAR SERVICEPROCEDURES.PROCEDURES.PROCEDURES.PROCEDURES.PROCEDURES.

NOTE: REFER TO THE SVX SERVICENOTE: REFER TO THE SVX SERVICENOTE: REFER TO THE SVX SERVICENOTE: REFER TO THE SVX SERVICENOTE: REFER TO THE SVX SERVICEMANUAL, SECTION 5-5, TO IDENTIFYMANUAL, SECTION 5-5, TO IDENTIFYMANUAL, SECTION 5-5, TO IDENTIFYMANUAL, SECTION 5-5, TO IDENTIFYMANUAL, SECTION 5-5, TO IDENTIFYTHE TEST HARNESSES AND THETHE TEST HARNESSES AND THETHE TEST HARNESSES AND THETHE TEST HARNESSES AND THETHE TEST HARNESSES AND THECONNECTOR NUMBERS.CONNECTOR NUMBERS.CONNECTOR NUMBERS.CONNECTOR NUMBERS.CONNECTOR NUMBERS.

98299AE000 Test Harness K

98299FA030 Test Harness H

98299FC000 Test Harness E

98299FC010 Test Harness F

98299FC020 Test Harness G

98299FC040 Test Harness I

98299FC041 Test Harness I 2

98299FE000 Test Harness L

98299FE020 Test Harness M

98299PA000 Test Harness A

98299PA011 Test Harness B

98299PA020 Test Harness C

98299PA040 Test Resistor 1

of 2 needed98299PA040 Airbag

Resistor 2 of 2 needed

CAUTION: NEVER USE TEST HAR-CAUTION: NEVER USE TEST HAR-CAUTION: NEVER USE TEST HAR-CAUTION: NEVER USE TEST HAR-CAUTION: NEVER USE TEST HAR-NESS "C" TO CHECK THE RESISTANCENESS "C" TO CHECK THE RESISTANCENESS "C" TO CHECK THE RESISTANCENESS "C" TO CHECK THE RESISTANCENESS "C" TO CHECK THE RESISTANCEOF THE AIR BAG MODULE.OF THE AIR BAG MODULE.OF THE AIR BAG MODULE.OF THE AIR BAG MODULE.OF THE AIR BAG MODULE.

CAUTION: THE DEPLOYMENTCAUTION: THE DEPLOYMENTCAUTION: THE DEPLOYMENTCAUTION: THE DEPLOYMENTCAUTION: THE DEPLOYMENTHARNESS SHOULD NEVER BEHARNESS SHOULD NEVER BEHARNESS SHOULD NEVER BEHARNESS SHOULD NEVER BEHARNESS SHOULD NEVER BECONNECTED TO THE AIR BAGCONNECTED TO THE AIR BAGCONNECTED TO THE AIR BAGCONNECTED TO THE AIR BAGCONNECTED TO THE AIR BAGMODULE WHILE THE MODULE IS INMODULE WHILE THE MODULE IS INMODULE WHILE THE MODULE IS INMODULE WHILE THE MODULE IS INMODULE WHILE THE MODULE IS INTHE VEHICLE.THE VEHICLE.THE VEHICLE.THE VEHICLE.THE VEHICLE.

CAUTION: ALWAYS US A DIGITALCAUTION: ALWAYS US A DIGITALCAUTION: ALWAYS US A DIGITALCAUTION: ALWAYS US A DIGITALCAUTION: ALWAYS US A DIGITALTYPE OHM METER WITH AN OUTPUTTYPE OHM METER WITH AN OUTPUTTYPE OHM METER WITH AN OUTPUTTYPE OHM METER WITH AN OUTPUTTYPE OHM METER WITH AN OUTPUTSPECIFICATION OF 100 MILLE-AMPSSPECIFICATION OF 100 MILLE-AMPSSPECIFICATION OF 100 MILLE-AMPSSPECIFICATION OF 100 MILLE-AMPSSPECIFICATION OF 100 MILLE-AMPSOR LESS WHEN TESTING THE AIR BAGOR LESS WHEN TESTING THE AIR BAGOR LESS WHEN TESTING THE AIR BAGOR LESS WHEN TESTING THE AIR BAGOR LESS WHEN TESTING THE AIR BAGMODULE OR SRS CIRCUITS. USE OFMODULE OR SRS CIRCUITS. USE OFMODULE OR SRS CIRCUITS. USE OFMODULE OR SRS CIRCUITS. USE OFMODULE OR SRS CIRCUITS. USE OFTHE INCORRECT TYPE OF METERTHE INCORRECT TYPE OF METERTHE INCORRECT TYPE OF METERTHE INCORRECT TYPE OF METERTHE INCORRECT TYPE OF METERMAY CAUSE ACCIDENTALMAY CAUSE ACCIDENTALMAY CAUSE ACCIDENTALMAY CAUSE ACCIDENTALMAY CAUSE ACCIDENTALDEPLOYMENT. IF YOU ARE NOT SUREDEPLOYMENT. IF YOU ARE NOT SUREDEPLOYMENT. IF YOU ARE NOT SUREDEPLOYMENT. IF YOU ARE NOT SUREDEPLOYMENT. IF YOU ARE NOT SUREABOUT THE SPECIFICATION OF YOURABOUT THE SPECIFICATION OF YOURABOUT THE SPECIFICATION OF YOURABOUT THE SPECIFICATION OF YOURABOUT THE SPECIFICATION OF YOURMETER, DO NOT USE IT UNTIL THEMETER, DO NOT USE IT UNTIL THEMETER, DO NOT USE IT UNTIL THEMETER, DO NOT USE IT UNTIL THEMETER, DO NOT USE IT UNTIL THESPECIFICATIONS CAN BE VERIFIED.SPECIFICATIONS CAN BE VERIFIED.SPECIFICATIONS CAN BE VERIFIED.SPECIFICATIONS CAN BE VERIFIED.SPECIFICATIONS CAN BE VERIFIED.

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1995 MODEL LEGACY

Dual supplemental restraint system air bagswill be standard equipment on all 1995MYLegacys and functions are similar to previousModel Year Legacys. The passenger side airbag module is wired in parallel with the driver’sside. Both sides will deploy in the event of afrontal collision of 12.5mph or greater.

Four (4) position, three (3) point seat belts withELRS are used in the front seats. The outerrear seat positions use a three (3) point seatbelt with ALR assemblies. The center rear seatposition uses a two (2) point seat belt.

CAUTION: BEFORE SERVICING ANYCAUTION: BEFORE SERVICING ANYCAUTION: BEFORE SERVICING ANYCAUTION: BEFORE SERVICING ANYCAUTION: BEFORE SERVICING ANYSRS COMPONENT, DISCONNECT THESRS COMPONENT, DISCONNECT THESRS COMPONENT, DISCONNECT THESRS COMPONENT, DISCONNECT THESRS COMPONENT, DISCONNECT THEBATTERY AND WAIT 30 SECONDS FORBATTERY AND WAIT 30 SECONDS FORBATTERY AND WAIT 30 SECONDS FORBATTERY AND WAIT 30 SECONDS FORBATTERY AND WAIT 30 SECONDS FORTHE CAPACACITORS TO DISCHARGE.THE CAPACACITORS TO DISCHARGE.THE CAPACACITORS TO DISCHARGE.THE CAPACACITORS TO DISCHARGE.THE CAPACACITORS TO DISCHARGE.

1996 MODEL LEGACY ANDOUTBACKAll 1996MY Legacy and Outback vehicles willhave dual air bags. However, the electricalsystems operating them will differ.

The Outback utilizes the same system as wasused on the 1995MY Legacy front sensors andsafety sensors incorporated in the SRS controlunit. The 1996MY Legacy vehicles no longerhave separate front sensors. A "G" sensorlocated in the control unit performs all impactsensing.

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15SRS (3/2001)


Both models use a floating type SRS air bagmodule. The 1996MY Legacy steering wheelwill no longer have horn buttons. To use thehorn, press on the SRS air bag module, whichactivates a switch plate.

1998 MODEL FORESTERThe SRS air bag system for the 1998MYForester employs both a driver and passengerside air bag. Please observe all warningprecautions listed on the appropriate servicepublications and warning labels of the vehicle.The driver side air bag is unchanged from thatof the 1997 Impreza. Dashboard configurationfor the passenger side requires a new air bagdesign. The air bag module can be removedor installed with the instrument panel in place.The inflator of the passenger side air bag is anew design. During deployment, a liquid fuel(Alcohol 10 millil iters) is ignited. Theexpansion of gasses during the burning of thefuel inflates the air bag.Gasses produced during burning includeArgon and Helium.

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Control unit location is just forward of theshifter assembly.The connector appearance and double lockfeature have changed.The control unit connector plate is designedfor use with other Subaru SRS systems as wellas the North American models. The connectoris yellow with 20 pins.

The connector is disengaged by pushing downon the top tab and gently pulling, applying forceto the tab and the connector.A plastic tab inside the connector areaseparates the contacts that monitor the circuitfor loose connections (Code 14).

The connector "double-locks" for the driver sideand passenger side air bag modules have alsochanged.To disengage, push down on the yellow taband slide the green tab in the direction of thearrow. Next, release the tab and pull gently onthe connector. Failure to release the tab beforeattemplting separartion will result in theconnector remaining engaged.The new test harnesses are labeled,respectfully: E, F, and G.E, F, and G.E, F, and G.E, F, and G.E, F, and G.The same test resistor is used when checkingdriver side or passenger side air bag moduleintegrity.The window of the Steering Roll Connectorhas been deleted. Follow the direction on theSteering Roll Connector and the servicemanual when working with an area that willchange the wheel to Steering Roll Connectorphasing.

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17SRS (3/2001)


The Legacy SRS air bag system utilizes thesame type of control unit and connectors withthe addition of two (2) front sub-sensorsmounted just forward of the wheel arch area.Their input to the SRS ECM influencesdeployment, however, deployment is notdependent on the front sensors switchesclosing. The ECM makes the finaldetermination to deploy or not using logic thatcontains preset values.Side SRS airbags are equipped on GT Limitedand Outback Limited models. They aredesigned to deploy on impact to the side ofthe vehicle. The severity of the impact isdetermined by the side air bag sensor locatedin the B-Pillar.

Side impacts to the rear door of the vehicleare absorbed by the door and body of thevehicle as well as to the shield under the rearpassenger seat. The transferred force is thendistributed through the shield and back in tothe body of the vehicle.

2000 MODEL LEGACY ANDOUTBACKThe SRS air bag control unit has beenchanged to include the addition of inputs andprovide the output necessary for side air bagand seat belt pretensioner operation.

This diagram illustrates the electrical layoutof the SRS air bag system without side airbags. The front sub-sensors are located in thefront bumper area. The seat belt pretensionerswill activate at the same time the front air bagsactivate.

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18SRS (3/2001)

This diagram illustrates the total SRS air bagsystem electrical layout. During a frontalimpact, the front sub-sensors and sensorscontained in the SRS control unit determinethe severity of impact. If the impact exceedspre-established parameters, the front air bags,driver and passenger side, as well as bothfront seatbelt pretensioners activate.

Seatbelt pretensioner operation winds the beltto restrain the occupant. The gas generatorwhen activated pushes a piston, which ismade onto a rack-type gear. This gear rotatesthe winding gear creating the motion and forcenecessary to wind the belt inward. When theforce of the belt reaches a fixed value, the forcelimiter contained in the seatbelt assemblyoperates to control the restraint force so it doesnot increase further.

The GT and Outback models have a 6-waypower driver seat. When serving this seat,disconnect the side SRS air bag connectorafter positioning the seat for mounting boltremoval and disconnecting the battery. (Wait30 seconds before proceeding).

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Supplemental Restraint System (SRS)2001 MODEL LEGACY

All Legacy vehicles will share an enhancementto the passenger side SRS Air Bag System.

The air bag module now contains 2 inflationunits. (Figure 57) Each one independentlycontrolled by the SRS ECM. During an impactof lower speeds (above the deploymentminimum specification) 1 side of the modulewill be activated followed by the other side.The time between the 2 sides activating fordeployment is controlled by the ECM todecrease the impact of the bag with thepassenger. The higher the impact speed, theshorter the time between the 2 sides activatingfor deployment. The 2 sides will be activatedtogether above a higher impact speed.

A new style of connector is used for thepassenger side airbag module. The connectoris disengaged by pulling down on the widerportion of the body harness while supportingthe lower portion.

There is no change to the driver side SRSAirbag.

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20SRS (3/2001)

The SRS Air Bag for Impreza 2002 will includethe addition of seat belt pretensioners for allmodels (Passenger side air bag module is thesingle deployment type).

The control unit is located in front of the gatetype shifter.

2002 MODEL IMPREZA WRXWRX models will have side air bags asstandard equipment.

Caution must be observed while removing thefront seats to ensure the SRS wiring harnessis not damaged.

The side impact switch is mounted on the leftand right B pillars behind the seat belt trimpanels.

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Supplemental Restraint System (SRS)NOTES:


22SRS (3/2001)

NOTES:

Subaru of America, Inc. 2001 MSA5P0136C

technicians reference booklet - ludicrous-speed€¦ · integrity. there are two (2) air bag...

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