Air Bag Restraint Systems Buick Century VI

DESCRIPTION & OPERATION

Supplemental Restraint (SIR) system is designed to supplement protection provided by driver-side and passenger-side seat belts. A frontal collisions of sufficient force will deploy driver-side and passenger-side air bags. Steering column and knee bolsters also absorb collision energy.

Vehicle is also equipped with a driver side impact air bag module which will deploy when a side impact of sufficient force occurs on driver-side of vehicle.

SIR system consists of Sensing and Diagnostic Module (SDM), driver-side and passenger-side air bag modules, driver side impact air bag module, driver Side Impact Sensor (SIS), SIR coil assembly and AIR BAG warning light. SDM maintains a 36 Volt Loop Reserve (VLR) energy supply to provide deployment energy for up to one minute after loss of battery voltage.

COMPONENT LOCATIONS

COMPONENT LOCATIONS

SYSTEM OPERATION CHECK

If system is functioning normally, AIR BAG warning light flashes 7 times, then turns off after ignition is turned on. System malfunction is indicated when light does not illuminate at all, light comes on while vehicle is driven, light flashes 7 times and remains on or light does not flash but remains on when ignition is turned on.

AIR BAG SAFETY PRECAUTIONS

Observe the following precautions when working with SIR system

1. SDM maintains sufficient voltage to cause air bag deployment for up to one minute after ignition is turned off, battery is disconnected or fuse powering SDM is removed. See «DISABLING & ACTIVATING AIR BAG SYSTEM»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__disabling-activating-air-bag-system) .
2. If vehicle interior is exposed to moisture and becomes soaked up to level of SDM, SDM and harness connector must be replaced. SDM could be activated when powered, causing air bag deployment.
3. After repairs, ensure AIR BAG warning light is working properly and no system faults are indicated. See «SYSTEM OPERATION CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__system-operation-check) .
4. Always wear safety glasses when servicing or handling an air bag module.
5. Air bag modules must be stored in original special containers until used for service. Store in a clean, dry place, away from sources of extreme heat, sparks or high electrical energy.
6. SIR components should not be subjected to temperatures greater than 150°F (65°C).
7. SIR components should not be used if they have been dropped from a height of 3 feet (0.9 m) or greater.
8. When placing a live air bag module on a bench or other surface, always make certain that trim cover faces up. This will reduce motion of module if accidentally deployed.
9. After deployment, air bag surface may contain deposits of sodium hydroxide, which can irritate skin. Always wear safety glasses, rubber gloves and long-sleeved shirt during clean-up and wash hands using mild soap and water.
10. At no time should any electrical source be allowed near inflator on back of air bag module.
11. DO NOT apply power to SIR system unless all components are connected or a diagnostic test requests it, as this will set a Diagnostic Trouble Code (DTC).
12. When carrying a live air bag module, trim cover should be pointed away from body to minimize injury in case of accidental deployment.
13. DO NOT attempt to service SIR components. If defective, these parts must be replaced.
14. DO NOT probe a wire through insulator. Wire will be damaged and eventually fail due to corrosion.
15. When performing electrical tests, prevent accidental shorting of terminals. Such mistakes can damage fuses or components and may cause a second DTC to set, making diagnosis of original problem more difficult.
16. When using diagnostic tests to diagnose SIR system, under no circumstances should a volt/ohmmeter, test light or any type of electrical equipment not specified by manufacturer be used.
17. If SIR system is not fully functional for any reason, vehicle should not be driven until system is repaired. DO NOT remove bulbs, modules, sensors or other components or in any way disable system from operating normally.

With Centering Window & Service Lock

Hold SIR coil face up. (Scheme 75) While depressing service lock, rotate coil hub clockwise until it stops. Rotate coil hub counterclockwise slowly until centering window appears Yellow and line-up marks are aligned. Release service lock.

With Centering Window & No Service Lock

Hold SIR coil face up. (Scheme 75) Rotate coil hub clockwise until it stops. Rotate coil hub counterclockwise slowly until centering window appears Yellow and both line-up marks are aligned. Prevent coil hub from moving until installed on steering column.

With Service Lock & No Centering Window

Hold SIR coil assembly with rear side facing up. (Scheme 75) While depressing service lock, rotate coil hub in direction indicated by directional arrow until it stops. Rotate coil hub in opposite direction 2 1/2 turns. Release service lock.

Without Centering Window Or Service Lock

Hold SIR coil assembly face up. (Scheme 75) Rotate coil hub in direction of arrow until it stops. Rotate coil hub in opposite direction 2 1/2 turns. Prevent coil hub from moving until installed on steering column.

Scheme 75

DISABLING & ACTIVATING AIR BAG SYSTEM

Note. SIR components are placed in various zones. Work being performed will determine applicable disabling and activating procedure. See REMOVAL & INSTALLATION. To identify disabling and activating component zones, refer to illustration. (Scheme 76)

Scheme 76

DISABLING SYSTEM

Note. When AIR BAG fuse is removed and ignition is on, AIR BAG warning light will be on. This does not indicate a system malfunction.

Zone 2

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key.
2. Remove right-side instrument panel end cover to access fuse block. Remove AIR BAG fuse from fuse block. Remove Side Impact Sensor (SIS). See «SIDE IMPACT SENSOR (SIS)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Remove Connector Position Assurance (CPA) clip from SIS. Disconnect electrical connector.

Zone 3

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key.
2. Remove right-side instrument panel end cover to access fuse block. Remove AIR BAG fuse from fuse block. Remove driver-side instrument panel knee bolster. Remove Connector Position Assurance (CPA) clip from driver-side air bag module connector, located at base of steering column and disconnect connector. (Scheme 77)

Scheme 77

Zone 5

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key.
2. Remove right-side instrument panel end cover to access fuse block. Remove AIR BAG fuse from fuse block. Remove driver-side instrument panel knee bolster. Remove Connector Position Assurance (CPA) clip from passenger-side air bag connector, located to right of steering column. (Scheme 78) Disconnect passenger-side air bag module connector.

Scheme 78

Zone 7

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key.
2. Remove right-side instrument panel end cover to access fuse block. Remove AIR BAG fuse from fuse block. Remove Connector Position Assurance (CPA) clip from driver side impact air bag module connector. (Scheme 79) Disconnect side impact air bag module connector.

Scheme 79

Zone 9

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off.
2. Remove right-side instrument panel end cover to access fuse block. Remove AIR BAG fuse from fuse block. Remove driver-side instrument panel knee bolster. Remove Connector Position Assurance (CPA) clip from driver-side air bag module connector, located at base of steering column. (Scheme 77) Disconnect connector.
3. Remove CPA clip from passenger-side air bag connector, located to right of steering column. (Scheme 78) Disconnect connector. Remove Side Impact Sensor from lower B-pillar. See «SIDE IMPACT SENSOR (SIS)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Remove CPA clip and disconnect SIS connector.

Ensure ignition is off and key is removed. Install Side Impact Sensor (SIS). See SIDE IMPACT SENSOR (SIS) under REMOVAL & INSTALLATION. Install AIR BAG fuse in fuse block. Install right-side instrument panel access hole cover. Staying well away from air bag modules, turn ignition on. Check SIR system for proper operation. See SYSTEM OPERATION CHECK .

1. Ensure ignition is off and key is removed. Connect driver-side air bag module connector, located to right of steering column. (Scheme 77) Install Connector Position Assurance (CPA) clip. Install driver-side knee bolster.
2. Install AIR BAG fuse in fuse block. Install right-side instrument panel access hole cover. Staying well away from air bag modules, turn ignition on. Check SIR system for proper operation. See «SYSTEM OPERATION CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__system-operation-check).

1. Ensure ignition is off and key is removed. Connect passenger-side air bag module connector, located to right of steering column. (Scheme 78) Install Connector Position Assurance (CPA) clip. Install driver-side knee bolster.
2. Install AIR BAG fuse in fuse block. Install right-side instrument panel access hole cover. Staying well away from air bag modules, turn ignition on. Check SIR system for proper operation. See «SYSTEM OPERATION CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__system-operation-check).

1. Ensure ignition is off and key is removed. Connect side impact air bag module connector. (Scheme 79) Install Connector Position Assurance (CPA) clip.
2. Install AIR BAG fuse in fuse block. Install right-side instrument panel access hole cover. Staying well away from air bag modules, turn ignition on. Check SIR system for proper operation. See «SYSTEM OPERATION CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__system-operation-check).

1. Ensure ignition is off and key is removed. Connect Side Impact Sensor (SIS) connector. Install Connector Position Assurance (CPA) clip. Install SIS. See «SIDE IMPACT SENSOR (SIS)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION.
2. Connect passenger-side air bag module connector, located to right of steering column. (Scheme 78) Install CPA clip. Connect driver-side air bag module connector, located to right of steering column. (Scheme 77) Install CPA clip. Install driver-side knee bolster.
3. Install AIR BAG fuse in fuse block. Install right-side instrument panel access hole cover. Staying well away from air bag modules, turn ignition on. Check SIR system for proper operation. See «SYSTEM OPERATION CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__system-operation-check).

DISPOSAL PROCEDURES

Note. If vehicle is to be scrapped, perform on-vehicle air bag deployment procedure. See ON-VEHICLE DEPLOYMENT . If vehicle will remain in service, perform off-vehicle deployment procedure. See OFF-VEHICLE DEPLOYMENT .

To prevent accidental deployment and personal injury, deploy air bags before disposal. DO NOT dispose of undeployed air bag modules at normal refuse locations. Undeployed air bag modules contain substances that can cause severe illness or personal injury if sealed container is damaged during disposal.

ON-VEHICLE DEPLOYMENT

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Disable air bag system. See «DISABLING & ACTIVATING AIR BAG SYSTEM»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__disabling-activating-air-bag-system). Turn ignition off, remove key and put on safety glasses. Disconnect driver-side and passenger-side air bag module connectors. (Scheme 77)& (Scheme 78). Disconnect driver side impact air bag module connector. (Scheme 79)
2. Cut air bag module harness connectors from vehicle leaving at least 6" (152 mm) of wire at connector. Strip 0.50" (13 mm) of insulation from each connector wire lead. Cut two 15-foot (4.6 m) deployment wires from 18-gauge multi-strand wire. Strip 0.50" (13 mm) of insulation from both ends of wires. Twist wires together at one end to short.
3. Twist together one connector wire lead to other end of each deployment wire. (Scheme 80) Bend twisted connection flat and wrap tightly with electrical tape to insulate. Repeat this step for other connector wire lead.
4. Remove all loose objects from front seat. Ensure no one is in vehicle. Connect deployment harness to air bag module connector. Stretch wires away from car as far as possible.
5. Repeat steps 2 through 4 for passenger-side air bag module and driver side impact air bag module. Cover windshield and front door openings with a drop cloth.
6. Separate wire ends. Connect each pair of wires to a 12-volt battery. Air bags should deploy. If air bags DO NOT deploy, go to step 8. If air bags did deploy, disconnect deployment harness wires from battery. DO NOT touch air bag module area for at least 10 minutes due to heat generated during deployment.
7. Wear gloves and safety glasses before handling deployed air bag modules. Wash hands with mild soap and water afterward. Deployed air bag modules can be disposed of like any other part. Repeat deployment procedure for passenger-side air bag and driver side impact air bag module.
8. Ensure deployment harness is disconnected from battery and air bag module. Carefully remove air bag module from vehicle. See «AIR BAG MODULES»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Temporarily store module with trim facing up. Contact manufacturer for additional instructions.

Scheme 80

OFF-VEHICLE DEPLOYMENT

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Turn ignition off, remove key and put on safety glasses. Short 2 SIR Deployment Harness (J-38826) leads together by fully seating one banana plug into the other. Connect appropriate pigtail adapter to SIR deployment harness. (Scheme 81)
2. Remove applicable air bag modules. See «AIR BAG MODULES»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Place driver-side air bag module, with trim cover facing up, in center of cleared area, preferably a paved, outdoor surface at least 6 feet (1.8 m) in diameter away from any loose or flammable objects. Extend SIR deployment harness and pigtail adapter to full length. Place a 12-volt battery near shorted end of SIR deployment harness.
3. Connect driver-side air bag module to pigtail adapter on SIR deployment harness. Ensure area around air bag module is clear of people or loose objects. Verify that air bag module is resting with trim cover facing up.
4. Separate 2 banana plugs on SIR deployment harness. Connect SIR deployment harness wires to battery. Air bag module should deploy immediately. If air bag module does not deploy, go to step 6. If air bag module does deploy, disconnect SIR deployment harness from battery. Short 2 SIR deployment harness leads together. DO NOT touch metal surfaces of air bag module for at least 10 minutes due to heat generated during deployment.
5. Wear gloves and safety glasses when handling deployed air bag module. Wash hands with mild soap and water after handling. Dispose of deployed air bag module as you would any other part. Inspect pigtail adapter and SIR deployment harness for damage after each use. Using SIR Deployment Fixture (J-39401-B) to hold passenger-side and driver side impact air bag modules, repeat deployment procedure.
6. Ensure that SIR deployment harness is disconnected from battery and that 2 banana plugs have been shorted together. Disconnect pigtail adapter from air bag module. Temporarily store air bag module with trim cover facing up. Contact manufacturer for additional instructions.

Scheme 81

POST-COLLISION INSPECTION

When a vehicle has been involved in a collision, certain components of the passive restraint system must be inspected or replaced. See AIR BAG/SRS COMPONENT INSPECTION & REPLACEMENT TABLES article in the GENERAL INFORMATION section.

REMOVAL & INSTALLATION

Removal & Installation (Driver-side)

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Disable air bag system. See «ZONE 3»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-3) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Turn steering wheel so opening on rear of steering wheel is accessible. Using Air Bag Remover (J-44298), release accessible driver-side air bag module spring loaded fasteners. (Scheme 82) Rotate steering wheel 180 degrees and repeat procedure for remaining two spring loaded fasteners. Pull driver-side air bag module away from steering wheel. (Scheme 83)
3. Note position of wire routing for correct reassembly. Remove Connector Position Assurance (CPA) clip from driver-side air bag module connector and disconnect connector. Disconnect horn lead. Remove air bag module.
4. To install, reverse removal procedure. Install air bag module to steering wheel by pressing on left and right sides of air bag module until spring clips engage. Ensure wiring is not pinched or damaged. Activate air bag system. See «ZONE 3»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 82

Scheme 83

Removal & Installation (Passenger-side)

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Disable air bag system. See «ZONE 5»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-5) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove instrument panel trim pad. See «INSTRUMENT PANEL TRIM PAD»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems). Remove passenger-side air bag module mounting bolts. (Scheme 84) Remove passenger-side air bag module from instrument panel cross-beam.
3. To install, reverse removal procedure. Tighten passenger-side air bag module bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__torque-specifications). Activate air bag system. See «ZONE 5»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 84

Removal & Installation (Side Impact)

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Disable air bag system. See «ZONE 7»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-7) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove applicable seat back cover (Scheme 85) Make note of bag module wire harness routing for use during assembly. Remove side impact air bag module nuts. Remove wire harness from cable clips. Remove side impact air bag module assembly.
3. To install, reverse removal procedure. Ensure side impact air bag wire harness is positioned correctly. Tighten side impact air bag module nuts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__torque-specifications). Activate air bag system. See «ZONE 7»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 85

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions) . Disconnect negative battery cable. Move shifter to "L" position. Remove shifter trim plate. Remove rubber pad from storage compartment. Remove bolts located at bottom of storage compartment. Remove nuts located at rear of shifter assembly.
2. Remove center console power accessory port. Disconnect wire harness connector from center console. Pull center console rearward to release retainers from instrument panel. Remove center console. To install, reverse removal procedure. Tighten bolts and nuts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__torque-specifications) .

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions) . Disconnect negative battery cable.
2. Remove IPC trim panel. Remove screws from IPC. Rotate top of IPC rearward, then disengage locating pins on bottom of instrument cluster. Disconnect IPC electrical connector. To install, reverse removal procedure.

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Position steering wheel in straight ahead position. Disable air bag system. See «ZONE 3»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-3) under DISABLING & ACTIVATING AIR BAG SYSTEM. See «ZONE 5»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-5) under DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect negative battery cable.
2. Remove left and right A-pillar trim. Lift upper trim panel 2" (51 mm) and pull rearward to remove. Disconnect ambient light and sunload sensors from upper trim panel. On models with center console, remove center console. See «CENTER CONSOLE»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems). On all models, remove instrument panel access hole covers at both ends of instrument panel.
3. Remove left and right-side knee bolsters. Remove steering column opening filler. Remove left and right kick panels. Remove hood release handle. Remove Data Link Connector (DLC). Remove left and right front inside door carpet retainers.
4. Remove steering column intermediate shaft from steering column. Remove shift indicator cable, shift cam casing and automatic control indicator/park lock cable from steering column. Disconnect automatic transmission range selector cable from ball stud on steering column.
5. Remove transaxle shift cable casing from steering column by depressing two tabs. Remove lower, then upper steering column bolts. Disconnect steering column electrical connectors. Remove steering column electrical connector bolt and separate steering column electrical connector halves. Remove steering column from vehicle.
6. Remove inside temperature air sensor. Remove headlight switch. Remove Instrument Panel Cluster (IPC). See «INSTRUMENT PANEL CLUSTER (IPC)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems). Remove radio. Remove A/C and heater control assembly.
7. Remove glove box. Disconnect glove box light switch. Remove fuse block from right-side of instrument panel. Remove air temperature sensor from front of instrument panel.
8. Remove 2 mounting bolts from right end of instrument panel, 6 mounting bolts from center and lower instrument panel and 3 mounting bolts from left end of instrument panel. Reposition wiring harness out of the way.
9. Remove 4 mounting bolts from upper instrument panel. (Scheme 86) Remove instrument panel.
10. To install, reverse removal procedure. Tighten steering column bolts to specification in the following order: right side lower, left side lower, left side upper and right side upper. Tighten remaining nuts and bolts to specifications. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__torque-specifications). Activate air bag system. See «ZONE 3»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM. See «ZONE 5»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 86

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Disable air bag system. See «ZONE 9»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-9) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove right-front seat. Remove carpet retainer. Roll back carpet and insulation to access SDM. Remove Connector Position Assurance (CPA) clip and disconnect SDM connector. (Scheme 87) Remove SDM mounting bolts. Remove SDM.
3. To install, reverse removal procedure. Ensure arrow on SDM is pointing towards front of vehicle. Tighten SDM bolts and seat mounting bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__torque-specifications). Activate air bag system. See «ZONE 9»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 87

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Disable air bag system. See «ZONE 2»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-2) under DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect negative battery cable.
2. Remove front seat carpet retainer. Remove driver-side lower B-pillar trim panel. Remove SIS mounting bolts. Remove SIS from B-pillar. (Scheme 88) Remove Connector Position Assurance (CPA) clip from SIS electrical connector. Disconnect SIS electrical connector. To install, reverse removal procedure. Tighten SIS mounting bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__torque-specifications). See «ZONE 2»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 88

SIR COIL ASSEMBLY

Note. New coil assemblies are pre-centered and include a centering tab that is removed once coil is installed.

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions). Position front wheels so they are in straight ahead position. Disable air bag system. See «ZONE 3»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-3) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove driver-side air bag module. See «AIR BAG MODULES»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems). Remove steering wheel. See «STEERING WHEEL»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems). Remove lower and upper steering column covers.
3. Remove SIR coil retaining ring. (Scheme 89) Remove wire harness straps from SIR coil wire leads. Disconnect SIR coil connectors. Remove SIR coil from steering column. Remove wave washer.
4. To install, reverse removal procedure. Tighten steering column cover screws and steering wheel nut to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__torque-specifications). Activate air bag system. See «ZONE 3»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 89

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__air-bag-safety-precautions) . Disable air bag system. See «ZONE 3»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__zone-3) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove driver-side air bag module. See «AIR BAG MODULES»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) . Scribe mark on steering shaft and steering wheel to ensure proper alignment during installation. Remove steering wheel nut. Using Steering Wheel Puller (J-1859-03), remove steering wheel. Ensure SIR coil wiring is not damaged when removing steering wheel.
3. To install, reverse removal procedure. Tighten steering wheel nut to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__torque-specifications) . Activate air bag system. See «ZONE 3»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under DISABLING & ACTIVATING AIR BAG SYSTEM.

DIAGNOSTICS

DIAGNOSTIC TROUBLE CODES (DTC'S)

Sensing and Diagnostic Module (SDM) provides a record of DTC's stored according to type. SDM performs diagnostic monitoring of SIR system electrical components and sets a DTC when a malfunction is detected. Current DTC's are stored in SDM and are erased when fault is corrected. Current DTC's can be read using a scan tool such as Tech 2.

SCAN TOOL DIAGNOSTICS

Scan Tool (Tech 2) reads and clears current and history codes. Ensure scan tool contains correct software cartridge for SIR diagnostics. To use scan tool, connect it to Data Link Connector (DLC), located under left side of instrument panel. Plug in scan tool power source. Turn ignition on. Follow scan tool manufacturer instructions.

DIAGNOSTIC PROCEDURES

Diagnostic procedures are designed to find and repair SIR malfunctions. It is important to use diagnostic tests and follow sequence listed below.

Perform SIR System Diagnostic Check

SIR diagnostic system check should always be starting point for any SIR diagnostics. It checks for proper AIR BAG warning light operation and SIR trouble codes using scan tool. See SIR DIAGNOSTIC SYSTEM CHECK under DIAGNOSTICS.

Refer To Proper Diagnostic Test

SIR diagnostic system check indicates correct test to diagnose SIR problems. Bypassing procedures may result in extended diagnostic time, incorrect diagnosis and incorrect parts replacement.

Repeat SIR Diagnostic System Check

Performing SIR diagnostic system check after all repair or diagnostic procedures ensures that repair has been made correctly and that no other conditions exist.

Circuit Description

Ignition switch supplies ignition voltage to Sensing and Diagnostic Module (SDM) connector terminal A1 via AIR BAG fuse, located in right end of instrument panel. When ignition is turned on, SDM responds by performing tests on SIR system while Instrument Panel Cluster (IPC) flashes AIR BAG warning light 7 times. If system is okay, AIR BAG warning light will turn off.

Diagnostic Procedure

1. Observe AIR BAG warning light when turning ignition on. If AIR BAG warning light flashes 7 times, go to next step. If AIR BAG warning light does not flash 7 times, inspect vehicle for damage to wiring system, visible body damage, faulty or intermittent electrical connections or addition of aftermarket devices which could affect SIR operation. Diagnose AIR BAG warning light malfunction. See «AIR BAG WARNING LIGHT CIRCUIT MALFUNCTION»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .
2. Install scan tool to Data Link Connector (DLC), located under left side of instrument panel, to right of steering column. If scan tool powers up, go to next step. If scan tool does not power up, inspect and repair data link communication circuits.
3. If scan tool communicates with SDM, go to next step. If scan tool does not communicate with SDM, inspect and repair data link communication circuits.
4. Select SIR DTC function on scan tool. If scan tool displays history or current SIR DTC's, go to next step. If scan tool does not display any history or current SIR DTC's, system is okay.
5. If scan tool displays any DTC's that begin with "U", inspect and repair applicable data link communication circuits and components. If no DTC's are displayed that begin with "U", go to next step.
6. If scan tool displays DTC B1000, go to «DTC B1000»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) . If scan tool displays other DTC's, diagnose and repair applicable SIR DTC's. See «DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) table.

DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

CONNECTOR IDENTIFICATION

Note. Refer to illustrations to identify SIR electrical connector terminals. (Scheme 90), (Scheme 91), (Scheme 92), (Scheme 93) & (Scheme 94).

Scheme 90

Scheme 91

Scheme 92

Scheme 93

Scheme 94

DIAGNOSTIC TESTS

Note. AIR BAG warning light will turn on if communication is lost between SDM and instrument cluster or if serial data communication is shorted to ground or voltage.

Ignition switch supplies ignition voltage to Sensing and Diagnostic Module (SDM) connector terminal A1 via AIR BAG fuse, located in right end of instrument panel. When ignition is turned on, SDM commands Instrument Panel Cluster (IPC) to flash AIR BAG warning light flashes 7 times, during which time SDM checks integrity of SIR system. If no malfunctions are present, SDM will command Instrument Panel Cluster (IPC) to turn AIR BAG warning light off.

Diagnostic Aids

If battery voltage is outside normal operating range, (9-16 volts) AIR BAG warning light will turn on with no DTC's set. AIR BAG warning light will also come in if an internal malfunction has occurred in IPC or SDM or if loss of serial data communication has occurred between SDM and IPC.

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).
2. Observe AIR BAG warning light when turning ignition on. If AIR BAG warning light does not flash 7 times, go to next step. If AIR BAG warning light flashes 7 times, go to step 4.
3. Replace Instrument Panel Cluster (IPC). See «INSTRUMENT PANEL CLUSTER (IPC)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to step 13.
4. If AIR BAG warning light turns off after flashing 7 times, inspect AIR BAG warning light circuits for loose or intermittent connections. See «WIRING DIAGRAMS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems). If AIR BAG warning light does not turn off after flashing 7 times, go to next step.
5. Connect scan tool to Data Link Connector (DLC), located under left side of instrument panel, to right of steering column. Using scan tool, attempt to communicate with Instrument Panel Cluster (IPC). If scan tool communicates with IPC, go to next step. If scan tool does not communicate with IPC, inspect and repair data link communication circuits.
6. Using scan tool, observe SIR DATA LIST display. If ignition voltage is 9 volts or less, go to step 8. If ignition voltage is more than 9 volts, go to next step.
7. If ignition voltage is more than 16 volts, inspect and repair battery and charging system. If ignition voltage is 16 volts or less, go to step 12.
8. Turn ignition off. Disconnect SDM connector. (Scheme 87) If SDM connector is damaged, replace connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 13. If SDM connector is okay, go to next step.
9. Inspect AIR BAG fuse, located in fuse block in right end of instrument panel. Check SDM voltage feed circuit 1139 for an open or high resistance. If open or high resistance is found and repaired, go to step 13. If open or high resistance is not found and repaired, go to next step.
10. Check voltage feed circuit to AIR BAG fuse for an open or high resistance. If open or high resistance is found and repaired, go to step 13. If open or high resistance is not found and repaired, go to next step.
11. Inspect SDM ground circuit 1751 for an open or high resistance. If open or high resistance is found and repaired, go to step 13. If open or high resistance is not found and repaired, go to next step.
12. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to next step.
13. Connect all SIR components. Road test vehicle. Turn ignition off. Check AIR BAG warning light operation when turning ignition on. If AIR BAG warning light operates correctly, system is okay. If AIR BAG warning light does not operate correctly, go to step 2.

When ignition is turned on, Sensing and Diagnostic Module (SDM) performs tests on deployment loops to check for circuit continuity and shorts to ground or voltage.

Conditions For Setting DTC

DTC B0016 will set when deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0017 will set when deployment loop high-side voltage is less than 2.4 volts and deployment loop resistance is 6 ohms or more for 500 milliseconds or when deployment loop resistance is more than 4.8 ohms for 500 milliseconds. DTC B0018 will set when high-side voltage is greater than 6 volts for 500 milliseconds or when deployment loop resistance is less than 6 ohms for 500 milliseconds.

Action Taken

SDM turns on AIR BAG warning light and sets DTC.

Conditions For Clearing DTC

Current DTC clears when condition responsible for setting DTC no longer exists and scan tool CLEAR DTC command has been used to clear DTC's. History DTC clears when 255 malfunction-free ignition cycles have occurred.

Malfunction is likely to be caused by a short between circuits 1403 or 1404 or by an open or high resistance or by a short to ground or voltage in either circuit. A malfunctioning electrical connector or SDM could also cause condition.

Note. For circuit number and wire color identification, see WIRING DIAGRAMS .

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).
2. Turn ignition off. Disconnect passenger-side air bag module Yellow 2-pin connector, located under passenger-side instrument panel. (Scheme 78) If harness-side of connector is damaged, go to next step. If passenger-side air bag module side of connector is damaged, go to step 7. If both sides of connector are okay, go to step 4.
3. Replace harness-side of connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 9.
4. Install SIR Driver/Passenger Load Tool (J-38715-A) using Load Tool Adapter (J-38715-100) to harness-side of passenger-side air bag module connector. Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0016, B0017 or B0018 is retrieved as a current code, go to next step. If DTC B0016, B0017 or B0018 is not retrieved as a current code, go to step 7.
5. Turn ignition off. Remove SIR driver/passenger load tool and adapter from harness connector. Disconnect SDM connector. (Scheme 87) If SDM connector is okay, go to next step. If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 9. NOTE: Use Digital Multimeter (J-39200) and Connector Test Adapter Kit (J-35616-A) or Flat WIre Probe Adapter Kit (J-42675) when performing electrical tests.
6. When diagnosing air bag system: If DTC B0016 is retrieved by scan tool, check for a short between circuits 1403 and 1404. If condition is found and corrected, go to step 9. If condition is not found, go to step 8. If DTC B0017 is retrieved, check for an open or high resistance in circuits 1403 or 1404. If condition is found and corrected, go to step 9. If condition is not found, go to step 8. If DTC B0018 is retrieved, check for a short to ground or voltage in circuits 1403 or 1404. If condition is found and corrected, go to step 9. If condition is not found, go to step 8.
7. Replace passenger-side air bag module. See «AIR BAG MODULES»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to step 9.
8. Turn ignition off. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to next step.
9. Reconnect all SIR components. Ensure all components are properly mounted. Using scan tool, clear all SIR DTC's. Road test vehicle, then check for DTC's. If current DTC is retrieved by scan tool, go to step 2. If current DTC is not retrieved by scan tool, system is okay. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).

When ignition is turned on, Sensing and Diagnostic Module (SDM) performs tests on deployment loops to check for circuit continuity and shorts to ground or voltage.

DTC B0022 will set when deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0024 will set when deployment loop high-side voltage is more than 6 volts for 500 milliseconds or when high-side voltage is less than 2.4 volts and deployment loop resistance is less than 6 ohms for 500 milliseconds. DTC B0026 will set when deployment loop high-side voltage is less than 2.4 volts and deployment loop resistance is more than 6 ohms for 500 milliseconds or when deployment loop resistance is more than 4.8 ohms for 500 milliseconds.

SDM turns on AIR BAG warning light and sets DTC.

Current DTC clears when condition responsible for setting DTC no longer exists and scan tool CLEAR DTC command has been used to clear DTC's. History DTC clears when 255 malfunction-free ignition cycles have occurred.

Malfunction is likely to be caused by a short between circuits 347 or 348 or by an open or high resistance condition or by a short to ground or voltage in either circuit. A malfunctioning electrical connector or SDM could also cause condition.

Note. For circuit number and wire color identification, see WIRING DIAGRAMS .

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).
2. Turn ignition off. Disconnect driver-side air bag Yellow 2-pin connector, located at base of steering column. (Scheme 77) If harness-side of connector is damaged, go to next step. If SIR coil side of connector is damaged, go to step 9. If both sides of connector are okay, go to step 4.
3. Replace harness-side of connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 11.
4. Install SIR Driver/Passenger Load Tool (J-38715-A) to harness-side of connector using Load Tool Adapter (J-38715-100). Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0022, B0024 or B0026 is retrieved as a current code, go to step 6. If DTC B0022, B0024 or B0026 is not retrieved as a current code, go to next step.
5. Remove SIR driver/passenger load tool from harness-side of connector. Reconnect driver-side air bag Yellow 2-pin connector. Remove driver-side air bag module. See «AIR BAG MODULES»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Install SIR driver/passenger load tool using Load Tool Adapter (J-38715-30A) to upper SIR coil connector. Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0022, B0024 or B0026 is retrieved as a current code, go to step 9. If DTC B0022, B0024 or B0026 is not retrieved as a current code, go to step 8.
6. Turn ignition off. Remove SIR driver/passenger load tool from harness connector. Disconnect SDM connector. (Scheme 87) If SDM connector is okay, go to next step. If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 11. NOTE: Use Digital Multimeter (J-39200) and Connector Test Adapter Kit (J-35616-A) or Flat WIre Probe Adapter Kit (J-42675) when performing electrical tests.
7. When diagnosing air bag system: If DTC B0022 is retrieved by scan tool, check for a short between circuits 347 and 348. If condition is found and corrected, go to step 11. If condition is not found, go to step 10. If DTC B0024 is retrieved, check for a short to ground or voltage in circuits 347 and 348. If condition is found and corrected, go to step 11. If condition is not found, go to step 10. If DTC B0026 is retrieved, check for an open or high resistance in circuits 347 and 348. If condition is found and corrected, go to step 11. If condition is not found, go to step 10.
8. Turn ignition off. Replace driver-side air bag module. See «AIR BAG MODULES»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to step 11.
9. Replace SIR coil. See «SIR COIL ASSEMBLY»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__sir-coil-assembly) under REMOVAL & INSTALLATION. Go to step 11.
10. Turn ignition off. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to next step.
11. Reconnect all SIR components. Ensure all components are properly mounted. Using scan tool, clear all SIR DTC's. Road test vehicle, then check for DTC's. If current DTC is retrieved by scan tool, go to step 2. If current DTC is not retrieved by scan tool, system is okay. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).

When ignition is turned on, Sensing and Diagnostic Module (SDM) performs tests on deployment loops to check for circuit continuity and shorts to ground or voltage.

DTC B0040 will set when deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0041 will set when deployment loop high-side voltage is less than 2.4 volts and deployment loop resistance is more than 6 ohms for 500 milliseconds or when deployment loop resistance is more than 4.8 ohms for 500 milliseconds. DTC B0045 will set when deployment loop high-side voltage is greater than 6 volts for 500 milliseconds or when high-side circuit voltage is less than 2.4 volts and deployment loop resistance is less than 6 ohms for 500 milliseconds.

SDM turns on AIR BAG warning light and sets DTC.

Current DTC clears when condition responsible for setting DTC no longer exists and scan tool CLEAR DTC command has been used to clear DTC's. History DTC clears when 255 malfunction-free ignition cycles have occurred.

Malfunction is likely to be caused by a short between circuits 2137 and 2138 or by an open or high resistance condition or by a short to ground or voltage in either circuit. A malfunctioning electrical connector or SDM could also cause condition.

Note. For circuit number and wire color identification, see WIRING DIAGRAMS .

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).
2. Turn ignition off. Disconnect driver side impact air bag module Yellow 2-pin connector, located under driver-side front seat. (Scheme 79) If harness-side of connector is damaged, go to next step. If side impact air bag module side of connector is damaged, go to step 4. If both sides of connector are okay, go to step 5.
3. Replace harness-side connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 10.
4. Replace side impact air bag module wiring harness between under seat connector and driver side impact air bag module. Go to step 10.
5. Install SIR Driver/Passenger Load Tool (J-38715-A) to harness-side of driver side impact air bag module wire harness, located under front seat. Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0040, B0041 or B0045 is retrieved as a current code, go to next step. If DTC B0040, B0041 or B0045 is not retrieved as a current code, go to step 8.
6. Turn ignition off. Remove load tool from connector. Disconnect SDM connector. (Scheme 87) If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 10. If SDM connector is okay, go to next step. NOTE: Use Digital Multimeter (J-39200) and Connector Test Adapter Kit (J-35616-A) or Flat WIre Probe Adapter Kit (J-42675) when performing electrical tests.
7. When diagnosing air bag system: If DTC B0040 is retrieved by scan tool, check for a short between circuits 2137 and 2138. If condition is found and corrected, go to step 10. If condition is not found, go to step 9. If DTC B0041 is retrieved, check for an open or high resistance in circuits 2137 and 2138. If condition is found and corrected, go to step 10. If condition is not found, go to step 9. If DTC B0045 is retrieved, check for a short to ground or voltage in circuits 2137 and 2138. If condition is found and corrected, go to step 10. If condition is not found, go to step 9.
8. Turn ignition off. Replace side impact air bag module. See «AIR BAG MODULES»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to step 10.
9. Turn ignition off. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to next step.
10. Reconnect all SIR components. Ensure all components are properly mounted. Using scan tool, clear all SIR DTC's. Road test vehicle, then check for DTC's. If current DTC is retrieved by scan tool, go to step 2. If current DTC is not retrieved by scan tool, system is okay. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).

Sensing and Diagnostic Module (SDM) contains a sensing device which converts vehicle velocity changes into an electrical signal. Signal is processed by SDM and compared to a value stored in memory. When signal exceeds stored value, additional signal processing is performed and signals are compared to values stored in memory. When 2 signals exceed stored values, SDM causes current to flow through air bag modules, deploying air bags and causing DTC B0051 to set.

DTC sets when ignition voltage is present and SDM has commanded deployment of driver-side and passenger-side air bag modules or driver side impact air bag module.

SDM sets DTC, turns on AIR BAG warning light and records crash data.

DTC B0051 is a latched code and cannot be cleared. Replace SDM only after completion of diagnostic procedure and applicable repairs.

Note. For circuit number and wire color identification, see WIRING DIAGRAMS .

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .
2. Turn ignition off. If air bags have deployed, go to step 5 . If air bags have not deployed, go to next step.
3. Inspect front of vehicle and undercarriage for signs of impact. If impact has occurred, go to step 5 . If no impact has occurred, go to next step.
4. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to step 6 .
5. Using scan tool, request SIR DTC display. If history DTC exists, refer to Diagnostic Aids for displayed DTC. Replace components and perform inspections as required following an accident. See «POST-COLLISION INSPECTION»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__post-collision-inspection) . Go to next step.
6. Reconnect all SIR components. Using scan tool, clear all DTC's. Road test vehicle, then check for DTC's. If DTC is retrieved by scan tool, go to step 2 . If DTC is not retrieved by scan tool, system is okay. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .

Sensing and Diagnostic Module (SDM) contains a sensing device which converts vehicle velocity changes into an electrical signal. Signal is processed by SDM and compared to a value stored in memory. When signal exceeds stored value, additional signal processing is performed and signals are compared to values stored in memory. When 2 signals exceed stored values, SDM causes current to flow through air bag modules, deploying air bags. DTC B0053 will set instead of DTC B0051 when a deployment occurs while an inflator circuit fault exists that could result in a non-deployment situation in one or more air bag modules.

DTC will set when SDM detects a frontal or side impact collision of sufficient force to warrant deployment of air bags and a deployment loop malfunction exists.

SDM sets DTC, turns on AIR BAG warning light and records crash data.

DTC B0053 is a latched code which cannot be cleared. Replace SDM only after completion of diagnostic procedure and applicable repairs.

DTC B0053 will be accompanied by another DTC, other than DTC B1000 and DTC B0051. Replace SDM only after completion of diagnostic procedure and applicable repairs.

Note. For circuit number and wire color identification, see WIRING DIAGRAMS .

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .
2. Turn ignition off. If air bags have deployed, go to step 5 . If air bags have not deployed, go to next step.
3. Inspect front of vehicle and undercarriage for signs of impact. If impact has occurred, go to step 5 . If no impact has occurred, go to next step.
4. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to step 6 .
5. Using scan tool, request SIR DTC display. If history DTC exists, refer to Diagnostic Aids for displayed DTC. Replace components and perform inspections as required following an accident. See «POST-COLLISION INSPECTION»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__post-collision-inspection) . Go to next step.
6. Reconnect all SIR components. Using scan tool, clear all DTC's. Road test vehicle, then check for DTC's. If DTC is retrieved by scan tool, go to step 2 . If DTC is not retrieved by scan tool, system is okay. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .

Side Impact Sensor (SIS) utilizes a unidirectional 2-circuit wire. SIS modulates current on the interface to send identification, State Of Health (SOH) and deployment commands to Sensing and Diagnostic Module (SDM). SDM serves as a power source and ground for SIS. When ignition is turned on and input power from SDM is first detected, SIS performs internal diagnostics, then sends an identification message to SDM. SDM considers this message valid if response time is less than 5 seconds. SIS continually communicates a status message to SDM, which determines if a fault is present in SIS circuit. When a fault is detected, SDM resets SIS twice by removing and reapplying power to SIS. If fault is still present, SDM will set appropriate DTC.

If DTC B0077 is set, a valid identification message was not received within 5 seconds of SIS powering up, a status message was not received or SDM has tried to reset SIS twice without detecting a valid identification message. If DTC B0079 is set, SDM has received an identification message from SIS which does not match identification stored in SDM memory or SDM has tried to reset SIS twice without detecting a valid identification message. If DTC B0080 has set, SDM has received a NOK (Not Okay) message from SIS.

SDM turns on AIR BAG warning light and sets DTC.

Current DTC clears when condition responsible for DTC no longer exists and CLEAR CODES command is issued via scan tool. History DTC clears when 255 malfunction free ignition cycles have occurred.

Condition could be caused by a short to ground or voltage, high or low resistance in circuits 2131 or 2132. An incorrect SIS can also cause condition.

Note. For circuit number and wire color identification, see WIRING DIAGRAMS .

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).
2. Install scan tool to Data Link Connector (DLC), located under left side of instrument panel, to right of steering column. Using scan tool, request SIR DTC's. If DTC B0079 or B0080 is displayed as a current DTC, go to step 10. If DTC B0079 or B0080 is not displayed as current DTC, go to next step.
3. Turn ignition off. Disconnect SIS connector. See «SIDE IMPACT SENSOR (SIS)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Inspect both component and connector sides of connector for damage or signs of corrosion. If damage or corrosion is found, go to next step. If damage or corrosion is not found, go to step 5.
4. If component side of connector is damaged, replace SIS. Go to step 11. If harness side of connector is damaged, replace connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 11.
5. Disconnect SDM connector. (Scheme 87) Inspect SDM and harness connector terminals for damage or corrosion. If connector and SDM terminals are okay, go to step 7. If harness connector or SDM terminals are damaged or corroded, go to next step.
6. If SDM connector is damaged, replace connector. See «WIRE REPAIR»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems__wire-repair). Go to step 11. If SDM terminals are damaged, replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to step 11. NOTE: Use Digital Multimeter (J-39200) and Connector Test Adapter Kit (J-35616-A) or Flat WIre Probe Adapter Kit (J-42675) when performing electrical tests.
7. Disconnect SIS connector. Check circuits 2131 and 2132 for an open or high resistance between SDM and SIS. If open or high resistance is found and corrected, go to step 11. If open or high resistance is not found and corrected, go to next step.
8. Check circuits 2131 and 2132 for continuity. If no continuity is found and corrected, go to step 11. If no continuity is not found and corrected, go to next step.
9. Turn ignition on. Check for a short to voltage in circuits 2131 and 2132. If short to voltage is found and corrected, go to step 11. If short to voltage is not found and corrected, go to next step.
10. Turn ignition off. Replace SIS. See «SIDE IMPACT SENSOR (SIS)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to next step.
11. Reconnect all SIR component connectors. Turn ignition on. Using scan tool, clear all SIR DTC's. Road test vehicle, then check for SIR DTC's. If DTC is retrieved, go to next step. If DTC is not retrieved, system is normal. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).
12. Turn ignition off. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to next step.
13. Turn ignition on. Using scan tool, erase DTC's. Road test vehicle, then check for DTC's. If applicable DTC is retrieved by scan tool, go to step 2. If applicable DTC is not retrieved by scan tool, system is normal. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems).

DTC B1000 indicates an internal SDM malfunction. No external circuits are involved.

DTC sets when SDM detects an internal malfunction.

SDM refuses all additional inputs.

Current DTC clears when malfunction is no longer present. History DTC clears when SDM ignition cycle counter reaches the reset threshold, without a repeat of malfunction.

DTC may be stored as history DTC without affecting operation of SDM. If DTC is retrieved only as a history DTC and not as a current DTC, DO NOT replace SDM. If DTC is retrieved as a history and current DTC, replace SDM.

Note. For circuit number and wire color identification, see WIRING DIAGRAMS .

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .
2. Connect scan tool to Data Link Connector (DLC), located under left side of instrument panel, to right of steering column. Turn ignition on. Using scan tool, request SIR DTC display. If DTC B1000 is retrieved as a current DTC, go to next step. If DTC B1000 is retrieved as a history DTC, go to «DIAGNOSTIC AIDS»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .
3. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Reconnect all SIR components. Go to next step.
4. Using scan tool, erase DTC's. Road test vehicle, then check for DTC's. IF DTC B1000 is retrieved by scan tool, go to step 2 . If DTC B1000 is not retrieved, system is normal. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .

When ignition is turned on, Sensing and Diagnostic Module (SDM) compares restraints identification stored in SDM to restraints identification stored in Body Control Module (BCM). Then, SDM compares Vehicle Identification Number (VIN) stored in SDM to VIN stored in BCM.

DTC sets when ignition voltage is within normal operating range and restraints identification or VIN stored in SDM does not match restraints identification or VIN stored in BCM.

SDM sets DTC, turns on AIR BAG warning light and disables deployment loops.

DTC clears when restraints identification and VIN stored in SDM matches restraints identification and VIN stored in BCM.

DTC is an indication that restraints identification stored in both BCM and SDM do not match. If either BCM or Powertrain Control Module (PCM) were replaced, replacement modules need to be reprogrammed for proper operation.

1. If SIR diagnostic system check has been performed, go to next step. If SIR diagnostic system check has not been performed, go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .
2. Connect scan tool to Data Link Connector (DLC), located under left side of instrument panel, to right of steering column. Using scan tool, verify PCM is programmed with correct VIN. If VIN is not correct, go to next step. If VIN is correct, go to step 4 .
3. Using scan tool, program correct VIN into PCM. Go to step 8 .
4. If BCM was not replaced, go to next step. If BCM was replaced, go to step 6 .
5. Using scan tool, verify BCM is programmed with correct VIN. If VIN is correct, go to step 7 . If VIN is not correct, go to next step.
6. Using scan tool, select BCM SPECIAL FUNCTIONS. Follow scan tool prompts to reprogram BCM. Go to step 8 .
7. Turn ignition off. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) under REMOVAL & INSTALLATION. Go to next step.
8. Reconnect all SIR components. Using scan tool, clear all DTC's. Road test vehicle, then check for DTC's. If DTC B1001 is retrieved by scan tool, go to step 2 . If DTC B1001 is not retrieved by scan tool, system is okay. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/buick/century/vi-1997-2005/remont/airbag/#air-bag-restraint-systems) .

WIRE REPAIR

SIR system requires special wiring repair procedures due to sensitive nature of circuitry. Wire Repair Kit (J-38125-B) contains special sealed splices for use in repairing SIR wiring. Splices use a heat shrink sleeve with sealing adhesive to produce a sealed splice and a cross-hatched core crimp to produce a positive contact for low energy circuits.

Repair damaged SIR wire harness connectors and terminals (except pigtails) using connector repair assembly packs and splice crimping tool provided. Terminals in SIR system are manufactured from a special metal to provide necessary contact integrity for sensitive, low-energy circuits. These terminals are only available in connector repair assembly packs and no other terminal should be substituted.

If individual terminals on SDM harness connector are damaged, SDM harness connector must be replaced using SDM harness connector pigtail assembly or SDM harness connector replacement kit. If individual terminals on any other SIR connector are damaged, entire connector must be replaced. Use appropriate connector repair assembly pack. Replace entire SIR wire harness, if necessary to maintain SIR circuit integrity.

DO NOT make wiring, connector or terminal repairs on components with wiring pigtails. If a wiring pigtail is damaged, entire component (including pigtail) should be replaced.

Any wiring other than a pigtail can be repaired by splicing in a new section of wire of same gauge. Sealed splices and crimping tool must be used for these splices. Open wire harness by removing tape as necessary, using a sewing seam ripper. Refer to instructions in kit for wiring repair procedure.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Air Bag System Wiring Diagram (Century, Regal). Scheme 95

See also:
• AIR BAG/SRS COMPONENT INSPECTION & REPLACEMENT TABLES
• AIR BAG SAFETY PRECAUTIONS
• DISABLING & ACTIVATING AIR BAG SYSTEM
• SYSTEM OPERATION CHECK
• REMOVAL & INSTALLATION
• SIDE IMPACT SENSOR (SIS)
• ON-VEHICLE DEPLOYMENT
• OFF-VEHICLE DEPLOYMENT
• ZONE 3
• ZONE 5
• TORQUE SPECIFICATIONS
• ZONE 7
• ZONE 9
• ZONE 2
• WIRE REPAIR
• SIR COIL ASSEMBLY
• POST-COLLISION INSPECTION