Supplemental Inflatable Restraint System Chevrolet Chevy Express H2500

DESCRIPTION & OPERATION

Supplemental Inflatable Restraint (SIR) system is designed to supplement protection provided by driver-side and passenger-side seat belts. A frontal collision of sufficient force up to 30 degrees off center line of vehicle will deploy driver-side and passenger-side air bag modules and seat belt pretensioners. Steering column and knee bolsters also absorb collision energy.

SIR system consists of Sensing and Diagnostic Module (SDM), driver-side and passenger-side dual stage (light-duty) or single stage (heavy-duty) air bag modules, driver-side and passenger-side seat belt pretensioners, driver and front passenger Seat Position Switches (SPS), front end discriminating sensor, SIR coil assembly, passenger-side air bag module disable switch and AIR BAG warning light.

COMPONENT LOCATIONS

COMPONENT LOCATIONS

SYSTEM OPERATION CHECK

If system is functioning normally, AIR BAG warning light flashes 7 times and then turns off when 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. Disable air bag system before working on vehicle. See «DISABLING & ACTIVATING AIR BAG SYSTEM»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__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. Follow correct disposal procedures. See «DISPOSAL PROCEDURES»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__disposal-procedures) .
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. DO NOT assume both stages of a dual stage air bag module have deployed. Only one stage of air bag module may have deployed.
13. When carrying a live air bag module, trim cover should be pointed away from body to minimize injury in case of accidental deployment.
14. When carrying a seat belt pretensioner, tube end of seat belt pretensioner should be pointed away from body to minimize injury in case of accidental deployment.
15. DO NOT attempt to service SIR components. If defective, these parts must be replaced.
16. DO NOT probe a wire through insulator. Wire will eventually fail due to corrosion.
17. When performing electrical tests, prevent accidental shorting of terminals. Such mistakes can damage fuses or components and may cause a second fault code to set, making diagnosis of original problem more difficult.
18. 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.
19. 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 BAGS fuse is removed and ignition is on, AIR BAG warning light will be on. This does not indicate a system malfunction.

Zone 1

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key.
2. Remove AIR BAG fuse from fuse block, located under vehicle hood. Remove Connector Position Assurance (CPA) clip from front end discriminating sensor, also known as Electronic Frontal Sensor (EFS). (Scheme 77) Disconnect connector.

Scheme 77

Zone 3

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key.
2. Remove AIR BAG fuse from fuse block, located under vehicle hood. Remove Connector Position Assurance (CPA) clip from driver-side air bag module connector. (Scheme 78) Disconnect driver-side air bag module connector.

Scheme 78

Zone 5

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key
2. Remove AIR BAG fuse from fuse block, located under vehicle hood. Remove passenger-side knee bolster bracket. Remove Connector Position Assurance (CPA) clip from passenger-side air bag module connector. (Scheme 79) Disconnect passenger-side air bag module connector.

Scheme 79

Zone 7

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key.
2. Remove AIR BAG fuse from fuse block, located under vehicle hood. Remove Connector Position Assurance (CPA) clip from driver-side air bag module connector. (Scheme 78) Disconnect connector.
3. Remove passenger-side knee bolster bracket. Remove CPA clip from passenger-side air bag module connector. (Scheme 79) Disconnect passenger-side air bag module connector.
4. Remove CPA clip from passenger-side seat belt pretensioner connector. (Scheme 80) Disconnect connector. Remove CPA clip from driver-side seat belt pretensioner connector. Disconnect driver-side seat belt pretensioner connector.

Scheme 80

Zone 9

1. Turn steering wheel to place vehicle wheels in straight-ahead position. Turn ignition off and remove key.
2. Remove AIR BAG fuse from fuse block, located under vehicle hood. Remove Connector Position Assurance (CPA) clip from passenger-side seat belt pretensioner connector. (Scheme 78) Disconnect passenger-side seat belt pretensioner connector.

1. Ensure ignition is off and key is removed. Connect electrical connector to front end discriminating sensor. (Scheme 77) Install Connector Position Assurance (CPA) clip.
2. Install AIR BAG fuse in underhood fuse block. Staying well away from air bag modules, turn ignition on. Check system for proper operation. See «SYSTEM OPERATION CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check).

1. Ensure ignition is off and key is removed. Connect driver-side air bag module electrical connector. (Scheme 78) Install Connector Position Assurance (CPA) clip.
2. Install AIR BAG fuse in underhood fuse block. Staying well away from air bag modules, turn ignition on. Check system for proper operation. See «SYSTEM OPERATION CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check).

1. Ensure ignition is off and key is removed. Connect passenger-side air bag module electrical connector. (Scheme 79) Install Connector Position Assurance (CPA) clip.
2. Install passenger-side knee bolster bracket. Tighten knee bolster nuts to specification.See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Install AIR BAG fuse in underhood fuse block. Staying well away from air bag modules, turn ignition on. Check system for proper operation. See «SYSTEM OPERATION CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check).

1. Ensure ignition is off and key is removed. Connect driver-side seat belt pretensioner connector. (Scheme 80) Install Connector Position Assurance (CPA) clip. Connect passenger-side seat belt pretensioner connector. Install CPA clip.
2. Connect passenger-side air bag module electrical connector. (Scheme 79) Install CPA clip. Install passenger-side knee bolster bracket. Tighten knee bolster nuts to specification.See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Connect driver-side air bag module connector. Install CPA clip.
3. Install AIR BAG fuse in underhood fuse block. Staying well away from air bag modules, turn ignition on. Check system for proper operation. See «SYSTEM OPERATION CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check).

1. Ensure ignition is off and key is removed. Connect passenger-side seat belt pretensioner connector. (Scheme 80) Install Connector Position Assurance (CPA) clip.
2. Install AIR BAG fuse in underhood fuse block. Staying well away from air bag modules, turn ignition on. Check system for proper operation. See «SYSTEM OPERATION CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__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 is remaining in service, perform off-vehicle deployment. See OFF-VEHICLE DEPLOYMENT .

ON-VEHICLE DEPLOYMENT

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Turn ignition off, remove key and put on safety glasses. Disable air bag system. See «DISABLING & ACTIVATING AIR BAG SYSTEM»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__disabling-activating-air-bag-system).
2. Cut air bag module and seat belt pretensioner harness connectors from vehicle leaving at least 6" (152 mm) of wire at the connector for each wire lead. Strip 0.50" (13 mm) of insulation from each wire lead. Cut 2 deployment wires at least 20 feet (6.1 m) long from 18-gauge multi-strand wire. Strip 0.50" (13 mm) of insulation from each connector wire lead. Twist wires together at one end to short.
3. For driver-side and passenger-side dual stage air bag module leads, twist together wires for Stage 1 and Stage 2 high-side deployment loops. See «WIRING DIAGRAMS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system). Connect twisted wire pair to end of one deployment wire. (Scheme 81) Bend twisted connection flat and wrap tightly with electrical tape to insulate. Repeat procedure for Stage 1 and Stage 2 low-side deployment loop leads.
4. For driver-side and passenger-side single stage air bag modules and seat belt pretensioner leads, connect lead from connector wire to end of each deployment wire. (Scheme 82) Bend twisted connection flat and wrap tightly with electrical tape to insulate. Repeat for remaining connector wire lead.
5. Remove all loose objects from front seats. Ensure no one is in vehicle. Connect deployment harness to driver-side air bag module connector. Stretch wires away from vehicle as far as possible. Cover windshield and front door openings with a drop cloth. Separate wire ends. Connect wires to a 12-volt battery. Driver-side air bag module should deploy. If air bag module did not deploy, go to step 7. If air bag module did deploy, disconnect wires from battery. DO NOT touch metal surfaces of air bag module for at least 10 minutes due to heat generated during deployment.
6. Repeat steps 2 through 5 for passenger-side air bag module and seat belt pretensioners. Wear gloves and safety glasses when handling deployed air bag modules. Wash hands with mild soap and water.
7. If air bag modules or seat belt pretensioners did not deploy, carefully remove from vehicle. See «AIR BAG MODULES»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) and «SEAT BELT PRETENSIONER»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Temporarily store air bag modules with trim cover facing up. Contact manufacturer for additional instructions.

Scheme 81

Scheme 82

OFF-VEHICLE DEPLOYMENT

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Turn ignition off and remove key. Put on safety glasses.
2. 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. Use Pigtail Adapter (J-38826-75) for driver-side air bag module and Pigtail Adapter (J-38826-80) for passenger-side air bag module. (Scheme 83) Remove driver-side air bag module. See «AIR BAG MODULES»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Remove horn lead, redundant steering wheel control leads, horn buttons and steering wheel control buttons from air bag module, if applicable.
3. Place driver-side air bag module with vinyl trim cover facing up, on ground (preferably paved surface outdoors) in center of an area at least 6 feet (1.8 m) in diameter. Extend SIR deployment harness and pigtail adapter to full length from air bag module. Place a 12-volt battery near shorted end of SIR deployment harness.
4. Connect 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.
5. Separate 2 banana plugs on SIR deployment harness. Connect SIR deployment harness wires to battery. Driver-side air bag module should deploy. Using Deployment Fixture (J-39401-B) to hold passenger-side air bag module and seat belt pretensioners, repeat deployment procedure.
6. If air bag modules fail to deploy, go to next step. If air bag modules did deploy, disconnect SIR deployment harness from battery. Short 2 SIR deployment harness leads together. DO NOT touch metal surfaces of air bag modules for at least 10 minutes due to heat generated during deployment. Wear gloves and safety glasses when handling deployed air bag modules. Wash hands with mild soap and water. Dispose of deployed components as you would any other part. Inspect pigtail adapter and SIR deployment harness for damage after each use.
7. If air bag modules or seat belt pretensioners did not deploy, 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 83

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disable air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-3) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Turn ignition on. Turn steering wheel 90 degrees to gain access to leaf spring access holes on rear of steering wheel. (Scheme 84) Insert screw driver into holes and push on leaf springs to release air bag module retaining pins. Turn steering wheel 180 degrees to access remaining holes. Release remaining spring clips. Tilt top of air bag module rear ward to gain access to air bag module wiring. Disconnect air bag wire harness from clips on air bag module and steering wheel. Remove Connector Position Assurance (CPA) clips from driver-side air bag module connectors and disconnect connectors. Remove driver-side air bag module.
3. To install, reverse removal procedure. Ensure that driver-side air bag module wiring is not pinched and air bag module is fastened securely to steering wheel. Activate air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 84

Removal & Installation (Passenger-side)

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disable air bag system. See «ZONE 5»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-5) and «ZONE 9»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-9) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Release tabs holding Body Control Module (BCM) to bracket, located below passenger-side air bag module. Remove BCM. Remove instrument panel trim pad. See «INSTRUMENT PANEL TRIM PAD»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system). Remove upper and lower passenger-side air bag module mounting bolts. (Scheme 85) Remove passenger-side air bag module from instrument panel.
3. To install, reverse removal procedure. Install lower bolts finger tight, then install upper bolts finger tight. Tighten passenger-side air bag module mounting bolts and knee bolster bracket nuts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Activate air bag system. See «ZONE 5»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) and «ZONE 9»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 85

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disable air bag system. See «DISABLING & ACTIVATING AIR BAG SYSTEM»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__disabling-activating-air-bag-system).
2. Remove Connector Position Assurance (CPA) clip and disconnect front end discriminating sensor harness connector. (Scheme 77) Remove front end discriminating sensor mounting nut. Remove front end discriminating sensor.
3. To install, reverse removal procedure. Ensure discriminating sensor is seated correctly in mounting hole. Tighten front end discriminating sensor mounting nut to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Activate air bag system.

Before proceeding, see AIR BAG SAFETY PRECAUTIONS . Disconnect negative battery cable. Remove IPC trim plate. Tilt steering column to full down position. Remove screws retaining IPC to instrument panel. Pull IPC away from instrument panel. Disconnect IPC electrical connectors. To install, reverse removal procedure. Tighten IPC screws to specification. See TORQUE SPECIFICATIONS .

Scheme 86

Scheme 87

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disable air bag system. See «ZONE 5»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-5) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove left and right A-pillar trim panels. Remove Instrument Panel Cluster trim plate. Remove screws from instrument panel upper trim pad. (Scheme 86) Lift upper trim pad up at an angle and slide rearward to remove. Remove upper and lower screws from passenger-side instrument panel trim pad. (Scheme 87) Remove trim pad.
3. To install, reverse removal procedure. Tighten instrument panel trim pad and upper trim pad screws to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Activate air bag system. See «ZONE 5»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under DISABLING & ACTIVATING AIR BAG SYSTEM.

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disable air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-3) and «ZONE 5»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-5) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove instrument panel trim plate. Release passenger-side air bag module disable switch locking tabs. (Scheme 88) Remove switch from trim panel. Disconnect electrical connector.
3. To install, reverse removal procedure. Activate air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-3) and «ZONE 5»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-5) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 88

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disable air bag system. For driver seat belt pretensioner, see «ZONE 7»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-7) under DISABLING & ACTIVATING AIR BAG SYSTEM.. For passenger-seat belt pretensioner, see «ZONE 9»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-9) under DISABLING & ACTIVATING AIR BAG SYSTEM..
2. Remove screws from applicable seat belt pretensioner trim cover. (Scheme 89) Disconnect seat belt pretensioner electrical connectors. (Scheme 80) Remove seat belt pretensioner bolt. Remove seat belt pretensioner.
3. To install, reverse removal procedure. Tighten seat belt pretensioner bolt to specification. Activate air bag system. For passenger-seat belt pretensioner, see «ZONE 9»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under DISABLING & ACTIVATING AIR BAG SYSTEM.. For driver seat belt pretensioner, see «ZONE 7»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under DISABLING & ACTIVATING AIR BAG SYSTEM..

Scheme 89

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disconnect applicable under seat electrical connectors. Remove seat from vehicle.
2. Disconnect electrical connector from SPS. (Scheme 90) Drill out rivets that retain SPS to seat track. Remove SPS.
3. To install, reverse removal procedure. Tighten seat mounting bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications).

Scheme 90

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disable air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-3) and «ZONE 7»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-7) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Disconnect electrical connectors under driver seat. Remove driver seat. Fold back carpet to access SDM. Remove Connector Position Assurance (CPA) clip from SDM connector and disconnect connector. Remove SDM mounting nuts. (Scheme 91) Remove SDM.
3. To install, reverse removal procedure. Ensure arrow on SDM is facing towards front of vehicle. Tighten SDM nuts and driver seat bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Activate air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) and «ZONE 7»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 91

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions). Disable air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-3) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove driver-side air bag module. See «AIR BAG MODULES»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system). Remove steering wheel. See «STEERING WHEEL»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system). Remove tilt lever by pulling straight out from steering column. Remove upper and lower steering column covers.
3. Remove upper steering column cover. Remove SIR coil wire harness straps. Disconnect SIR coil assembly connector. Remove SIR coil assembly retaining ring. (Scheme 92) Remove SIR coil assembly. Remove wave washer.
4. To install, reverse removal procedure. Tighten upper and lower steering column cover Torx screws and steering wheel nut to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Activate air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under DISABLING & ACTIVATING AIR BAG SYSTEM.

Scheme 92

1. Before proceeding, see «AIR BAG SAFETY PRECAUTIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-safety-precautions) . Disable air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__zone-3) under DISABLING & ACTIVATING AIR BAG SYSTEM.
2. Remove driver-side air bag module. See «AIR BAG MODULES»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) . Scribe marks on steering shaft and steering wheel for reference during assembly. Remove steering wheel nut. Using Steering Wheel Puller (J-1859-A), remove steering wheel.
3. To install, reverse removal procedure. Tighten steering wheel nut to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications) . Activate air bag system. See «ZONE 3»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under DISABLING & ACTIVATING AIR BAG SYSTEM.

DIAGNOSTICS

DIAGNOSTIC TROUBLE CODES (DTC'S)

Sensing & 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 power source and turn ignition on. Follow scan tool manufacturer instructions for communication with SIR system.

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 Diagnostic System 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. See SIR DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC TESTS.

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.

SIR DIAGNOSTIC SYSTEM CHECK

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, inspect vehicle and easily accessible air bag system components for obvious damage, addition of aftermarket accessories, faulty or intermittent electrical connections or conditions which could cause malfunction. Diagnose air bag warning light problems. See «AIR BAG WARNING LIGHT MALFUNCTION»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) .
2. Install scan tool to Data Link Connector (DLC), located under left side of instrument panel. If scan tool powers up, go to next step. If scan tool does not power up, inspect data link communications circuits.
3. If scan tool communicates with SDM, go to next step. If scan tool does not communicate with SDM, inspect data link communications circuits.
4. Using scan tool, request Diagnostic Trouble Codes (DTC's). If current or history DTC's exist, record DTC's. Go to next step. If no DTC's exist, system is okay at this time.
5. If scan tool displays any "U" type DTC's, diagnose and repair other system DTC's before attempting SIR system repairs. If other DTC's are displayed, diagnose applicable DTC's. See «DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) table.

DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

CONNECTOR IDENTIFICATION

Note. Refer to illustrations to identify SIR connector terminals. (Scheme 93), (Scheme 94), (Scheme 95), (Scheme 96), (Scheme 97), (Scheme 98), (Scheme 99), (Scheme 100) & (Scheme 101).

Scheme 93

Scheme 94

Scheme 95

Scheme 96

Scheme 97

Scheme 98

Scheme 99

Scheme 100

Scheme 101

Circuit Description

AIR BAG warning light is controlled by Sensing and Diagnostic Module (SDM). When ignition is turned on, AIR BAG warning light will flash 7 times, during which time SDM checks SIR system for malfunctions. If no malfunctions are detected, AIR BAG warning light will go off. If a malfunction is detected, AIR BAG warning light will stay on.

If ignition voltage is outside of normal operation range (9-16 volts), AIR BAG warning light will stay on with no Diagnostic Trouble Codes (DTC's) set.

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check).
2. Inspect Instrument Panel Cluster (IPC) for proper operation. If IPC is working correctly, go to next step. If IPC is not working correctly, diagnose and repair IPC malfunction.
3. Turn ignition off. Observe AIR BAG warning light while 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, go to step 10.
4. Turn ignition off. Connect scan tool to Data Link Connector (DLC), located under left side of instrument panel. Turn ignition on. Using scan tool, request SIR data list display. If ignition voltage is greater than 9 volts, go to next step. If ignition voltage is 9 volts or less, go to step 6. 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.
5. If ignition voltage is more than 16 volts, inspect battery and charging system. If ignition voltage is 16 volts or less, go to step 9.
6. Turn ignition off. Disconnect SDM connector. (Scheme 91) Check Pink wire between SDM connector terminal No. 1 and SIR fuse for an open or high resistance. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If an open or high resistance is found and corrected, go to step 12. If an open or high resistance is not found, go to next step.
7. Check voltage feed wire between AIR fuse and battery for an open or high resistance. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If an open or high resistance is found and corrected, go to step 12. If an open or high resistance is not found, go to next step.
8. Check Black/White wire between SDM connector terminal No. 32 and ground for an open or high resistance. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If an open or high resistance is found and corrected, go to step 12. If an open or high resistance is not found, go to next step.
9. Inspect SDM connector for damage or signs of corrosion. If connector is damaged, replace connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). Go to step 12. If connector is not damaged, go to step 11.
10. Inspect Instrument Panel Cluster (IPC) connector. See «INSTRUMENT PANEL CLUSTER (IPC)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system). If connector shows signs of corrosion, poor connections or damage, replace connector. Go to step 12. If connector is okay, replace IPC. Go to step 12.
11. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 12.
12. Reconnect all SIR and IPC system components. Ensure that all components are properly mounted. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check).

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 B0012 will set when Stage 2 deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0013 will set when Stage 2 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 B0014 will set when Stage 2 deployment loop high-side circuit is shorted to ground or voltage for more than 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.

DTC B0016 will set when Stage 1 deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0017 will set when Stage 1 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 B0018 will set when Stage 1 deployment loop high-side circuit is shorted to ground or voltage for more than 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.

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.

Diagnostic Aids

Malfunction is likely to be caused by a short between circuits 3024 and 3025 or 3026 and 3027 or by an open or high resistance condition or by a short to ground or voltage in any 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, «SIR DIAGNOSTIC SYSTEM CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check).
2. Turn ignition off. Disconnect passenger-side air bag module connector, located under passenger-side instrument panel. (Scheme 79) 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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). Go to step 9.
4. Install SIR Driver/Passenger Load Tool (J-38715-A) using Load Tool Adapter (J-38715-80) for dual stage air bag modules or Load Tool Adapter (J-38715-100) for single stage air bag modules to harness-side of passenger-side air bag module connector. Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0012, B0013, B0014, B0016, B0017 or B0018 is retrieved as a current code, go to next step. If DTC B0012, B0013, B0014, 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 91) If SDM connector is okay, go to next step. If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__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 B0012 or B0016 is retrieved by scan tool, check for a short between circuits 3026 and 3027 or 3024 and 3025. If condition is found and corrected, go to step 9. If condition is not found, go to step 8. If DTC B0013 or B0017 is retrieved, check for an open or high resistance in circuits 3026 and 3027 or 3024 and 3025. If condition is found and corrected, go to step 9. If condition is not found, go to step 8. If DTC B0014 or B0018 is retrieved, check for a short to ground or voltage in circuits 3026 and 3027 or 3024 and 3025. 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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 9.
8. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
9. Reconnect all SIR components. 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.

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 Stage 1 deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0024 will set when Stage 1 deployment loop high-side circuit is shorted to ground or voltage for more than 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. DTC B0026 will set when Stage 1 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 B0042 will set when Stage 2 deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0043 will set when Stage 2 deployment loop high-side circuit is shorted to ground or voltage for more than 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. DTC B0044 will set when Stage 2 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 3020 and 3021 or 3022 and 3023 or by an open or high resistance condition or by a short to ground or voltage in any 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, «SIR DIAGNOSTIC SYSTEM CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check).
2. Turn ignition off. Disconnect driver-side air bag module connector (lower SIR coil connector), located at base of steering column. (Scheme 78) 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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__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-38715-80) for dual stage air bag modules or Load Tool Adapter (J-38715-100) for single stage air bag modules. Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0022, B0024, B0026, B0042, B0043 or B0044 is retrieved as a current code, go to step 6. If DTC B0022, B0024, B0026, B0042, B0043 or B0044 is not retrieved as a current code, go to next step.
5. Remove SIR driver/passenger load tool from harness-side of connector. Reconnect lower SIR connector. Remove driver-side air bag module. See «AIR BAG MODULES»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Install SIR driver/passenger load tool using Load Tool Adapter (J-38715-120) for dual stage air bag modules or Load Tool Adapter (J-38715-30A) for single stage air bag modules to upper SIR coil connector. Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0022, B0024, B0026, B0042, B0043 or B0044 is retrieved as a current code, go to step 9. If DTC B0022, B0024, B0026, B0042, B0043 or B0044 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 91) If SDM connector is okay, go to next step. If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__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 or B0042 is retrieved by scan tool, check for a short between circuits 3020 and 3021 or 3022 and 3023. If condition is found and corrected, go to step 11. If condition is not found, go to step 10. If DTC B0024 or B0043 is retrieved, check for a short to ground or voltage in circuits 3020, 3021, 3022 and 3023. If condition is found and corrected, go to step 11. If condition is not found, go to step 10. If DTC B0026 or B0044 is retrieved, check for an open or high resistance in circuits 3020, 3021, 3022 and 3023. If condition is found and corrected, go to step 11. If condition is not found, go to step 10.
8. Replace driver-side air bag module. See «AIR BAG MODULES»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 11.
9. Replace SIR coil. See «SIR COIL ASSEMBLY»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-coil-assembly) under REMOVAL & INSTALLATION. Go to step 11.
10. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
11. Reconnect all SIR components. 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.

Sensing and Diagnostic Module (SDM) contains an accelerometer which converts vehicle velocity changes to an electrical signal. Electrical 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 SDM commands an air bag deployment.

SDM sets DTC B0051, turns on AIR BAG warning light and records crash data.

DTC B0051 is a latched code and cannot be cleared. Replace SDM after following instructions in diagnostic procedure.

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .
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 vehicle 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)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 6 .
5. Replace components and perform inspections as required following an accident. See «POST-COLLISION INSPECTION»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__post-collision-inspection) . Go to next step.
6. Reconnect all SIR components. Ensure that all components are properly mounted. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .

Sensing and Diagnostic Module (SDM) contains a sensing device which converts vehicle velocity changes to an electrical signal. Electrical 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 will cause 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 sets when ignition voltage is present and SDM commands an air bag deployment with deployment loop faults present.

SDM sets DTC B0053 and B0051, turns on AIR BAG warning light and records crash data.

DTC B0053 is a latched code and cannot be cleared. Replace SDM after following instructions in diagnostic procedure.

DTC B0053 will be accompanied by another DTC (other than DTC B0051). Repair malfunction causing other DTC's before installing new 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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .
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 vehicle 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)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 6 .
5. Replace components and perform inspections as required following an accident. See «POST-COLLISION INSPECTION»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__post-collision-inspection) . Go to next step.
6. Reconnect all SIR components. Ensure that all components are properly mounted. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .

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 B0057 will set when deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0058 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 B0059 will set when deployment loop high-side circuit voltage is more than 6 volts for 500 milliseconds or when high-side circuit voltage is less more 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 2116 or 2117 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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check).
2. Turn ignition off. Disconnect passenger side seat belt pretensioner connector, located under passenger-side front seat. (Scheme 80) If harness-side of connector is damaged, go to next step. If passenger seat belt pretensioner side of connector is damaged, go to step 8. If both sides of connector are okay, go to step 4.
3. Replace harness-side connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). Go to step 10.
4. Install SIR Driver/Passenger Load Tool (J-38715-A) to harness-side of passenger seat belt pretensioner connector. Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0057, B0058 or B0059 is retrieved as a current code, go to step 6. If DTC B0057, B0058 or B0059 is not retrieved as a current DTC, go to next step.
5. Turn ignition off. Remove SIR driver/passenger load tool from harness connector. Go to step 8.
6. Turn ignition off. Remove load tool from seat belt pretensioner connector. Disconnect SDM connector. (Scheme 91) If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__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 B0057 is retrieved by scan tool, check for a short between circuits 2116 and 2117. If condition is found and corrected, go to step 10. If condition is not found, go to step 9. If DTC B0058 is retrieved, check for an open or high resistance in circuits 2116 and 2117. If condition is found and corrected, go to step 10. If condition is not found, go to step 9. If DTC B0059 is retrieved, check for a short to ground or voltage in circuits 2116 and 2117. If condition is found and corrected, go to step 10. If condition is not found, go to step 9.
8. Replace seat belt pretensioner. See «SEAT BELT PRETENSIONER»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 10.
9. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
10. Reconnect all SIR components. 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.

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 B0064 will set when deployment loop resistance is less than 1.3 ohms for 500 milliseconds. DTC B0065 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 B0066 will set when deployment loop high-side circuit voltage is more than 6 volts for 500 milliseconds or when high-side circuit voltage is less more 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 2118 or 2119 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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check).
2. Turn ignition off. Disconnect driver side seat belt pretensioner connector, located under driver-side front seat. (Scheme 80) If harness-side of connector is damaged, go to next step. If driver seat belt pretensioner side of connector is damaged, go to step 8. If both sides of connector are okay, go to step 4.
3. Replace harness-side connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). Go to step 10.
4. Install SIR Driver/Passenger Load Tool (J-38715-A) to harness-side of driver seat belt pretensioner connector. Turn ignition on. Using scan tool, check for SIR DTC's. If DTC B0064, B0065 or B0066 is retrieved as a current DTC, go to step 6. If DTC B0064, B0065 or B0066 is not retrieved as a current code, go to next step.
5. Turn ignition off. Remove SIR driver/passenger load tool from harness connector. Go to step 8.
6. Turn ignition off. Remove load tool from seat belt pretensioner connector. Disconnect SDM connector. (Scheme 91) If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__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 B0064 is retrieved by scan tool, check for a short between circuits 2118 and 2119. If condition is found and corrected, go to step 10. If condition is not found, go to step 9. If DTC B0065 is retrieved, check for an open or high resistance in circuits 2118 and 2119. If condition is found and corrected, go to step 10. If condition is not found, go to step 9. If DTC B0066 is retrieved, check for a short to ground or voltage in circuits 2118 and 2119. If condition is found and corrected, go to step 10. If condition is not found, go to step 9.
8. Replace seat belt pretensioner. See «SEAT BELT PRETENSIONER»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 10.
9. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
10. Reconnect all SIR components. 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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check).

Seat Position Switch (SPS) is used to determine driver or front passenger seat position. SPS interfaces with Sensing and Diagnostic Module (SDM). State of SPS allows SDM to disable Stage 2 deployment of applicable air bag module. SPS is a Hall effect sensor mounted on seat tracks. Shunted state of SPS represents rearward seat position, while non-shunted state represents a forward seat position. SPS is secondary to passenger-side air bag module disable switch.

DTC sets when SDM detects SPS circuit amperage is 4 milliamps or less for 500 milliamps, when circuit amperage is 18 milliamps or more for 500 milliseconds or when circuit amperage is between 8 milliamps and 11 milliamps for 500 milliseconds.

SDM defaults SPS to forward threshold, sets DTC and turns on AIR BAG warning light.

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 between circuits 5017 and 5055 or 5017 and 5056. An open or high resistance in any circuit 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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check).
2. Turn ignition off. If DTC B0083 is present, disconnect passenger SPS connector, located on front passenger seat inboard seat track. If DTC B0084 is present, disconnect driver SPS connector, located on driver seat outboard seat track. Inspect both sides of applicable connector for corrosion, poor connections or damage. If either half of connector is damaged, go to next step. If both halves of connector are okay, go to step 4.
3. If SPS terminals are damaged, replace applicable SPS. See «SEAT POSITION SWITCH (SPS)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 12. If harness side of connector shows signs of corrosion, poor connections or damage, replace applicable connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). Go to step 12.
4. If DTC B0083 is present, disconnect right main seat harness connector, located under passenger front seat. If DTC B0084 is present, disconnect left main seat harness connector, located under driver seat. If either half of connector shows signs of damage, poor connections or corrosion, replace connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). Go to step 12. If both halves of connector are okay, go to next step.
5. Disconnect SDM connector. (Scheme 91) If SDM connector shows signs of corrosion, poor connections or damage, replace connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). Go to step 12. If 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.
6. If DTC B0083 is current, test circuit 5056 for a short to ground, high resistance or an open. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If condition is found and corrected, go to step 12. If condition is not found, go to next step. If DTC B0084 is current, test circuit 5055 for a short to ground, high resistance or an open. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If condition is found and corrected, go to step 12. If condition is not found, go to next step.
7. If DTC B0083 is current, test circuit 5017 for a short to ground, high resistance or an open. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If condition is found and corrected, go to step 12. If condition is not found, go to next step. If DTC B0084 is current, test circuit 5017 for a short to ground, high resistance or an open. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If condition is found and corrected, go to step 12. If condition is not found, go to next step.
8. Turn ignition on. If DTC B0083 is current, test circuits 5017 and 5056 for a short to voltage. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If condition is found and corrected, go to step 12. If condition is not found, go to next step. If DTC B0084 is current, test circuits 5017 and 5055 for a short to voltage. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair). If condition is found and corrected, go to step 12. If condition is not found, go to next step.
9. For DTC B0083, replace passenger SPS. See «SEAT POSITION SWITCH (SPS)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step. For DTC B0084, replace driver SPS. Go to next step.
10. Reconnect all SIR components. Using scan tool, clear all DTC's. Road test vehicle. If DTC resets, go to next step. If DTC does not reset, system is okay.
11. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
12. Reconnect all SIR components. Ensure all components are properly mounted. Using scan tool, clear all SIR DTC's. Road test vehicle. If DTC resets, go to step 2. If DTC does not reset, system is normal.

When ignition is turned on, Sensing and Diagnostic Module (SDM) performs tests to diagnose critical internal malfunctions. SDM monitors voltage levels at passenger-side air bag module disable switch signal and passenger-side air bag module suppression indicator control circuits to determine position of air bag disable switch. If malfunction is detected, DTC will set.

DTC will set if voltage at disable switch signal and suppression indicator control circuits is low or high with disable switch indicator off for 500 milliseconds.

Air bag disable switch is defaulted to a calibration state and SDM turns AIR BAG warning light on.

Current DTC clears when condition responsible for setting DTC no longer exists and a CLEAR DTC's command is issued via scan tool. History DTC will clear once 255 malfunction-free ignition cycles have occurred.

Condition can be caused by a short between disable switch signal and suppression indicator control circuits.

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .
2. Turn ignition off. Turn air bag disable switch on. Turn ignition on. If ON light illuminates in disable switch, go to step 7 . If ON light does not illuminate in disable switch, go to next step.
3. Turn ignition off. Remove passenger-side air bag module disable switch from instrument panel. See «PASSENGER-SIDE AIR BAG MODULE DISABLE SWITCH»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. If air bag disable switch terminals are corroded, damaged or have poor connections, correct condition. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . Go to step 13 . If connector is okay, go to next step.
4. Disconnect SDM connector. If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . Go to step 13 . 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.
5. Inspect Pink wire between fuse block terminal D4 and passenger-side air bag module disable switch connector terminal "B" for an open or high resistance. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . If an open or high resistance is found and corrected, go to step 13 . If an open or high resistance is not found, go to next step.
6. Inspect Black/White wire between passenger air bag disable switch connector terminal "F" and ground for an open or high resistance. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . If an open or high resistance is found and corrected, go to step 13 . If an open or high resistance is not found, go to next step.
7. Install scan tool to Data Link Connector (DLC), located under left side of instrument panel. Turn air bag disable switch to ON position. Turn ignition on. If SIR INPUTS list on scan tool display shows disable switch in ENABLED state, go to step 9 . If scan tool does not show switch in ENABLED state, go to next step.
8. Turn ignition off. Inspect Tan/Black wire between SDM connector terminal No. 2 and disable switch connector terminal "A" for an open or high resistance. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . If an open or high resistance is found and corrected, go to step 13 . If an open or high resistance is not found, go to next step.
9. Inspect Tan/Black wire between SDM connector terminal No. 2 and disable switch connector terminal "A" for a short. If a short to ground or voltage is found and corrected, go to step 13 . If a short to ground or voltage is not found, go to next step.
10. Inspect Pink wire between SDM connector terminal No. 4 and disable switch connector terminal "E" for a short. If a short to ground or voltage is found and corrected, go to step 13 . If a short to ground or voltage is not found, go to next step.
11. Inspect Pink wire between SDM connector terminal No. 4 and disable switch connector terminal "E" for an open or high resistance. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . If an open or high resistance is found and corrected, go to step 13 . If an open or high resistance is not found, go to next step.
12. Replace passenger-side air bag module disable switch. See «PASSENGER-SIDE AIR BAG MODULE DISABLE SWITCH»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
13. Reconnect all SIR components. Ensure that all components are properly mounted and connected. Using scan tool, clear all SIR DTC's. Road test vehicle, then check for DTC's. If DTC is retrieved, go to step 2 . If DTC is not retrieved, system is normal.

When ignition is turned on, Sensing and Diagnostic Module (SDM) performs tests to diagnose critical internal malfunctions. SDM monitors voltage levels at passenger-side air bag module disable switch signal and passenger-side air bag module suppression indicator control circuits to determine position of air bag disable switch. If malfunction is detected, DTC will set.

DTC will set if voltage in disable switch signal circuit is low with air bag module disable switch on and voltage in disable switch indicator control circuit is high for 500 milliseconds.

Disable switch is defaulted to a calibrated state. SDM turns on AIR BAG warning light and switches air bag disable switch ON light off and on every 5 seconds.

Current DTC clears when condition responsible for setting DTC no longer exists and a CLEAR DTC's command is issued via scan tool. History DTC will clear once 255 malfunction-free ignition cycles have occurred.

Condition can be caused by a short between disable switch signal and indicator control circuits.

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .
2. Turn ignition off. Disconnect passenger-side air bag module disable switch connector. See «PASSENGER-SIDE AIR BAG MODULE DISABLE SWITCH»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. If connector shows signs of corrosion or damage, repair condition. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . Go to step 11 . If connector is okay, go to next step.
3. Reconnect passenger-side air bag module disable switch connector. Connect scan tool to Data Link Connector (DLC), located under left side of instrument panel. Turn air bag disable switch off. Turn ignition on. Using scan tool, request IP MODULE DISABLE (ACTIVE) SWITCH data parameter. If scan tool indicates that IP MODULE DISABLE (ACTIVE) switch is disabled, go to next step. If scan tool does not indicate that IP MODULE DISABLE (ACTIVE) switch is disabled, go to step 5 .
4. Turn air bag disable switch on. Using scan tool, request IP MODULE DISABLE (ACTIVE) switch data parameter. If a change of state is observed on scan tool, go to «DIAGNOSTIC AIDS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) . If a change of state is not observed, go to next step.
5. Turn ignition off. Disconnect passenger-side air bag module disable switch connector. Turn ignition on. Using scan tool, request IP MODULE DISABLE (ACTIVE) switch data parameter. If scan tool indicates that switch is disabled, go to step 10 . If scan tool does not indicate that switch is disabled, 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.
6. Inspect passenger-side air bag module disable switch signal circuit (Tan/Black wire) for a short to ground or voltage. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . If short to ground or voltage is found and corrected, go to step 11 . If short to ground or voltage is not found, go to next step.
7. Inspect passenger-side air bag module suppression indicator control signal circuit (Pink wire) for a short to ground or voltage. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . If short to ground or voltage is found and corrected, go to step 11 . If short to ground or voltage is not found and corrected, go to next step.
8. Turn ignition off. Disconnect SDM connector. If SDM connector shows signs of corrosion or damage, replace SDM connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . Go to step 11 . If SDM connector is okay, go to next step.
9. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to step 11 .
10. Replace passenger-side air bag module disable switch. See «PASSENGER-SIDE AIR BAG MODULE DISABLE SWITCH»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
11. Reconnect all SIR components. Ensure that all components are properly mounted and connected. Using scan tool, clear all SIR DTC's. Road test vehicle, then check for DTC's. If DTC is retrieved, go to step 2 . If DTC is not retrieved, system is normal.

Electronic Frontal Sensor (EFS), also known as a front end discriminating sensor, uses a unidirectional 2-wire circuit. 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 EFS. When ignition is turned on and EFS detects power from SDM, EFS responds by performing internal diagnostics and sending identification to SDM. SDM considers identification message to be valid if received within 5 seconds of EFS powering up. EFS continually communicates a status message to SDM. When fault is detected, SDM will attempt to reset EFS twice by removing and applying power. If fault is still present, DTC will set.

DTC B0100 sets when SDM does not receive a valid identification message from EFS within 5 seconds of EFS being powered up, when a status message is not received or when SDM has tried twice to reset EFS.

DTC B0101 sets when SDM receives 4 consecutive NOK messages from EFS. DTC. DTC B0102 will set when SDM has received an identification message from EFS which does not match identification message stored in SDM and SDM has tried twice to reset EFS.

SDM turns on AIR BAG warning light and sets DTC.

DTC will clear when condition responsible for setting DTC no longer exists and CLEAR DTC command is issued via scan tool. History DTC will clear once 255 malfunction free ignition cycles have occurred.

Condition could be caused by a short between circuits 354 and 5045, by a short to ground or voltage or high or low resistance in either circuit.

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .
2. Using scan tool, request SIR DTC display. If DTC B0101 or B0102 is current, go to step 12 . If DTC B0101 or B0102 is not current, go to next step.
3. Turn ignition off. Disconnect EFS connector. See «FRONT END DISCRIMINATING SENSOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. If connector shows signs of damage or corrosion, go to next step. If connector is okay, go to step 5 .
4. If EFS side of connector is damaged, replace EFS. Go to step 13 . If harness side of connector is damaged, replace connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . Go to step 13 .
5. Disconnect SDM connector. If SDM connector shows signs of damage or corrosion, replace connector. See «WIRE REPAIR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__wire-repair) . Go to step 13 . 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.
6. Inspect EFS signal circuit (Yellow wire) for a short to ground, an open or high resistance. If condition is found and corrected, go to step 13 . If condition is not found, go to next step.
7. Inspect EFS reference circuit (Tan/Orange wire) for a short to ground, an open or high resistance. If condition is found and corrected, go to step 13 . If condition is not found, go to next step.
8. Turn ignition on. Check EFS signal and reference circuits for a short to voltage. If a short to voltage is found and corrected, go to step 13 . If a short to voltage is not found and corrected, go to next step.
9. Replace EFS (front end discriminating sensor). See «FRONT END DISCRIMINATING SENSOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
10. Reconnect all SIR components. Using scan tool, clear all SIR DTC's. Road test vehicle, then check for DTC's. If DTC's are retrieved, go to next step. If DTC's are not retrieved, system is normal.
11. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
12. Replace EFS (front end discriminating sensor). See «FRONT END DISCRIMINATING SENSOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
13. Using scan tool, clear all SIR DTC's. Road test vehicle, then check for DTC's. If DTC's are retrieved, go to step 2 . If DTC is not retrieved, system is normal.

DTC B1000 is an indication of a potential internal Sensing and Diagnostic Module (SDM) malfunction.

SDM turns on AIR BAG warning light.

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.

DTC B1000 be stored as a history DTC without affecting operation of SDM. If DTC B1000 is stored only as a history DTC and not as a current DTC, DO NOT replace SDM. If DTC B1000 is stored as both a current and history DTC, replace SDM.

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .
2. Using scan tool, request SIR DTC display. If DTC B1000 is retrieved as both a current and history DTC, go to next step. If DTC B1000 is not retrieved as both a current and history DTC, go to «DIAGNOSTIC AIDS»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) .
3. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
4. Reconnect all SIR components. Ensure all components are properly mounted. Using scan tool, clear all SIR DTC's. Road test vehicle. If DTC resets, go to step 2 . If DTC does not reset, system is normal.

When ignition is turned on, SDM compares restraints identification stored in SDM to restraints identification stored in Body Control Module (BCM). SDM then compares Vehicle Identification Number (VIN) stored in SDM to VIN stored in Powertrain Control Module (PCM).

DTC will only set when ignition voltage is within normal range (9-16 volts).

SDM sets DTC, turns on AIR BAG warning light and disables all air bag deployments.

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.

DTC B1001 is an indication that restraints identification stored in BCM and SDM DO NOT match, or that VIN's stored in PCM and SDM do not match. If BCM or SDM have been replaced, Vehicle Theft Deterrent (VTD) will need to be reprogrammed.

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»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .
2. 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 9 .
4. If BCM was replaced, go to next step. If BCM was not replaced, go to step 6 .
5. Using scan tool, program BCM to learn restraints identification from SDM. Go to step 8 .
6. If SDM was replaced, Go to step 8 . If SDM was not replaced, go to next step.
7. Replace SDM. See «SENSING & DIAGNOSTIC MODULE (SDM)»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Go to next step.
8. Using scan tool, reprogram Vehicle Theft Deterrent (VTD) system. Go to next step.
9. Reconnect all SIR components. Ensure that all components are properly mounted. Go to «SIR DIAGNOSTIC SYSTEM CHECK»(/chevrolet/chevy-express-h2500/2003-2003/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) .

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 (Express, Savana-1 Of 2). Scheme 102

Air Bag System Wiring Diagram (Express, Savana-1 Of 2). Scheme 103

See also:
• AIR BAG/SRS COMPONENT INSPECTION & REPLACEMENT TABLES
• AIR BAG SAFETY PRECAUTIONS
• DISABLING & ACTIVATING AIR BAG SYSTEM
• SYSTEM OPERATION CHECK
• DISPOSAL PROCEDURES
• REMOVAL & INSTALLATION
• TORQUE SPECIFICATIONS
• ON-VEHICLE DEPLOYMENT
• OFF-VEHICLE DEPLOYMENT
• WIRING DIAGRAMS
• ZONE 3
• ZONE 5
• ZONE 9
• ZONE 7
• SIR DIAGNOSTIC SYSTEM CHECK
• WIRE REPAIR
• SIR COIL ASSEMBLY
• POST-COLLISION INSPECTION