Supplemental Inflatable Restraint System Cadillac Eldorado X

IDENTIFICATION

All models equipped with a Supplemental Inflatable Restraint (SIR) system have a number "2" (driver and passenger-side air bag modules) in the seventh position of the Vehicle Identification Number (VIN). The words Inflatable Restraint are marked on the steering wheel hub. Steering wheel hub is slightly larger in order to accommodate the driver-side air bag module.

SUPPLEMENTAL INFLATABLE RESTRAINT (SIR) SYSTEM

The Supplemental Inflatable Restraint (SIR) system is designed to protect the driver and passenger in a frontal collision. The air bag modules will deploy, from steering wheel and instrument panel, only upon frontal or near frontal impact of no more than 30 degrees off the center line of vehicle. The steering columns and knee bolsters absorb crash energy.

The Side Impact Air Bag System (Deville model only) supplements protection offered by driver-side and front passenger-side doors, and vehicle structure. Upon a side crash of sufficient force, the side impact air bag system will deploy an air bag from driver-side or front passenger-side door panel.

SENSING AND DIAGNOSTIC MODULE (SDM)

The SDM monitors vehicle velocity changes to detect frontal crashes which are severe enough to warrant air bag module deployment. When a frontal crash of sufficient force is detected, SDM will cause enough current to flow through air bag modules to deploy air bag modules. The SDM also maintains a 23 Volt Loop Reserve (23 VLR) energy supply to provide deployment energy in cases where ignition voltage is lost in a frontal crash.

Additionally, the SDM provides diagnostic monitoring of the SIR system electrical components. When a malfunction is detected, the SDM sets a diagnostic trouble code (DTC) which is retrieved using a scan tool. The SDM warns the driver of system malfunctions by controlling the AIR BAG warning light. (Scheme 1)

Scheme 1

SIDE IMPACT SENSING MODULE (SISM) (DEVILLE MODEL ONLY)

The Side Impact Sensing Module (SISM) monitors door velocity changes to detect side crashes which are severe enough to warrant air bag module deployment. When a side crash of sufficient force is detected, SISM on impact side will cause enough current to flow through air bag modules to deploy respective air bag module. The SISM also maintains a 23 Volt Loop Reserve (23 VLR) energy supply to provide deployment energy in cases where ignition voltage is lost in a frontal crash.

Additionally, the SISM provides diagnostic monitoring of the side impact SIR system electrical components. When a malfunction is detected, both SISMs communicates status of side impact system to SDM which sets a diagnostic trouble code (DTC) that is retrieved using a scan tool. The SDM warns the driver of system malfunctions by controlling the AIR BAG warning light.

AIR BAG WARNING LIGHT

When ignition switch is in RUN or START positions, battery voltage is applied to AIR BAG warning light. SDM illuminates this light by providing a ground to a lamp driver. When ignition is first turned on, AIR BAG warning light verifies light and SDM operation by flashing 7 times. Light is also used to warn driver of SIR electrical system faults which could potentially affect SIR system operation. AIR BAG warning light is the key to driver notification of SIR system faults.

FRONT END DISCRIMINATING SENSOR

The front end discriminating sensor is an auxiliary sensor which assists the SDM in determining when deployment should occur by providing the SDM with an input signal. Although the front end discriminating sensor is a mechanical sensor, it is not part of the deployment loop.

SIR COIL ASSEMBLY

SIR coil assembly consists of 2 or more current-carrying coils. It is installed in steering column and allows rotation of steering wheel while maintaining continuous (directly wired) contact of deployment loop through driver-side air bag module.

There is a shorting bar on the Yellow 2-way connector near base of steering column which connects SIR coil assembly to SIR wiring harness. The shorting bar shorts the circuits to main coil and driver-side air bag module when Yellow 2-way connector is disconnected. This shorts the circuit to the driver-side air bag module, preventing unwanted deployment of the air bag module when servicing the steering column or other SIR components.

AIR BAG MODULES

When the vehicle is in an accident of sufficient force to close the discriminating sensor, nitrogen gas inflates the cloth bag packed inside the steering wheel hub and in passenger-side instrument panel. The bag(s) inflate in less than 1/20 of a second. As air bag is contacted by driver or passenger, the gas is vented through openings in the bag, which deflates almost as soon as it is completely deployed.

KNEE BOLSTERS

Knee bolsters are used to absorb energy and control forward movement of front passengers. This is accomplished by limiting leg movement during a frontal crash.

SERVICE PRECAUTIONS

The following precautions should be observed when working with SIR system

1. The SDM maintains sufficient voltage to cause air bag deployment for up to 10 minutes after ignition is turned OFF, battery is disconnected, or fuse powering SDM is removed. In order to begin servicing immediately, inflator modules must be removed from the deployment loop. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system) .
2. After repairs, ensure AIR BAG warning light is working properly and no system faults are indicated. See «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check) .
3. Always wear safety glasses when servicing or handling an air bag module.
4. Air bag module must be stored in its original special container until used for service. It must be stored in a clean, dry place, away from sources of extreme heat, sparks, or high electrical energy.
5. Air bag modules or SDMs should not be subjected to temperatures above 150°F (65°C).
6. Air bag modules or SDMs should not be used if they have been dropped from a height of 3 ft (0.9 m) or greater.
7. When placing a live air bag module on a bench or other surface, always make certain that the trim cover (finished side) is up and away from surface. This will reduce motion of module if accidentally deployed.
8. 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»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disposal-procedures) .
9. At no time should any electrical source be allowed near inflator on back of air bag module.
10. DO NOT apply power to SIR system unless all components are connected or a diagnostic chart requests it, as this will set a diagnostic trouble code.
11. When carrying a live air bag module, trim cover should be pointed away from your body to minimize injury in case of accidental deployment.
12. DO NOT attempt to service SDM, front end discriminating sensor, SIR coil assembly, or air bag modules. If defective, these parts must be replaced.
13. DO NOT probe a wire through insulator; this will damage it and eventually cause failure due to corrosion.
14. 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.
15. When using diagnostic charts 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. See «SPECIAL TOOLS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__special-tools) .
16. 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. If SIR system is not functional, park vehicle until repairs can be made.

SPECIAL TOOLS

To avoid deployment when working on SIR system, DO NOT use electrical test equipment such as test lights, battery or A/C-powered volt/ohmmeter, or any type of electrical equipment other than those specified by manufacturer. See SIR RECOMMENDED TOOLS table.

SIR RECOMMENDED TOOLS

DISABLING & ACTIVATING AIR BAG SYSTEM

DISABLING SYSTEM

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

Frontal Air Bag System

1. Turn steering wheel to place vehicle wheels in straight-ahead position and remove key from ignition switch.
2. Remove SIR fuse from trunk fuse block, located behind carpet in left front corner of trunk. Remove left sound insulator panel. Remove Connector Position Assurance (CPA) clip and disconnect driver-side Yellow 2-way connector and CPA at base of steering column. (Scheme 2)
3. Open glove box and disconnect CPA and passenger-side Yellow 2-way connector through trap door in glove box. (Scheme 11) If connector is not visible, instrument panel must be removed to access connector.

Scheme 2

Side Air Bag System (Deville)

1. Remove key from ignition switch. Remove SIR fuse from trunk fuse block, located behind carpet in left front corner of trunk. Remove left front door panel. Remove Connector Position Assurance (CPA) and disconnect driver-side door side impact inflator module Yellow 2-way connector located near SISM in door. (Scheme 12)
2. Remove right front door panel. Remove CPA and disconnect passenger-side door side impact inflator module Yellow 2-way connector located near SISM in door.

1. Remove key from ignition switch. Install CPA and connect passenger-side Yellow 2-way connector through trap door in glove box. (Scheme 11) Attach passenger-side Yellow 2-way connector to I/P metal structure and ensure wiring harness is routed away from HVAC mix door actuator. Close trap door and close glove box. If connector was not accessible through trap door, install instrument panel.
2. Connect driver-side Yellow 2-way connector and CPA at base of steering column. (Scheme 2) Install left sound insulator panel and SIR fuse. Stay away from air bags and turn ignition switch to RUN position. Check AIR BAG warning light for proper system function. See «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check).

1. Remove key from ignition switch. Install CPA and connect passenger-side door side impact inflator module Yellow 2-way connector located near SISM in door. (Scheme 12) Install right front door panel.
2. Install CPA and connect driver-side door side impact inflator module Yellow 2-way connector located near SISM in door. Install left front door panel. Install SIR fuse to trunk fuse block, located behind carpet in left front corner of trunk. Stay away from air bags and turn ignition switch to RUN position. Check AIR BAG warning light for proper system function. See «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check).

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 PASSIVE RESTRAINT SYSTEM INSPECTION article in the GENERAL INFORMATION section for post-collision inspection information.

CENTERING COIL ASSEMBLY

1. Position wheels to straight-ahead position. Remove SIR coil assembly. See «SIR COIL ASSEMBLY»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Hold coil assembly with clear bottom up to see coil ribbon.
2. While holding coil assembly, depress spring lock to rotate hub in direction of arrow until it stops. The coil ribbon should be wound up snug against center hub.
3. Rotate coil hub in opposite direction approximately 2.5 turns. Release spring lock between locking tabs in front of arrow.

Scheme 3

DISPOSAL PROCEDURES

ON-VEHICLE DEPLOYMENT

1. Turn ignition switch to LOCK position. Disconnect driver-side and passenger-side frontal air bag module Yellow 2-way connectors. (Scheme 2)and (Scheme 11). Disconnect driver-side and passenger-side side impact air bag module Yellow 2-way connectors. (Scheme 12)
2. Cut air bag module harness connector from vehicle leaving at least 6 in (16 cm) of wire at the connector. Strip 1/2 in (13 mm) of insulation from each wire lead to the connector. Cut 2 deployment wires at least 20 feet (610 cm) long from 18 gauge (0.8 mm 2 ) multi-strand wire. Strip 1/2 in (13 mm) of insulation from both ends of wire. Twist ends of wire together to short.
3. Twist together one connector wire lead to one deployment wire. (Scheme 4) Bend twisted connection flat and wrap tightly with electrical tape to insulate. Repeat this step for the other connector wire lead.
4. Remove all loose objects from front seat, and ensure no one is in vehicle. Connect deployment harness to air bag module Yellow 2-way connector. Stretch wires away from car as far as possible.
5. Repeat steps 2-4 for passenger-side or either side impact air bag modules.
6. Separate wire ends and connect wires to a 12-volt battery. Air bag should deploy. DO NOT touch air bag module area for at least 10 minutes due to heat generated during deployment. Wear gloves and safety glasses before handling deployed air bag module. 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 or side impact air bag modules.
7. Carefully remove air bag modules if they do not deploy. See DRIVER-SIDE, PASSENGER-SIDE, and SIDE IMPACT AIR BAG MODULES under REMOVAL & INSTALLATION. Temporarily store module with trim facing up. Contact manufacturer for further instructions.

Scheme 4

OFF-VEHICLE DEPLOYMENT

1. Turn ignition switch to LOCK position. Short the two Deployment Harness (J-38826) leads together by fully seating one banana plug into the other. Connect pigtail adapter to SIR deployment harness.
2. Remove driver-side air bag module. See «DRIVER-SIDE AIR BAG MODULE»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system) under REMOVAL & INSTALLATION. Place air bag module on a work bench with trim cover facing up.
3. Place air bag module on ground (preferably outdoors) at least 6 feet (1.85 m) away from any people or objects. Stretch SIR deployment harness and pigtail adapter from air bag module to its full length. Place a 12-volt battery near shorted end of SIR deployment harness.
4. Connect air bag module to pigtail adapter on SIR deployment harness. (Scheme 5) Ensure area around air bag module is clear of people and objects. Verify that air bag module is resting with trim cover facing up.
5. Separate the two banana plugs on SIR deployment harness. Connect SIR deployment harness wires to battery. (Scheme 5) Air bag module will deploy immediately. If air bag module does not deploy, go to next step. Disconnect SIR deployment harness from battery. Short the two SIR deployment harness leads. DO NOT touch air bag module area for at least 10 minutes due to heat generated during deployment. Wear gloves and safety glasses before handling deployed air bag module. Wash hands with mild soap and water afterward. Dispose of deployed air bag modules as you would any other part. Repeat deployment procedure for passenger-side and side impact air bag modules.
6. Ensure that SIR deployment harness is disconnected from battery and that the two 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 further instructions.

Scheme 5

REMOVAL & INSTALLATION

Removal

1. Before proceeding, read air bag service precautions section. See «SERVICE PRECAUTIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__service-precautions). Disable air bag system. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system).
2. Remove driver seat. Remove left front sill plate. Fold back carpet and insulation to access SDM. Remove connector position assurance (CPA) clip and disconnect electrical connector. Remove SDM fasteners. (Scheme 6) Remove SDM.

Scheme 6

Installation

1. Mount SDM on vehicle, ensuring arrow is pointing toward front of vehicle. Install SDM fasteners. (Scheme 6) Tighten to specification. See «TORQUE SPECIFICATIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Reconnect electrical connector and CPA.
2. Position carpet and insulation over SDM. Install driver seat and left front sill plate. Reactivate air bag system. See «ACTIVATING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system). Ensure system is functioning properly. See procedures under «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check).

1. Before proceeding, read air bag service precautions section. See «SERVICE PRECAUTIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__service-precautions). Disable air bag system. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system).
2. Remove underhood fuse block cover. Remove CPA clip and disconnect electrical connector. Remove plastic radiator support cover and air cleaner housing cover. Remove sensor pigtail clips and sensor fasteners. Remove sensor. (Scheme 7)

Scheme 7

1. Align sensor to vehicle, ensuring arrow on sensor body is pointing toward front of vehicle. Install and tighten sensor fasteners. See «TORQUE SPECIFICATIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications) . Install plastic radiator support cover. Install sensor pigtail clips. Install air cleaner housing cover. Reconnect electrical connector and reinstall CPA clip. Install underhood fuse block cover.
2. Reactivate air bag system. See «ACTIVATING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system) . Ensure proper system function. See «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check) .

1. Before proceeding, read air bag service precautions section. See «SERVICE PRECAUTIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__service-precautions). Disable air bag system. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system).
2. Remove connector position assurance (CPA) clip and disconnect electrical connector. Remove side impact sensing module fasteners. (Scheme 8) Remove side impact sensing module.

Scheme 8

1. Mount module on vehicle, ensuring connector is toward rear of vehicle. Install SDM fasteners. (Scheme 8) Tighten to specification. See «TORQUE SPECIFICATIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications). Reconnect electrical connector and CPA.
2. Reactivate air bag system. See «ACTIVATING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system). Ensure system is functioning properly. See «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check).

Note. Front wheels of vehicle must be turned to straight-ahead position before beginning service. Failure to do so can result in coil assembly being removed without being centered. Reinstalling coil assembly under such circumstances causes ribbon in coil assembly to break when steering wheel is turned fully in one direction. Ensure key is always in LOCK position to prevent wheel from turning and uncentering coil assembly. To re-center coil assembly, see CENTERING COIL ASSEMBLY under ADJUSTMENTS.

1. Before proceeding, read air bag service precautions section. See «SERVICE PRECAUTIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__service-precautions). Disable air bag system. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system).
2. Remove air bag module. See «AIR BAG MODULE»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-modules). Remove steering wheel. See «STEERING WHEEL»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system). Remove coil assembly retaining clip. Remove coil assembly off shaft end letting coil hang freely. (Scheme 9)
3. Remove wave washer. Using Lock Plate Compressor (J-23563-SIR), depress shaft lock and remove shaft lock retaining ring. Remove shaft lock. Remove turn signal canceling cam assembly. Remove upper bearing spring, inner race seat, and inner race.
4. Turn signal to right turn (up) position. Remove multifunction lever and hazard knob assembly. Remove turn signal switch arm. Remove turn signal switch assembly. Attach mechanics wire to coil assembly lower connector at base of steering column and carefully pull wire through gear shift lever bowl, column housing and lock housing cover. Remove mechanic's wire.

Scheme 9

1. Using a mechanic's wire, carefully feed coil assembly wire and lower connector through lock housing cover, column housing, and gear shift lever bowl. Allow coil assembly to hang freely. Remove mechanic's wire. Install wiring protector.
2. Install turn signal switch assembly and arm. Tighten screws to specification. See «TORQUE SPECIFICATIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications) . Install hazard knob assembly and multifunction lever. Install inner race, upper bearing inner race seat, and spring. Install turn signal canceling cam and shaft lock. Install NEW shaft lock retaining ring. Using Lock Plate Compressor (J-23653-SIR), align block tooth on shaft, and depress shaft lock plate. Install wave washer.
3. Ensure coil assembly hub and steering shaft are centered. See «CENTERING COIL ASSEMBLY»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__centering-coil-assembly) under ADJUSTMENTS. Coil assembly will become uncentered if column is separated from steering gear and is allowed to rotate, or if centering spring is depressed, allowing hub to rotate while coil assembly is removed from column.
4. Install coil assembly, using horn tower on canceling cam to align hole on inner ring of coil and projections on steering column housing with projections on outer ring of coil.
5. Install steering wheel. See «STEERING WHEEL»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system) . Install driver-side air bag module. See «AIR BAG MODULE»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-modules) . Reactivate air bag system. See «ACTIVATING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system) . Ensure proper system function. See «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check) .

1. Before proceeding, read air bag service precautions section. See «SERVICE PRECAUTIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__service-precautions). Disable air bag system. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system).
2. Loosen 4 screws from back of steering wheel until back of air bag module can be accessed. (Scheme 10) Disconnect horn contact by pushing slightly and twisting counterclockwise. Disconnect CPA and coil assembly connector from air bag module. Remove air bag module.

Scheme 10

1. Turn ignition off. Connect horn contact to steering column. Connect coil assembly connector and CPA to air bag module. Install air bag module to steering wheel, ensuring no wires are pinched. Tighten 4 air bag module screws through back of steering wheel. Tighten screws to specification. See «TORQUE SPECIFICATIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications) .
2. Reactivate air bag system. See «ACTIVATING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system) . Ensure proper system function. See «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check) .

1. Before proceeding, read air bag service precautions section. See «SERVICE PRECAUTIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__service-precautions). Disable air bag system. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system).
2. Remove instrument panel upper trim pad. Remove bracket fastener behind trap door in rear of glove box. Remove 4 air bag module fasteners. Remove passenger-side air bag module and pigtail. (Scheme 11)

Scheme 11

Turn ignition off. Install air bag module and pigtail. Install 4 air bag module fasteners to specification. See TORQUE SPECIFICATIONS . Install bracket fastener behind trap door in rear of glove box and tighten to specification. Install instrument panel upper trim pad. Reactivate air bag system. See ACTIVATING SYSTEM . Ensure proper system function. See SYSTEM OPERATION CHECK .

1. Before proceeding, read air bag service precautions section. See «SERVICE PRECAUTIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__service-precautions). Disable air bag system. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system).
2. Remove 4 air bag module fasteners. Remove side impact air bag module and pigtail. (Scheme 12)

Scheme 12

Install air bag module and pigtail. Install 4 air bag module fasteners to specification. See TORQUE SPECIFICATIONS . Reactivate air bag system. See ACTIVATING SYSTEM . Ensure proper system function. See SYSTEM OPERATION CHECK .

1. Before proceeding, read air bag service precautions section. See «SERVICE PRECAUTIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__service-precautions) . Disable air bag system. See «DISABLING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__disabling-system) .
2. Remove air bag module. See «DRIVER-SIDE AIR BAG MODULE»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system) . Remove steering wheel nut. Using Steering Wheel Puller (J-1859-03), remove steering wheel.
3. To install steering wheel, feed coil assembly lead through slot in steering wheel. Install steering wheel and tighten nut to specification. See «TORQUE SPECIFICATIONS»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__torque-specifications) . Install driver-side air bag module. See Installation (Driver-Side) under «AIR BAG MODULE»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__air-bag-modules) in this section.
4. Reactivate air bag system. See «ACTIVATING SYSTEM»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system) . Ensure proper system function. See «SYSTEM OPERATION CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__system-operation-check) .

SYSTEM OPERATION CHECK

If system is functioning normally, air bag warning light will flash 7 times and then go out when ignition switch is turned to ON position.

Four possible warning light conditions can indicate a system failure

1. Light does not illuminate at all.
2. Light comes on while vehicle is driven.
3. Light flashes 7 times, and remains on.
4. Light does not flash but remains lit when ignition is turned on.

SIR system faults are usually due to a disconnected/loose electrical connector caused by previous service on vehicle. Always check Yellow SIR connector at base of steering column for loose or damaged wiring.

WIRE REPAIR

Because of sensitive nature of circuitry, manufacturer has developed special wiring repair procedures. Wire Repair Kit (J-38125-A) contains special sealed splices for use in repairing SIR wiring. Sealed splices are 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.

If any terminal or connector in SIR wire harness (except pigtails) is damaged, component can be repaired using one of connector repair assembly packs. Terminals in SIR system are manufactured from a special metal to provide necessary contact for low energy circuits. These terminals are only available in wiring kit, and no other terminal should be substituted.

If an SIR wire pigtail is damaged, entire component (including pigtail) should be replaced. Under no circumstances should wire, connector or terminal repair be attempted on passenger compartment discriminating sensor, forward discriminating sensor, air bag module, or SIR coil assembly.

If any wire except a pigtail is damaged, wire 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. To open wiring harness, remove tape as necessary. To avoid wire insulation damage, manufacturer recommends use of a sewing seam ripper. Refer to instructions in kit for wire repair procedure.

CONNECTOR IDENTIFICATION

Note. To identify SIR wiring connector terminals (Scheme 13)

Scheme 13

DIAGNOSIS & TESTING

Diagnostic Trouble Codes (DTCs)

The Sensing & Diagnostic Module (SDM) provides a record of DTCs stored according to type. The SDM performs diagnostic monitoring of the SIR system electrical components and sets a diagnostic trouble code (DTC) when a malfunction is detected. Current DTCs are stored in SDM and are erased when fault is corrected. Current DTCs can be read using a scan tool such as Tech 1. History DTCs, stored in EEPROM, are malfunctions detected since last time history memory was cleared.

Any DTC beginning with a "U" is a Serial Data Line Class 2 State of Health (SOH) DTC and indicates a Serial Data Line Class 2 malfunction. These DTCs will not cause the AIR BAG warning light to come on and will be accompany a SIR DTC. Once the malfunction which caused the SIR DTC to set is repaired, the SOH DTC may clear.

Scan Tool Diagnostics

A scan tool (Tech 2) will read and clear current codes and history codes. Ensure scan tool contains correct cartridge for SIR diagnostics. To use scan tool, connect it to DLC connector, plug in power source and turn ignition switch to RUN position. Follow scan tester manufacturer instructions for communication with SIR system. Scan tester reads serial data from SDM Serial Data Line Class 2 output terminal No. 5 and 17 to DLC connector terminal No. 2.

Diagnostic Procedure

1. SIR SYSTEM DIAGNOSTIC CHECK should always be starting point of SIR diagnostics. See «SIR DIAGNOSTIC SYSTEM CHECK»(/cadillac/eldorado/x-1992-2002/remont/airbag/#supplemental-inflatable-restraint-system__sir-diagnostic-system-check) under DIAGNOSTIC TABLES . SIR DIAGNOSTIC SYSTEM CHECK checks for proper INFLATABLE RESTRAINT indicator light operation and SIR trouble codes using flash code and scan tester methods.
2. SIR DIAGNOSTIC SYSTEM CHECK will lead to correct diagnostic chart to diagnose SIR problems. Always perform SIR DIAGNOSTIC SYSTEM CHECK after repair or diagnostic procedures to ensure repair is correct and no other problems are present.

SIR DIAGNOSTIC SYSTEM CHECK

Description

When ignition switch is turned RUN position, IGNITION 1 voltage is applied from SIR fuse to SDM (inflatable restraint Sensing and Diagnostic module) at IGNITION 1 input terminal No. 3 and to Instrument Panel Cluster (IPC). SDM responds by flashing AIR BAG indicator 7 times while performing tests on SIR system. If SDM detects no faults within system, AIR BAG warning light will turn off. If a fault is detected by SDM, warning light will come on. If IPC receives no message from SDM, AIR BAG warning light will come on.

Diagnostic Aids

The order in which diagnostic trouble codes are diagnosed is very important. Failure to diagnose trouble codes in order specified may result in extended diagnostic time, incorrect diagnosis and parts replacement. If AIR BAG warning light does not flash 7 times when ignition is turned to RUN position, then the IPC is malfunctioning. If scan tool cannot communicate with SDM, then Serial Data Line Class 2 may be damaged. If State of Health (SOH) DTCs are present, refer to Diagnostic Aids for specific SOH DTC.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. AIR BAG indicator should flash 7 times after ignition switch is turned to RUN position.
2. AIR BAG indicator should turn OFF after flashing 7 times.
3. This test checks for proper operation of Serial Data Line.
4. This test will identify stored DTCs and whether they are current or history.
5. This test checks for proper operation of Serial Data Line and will determine if history DTCs are stored and identify them.

Scheme 14

TABLE A - SDM INTEGRITY CHECK

When ignition switch is turned RUN position, IGNITION 1 voltage is applied from SIR fuse to SDM (inflatable restraint Sensing and Diagnostic module) at IGNITION 1 input terminal No. 3 and to Instrument Panel Cluster (IPC). SDM responds by flashing AIR BAG indicator 7 times. At this time SDM performs POWER-ON, RESISTANCE MEASUREMENT, and CONTINUOUS MONITORING tests. If no system faults are present, SDM will command IPC to turn AIR BAG warning light off. If system fault(s) are detected, SDM will turn AIR BAG warning light on.

The SDM will clear current DTCs and move them to history file when the malfunction is no longer detected, or when ignition is cycled. This does not include DTCs B1151, B1152, B1153, and B1171. DTCs B1151 and B1153 can only be cleared using scan tool CLEAR CODES command. DTCs B1152 and B1171 may not clear after CLEAR CODES command.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test confirms a current malfunction. If not current malfunction is occurring (History DTC set) Diagnostic Aids for appropriate diagnostic trouble code should be referenced. SDM should not be replaced for a History DTC except when directed.
2. 3) This test checks for a malfunction introduced into SIR system during diagnostic process. It is extremely unlikely that a malfunctioning SDM would cause a new malfunction to occur during diagnostic process.
3. 4) When all circuitry outside SDM has been found to operate properly, as indicated by appropriate diagnostic table, then and only then should SDM be replaced.

Scheme 15

TABLE B - AIR BAG WARNING LIGHT FLASHES SEVEN TIMES AND STAYS RUN WITH NO DTCS SET

When ignition switch is turned RUN position, IGNITION 1 voltage is applied from SIR fuse to SDM (inflatable restraint Sensing and Diagnostic module) at IGNITION 1 input terminal No. 3 and to Instrument Panel Cluster (IPC). SDM responds by flashing AIR BAG indicator 7 times then turning off while performing tests on SIR system. If SDM detects no faults within system, AIR BAG warning light will turn off. If a fault is detected by SDM, warning light will come on.

If the IPC receives no message from SDM, the IPC will do the following when ignition switch is turned to RUN position: flash AIR BAG warning light 7 times, turn warning light on, and set DTC U1088.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test checks if SDM can communicate with scan tool.
2. 3) This test checks for sufficient IGNITION 1 voltage applied to SDM.
3. 5) This test determines whether the Serial Data Line Class 2 is malfunctioning.
4. 6) This test checks for an open SIR fuse.
5. 7) This test determines whether a short to ground caused SIR fuse to open.
6. 8) This test determines whether the short to ground is due to a short in wiring or internal to SDM.
7. 12) This test checks for a disconnected SDM.
8. 18) This test checks for an open in IGNITION 1 circuit.

Scheme 16

Scheme 17

Scheme 18

DTC B1115 - PASSENGER-SIDE DEPLOYMENT LOOP RESISTANCE HIGH

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1 and deployment voltages are measured to ensure they are within normal voltage ranges. SDM then proceeds with RESISTANCE MEASUREMENT test, PASSENGER-SIDE FRONTAL LOW terminal No. 8 is grounded through a resistor and passenger current source connected to PASSENGER-SIDE FRONTAL HIGH terminal No. 7 allows known amount of current to flow. By monitoring voltage difference between PASSENGER-SIDE HIGH and PASSENGER-SIDE LOW SDM calculates combined resistance of passenger-side inflator module (inflatable restraint instrument panel module), harness wiring CKTs 1403 and 1404 and connector terminal contacts (passenger-side deployment loop).

DTC Will Set

When driver-side and passenger-side deployment loops are not open or shorted to voltage, passenger-side deployment loop is not shorted to ground or resistance is more than 3 ohms during RESISTANCE MEASUREMENT test. This test is run once each ignition cycle when IGNITION 1 is within normal operating range.

Action Taken

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

DTC Will Clear

Current DTC will clear when ignition switch is cycled and passenger-side deployment loop resistance is less than 3 ohms. History DTC will clear when a scan tool CLEAR CODES command is issued or when 250 malfunction free ignition cycles have occurred. If CLEAR CODES command is issued, and DTC still present, DTC will not appear until next ignition cycle.

An intermittent condition is likely to be caused by a poor connection at passenger inflator module harness connector terminals A or B, SDM terminal No. 7 or 8, or a poor wire to terminal connection in CKT 1403 or 1404.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test checks for proper contact or corrosion of passenger inflator module Yellow 2-way connector.
2. 9) This test isolates malfunction to one side of passenger-side air bag Yellow 2-way connector.
3. 11) This test checks for proper contact and/or corrosion of SDM connector.
4. 16) This test checks if malfunction is in CKT 1403.
5. 18) This test checks if malfunction is in CKT 1404.

Scheme 19

Scheme 20

Scheme 21

DTC B1116 - PASSENGER-SIDE DEPLOYMENT LOOP RESISTANCE LOW

When ignition switch is turned RUN position, SDM will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1 and deployment voltages are measured to ensure they are within normal voltage ranges. SDM then proceeds with RESISTANCE MEASUREMENT Test, PASSENGER-SIDE FRONTAL LOW terminal No. 8 is grounded through an internal current sink and passenger current source connected to PASSENGER-SIDE FRONTAL HIGH terminal No. 7 produces voltage drops in deployment loop. By monitoring voltage difference between PASSENGER-SIDE FRONTAL HIGH and PASSENGER-SIDE FRONTAL LOW SDM calculates combined resistance of passenger-side inflator module (inflatable restraint instrument panel module), harness wiring CKTs 1403 and 1404 and connector terminal contacts (passenger-side deployment loop).

When driver-side and passenger-side deployment loops are not open or shorted to voltage, passenger-side deployment loop is not shorted to ground or resistance is less than 1.4 ohms during RESISTANCE MEASUREMENT test. This test is run once each ignition cycle when IGNITION 1 is within normal operating range.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when ignition switch is cycled and passenger-side deployment loop resistance is more than 1.4 ohms. History DTC will clear when a scan tool CLEAR CODES command is issued or when 250 malfunction free ignition cycles have occurred. If CLEAR CODES command is issued, and DTC still present, DTC will not appear until next ignition cycle.

An intermittent condition is likely to be caused by a short between CKT 1403 and CKT 347, 348 or 1404, or a malfunctioning shorting bar on passenger-side inflator module connector which would require replacement of component. When scan tool CLEAR CODES command is issued and the malfunction is still present, DTC will not reappear until next ignition cycle.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test checks for short from CKT 1403 to 347.
2. 5) This test isolates malfunction to one side of passenger-side air bag module Yellow 2-way connector.
3. 7) This test checks for short from CKT 1403 to 1404.
4. 9) This test checks for short from CKT 1403 to 348.

Scheme 22

Scheme 23

DTC B1117 - PASSENGER-SIDE DEPLOYMENT LOOP OPEN

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1 voltage is measured to ensure it is within normal voltage range. SDM then proceeds with DEPLOYMENT LOOP CONTINUITY Test, during which the SDM measures voltage difference between PASSENGER-SIDE FRONTAL HIGH and PASSENGER-SIDE FRONTAL LOW.

When voltage difference between PASSENGER-SIDE FRONTAL HIGH terminal No. 7 and PASSENGER-SIDE FRONTAL LOW terminal No. 8 is more or equal to 426 millivolts for 500 milliseconds during DEPLOYMENT LOOP CONTINUITY, RESISTANCE MEASUREMENT, or CONTINUOUS MONITORING tests.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when voltage difference between PASSENGER-SIDE FRONTAL HIGH terminal No. 7 and PASSENGER-SIDE FRONTAL LOW terminal No. 8 is less than 426 millivolts for 500 milliseconds. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred.

An intermittent condition is likely to be caused by a poor connection at passenger-side inflator module harness connector terminal No. A or B, SDM terminal No. 7 or 8, or an open in CKT 1403 or 1404.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test determines passenger-side deployment loop voltage difference measured by SDM.
2. 3) This test checks for proper contact and/or corrosion of Yellow 2-way connector.
3. 10) This test isolates malfunction to one side of passenger-side air bag module Yellow 2-way connector.
4. 12) This test checks for proper contact and/or corrosion of SDM connector.
5. 17) This test determines whether malfunction is in CKT 1403.
6. 19) This test determines whether malfunction is in CKT 1404.

Scheme 24

Scheme 25

Scheme 26

DTC B1121 - DRIVER-SIDE DEPLOYMENT LOOP RESISTANCE HIGH

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1 and deployment loop voltages are measured to ensure they are within normal voltage ranges. The SDM then proceeds with RESISTANCE MEASUREMENT test during which DRIVER-SIDE FRONTAL LOW terminal No. 9 is grounded through internal current sink and the driver current source connected to DRIVER-SIDE FRONTAL HIGH terminal No. 10 produces voltage drops in deployment loop. By monitoring the voltage difference between DRIVER-SIDE HIGH and DRIVER-SIDE LOW the SDM calculates the combined resistance of the driver-side inflator module (inflatable restraint steering wheel module), SIR coil assembly, harness wiring CKTs 347 and 348 and connector terminal contact (driver-side deployment loop).

When driver-side and passenger-side deployment loops are not open or shorted to voltage, driver-side deployment loop is not shorted to ground or resistance is more than 3.8 ohms during RESISTANCE MEASUREMENT test. This test is run once each ignition cycle when IGNITION 1 is within normal operating range.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when ignition switch is cycled and driver-side deployment loop resistance is less than 3.8 ohms. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred. If CLEAR CODES command is issued, and DTC still present, DTC will not appear until next ignition cycle.

An intermittent condition is likely to be caused by a poor connection at driver-side inflator module or SIR coil assembly harness connector terminals A or B, SDM terminal No. 9 or 10, or a poor wire to terminal connection in CKT 347 or 348.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test checks for proper contact and/or corrosion of Yellow 2-way connector.
2. 9) This test isolates malfunction to one side of driver-side air bag Yellow 2-way connector.
3. 10) This test determines whether malfunction is in SIR coil assembly or driver-side air bag module.
4. 13) This test checks for proper contact and/or corrosion of SDM connector.
5. 18) This test determines whether malfunction is in CKT 347.
6. 20) This test determines whether malfunction is in CKT 348.

Scheme 27

Scheme 28

Scheme 29

DTC B1122 - DRIVER-SIDE DEPLOYMENT LOOP RESISTANCE LOW

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1 and deployment loop voltages are measured to ensure they are within normal voltage ranges. The SDM then proceeds with RESISTANCE MEASUREMENT test during which DRIVER-SIDE FRONTAL LOW terminal No. 9 is grounded through internal current sink and the driver current source connected to DRIVER-SIDE FRONTAL HIGH terminal No. 10 produces voltage drops in deployment loop. By monitoring the voltage difference between DRIVER-SIDE FRONTAL HIGH and DRIVER-SIDE FRONTAL LOW the SDM calculates the combined resistance of the driver-side inflator module (inflatable restraint steering wheel module), SIR coil assembly, harness wiring CKTs 347 and 348 and connector terminal contact (driver-side deployment loop).

When driver-side and passenger-side deployment loops are not open or shorted to voltage, driver-side deployment loop is not shorted to ground or resistance is less than 1.7 ohms during RESISTANCE MEASUREMENT test. This test is run once each ignition cycle when IGNITION 1 is within normal operating range.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when ignition switch is cycled and driver-side deployment loop resistance is more than 1.7 ohms. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred. If CLEAR CODES command is issued, and DTC still present, DTC will not appear until next ignition cycle.

An intermittent condition is likely to be caused by a short between CKT 347 and CKT 348, 1403, or 1404, or a malfunctioning shorting bar on driver-side inflator module or SIR coil assembly connector which would require replacement of component.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test checks for short from CKT 347 to 1403.
2. 4) This test isolates malfunction to one side of driver-side air bag module Yellow 2-way connector.
3. 5) This test determines whether malfunction is in SIR coil assembly or driver-side air bag module.
4. 9) This test checks for short from CKT 347 to 348.
5. 11) This test checks for short from CKT 347 to 1404.

Scheme 30

Scheme 31

Scheme 32

DTC B1124 - DRIVER-SIDE OR PASSENGER-SIDE DEPLOYMENT LOOP SHORT TO GROUND

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1, 23 VLR, and deployment loop voltages are measured to ensure they are within normal voltage ranges. The SDM monitors the voltages at DRIVER-SIDE FRONTAL LOW terminal No. 9 and PASSENGER-SIDE FRONTAL LOW terminal No. 8 to detect shorts to ground in inflator module circuits (inflatable restraint steering wheel and instrument panel modules).

When driver-side and passenger-side deployment loops are not open, or voltage at DRIVER-SIDE FRONTAL LOW terminal No. 9 or PASSENGER-SIDE FRONTAL LOW terminal No. 8 is less than 2.2 volts for 500 milliseconds during POWER-ON, RESISTANCE MEASUREMENT, and CONTINUOUS MONITORING tests while IGNITION 1 is within normal operating voltage range.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

When voltage measured at DRIVER-SIDE FRONTAL LOW and PASSENGER-SIDE FRONTAL LOW is above 2.2 volts for 500 milliseconds, or ignition switch is turned to OFF position.

An intermittent condition is likely to be caused by a short to ground in the inflator module circuits. Moving wires while monitoring DRIVER SENSELO or PASSENGER SENSELO may help locate malfunction. Inspect CKTs 347, 348, 1403 and 1404 carefully for cutting or chafing. Note and compare value of DRIVER and PASSENGER SENSELO to determine if intermittent condition exists.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test isolates malfunction to one side of driver-side air bag module Yellow 2-way connector.
2. 3) This test determines whether malfunction is in SIR coil assembly or driver-side air bag module.
3. 6) This test determines whether malfunction is in CKT 347.
4. 8) This test determines whether malfunction is in CKT 348.
5. 10) This test isolates malfunction to one side of passenger-side air bag module Yellow 2-way connector.
6. 14) This test determines whether malfunction is in CKT 1403.
7. 16) This test determines whether malfunction is in CKT 1404.

Scheme 33

Scheme 34

Scheme 35

DTC B1125 - DRIVER-SIDE OR PASSENGER-SIDE DEPLOYMENT LOOP SHORT TO VOLTAGE

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1, 23 VLR, and deployment loop voltages are measured to ensure they are within normal voltage ranges. The SDM monitors the voltages at DRIVER-SIDE FRONTAL LOW terminal No. 9 and PASSENGER-SIDE FRONTAL LOW terminal No. 8 to detect shorts to voltage in inflator module circuits (inflatable restraint steering wheel and instrument panel modules).

When voltage at DRIVER-SIDE FRONTAL LOW terminal No. 9 or PASSENGER-SIDE FRONTAL LOW terminal No. 8 is more than 4.0 volts for 500 milliseconds during POWER-ON, RESISTANCE MEASUREMENT, and CONTINUOUS MONITORING tests while IGNITION 1 is within normal operating voltage range.

SDM sets diagnostic trouble codes DTC B1125 and B1171, and commands IPC to turn on AIR BAG warning light.

When voltage measured at DRIVER-SIDE FRONTAL LOW and PASSENGER-SIDE FRONTAL LOW is below 4.0 volts for 500 milliseconds, or ignition switch is turned to OFF position (DTC B1171 will remain current).

An intermittent condition is likely to be caused by a short to voltage in the inflator module circuits. Moving wires while monitoring DRIVER SENSELO or PASSENGER SENSELO may help locate malfunction. Inspect CKTs 347, 348, 1403 and 1404 carefully for cutting or chafing. To ensure replacement SDM will not be damaged, carefully inspect circuits and components indicated. Note and compare value of DRIVER and PASSENGER SENSELO to determine if intermittent condition exists.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test determines voltage at DRIVER-SIDE FRONTAL LOW measured by SDM and if malfunction is in driver-side frontal deployment loop.
2. 3) This test isolates malfunction to one side of driver-side air bag module Yellow 2-way connector.
3. 4) This test determines whether malfunction is in SIR coil assembly or driver-side air bag module.
4. 7) This test determines whether malfunction is in CKT 347.
5. 9) This test determines whether malfunction is in CKT 348.
6. 10) This test isolates malfunction to one side of passenger-side air bag module Yellow 2-way connector.
7. 13) This test determines whether malfunction is in CKT 1403.
8. 15) This test determines whether malfunction is in CKT 1404.

Scheme 36

Scheme 37

Scheme 38

DTC B1126 - DRIVER-SIDE DEPLOYMENT LOOP OPEN

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1 voltage is measured to ensure it is within normal voltage range. SDM then proceeds with DEPLOYMENT LOOP CONTINUITY Test, during which the SDM measures voltage difference between DRIVER-SIDE FRONTAL HIGH and DRIVER-SIDE FRONTAL LOW.

When voltage difference between DRIVER-SIDE FRONTAL HIGH terminal No. 10 and DRIVER-SIDE FRONTAL LOW terminal No. 9 is more or equal to 426 millivolts for 500 milliseconds during DEPLOYMENT LOOP CONTINUITY, RESISTANCE MEASUREMENT, or CONTINUOUS MONITORING tests.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when voltage difference between DRIVER-SIDE FRONTAL HIGH terminal No. 10 and DRIVER-SIDE FRONTAL LOW terminal No. 9 is less than 426 millivolts for 500 milliseconds. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred.

An intermittent condition is likely to be caused by a poor connection at driver-side inflator module or SIR coil assembly harness connector terminal No. A or B, SDM terminal No. 9 or 10, or an open in CKT 347 or 348.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test determines deployment loop voltage difference measured by SDM.
2. 3) This test checks for proper contact and/or corrosion of Yellow 2-way connector.
3. 10) This test isolates malfunction to one side of driver-side air bag module Yellow 2-way connector.
4. 11) This test determines whether malfunction is in SIR coil assembly or driver-side air bag module.
5. 14) This test checks for proper contact and/or corrosion of SDM connector.
6. 16) This test checks for proper contact and/or corrosion of SDM connector.
7. 19) This test determines whether malfunction is in CKT 347.
8. 21) This test determines whether malfunction is in CKT 348.

Scheme 39

Scheme 40

Scheme 41

DTC B1135 - DISCRIMINATING SENSOR CLOSED OR SHORT TO GROUND

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1, 23 VLR, and deployment loop voltages are measured to ensure they are within normal voltage ranges. The SDM then proceeds with CONTINUOUS MONITORING. The SDM contains a resistor network connected to 5 volts, ground, and to SDM SENSOR FEED terminal No. 4. The 1.0 Kohm resistor in the front end discriminating sensor parallel to normally open switch provides a parallel path to ground. This causes a specified percentage of voltage at SDM sensor feed input. SDM monitors this voltage to detect shorts to ground or a closed front end discriminating sensor.

When SDM is configured for front end discriminating sensor, or voltage at SENSOR FEED terminal No. 4 is less than 0.7 volts for 500 milliseconds during CONTINUOUS MONITORING while IGNITION 1 is within normal operating voltage range.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when voltage at SENSOR FEED terminal No. 4 is more than 0.7 volts for 500 milliseconds. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred.

An intermittent condition is may be caused by a short to ground in front end discriminating sensor. Inspect CKT 349 carefully for cutting or chafing.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test checks for a malfunctioning front end discriminating sensor.
2. 4) This test checks for short to ground in CKT 349.

Scheme 42

DTC B1136 - DISCRIMINATING SENSOR OPEN OR SHORT TO VOLTAGE

When ignition switch is turned RUN position, SDM (inflatable restraint Sensing and Diagnostic Module) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, IGNITION 1, 23 VLR, and deployment loop voltages are measured to ensure they are within normal voltage ranges. The SDM then proceeds with CONTINUOUS MONITORING. The SDM contains a resistor network connected to 5 volts, ground, and to SDM SENSOR FEED terminal No. 4. The 1.0 Kohm resistor in the front end discriminating sensor parallel to normally open switch provides a parallel path to ground. This causes a specified percentage of voltage at SDM sensor feed input. SDM monitors this voltage to detect shorts to power or an open front end discriminating sensor.

When SDM is configured for front end discriminating sensor, or voltage at SENSOR FEED terminal No. 4 is more than 3.4 volts for 500 milliseconds during CONTINUOUS MONITORING while IGNITION 1 is within normal operating voltage range.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when voltage at SENSOR FEED terminal No. 4 is less than 3.4 volts for 500 milliseconds. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred.

An intermittent condition is may be caused by a broken wire or poor connection in front end discriminating sensor circuit. Inspect CKT 349 and 1751E carefully for cutting or chafing.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) This test checks for proper contact and/or corrosion of Yellow 2-way connector.
2. 7) This test checks for a malfunctioning front end discriminating sensor.
3. 8) This test checks for an open in CKT 1751E.
4. 10) This test checks for proper contact and/or corrosion of SDM connector.
5. 15) This test checks for an open in CKT 349.
6. 17) This test checks for short to voltage in CKT 349.

Scheme 43

Scheme 44

Scheme 45

DTC B1147 - DRIVER-SIDE AIR BAG SYSTEM MALFUNCTION

When ignition switch is turned RUN position, SISM (inflatable restraint Side Impact Sensing Module) will perform tests to diagnose critical malfunctions within itself. The SISM then tests deployment loop for an open, a short to ground or ignition, a resistance high or low, or a reserve energy failure condition. SISM transmits a 300 millisecond, 50 percent duty cycle, pulse width modulated signal to SDM (inflatable restraint Sensing and Diagnostic Module) over CKT 985, to indicate normal operation and no malfunctions exist. SISM communicates that it is turning off (ignition OFF) by sending a 20 millisecond, 50 percent duty cycle, pulse width modulated signal.

When SDM receives a pulse width signal other than specified for normal operation, or no signal. SISM performs tests during POWER-ON, CONTINUOUS MONITORING, and ASYNCHRONOUSLY.

SDM sets DTC B1147 and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when SDM receives normal operation signal from SISM, or when ignition is cycled. If side impact deployment occurs SISM must be replaced. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred.

An intermittent condition may be caused by a poor connection in SDM, side impact air bag module, SDM terminal No. 13, or wire to terminal connections of all circuits going to SDM.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) If driver-side side impact air bag module has deployed, DTC B1147 will set.
2. 3) Components require inspection and possibly replacement after a side impact accident, whether deployment occurred or not.
3. 5) This test determines if malfunction is in side impact air bag module.
4. 11) This test checks for an open in CKT 1751.
5. 13) This test checks for an open in CKT 1139.
6. 15) This test checks for a short to ground in CKT 978.
7. 17) This test checks for high resistance or open in CKT 978.
8. 19) This test checks for a short to voltage in CKT 978.
9. 21) This test checks for a short to voltage in CKT 979.
10. 23) This test checks for a short to ground in CKT 979.
11. 25) This test checks for high resistance or open in CKT 979.
12. 27) This test checks for a short to ground in CKT 985.
13. 29) This test checks for a short to voltage in CKT 985.
14. 35) This test checks for high resistance or open in CKT 985.
15. 37) If all wiring and connections are OK, replace SISM.

Scheme 46

Scheme 47

Scheme 48

Scheme 49

DTC B1148 - PASSENGER-SIDE AIR BAG SYSTEM MALFUNCTION

When ignition switch is turned RUN position, SISM (inflatable restraint Side Impact Sensing Module) will perform tests to diagnose critical malfunctions within itself. The SISM then tests deployment loop for an open, a short to ground or ignition, a resistance high or low, or a reserve energy failure condition. SISM transmits a 300 millisecond, 50 percent duty cycle, pulse width modulated signal to SDM (inflatable restraint Sensing and Diagnostic Module) over CKT 974, to indicate normal operation and no malfunctions exist. SISM communicates that it is turning off (ignition OFF) by sending a 20 millisecond, 50 percent duty cycle, pulse width modulated signal.

When SDM receives a pulse width signal other than specified for normal operation, or no signal. SISM performs tests during POWER-ON, CONTINUOUS MONITORING, and ASYNCHRONOUSLY.

SDM sets DTC B1148 and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when SDM receives normal operation signal from SISM, or when ignition is cycled. If side impact deployment occurs SISM must be replaced. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred.

An intermittent condition may be caused by a poor connection in SDM, side impact air bag module, SDM terminal No. 14, or wire to terminal connections of all circuits going to SDM.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) If passenger-side side impact air bag module has deployed, DTC B1148 will set.
2. 3) Components require inspection and possibly replacement after a side impact accident, whether deployment occurred or not.
3. 5) This test determines if malfunction is in side impact air bag module.
4. 11) This test checks for an open in CKT 1751.
5. 13) This test checks for an open in CKT 1139.
6. 15) This test checks for a short to ground in CKT 976.
7. 17) This test checks for high resistance or open in CKT 976.
8. 19) This test checks for a short to voltage in CKT 976.
9. 21) This test checks for a short to voltage in CKT 977.
10. 23) This test checks for a short to ground in CKT 977.
11. 25) This test checks for high resistance or open in CKT 977.
12. 27) This test checks for a short to ground in CKT 974.
13. 29) This test checks for a short to voltage in CKT 974.
14. 35) This test checks for high resistance or open in CKT 974.
15. 37) If all wiring and connections are OK, replace SISM.

Scheme 50

Scheme 51

Scheme 52

Scheme 53

DTC B1151 - DEPLOYMENT COMMANDED

SDM (inflatable restraint Sensing and Diagnostic Module) contains a sensing device which converts vehicle velocity changes to an electrical signal. The electrical signal is processed by the SDM and compared to a value stored in memory. When signal exceeds stored value, additional signal processing is performed and signals are compared to signals stored in memory. When 2 of the signals exceed stored values, SDM will cause sufficient current to flow through inflator modules deploying air bags and causing DTC B1151 to set. A side impact air bag deployment will not set DTC B1151.

When SDM detects a frontal crash, up to 30 degrees off centerline of vehicle, of sufficient force to warrant deployment of air bags.

SDM commands IPC to turn on AIR BAG warning light, records CRASH DATA, sets diagnostic trouble code (DTC), and sends message over Serial Data Line Class 2.

When scan tool CLEAR CODES command is received by SDM.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 3) If frontal air bag modules have not deployed, DTC B1151 may have set falsely.
2. 4) If DTC B1151 has set with no signs of frontal impact, the diagnostic trouble codes has set falsely.
3. 5) This test checks for SDM malfunction setting DTC.
4. 7) DTC B1151 may have set falsely while diagnosing vehicle.

Scheme 54

DTC B1152 - DATA AREA FULL

SDM (inflatable restraint Sensing and Diagnostic Module) contains a sensing device which converts vehicle velocity changes to an electrical signal. When SDM detects a frontal crash, up to 30 degrees off centerline of vehicle, of sufficient force to warrant deployment of air bags, DTC B1151 will set. SDM will record SIR system and vehicle status in EEPROM. DTC B1152 will set when SDM has stored information for two frontal crash events.

When SDM attempts to store frontal crash information and finds EEPROM data area full. This test is run each time SDM stores or attempts to store information for frontal crash event and also during POWER-ON tests.

SDM commands IPC to turn on AIR BAG warning light and sets a diagnostic trouble code.

When scan tool CLEAR CODES command is received by SDM. If, at next ignition RUN after receiving CLEAR CODES command, SDM detects data area full, history diagnostic trouble code is set. This allows AIR BAG warning light to illuminate should any additional malfunctions be detected.

Scheme 55

DTC B1153 - DEPLOYMENT COMMANDED WITH LOOP MALFUNCTIONS PRESENT

SDM contains a sensing device which converts vehicle velocity changes to an electrical signal. The electrical signal is processed by the SDM and compared to a value stored in memory. When signal exceeds stored value, additional signal processing is performed and signals are compared to signals stored in memory. When 2 of the signals exceed stored values, SDM will cause sufficient current to flow through inflator modules deploying air bags and causing DTC to set. DTC B1153 will set with DTC B1151 when deployment occurs while frontal inflator circuit malfunction is present that could possibly result in non-deployment situation in one or both frontal air bag modules (inflatable restraint steering wheel and instrument panel modules). A side impact air bag deployment will not set DTC 1151/53.

When SDM detects a frontal crash, up to 30 degrees off centerline of vehicle, of sufficient force to warrant deployment of air bags and an inflator malfunction is present.

SDM commands IPC to turn on AIR BAG warning light, records CRASH DATA, sets diagnostic trouble code (DTC), and sends message over Serial Data Line Class 2.

When scan tool CLEAR CODES command is received by SDM.

DTC B1153 will set with other DTC(s) (other than DTC B1151). Repair malfunction causing other DTC(s) (other than DTC B1171) before replacing SDM.

Note. Test numbers refer to test numbers on diagnostic table. For circuit number identification, see WIRING DIAGRAMS .

1. 2) If frontal inflator modules have not deployed, DTC B1151/53 may have set falsely.
2. 3) If DTC B1151/53 has set with no signs of frontal impact, diagnostic trouble code has set falsely.
3. 4) This test checks for an SDM malfunction setting the DTC.

Scheme 56

DTC B1155/59/60 - SDM CALIBRATION MIS-MATCH

While ignition is turned to RUN position, the Instrument Control Panel (IPC) sends two messages over the Serial Data Line Class 2 containing identification information. The first message contains serial data keying information and the second message contains a partial Vehicle Identification Number (VIN). SDM receives these messages and compares them to information stored in memory. These messages are set once per ignition cycle at POWER-ON.

If either or both of messages from IPC does not match information stored in SDM memory, DTC B1155 will set along with DTC B1159 and/or DTC B1160 depending on message that does not match. If SDM does not receive serial data keying message from IPC, DTC B1159 will set without DTC B1155. If SDM does not receive a partial VIN message from IPC, DTC B1160 will set without DTC B1155. The POWER-ON test checks for these DTCs. IPC sends messages only at IPC POWER-ON.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC B1155 will clear when ignition is turned to OFF position. Current DTC B1159 and B1160 will clear when SDM receives correct message over Serial Data Line Class 2. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred.

DTC B1155 sets only when incorrect message is sent by IPC. State of Health (SOH) DTCs may set in addition to DTC B1155/59/60. SOH DTCs will clear when malfunction causing DTC B1155/59/60 to set is repaired. Refer to Diagnostic Aids to specific SOH DTC.

Scheme 57

Scheme 58

DTC B1163/U1096 - AIR BAG WARNING LIGHT CIRCUIT FAILURE

When the ignition key is first turned RUN position, the IPC (Instrument Panel Cluster) flashes AIR BAG warning light 7 times. SDM then commands IPC to turn off warning light, if no SIR DTCs are present, by sending message over Serial Data Line Class 2. IPC returns message to SDM that AIR BAG warning light is off.

If SDM does not receive response from IPC after sending AIR BAG warning light message 6 times, SDM will set DTC B1163. If IPC responds that the warning light is off when SDM is commanding warning light on, SDM will set DTC B1163. A loss of State of Health DTC U1096 is also set. This test is run asynchronously during CONTINUOUS MONITORING.

SDM sets a diagnostic trouble code.

Current DTC will clear when ignition switch is turned to OFF position or SDM receives IPC message response over Serial Data Line Class 2. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred.

History DTC B1163 will set if IPC lost B+ or ground with ignition switch in RUN, or an intermittent short to B+ or ground or open in CKT 1807 Serial Data Line Class 2. DTCs B1159, B1160, B1163, and U1096 will all be set history if Serial Data Line Class 2 failure occurred and is now repaired. The State of Health (SOH) DTC U1096 and SIR DTCs B1159 and B1160 will set with DTC B1163, indicating that communication is lost between IPC and SDM. Check that the IPC is functioning properly.

Scheme 59

DTC B1171 - INTERNAL SDM FAULT

DTC B1171 indicates potential internal SDM malfunction and will set if any of the following conditions are detected

1. Frontal 23 VLR Voltage out of normal operating range.
2. Crash data recording reserve voltage discharge time failure for 3 consecutive ignition cycles.
3. Calculated checksum for internal memory does not match stored value.
4. Voltage measured at DRIVER-SIDE FRONTAL LOW and PASSENGER-SIDE FRONTAL LOW are too high.
5. Sensing device inside SDM which converts vehicle velocity changes to electrical signal is malfunctioning.
6. Driver current source and/or passenger current source is malfunctioning.
7. Temporary memory storage area is malfunctioning.
8. SDM unable to read from or write to EEPROM.
9. Arming sensor inside SDM is not closed during deployment event.
10. Permanent memory storage area is malfunctioning.
11. Passenger-side frontal FET driver is malfunctioning.
12. Driver-side frontal FET driver is malfunctioning.
13. DTC B1125 is set current or history.

When any of the indicated malfunctions are detected by the SDM. The malfunctions are tested at different times

1. POWER-OFF.
2. POWER-OFF.
3. POWER-ON.
4. CONTINUOUS MONITORING.
5. POWER-ON and CONTINUOUS MONITORING.
6. POWER-ON.
7. POWER-ON.
8. POWER-OFF.
9. Asynchronously.
10. POWER-ON.
11. POWER-ON.
12. POWER-ON.
13. CONTINUOUS MONITORING.

SDM sets diagnostic trouble code (DTC) and commands IPC to turn on AIR BAG warning light.

Current DTC will clear when malfunction has not been detected for 500 milliseconds. History DTC will clear when a scan tool CLEAR CODES command is issued or 250 malfunction free ignition cycles have occurred. When a scan tool CLEAR CODES command is issued, some of indicated malfunctions will only allow AIR BAG warning light to go out briefly then come back on.

DTC B1171 indicates malfunction within SDM. Replace SDM if DTC B1171 sets current or history.

Scheme 60

DTC U1088 - LOSS OF SERIAL COMMUNICATION (SDM)

While the ignition switch is in RUN position, all modules communicating on class 2 serial data line send a State of Health (SOH) message every 5 seconds to ensure that the system is operating properly.

When Instrument Panel Cluster (IPC) does not receive a State of Health (SOH) message from the SDM after three consecutive monitoring cycles.

The AIR BAG warning light comes on and a SERVICE AIR BAG message is displayed on driver-side message center.

The SDM transmits a State of Health (SOH) message to the IPC.

If there are multiple class 2 DTCs check for an intermittent short to power or ground in circuit 1807 (Purple wire). If DTC is current attempt to establish communications with SDM using scan tool. If communication cannot be established, refer to SIR. If communication can be established, replace the IPC. If DTC is history, check for intermittent open in circuit 1807 (Purple wire).

DTC U1255 - SERIAL DATA LINE CLASS 2 INITIALIZATION ERROR

While the ignition switch is in RUN position, the SDM sends messages to other modules communicating on Serial Data Line Class 2.

When the SDM requests information from another module and does not receive a response after 6 tries.

SDM sets DTC and AIR BAG warning light does not come on.

For current DTC: ignition switch turned to OFF position, or SDM receives message response over Serial Data Line Class 2. For history DTC: a scan tool CLEAR CODES command is issued, or 250 malfunction free ignition cycles have occurred.

If DTC U1255 is set, clear DTCs and cycle the ignition. If DTC U1255 is still current, ensure all of the modules are functioning properly and the Serial Data Line Class 2 is not shorted to ground or voltage. It is highly unlikely that the SDM will set a State of Health (SOH) message if SDM is malfunctioning. Other SOH codes may set in addition to DTC U1255.

DTC U1300 - SERIAL DATA LINE CLASS 2 SHORTED TO GROUND

While the ignition switch is in RUN position, the SDM sends messages to other modules communicating on Serial Data Line Class 2. The SDM monitors the Serial Data Line Class 2 (CKT 1807) on terminals No. 5 and 17 for shorts to voltage and shorts to ground.

When SDM detects short to ground at terminals No. 5 and 17.

SDM sets DTC and AIR BAG warning light does not come on. Other SIR DTCs will set that turn AIR BAG warning light on when a malfunction occurs on Serial Data Line Class 2.

For current DTC: ignition switch turned to OFF position, or SDM does not detect a short to ground at terminals No. 5 and 17. For history DTC: a scan tool CLEAR CODES command is issued, or 250 malfunction free ignition cycles have occurred.

If DTC U1300 is set, isolate CKT 1807 and determine where a short to ground is occurring. Disconnecting modules on Serial Data Line Class 2 and check each individual circuit is the fastest way to find the short. It is highly unlikely that the SDM will set a State of Health (SOH) message if SDM is malfunctioning. Other SOH codes may set in addition to DTC U1300. These DTCs should clear once the short to ground condition is repaired.

DTC U1301 - SERIAL DATA LINE CLASS 2 SHORTED TO VOLTAGE

While the ignition switch is in RUN position, the SDM sends messages to other modules communicating on Serial Data Line Class 2. The SDM monitors the Serial Data Line Class 2 (CKT 1807) on terminals No. 5 and 17 for shorts to voltage and shorts to ground.

When SDM detects short to ground at terminals No. 5 and 17.

SDM sets DTC and AIR BAG warning light does not come on. Other SIR DTCs will set that turn AIR BAG warning light on when a malfunction occurs on Serial Data Line Class 2.

For current DTC: ignition switch turned to OFF position, or SDM does not detect a short to ground at terminals No. 5 and 17. For history DTC: a scan tool CLEAR CODES command is issued, or 250 malfunction free ignition cycles have occurred.

If DTC U1301 is set, isolate CKT 1807 and determine where a short to voltage is occurring. Disconnecting modules on Serial Data Line Class 2 and check each individual circuit is the fastest way to find the short. It is highly unlikely that the SDM will set a State of Health (SOH) message if SDM is malfunctioning. Other SOH codes may set in addition to DTC U1301. These DTCs should clear once the short to voltage condition is repaired.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

SIR System Wiring Diagram (DeVille & Concours). Scheme 61

SIR System Wiring Diagram (Eldorado, & Seville). Scheme 62

See also:
• COMPUTER RELEARN PROCEDURES
• PASSIVE RESTRAINT SYSTEM INSPECTION
• DISABLING SYSTEM
• SYSTEM OPERATION CHECK
• DISPOSAL PROCEDURES
• SPECIAL TOOLS
• SIR COIL ASSEMBLY
• SERVICE PRECAUTIONS
• TORQUE SPECIFICATIONS
• CENTERING COIL ASSEMBLY
• AIR BAG MODULE
• SIR DIAGNOSTIC SYSTEM CHECK