Supplemental Inflatable Restraint System Chevrolet Chevy Express G2500

Fastener Tightening Specifications

Fastener Tightening Specifications

SIR Schematic Icons

SIR Schematic Icons Icon Icon Definition CAUTION: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR Disabling and Enabling Zones. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury, or unnecessary SIR system repairs. IMPORTANT: In order to prevent accidental deployment, the shorting bars close in order to short the connectors when the connectors are separated. Twisted-pair wires provide an effective shield that helps protect sensitive electronic components from electrical interference. If the wires were covered with shielding, install new shielding. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted-pair wires shown : The wires must be twisted a minimum of 9 turns per 31 cm (12 in) as measured anywhere along the length of the wires The outside diameter of the twisted wires must not exceed 6.0 mm (0.25 in)

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SIR Zone Identification Views

The SIR Zone Identification Views shown below illustrate the approximate location of all SIR components available for the vehicle. This will assist in determining the appropriate SIR Disabling and Enabling Zones for a given service procedure, refer to SIR Disabling and Enabling Zones .

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SIR Connector End Views

Inflatable Restraint Front End Sensor (Heavy Duty) Connector Part Information 15356721 2-Way F GT 150 Series Sealed 4.0 (YE) Pin Wire Color Circuit No. Function 1 YE 354 Front End Sensor - Signal 2 TN/OG 5045 Front End Sensor - Low Reference

Inflatable Restraint Front End Sensor (Light Duty) Connector Part Information 15356720 2-Way F GT 150 Series Sealed 4.0 (YE) Pin Wire Color Circuit No. Function 1 YE 354 Front End Sensor - Signal 2 TN/OG 5045 Front End Sensor - Low Reference

Inflatable Restraint I/P Module (Heavy Duty) Connector Part Information 12186989 2-Way M Metri-Pack 280 - Pull To Seat (YE) Pin Wire Color Circuit No. Function A YE 3025 I/P Module - Stage 1 - High Control B OG 3024 I/P Module - Stage 1 - Low Control

Inflatable Restraint I/P Module (Light Duty) Connector Part Information 15336476 4-Way M Metri-Pack 280 Series (YE) Pin Wire Color Circuit No. Function A1 YE 3025 I/P Module - Stage 1 - High Control A2 OG 3024 I/P Module - Stage 1 - Low Control B1 GY 3027 I/P Module - Stage 2 - High Control B2 PU 3026 I/P Module - Stage 2 - Low Control

Inflatable Restraint I/P Module Disable Switch (Heavy Duty) Connector Part Information 15305286 6-Way F Metri-Pack 150 Series (YE) Pin Wire Color Circuit No. Function A TN/BK 371 I/P Module Disable Switch - Signal B PK 1139 Ignition 1 Voltage C BN 2309 Front Park Lamps Supply Voltage D BN/WH 230 Instrument Panel Lamps Dimming Control E PK 353 I/P Module Suppression Indicator Control F BK/WH 1751 Ground

Inflatable Restraint Seat Position Sensor (SPS) - Left (Light Duty) Connector Part Information 12052832 2-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A L-GN 5055 Seat Position Sensor - Left - Signal B PK 5017 Low Reference

Inflatable Restraint Seat Position Sensor (SPS) - Right (Light Duty) Connector Part Information 12052832 2-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A L-BU 5056 Seat Position Sensor - Right - Signal B PK 5017 Low Reference

Inflatable Restraint Sensing and Diagnostic Module (SDM) Connector Part Information 15356922 (Early Production) 15449363 (Late Production) 42-Way F Micro-Pack 100W (YE) Pin Wire Color Circuit No. Function 1 PK 1139 Ignition 1 Voltage 2 TN/BK 371 I/P Module Disable Switch - Signal (Heavy Duty) 3 TN/WH 238 Seat Belt Switch - Left 4 PK 353 I/P Module Suppression Indicator Control (Heavy Duty) 5 YE 354 Front End Sensor - Signal 6-8 - - Not Used 9 YE 3025 I/P Module - Stage 1 - High Control 10 OG 3024 I/P Module - Stage 1 - Low Control 11 PK 5017 Low Reference (Light Duty) 12 BN 3020 Steering Wheel Module - Stage 1 - Low Control 13 TN 3021 Steering Wheel Module - Stage 1 - High Control 14-22 - - Not Used 23 D-BU 1128 Class 2 Serial Data 24 L-GN 5055 Seat Position Sensor - Left - Signal (Light Duty) 25 L-BU 5056 Seat Position Sensor - Right - Signal (Light Duty) 26 TN/OG 5045 Front End Sensor - Low Reference 27-29 - - Not Used 30 GY 3027 I/P Module - Stage 2 - High Control (Light Duty) 31 PU 3026 I/P Module - Stage 2 - Low Control (Light Duty) 32 BK/WH 1751 Ground 33 PK 3022 Steering Wheel Module - Stage 2 - Low Control (Light Duty) 34 WH 3023 Steering Wheel Module - Stage 2 - High Control (Light Duty) 35 L-GN 2116 Seat Belt Pretensioner - Right - High Control (Light Duty) 36 OG 2117 Seat Belt Pretensioner - Right - Low Control (Light Duty) 37 OG/BK 2119 Seat Belt Pretensioner - Left - Low Control (Light Duty) 38 TN/WH 2118 Seat Belt Pretensioner - Left - High Control (Light Duty) 39-42 - - Not Used

Inflatable Restraint Steering Wheel Module Coil C1 (Heavy Duty) Connector Part Information 12110288 2-Way M Metri-Pack 280 Series (YE) Pin Wire Color Circuit No. Function A TN 3021 Steering Wheel Module - Stage 1 - High Control B BN 3020 Steering Wheel Module - Stage 1 - Low Control

Inflatable Restraint Steering Wheel Module Coil C2 (Heavy Duty) Connector Part Information 54560210 2-Way F ABX-3 Code C (YE) Pin Wire Color Circuit No. Function A WH 3021 Steering Wheel Module - Stage 1 - High Control B D-GN 3020 Steering Wheel Module - Stage 1 - Low Control

Inflatable Restraint Steering Wheel Module Coil C1 (Light Duty) Connector Part Information 15336476 4-Way M Metri-Pack 280 Series (YE) Pin Wire Color Circuit No. Function A1 TN 3021 Steering Wheel Module - Stage 1 - High Control A2 BN 3020 Steering Wheel Module - Stage 1 - Low Control B1 WH 3023 Steering Wheel Module - Stage 2 - High Control B2 PK 3022 Steering Wheel Module - Stage 2 - Low Control

Inflatable Restraint Steering Wheel Module Coil C2 (Light Duty) Connector Part Information 54560208 2-Way F ABX-3 Code B (WH) Pin Wire Color Circuit No. Function A TN 3021 Steering Wheel Module - Stage 1 - High Control B BN 3020 Steering Wheel Module - Stage 1 - Low Control

Inflatable Restraint Steering Wheel Module Coil C3 (Light Duty) Connector Part Information 54550271 2-Way F ABX-3 Code G (PK) Pin Wire Color Circuit No. Function A WH 3023 Steering Wheel Module - Stage 2 - High Control B PK 3022 Steering Wheel Module - Stage 2 - Low Control

Diagnostic Starting Point - SIR

Begin the system diagnosis with the Diagnostic System Check - SIR . The Diagnostic System Check - SIR will provide the following information

1. The identification of the control modules which commands the system
2. The ability of the control modules to communicate through the serial data circuit
3. The identification of any stored diagnostic trouble codes (DTCs) and their status

The use of the Diagnostic System Check - SIR will identify the correct procedure for diagnosing the system and where the procedure is located.

Diagnostic System Check - SIR

These diagnostic procedures will help you find and repair SIR system malfunctions. For best results, use the diagnostic tables and follow the sequence listed below

1. Refer to the diagnostic tables as directed by the Diagnostic System Check - SIR. The diagnostic tables will assist you in diagnosing SIR system malfunctions. Bypassing these procedures may result in the following: Extended diagnostic time Incorrect diagnosis Incorrect parts replacement
2. Repeat the Diagnostic System Check - SIR after you perform any repairs or diagnostic procedures. This will verify that you correctly performed the repair. This will also verify that no other SIR system malfunctions exist.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 1: This step checks to see if the AIR BAG indicator flashes seven times when the ignition switch is first turned ON.
2. 2: This step checks to see if the scan tool powers up.
3. 3: This step checks to see if the scan tool can communicate with the SDM.
4. 4: This step checks to see if there are any current or history DTCs present.
5. 5: This step checks to see if there are communication DTCs, U-codes, present.
6. 6: This step checks to see if DTC B1000 is present.

Diagnostic System Check - SIR

Scan Tool Data List

The SIR Scan Tool Data List contains all restraint system related parameters that are available on the scan tool. The parameters in the list are arranged in alphabetical order. The column "Data List," indicates the location of the parameter within the scan tool menu selections.

Use the SIR Scan Tool Data List as directed by a diagnostic table or to supplement the diagnostic procedures. Begin all of the diagnostic procedures with the Diagnostic System Check - SIR. Refer to the Diagnostic System Check - SIR . Use the SIR Scan Tool Data List after determining the following

1. There are no published DTC procedures nor published symptom procedures for the customer concern.
2. The DTC or symptom diagnostic procedure indicated by the Diagnostic System Check - SIR does not resolve the customer concern.

The Typical Data Values are obtained from a properly operating vehicle under the conditions specified in the first row of the Scan Tool Data List table. Comparison of the parameter values from the suspect vehicle with the Typical Data Values may reveal the source of the customer concern.

Scan Tool Data List

Scan Tool Data Definitions

The SIR scan tool data definitions contain a brief description of all SIR related parameters available on the scan tool. The parameters that are available on the scan tool are listed below in alphabetical order.

Diagnostic Trouble Code (DTC) List

Diagnostic Trouble Code (DTC) List

Circuit Description

The following diagnostics are designed to diagnose circuit failures for both single stage and dual stage air bag systems. The light duty G/H models are equipped with dual stage air bags and the heavy duty G/H models are equipped with single stage air bags. The inflatable restraint I/P module deployment loop consists of an I/P module, I/P module high control, and I/P module low control circuits. There are shorting bars used within the I/P module connector which will short together the I/P module high and I/P module low control circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a diagnostic trouble code (DTC) will be stored in memory.

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC

1. DTC B0012-stage 2 or B0016-stage 1 will set when the SDM detects the I/P module deployment loop resistance is less than 1.3 ohms for 500 milliseconds.
2. DTC B0013-stage 2 or B0017-stage 1 will set when one of the following conditions occurs: The SDM detects the I/P module deployment loop resistance is greater than 4.8 ohms for 500 milliseconds. The SDM detects the voltage at I/P module high control is less than 2.4 volts and I/P module deployment loop resistance is 6 ohms or greater for 500 milliseconds.
3. DTC B0014-stage 2 or B0018-stage 1 will set when one of the following conditions occurs: The SDM detects the voltage at I/P module high control is shorted to ground or voltage for 500 milliseconds. The SDM detects the voltage at I/P module high control is less than 2.4 volts and I/P module deployment loop resistance is less than 6 ohms for 500 milliseconds.

Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON via Class 2 serial data.

Conditions for Clearing the DTC

1. The condition responsible for setting the DTC no longer exists.
2. You issue a scan tool CLEAR DTCs command.
3. A history DTC will clear once 255 malfunction free ignition cycles have occurred.

Diagnostic Aids

The following can cause an intermittent condition

1. A short between the I/P module high and low control circuits
2. An open or a high resistance in the I/P module high or low control circuits
3. A malfunctioning shorting bar on the I/P module connector

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: Inspects the I/P module in-line connector.
2. 4: Tests for a malfunctioning I/P module.
3. 6: Tests for current DTCs. If DTC B0012 or B0016 is present, test for a short between the I/P module high and I/P module low control circuits for stage 1 or stage 2. If DTC B0013 or B0017 is present, test for an open or high resistance in the I/P module high and I/P module low control circuits for stage 1 or stage 2. If DTC B0014 or B0018 is present, test for a short to ground or voltage in the I/P module high and I/P module low control circuits for stage 1 or stage 2.

DTC B0012, B0013, B0014, B0016, B0017, or B0018

The following diagnostics are designed to diagnose circuit failures for both single stage and dual stage air bag systems. The light duty G/H models are equipped with dual stage air bags and the heavy duty G/H models are equipped with single stage air bags. The inflatable restraint steering wheel module deployment loop consists of a steering wheel module, steering wheel module coil, steering wheel module high control, and steering wheel module low control circuits. There are shorting bars used within the steering wheel module coil connector which will short together the steering wheel module high and steering wheel module low control circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a diagnostic trouble code (DTC) will be stored in memory.

Ignition 1 voltage is within the normal operating voltage range.

1. DTC B0022-stage 1 or B0042-stage 2 will set when the steering wheel module deployment loop resistance is less than 1.3 ohms for 500 milliseconds.
2. DTC B0024-stage 1 or B0043-stage 2 will set when one of the following conditions occur: The SDM detects the voltage at steering wheel module high control is shorted to ground or voltage for 500 milliseconds. The SDM detects the voltage at steering wheel module high control is less than 2.4 volts and steering wheel module deployment loop resistance is less than 6 ohms for 500 milliseconds.
3. DTC B0026-stage 1 or B0044-stage 2 will set when one of the following conditions occurs: The SDM detects the steering wheel module deployment loop resistance is greater than 4.8 ohms for 500 milliseconds. The SDM detects the voltage at steering wheel module high control is less than 2.4 volts and steering wheel module deployment loop resistance is 6 ohms or greater for 500 milliseconds.

The SDM commands the AIR BAG indicator ON via Class 2 serial data.

1. The condition responsible for setting the DTC no longer exists.
2. You issue a scan tool CLEAR DTCs command.
3. A history DTC will clear once 255 malfunction free ignition cycles have occurred.

The following can cause an intermittent condition

1. A short between the steering wheel module high and low control circuits
2. An open or a high resistance in the steering wheel module high or low control circuits
3. A malfunctioning shorting bar on the steering wheel module coil connector

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: Inspects the steering wheel module coil in-line connector.
2. 5: Tests for a malfunctioning steering wheel module or steering wheel module coil.
3. 7: Tests for current DTCs. If DTC B0022 or B0042 is present, test for a short between the steering wheel module high and steering wheel module low control circuits for stage 1 or stage 2. If DTC B0024 or B0043 is present, test for a short to ground or voltage in the steering wheel module high and steering wheel module low control circuits for stage 1 or stage 2. If DTC B0026 or B0044 is present, test for an open or high resistance in the steering wheel module high and steering wheel module low control circuits for stage 1 or stage 2.

DTC B0022, B0024, B0026, B0042, B0043, or B0044

The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device that converts changes in vehicle velocity to an electrical signal. The SDM compares this signal to a value stored in memory. When the generated signal exceeds the stored value, the SDM performs additional signal processing and compares the generated signals to values stored in memory. When two of the generated signals exceed the stored values, the SDM will cause current to flow through the inflator modules, deploying the air bags and causing DTC B0051 to set.

This DTC is set when the SDM has commanded an air bag deployment with no faults present.

The SDM must be powered up.

Ignition 1 voltage must be present and the SDM must have commanded an air bag deployment.

1. The SDM commands the AIR BAG indicator ON via Class 2 serial data.
2. The SDM records crash data.

DTC B0051 is a latched code. You cannot clear a latched code. Replace the SDM after following the instructions in the following diagnostic table.

DTC B0051

The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device that converts changes in vehicle velocity to an electrical signal. The SDM compares this signal to a value stored in memory. When the generated signal exceeds the stored value, the SDM performs additional signal processing and compares the generated signals to values stored in memory. When two of the generated signals exceed the stored values, the SDM will cause current to flow through the inflator modules, deploying the air bags. DTC B0053 will set instead of DTC B0051 when a deployment occurs while an inflator circuit fault is present that may result in a non-deployment situation in one or more of the inflator modules.

The SDM must be powered up.

Ignition 1 voltage must be present and the SDM must have commanded an air bag deployment with inflator circuit faults.

1. The SDM commands the AIR BAG indicator ON via Class 2 serial data.
2. The SDM records crash data.

DTC B0053 is a latched code. You cannot clear a latched code. Replace the SDM after following the instructions in the following diagnostic table.

When DTC B0053 is accompanied by additional DTCs, other than B0051, repair the malfunction causing the other DTCs before replacing the SDM.

DTC B0053

The inflatable restraint seat position sensor (SPS) is used to determine the proximity of a front driver or passenger seat position with respect to the frontal air bag. The SPS interfaces with the SDM. The state of the SPS allows the SDM to disable stage 2 of the frontal air bag for a front seat that is forward of a forward/rearward point in seat track travel. The SPS is a Hall effect sensor that is mounted on the seat track of both the driver and passenger seats. The seat track includes a metal bracket that shunts the SPS magnetic circuit creating two states of seat position. The shunted state represents a rearward seat position. The non-shunted state represents a forward position. The SPS provides two current ranges, one range for the shunted state and a second range for a non-shunted state. These two states are inputs to the sensing and diagnostic module (SDM). State 1 (shunted) being the rearward threshold and state 2 (non-shunted) being the forward threshold. When the SDM receives input from a SPS that state 1 threshold is reached (seat is rearward) the SDM will not disable stage 2 deployment, if required by the deployment sensors. When state 2 threshold is reached (seat is forward) the SDM will disable stage 2 deployment on the side the seat is forward. The SDM monitors the SPS circuit and if a fault is detected the SDM will set codes B0083 or B0084 and defaults to disabling stage 2 frontal deployment. This will only default on the side of the vehicle the sensor has a fault. It's important to understand that the SPS is secondary to the passenger presence system (PPS) and the manual I/P module disable switch. If either one of these devices are in the disable mode the passenger air bag will not deploy regardless of the SPS status.

Ignition 1 voltage is within the normal operating voltage range.

DTC B0083 and B0084 will set when one of the following conditions occur

1. The SDM detects the SPS circuit amperage is 4 mA or less for 500 milliseconds.
2. The SDM detects the SPS circuit amperage is between 8 mA and 11 mA for 500 milliseconds.
3. The SDM detects the SPS circuit amperage is 18 mA or greater for 500 milliseconds.

1. The SDM commands the AIR BAG indicator ON via Class 2 serial data.
2. The SDM defaults the SPS to seat forward threshold.

1. The condition responsible for setting the DTC no longer exists.
2. You issue a scan tool CLEAR DTCs command.
3. A history DTC will clear once 255 malfunction free ignition cycles have occurred.

The following can cause an intermittent condition

1. A short between the SPS signal and low reference circuits
2. High or low resistance in the SPS signal and low reference circuits
3. Inspect the SPS signal and return circuits carefully for cutting and/or chafing

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

The numbers below refer to the step numbers on the diagnostic table

1. 2: Inspects the SPS connector and terminals.
2. 6: Tests for a short to ground, a high resistance, or an open in the SPS signal circuit.
3. 7: Tests for a short to ground, a high resistance, or an open in the SPS low reference circuit.
4. 8: Tests for a short to voltage in the SPS signal and low reference circuits.

DTC B0083 or B0084

The inflatable restraint I/P module disable switch circuit consists of an I/P module disable switch, I/P module disable switch indicator, I/P module disable switch signal circuit, and I/P module suppression indicator control circuit. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the voltage levels at the I/P module disable switch signal and the I/P module suppression indicator control circuits of the SDM to determine the position of the I/P module disable switch. If a malfunction is detected, a DTC will be stored.

Ignition 1 voltage is within the normal operating voltage range.

The voltage at I/P module disable switch signal and I/P module suppression indicator control is low or high with the I/P module disable switch indicator OFF for 500 milliseconds.

1. The I/P module disable switch is defaulted to a calibration state.
2. The SDM commands ON the AIR BAG indicator via Class 2 serial data.

1. The condition responsible for setting the DTC no longer exists.
2. You issue a scan tool CLEAR DTCs command.
3. A history DTC will clear once 255 malfunction free ignition cycles have occurred.

The following can cause an intermittent condition

A short between the I/P module disable switch signal and I/P module suppression indicator control circuits. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

The numbers below refer to the step numbers on the diagnostic table

1. 5: Tests for an open or high resistance in the I/P module disable switch power feed circuit.
2. 6: Tests for an open or high resistance in the I/P module disable switch ground circuit.
3. 8: Tests for an open or high resistance in the I/P module disable switch signal circuit.
4. 9: Tests for a short in the I/P module disable switch signal circuit.
5. 10: Tests for short in the I/P module suppression indicator control circuit.
6. 11: Tests for an open or high resistance in the I/P module suppression indicator control circuit.

DTC B0090

The inflatable restraint I/P module disable switch circuit consists of an I/P module disable switch, I/P module disable switch indicator, I/P module disable switch signal circuit, and I/P module suppression indicator control circuit. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the voltage levels at the I/P module disable switch signal and the I/P module suppression indicator control circuits of the SDM to determine the position of the I/P module disable switch. If a malfunction is detected, a DTC will be stored.

Ignition 1 voltage is within the normal operating voltage range.

The voltage at I/P module disable switch signal is low with the I/P module disable switch indicator ON and the voltage at I/P module suppression indicator control is high for 500 milliseconds.

1. The I/P module disable switch is defaulted to a calibrated state.
2. The SDM commands ON the AIR BAG indicator via Class 2 serial data.
3. The SDM toggles the I/P module disable switch AIR BAG indicator ON and OFF every 5 seconds.

1. The condition responsible for setting the DTC no longer exists.
2. You issue a scan tool CLEAR DTCs command.
3. A history DTC will clear once 255 malfunction free ignition cycles have occurred.

The following can cause an intermittent condition

A short between the I/P module disable switch signal and the I/P module suppression indicator control circuits. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

The numbers below refer to the step numbers on the diagnostic table.

1. 3: Observes the state of the I/P module disable switch, normal state being ON.
2. 4: Tests for a malfunctioning I/P module disable switch.
3. 5: Tests for a malfunctioning SDM.
4. 6: Tests for a short in the I/P module disable switch signal circuit.
5. 7: Tests for a short in the I/P module suppression indicator control circuit.

DTC B0091

The inflatable restraint front end sensor also known as the electronic frontal sensor (EFS) utilizes a unidirectional 2-wire circuit. The front end sensor modulates current on the interface to send ID, State of Health, and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the front end sensor. When the ignition is turned on and input power from the SDM is first detected, the front end sensor responds by performing internal diagnostics and sending an ID to the SDM. The SDM considers the ID to be valid if the response time is less than 5 seconds. The front end sensor continually communicates status messages to the SDM, which determines if a fault is present in the front end sensor circuit. When a fault is detected, the SDM resets the front end sensor twice by removing and reapplying power. If the fault is still present, the SDM will set a diagnostic trouble code (DTC).

Ignition 1 voltage is within the normal operating voltage range.

1. DTC B0100 will set when one of the following conditions occur: A valid ID message is not received within 5 seconds of the front end sensor being powered up. Status message is not received. The SDM has failed twice to reset the front end sensor.
2. DTC B0101 will set when the SDM has received 4 consecutive NOK (Not OK) messages from the front end sensor.
3. DTC B0102 will set when one of the following conditions occur: The SDM has received an ID message from the front end sensor which does not match the ID stored in the SDM memory. When two front end sensor resets are attempted without the correct identification being detected by the SDM.

1. The SDM commands the AIR BAG indicator ON via Class 2 serial data.
2. The SDM attempts to reset the front end sensor.

1. The condition responsible for setting the DTC no longer exists.
2. You issue a scan tool CLEAR DTCs command.
3. A history DTC will clear once 255 malfunction free ignition cycles have occurred.

The following can cause an intermittent condition

1. A short between the front end sensor signal and low reference circuits
2. High or low resistance in the front end sensor signal and low reference circuits
3. Inspect the front end sensor signal and low reference circuits carefully for cutting and/or chafing
4. Verify that the correct front end sensor is installed in the vehicle

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

The numbers below refer to the step numbers on the diagnostic table

1. 2: Tests the communication status of the front end sensor.
2. 6: Tests for a short to ground, a high resistance, or an open in the front end sensor signal circuit.
3. 7: Tests for a short to ground, a high resistance, or an open in the front end sensor low reference circuit.
4. 8: Tests for a short to voltage in the front end sensor signal and low reference circuits.

DTC B0100, B0101, or B0102

When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) compares the restraints ID stored in the SDM to the restraints ID stored in the body control module (BCM). The restraints ID being compared contains the last four digits of the SDM part number. For more detailed information concerning Class 2 serial data lines, refer to Data Link Communications Description and Operation in Data Link Communications.

Ignition 1 voltage is within the normal operating voltage range.

1. The SDM disables all AIR BAG deployments.
2. The SDM commands the AIR BAG indicator ON via Class 2 serial data.

1. The condition responsible for setting the DTC no longer exists.
2. You issue a scan tool CLEAR DTCs command.
3. A history DTC will clear once 255 malfunction free ignition cycles have occurred.

DTC B1001 is an indication that the restraints ID stored in both the BCM and SDM do not match. If either the BCM or PCM were replaced, the replacement modules need to be reprogrammed for proper operation. In addition, if the BCM or SDM were replaced, the vehicle theft deterrent (VTD) system will also need to be reprogrammed.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step checks to see if the correct VIN is programmed in the PCM.
2. 3: This step explains the proper steps to perform after a PCM has been replaced in order for the PCM to operate properly.
3. 5: This step explains the proper steps to perform after a BCM has been replaced in order for the BCM to operate properly.
4. 8: This step explains how to properly program the vehicle theft deterrent (VTD) system.

DTC B1001

Symptoms - SIR

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the SIR system. Refer to «Checking Aftermarket Accessories»(/chevrolet/chevy-express-g2500/1996-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__checking-aftermarket-accessories) in Wiring Systems.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Symptom List

Refer to Air Bag Indicator Circuit Malfunction in order to diagnose the symptom.

When the ignition is turned ON, the instrument panel cluster (IPC) flashes the AIR BAG indicator seven times. The inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within the SIR system. If no SIR system malfunctions exists, the SDM will request the IPC to turn the AIR BAG indicator OFF after it has flashed seven times. The AIR BAG indicator is controlled by the SDM via Class 2 serial data.

1. If Ignition 1 voltage is outside of the normal operating voltage range (9-16 volts), the AIR BAG indicator will come ON solid with no DTCs set.
2. The loss of serial data communication between the SDM and the instrument panel cluster (IPC) will cause the AIR BAG indicator to come ON solid. Refer to «DTC U1001-U1254»(/chevrolet/chevy-express-g2500/1996-2012/remont/communication-devices/#data-link-communication-system) in Data Link Communications.

The numbers below refer to the step numbers on the diagnostic table.

1. 4: This step determines if ignition 1 voltage to the SDM is more than 9 V.
2. 5: This step determines if ignition 1 voltage to the SDM is more than 16 V.
3. 6: Tests for an open or high resistance in the ignition 1 voltage circuit between the SDM and the SIR fuse.
4. 7: Tests for an open or high resistance in the ignition 1 voltage circuit that feeds the SIR fuse.
5. 8: Tests for an open or high resistance in the SDM ground circuit.

Air Bag Indicator Circuit Malfunction

SIR Disabling and Enabling Zones

The SIR system has been divided into Disabling and Enabling Zones. When performing service on or near SIR components or SIR wiring, it may be necessary to disable the SIR components in that zone. It may be necessary to disable more than one zone depending on the location of other SIR components and the area being serviced, refer to SIR Zone Identification Views . Refer to the illustration below, to identify the specific zone or zones in which service will be performed. After identifying the zone or zones, proceed to the disabling and enabling procedures for that particular zone or zones.

Scheme 9

SIR Disabling and Enabling Zones

SIR Service Precautions

The inflatable restraint sensing and diagnostic module (SDM) maintains a reserved energy supply. The reserved energy supply provides deployment power for the air bags. Deployment power is available for as much as 1 minute after disconnecting the vehicle power. Disabling the SIR system prevents deployment of the air bags from the reserved energy supply.

General Service Instructions

The following are general service instructions which must be followed in order to properly repair the vehicle and return it to its original integrity

1. Do not expose inflator modules to temperatures above 65°C (150°F).
2. Verify the correct replacement part number. Do not substitute a component from a different vehicle.
3. Use only original GM replacement parts available from your authorized GM dealer. Do not use salvaged parts for repairs to the SIR system.

Discard any of the following components if it has been dropped from a height of 91 cm (3 ft) or greater

1. Inflatable restraint front end sensor
2. Inflatable restraint I/P module
3. Inflatable restraint seat position sensor (SPS)
4. Inflatable restraint sensing and diagnostic module (SDM)
5. Inflatable restraint steering wheel module
6. Inflatable restraint steering wheel module coil

Disabling Procedure

1. Turn the steering wheel so that the vehicle's wheels are pointing straight ahead.
2. Turn OFF the ignition.
3. Remove the key from the ignition.
4. Remove the SIR fuse from the fuse block.
5. Raise and support the vehicle.
6. Remove the connector position assurance (CPA) from the front end sensor connector located on the frame crossmember.
7. Disconnect the front end sensor connector.

Enabling Procedure

1. Remove the key from the ignition.
2. Connect the front end sensor connector to the front end sensor.
3. Install the CPA to the front end sensor connector.
4. Install the SIR fuse into the fuse block.
5. Staying well away from all air bags, turn ON the ignition, with the engine OFF. The AIR BAG indicator will flash 7 times. The AIR BAG indicator will then turn OFF.
6. Perform the «Diagnostic System Check - SIR»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system__diagnostic-system-check-sir) if the AIR BAG indicator does not operate as described.

1. Turn the steering wheel until the vehicle's wheels are pointing straight ahead.
2. Turn OFF the ignition.
3. Remove the key from the ignition.
4. Remove the SIR fuse from the fuse block.
5. Remove the connector position assurance (CPA) (1) from the steering wheel module yellow 4-way connector (2) located left of the steering column near the knee bolster.
6. Disconnect the steering wheel module yellow 4-way connector (2).

1. Remove the key from the ignition.
2. Connect the steering wheel module yellow 4-way connector (2) located left of the steering column near the knee bolster.
3. Install the CPA (1) to the steering wheel module yellow 4-way connector (2).
4. Install the SIR fuse to the fuse block.
5. Staying well away from all air bags, turn ON the ignition, with the engine OFF. The AIR BAG indicator will flash 7 times. The AIR BAG indicator will then turn OFF.
6. Perform the «Diagnostic System Check - SIR»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system__diagnostic-system-check-sir) if the AIR BAG indicator does not operate as described.

1. Turn the steering wheel until the vehicle's wheels are pointing straight ahead.
2. Turn OFF the ignition.
3. Remove the key from the ignition.
4. Remove the SIR fuse from the fuse block.
5. Remove the right knee bolster bracket. Refer to «Trim Pad Replacement - Instrument Panel (I/P)»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
6. Remove the connector position assurance (CPA) from the I/P module yellow 4-way connector (1) located behind the I/P support.
7. Disconnect the I/P module yellow 4-way connector (1).

1. Remove the key from the ignition.
2. Connect the I/P module yellow 4-way connector (1) located behind the main I/P support.
3. Install the CPA to the I/P module yellow 4-way connector (1).
4. Install the right knee bolster bracket. Refer to «Trim Pad Replacement - Instrument Panel (I/P)»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
5. Install the SIR fuse to the fuse block.
6. Staying well away from all air bags, turn ON the ignition, with the engine OFF. The AIR BAG indicator will flash 7 times. The AIR BAG indicator will then turn OFF.
7. Perform the «Diagnostic System Check - SIR»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system__diagnostic-system-check-sir) if the AIR BAG indicator does not operate as described.

1. Turn the steering wheel until the vehicle's wheels are pointing straight ahead.
2. Turn OFF the ignition.
3. Remove the key from the ignition.
4. Remove the SIR fuse from the fuse block.
5. Remove the connector position assurance (CPA) (1) from the steering wheel module yellow 4-way connector (2) located left of the steering column near the knee bolster.
6. Disconnect the steering wheel module yellow 4-way connector (2).
7. Remove the right knee bolster bracket. Refer to «Trim Pad Replacement - Instrument Panel (I/P)»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
8. Remove the CPA from the I/P module yellow 4-way connector (1) located behind the I/P support.
9. Disconnect the I/P module yellow 4-way connector (1).

1. Remove the key from the ignition.
2. Connect the steering wheel module yellow 4-way connector (2) located left of the steering column near the knee bolster.
3. Install the CPA (1) to the steering wheel module yellow 4-way connector (2).
4. Connect the I/P module yellow 4-way connector (1) located behind the I/P support.
5. Install the CPA to the I/P module yellow 4-way connector (1).
6. Install the right knee bolster bracket. Refer to «Trim Pad Replacement - Instrument Panel (I/P)»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
7. Install the SIR fuse to the fuse block.
8. Staying well away from all air bags, turn ON the ignition, with the engine OFF. The AIR BAG indicator will flash 7 times. The AIR BAG indicator will then turn OFF.
9. Perform the «Diagnostic System Check - SIR»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system__diagnostic-system-check-sir) if the AIR BAG indicator does not operate as described.

Removal Procedure

1. Disable the SIR. Refer to «SIR Disabling and Enabling Zone 1»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
2. Raise the vehicle and support. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the Connector Position Assurance (CPA) from the inflatable restraint front end discriminating sensor electrical connector.
4. Disconnect the inflatable restraint front end sensor electrical connector.
5. Loosen the inflatable restraint front end sensor mounting nut (1).
6. Slide the inflatable restraint front end sensor (1) towards the front of the vehicle.
7. Remove the sensor (1) from the keyhole slot in the lower radiator support (2).

Installation Procedure

1. Remove any dirt, grease, or other impurities from the mounting surface.
2. Point the arrow on the sensor toward the front of the vehicle.
3. Install the inflatable restraint front end sensor (1) into the keyhole slot in lower radiator support (2).
4. Push the sensor towards the rear of the vehicle to seat the sensor in the keyhole slot in the lower radiator support (2). Tighten: Tighten the nut (1) to 10 N.m (89 lb in).
5. Connect the inflatable restraint front end sensor electrical connector.
6. Install the CP to the electrical connector.
7. Remove the safety stands and lower the vehicle.
8. Enable the SIR system. Refer to «SIR Disabling and Enabling Zone 1»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .

1. Disable the SIR system. Refer to «SIR Disabling and Enabling Zone 7»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) and «SIR Disabling and Enabling Zone 3»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
2. Remove the driver seat. Refer to «Seat Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/seats/#seat-system) in Seats.
3. Fold back the carpet to access the inflatable restraint sensing and diagnostic module (SDM).
4. Remove the connector position assurance (CPA) from the SDM electrical connector.
5. Disconnect the SDM electrical connector.
6. Remove the SDM (2) mounting nuts (1).
7. Remove the SDM (2) from the vehicle.
8. Repair the studs using the following procedure: Remove and discard the stripped nut. Drill out the weld spots for the weld stud that has been damaged, remove and discard the damaged stud. Condition the floor panel attaching surface where the new stud is to be installed. Install new weld stud GM P/N 115115602 and clamp the weld stud into place. Migweld the stud at the drilled holes. Apply body sealer GM P/N 9984248 around any exposed openings. Install a new nut (1) GM P/N 11515933.

1. Remove any dirt, grease, or other impurities from the mounting surface.
2. Install the SDM (2) horizontally to the studs.
3. Point the arrow on the SDM toward the front of the vehicle.
4. Install the SDM mounting nuts (1). Tighten: Tighten the nuts (1) to 10 N.m (89 lb in).
5. Install the SDM (2) electrical connector.
6. Install the CPA to the SDM electrical connector.
7. Install the carpet to cover SDM (2).
8. Install the driver seat. Refer to «Seat Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/seats/#seat-system) in Seats.
9. Enable the SIR system. Refer to «SIR Disabling and Enabling Zone 3»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) and to «SIR Disabling and Enabling Zone 7»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .

1. Disable the inflatable restraint steering wheel module. Refer to «SIR Disabling and Enabling Zone 3»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
2. Using a blunt-ended tool, push the leaf spring fasteners (2) inward through the access holes. The access holes are located on both sides of the steering wheel shroud.
3. Lift and partially remove the inflatable restraint steering wheel module from the steering wheel in order to expose the electrical connectors.
4. Disconnect the connector-position assurance (CPA) retainers from the electrical connectors.
5. Disconnect the electrical connectors from the inflatable restraint steering wheel module.
6. Remove the inflatable restraint module from the steering wheel.
7. Fully deploy the module before disposal. If the module was replaced under warranty, fully deploy and dispose of the module after the required retention period. Refer to «Inflator Module Handling and Scrapping»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .

1. Position the inflatable restraint module to the steering wheel.
2. Connect the electrical connectors to the inflatable restraint steering wheel module.
3. Connect the CPA retainers into the electrical connectors. Seat and lock the connections.
4. Position the alignment posts of the inflatable restraint module to the holes that are located on the steering wheel housing.
5. Push the inflatable restraint module into the steering wheel in order to engage and in order to latch the 2 leaf spring fasteners (1).
6. After installation, pull the sides of the inflatable restraint module in order to ensure that both leaf spring fasteners are engaged.
7. Enable the inflatable restraint steering wheel module. Refer to «SIR Disabling and Enabling Zone 3»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .

Tools Required

J 42640 Steering Column Anti Rotation Pin

1. Disable the SIR System. Refer to «SIR Disabling and Enabling Zone 3»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
2. Verify the following before removing the SIR coil: The wheels on the vehicle are straight ahead. That J 42640 is installed or the ignition switch is in the LOCK position.
3. Remove the steering wheel from the steering shaft. Refer to «Steering Wheel Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
4. On vehicles with a tilt column, pull the tilt lever straight out from the steering column.
5. Remove 2 TORX® head screws (1) from the lower trim cover (2).
6. Remove the lower trim cover (2).
7. Remove 2 TORX® head screws (2) from the upper trim cover (1).
8. Remove the upper trim cover (1).
9. Remove the wire harness straps from the steering wheel column wire harness.
10. Remove the retaining ring (3).
11. Remove the SIR coil (4) from the steering shaft.
12. If replacing, discard the SIR coil.

1. Verify the following: The wheels on the vehicle are straight ahead. That J 42640 is installed or the ignition switch is in the LOCK position.
2. If reusing the existing coil it MUST be centered, refer to «Inflatable Restraint Steering Wheel Module Coil Centering»(/chevrolet/chevy-express-g2500/1996-2012/remont/ignition-switchsteering-lock/#steering-wheel-steering-column__inflatable-restraint-steering-wheel-module-coil) in Steering Wheel and Column.
3. Align the SIR coil assembly (1) with the horn tower on the turn signal cancel cam assembly (2).
4. Slide the SIR coil (4) onto the steering shaft assembly (2).
5. Firmly seat the retaining ring (3) into the groove on the steering shaft assembly (2).
6. Remove and discard the centering tab from the new SIR coil (4).
7. Install the upper trim cover (1) and secure by using 2 TORX® head screws (2). Tighten: Tighten the screws to 1.5 N.m (13 lb in).
8. Install the lower trim cover (2) and secure by using 2 TORX® head screws (1).
9. Verify that the tabs on the lower trim cover (1) engage with the tabs on the upper trim cover (2). Snap the tabs together. Tighten: Tighten the screws to 1.5 N.m (13 lb in).
10. On vehicles with a tilt column, align the tilt lever into the steering column.
11. Slide the tilt lever handle into the steering column until the handle locks into position.
12. Install the steering wheel onto the steering shaft. Refer to «Steering Wheel Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
13. Enable the SIR system. Refer to «SIR Disabling and Enabling Zone 3»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .

1. Disable the SIR system. Refer to «SIR Disabling and Enabling Zone 5»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
2. Remove the right knee bolster bracket. Refer to «Knee Bolster Bracket Replacement - Right»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
3. Remove the passenger instrument panel (I/P) trim pad. Refer to «Trim Pad Replacement - Instrument Panel (I/P)»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
4. Remove the body control module. Refer to «Body Control Module Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/communication-devices/#body-control-system) in Body Control System.
5. Remove the connector position assurance (CPA) from the harness connector on the inflatable restraint I/P module.
6. Disconnect the I/P module electrical connector (1).
7. Remove the upper bolts (3) from the I/P module (1).
8. Remove the lower bolts (2) from the I/P module (1).
9. Remove the I/P module (1).
10. Ensure that the I/P module is fully deployed before disposal. If the module was replaced under warranty, fully deploy and dispose of the module after the required retention period. Refer to «Inflator Module Handling and Scrapping»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .

1. Install the inflatable restraint I/P module (1) to the I/P carrier.
2. Install the lower bolts (2) hand tight.
3. Install the lower bolts (3) to the inflatable restraint I/P module. Tighten: Tighten the bolts to 10 N.m (89 lb in).
4. Install the right knee bolster bracket. Refer to «Knee Bolster Bracket Replacement - Right»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
5. Install the passenger I/P trim pad. Refer to «Trim Pad Replacement - Instrument Panel (I/P)»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
6. Connect the electrical connector (1) to the inflatable restraint I/P module.
7. Install the CPA to the I/P module electrical connector.
8. Install the body control module. Refer to «Body Control Module Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/communication-devices/#body-control-system) in Body Control System.
9. Enable the SIR system. Refer to «SIR Disabling and Enabling Zone 5»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .

1. Remove the seat from the vehicle. Refer to «Seat Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/seats/#seat-system) in Seats.
2. Disconnect the electrical connector from the seat position sensor.
3. Drill out the rivets that retain the seat position sensor (1) to the seat adjuster track bracket.
4. Remove the seat position sensor from the seat adjuster track bracket.

1. Install the seat position sensor to the seat adjuster bracket.
2. Install the rivets that retain the seat position sensor (1) to the seat adjuster track bracket.
3. Connect the electrical connector to the seat position sensor.
4. Install the passenger seat to the vehicle. Refer to «Seat Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/seats/#seat-system) in Seats.

1. Disable the SIR system. Refer to «SIR Disabling and Enabling Zone 5»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) and «SIR Disabling and Enabling Zone 3»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
2. Remove the I/P cluster trim plate. Refer to «Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.
3. Release the passenger AIR BAG disable switch (1) locking tabs.
4. Remove the switch (1) from the I/P accessory trim panel.
5. Disconnect the passenger AIR BAG disable switch electrical connection (2).

1. Install the I/P cluster trim plate. Refer to «Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.
2. Connect the electrical connector (2) to the passenger AIR BAG disable switch (1).
3. Install the switch (1) to the instrument panel cluster trim bezel.
4. Enable the SIR system. Refer to «SIR Disabling and Enabling Zone 5»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) and «SIR Disabling and Enabling Zone 3»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .

Accident With or Without Air Bag Deployment - Component Inspections

After any collision, inspect the following components as indicated. If you detect any damage, replace the component. If you detect any damage to the mounting points or mounting hardware, repair or replace the mounting points and mounting hardware as needed.

1. Steering column-Perform the steering column accident damage checking procedures. Refer to «Steering Column Accident Damage Inspection»(/chevrolet/chevy-express-g2500/1996-2012/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
2. I/P Knee Bolsters and Mounting Points-Inspect the knee bolsters for bending, twisting, buckling, or any other type of damage.
3. I/P brackets, braces, etc.-Inspect for bending, twisting, buckling, or any other type of damage.
4. Seat Belts-Perform the seat belt operational and functional checks. Refer to «Operational and Functional Checks»(/chevrolet/chevy-express-g2500/1996-2012/remont/restraints-control-systems/#seat-belt-system__operational-and-functional-checks) in Seat Belts.
5. Seats and Seat Mounting Points-Inspect for bending, twisting, buckling, or any other type of damage.

Accident With Frontal Air Bag Deployment - Component Replacement and Inspections

After a collision involving frontal air bag deployment, replace the following components. If you detect any damage to the mounting points or mounting hardware, repair or replace the mounting points and mounting hardware as needed.

1. Inflatable restraint front end sensor
2. Inflatable restraint I/P module
3. Inflatable restraint sensing and diagnostic module (SDM)
4. Inflatable restraint steering wheel module

After a collision involving frontal air bag deployment, inspect the steering wheel module coil and the coil wiring pigtail for melting, scorching, or other damage due to excessive heat. Perform this component inspection in addition to the inspections indicated above in Accident With or Without Air Bag Deployment. If you detect any damage, replace the component. If you detect any damage to the mounting points or mounting hardware, repair or replace the mounting points and mounting hardware as needed.

Sensor Replacement Guidelines

The SIR sensor replacement policy requires replacing sensors in the area of accident damage. The area of accident damage is defined as the portion of the vehicle which is crushed, bent, or damaged due to a collision. For example, a moderate collision where the front of the vehicle impacts a tree. If the vehicle has an SIR sensor mounted forward of the radiator, it must be replaced.

1. Replace the sensor whether or not the air bags have deployed.
2. Replace the sensor even if it appears to be undamaged.

Sensor damage which is not visible, such as slight bending of the mounting bracket or cuts in the wire insulation, can cause improper operation of the SIR sensing system. Do not try to determine whether the sensor is undamaged, replace the sensor. Also, if you follow a Diagnostic Trouble Code (DTC) table and a malfunctioning sensor is indicated, replace the sensor.

Live (Undeployed) Inflator Module

Scheme 10

Use special care when handling or storing live, undeployed, inflator modules. Inflator module deployment produces a rapid generation of gas. This may cause the inflator module, or an object in front of the inflator module, to project through the air in the event of an unlikely deployment.

Dual Stage Inflator Modules

Dual stage inflator modules have two deployment stages. If stage 1 was used to deploy the inflator module, stage 2 may still be active. Therefore, a deployed dual stage inflator module must be treated as an active module. If disposal of a deployed or undeployed dual stage module is required both deployment loops must be energized to deploy the air bag.

Scrapping Procedure

During the course of a vehicle's useful life, certain situations may arise which will require the disposal of a live, undeployed, inflator module. Do not dispose of a live, undeployed, inflator module through normal disposal channels until the inflator module has been deployed. The following information covers the proper procedures for disposing of a live, undeployed, inflator module.

Do not deploy an inflator module in the following situations

1. After replacement of an inflator module under warranty. The inflator module may need to be returned undeployed to the manufacturer.
2. If the vehicle is the subject of a product liability report (GM-1241) related to the SIR system. When a vehicle is the subject of a product liability report, do not alter the SIR system in any manner.
3. If the vehicle is involved in a campaign affecting the inflator modules. Follow the instructions in the Campaign Service Bulletin for proper SIR handling procedures.

Deployment Procedures

Inflator modules can be deployed inside or outside of the vehicle. The method used depends upon the final disposition of the vehicle. Review the following procedures in order to determine which will work best in a given situation.

Deployment Outside Vehicle - I/P Module and Steering Wheel Module

Deploy the inflator module outside of the vehicle when the vehicle will be returned to service. Situations that require deployment outside of the vehicle include the following

1. Using the SIR diagnostics, you determine that the inflator module is malfunctioning.
2. The inflator module is cosmetically damaged (scratched or ripped).
3. The inflator module pigtail, if equipped, is damaged.
4. The inflator module connector is damaged.
5. The inflator module connector terminals are damaged.

Deployment and disposal of a malfunctioning inflator module is subject to any required retention period.

Tools Required

1. J 38826 SIR Deployment Harness. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
2. J 39401-B SIR Deployment Fixture. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
3. J 38826-75 Steering wheel module adapter
4. J 38826-80 I/P module adapter

1. Turn OFF the ignition.
2. Remove the ignition key.
3. Put on safety glasses.
4. Remove the inflator module. Refer to the following: When removing the steering wheel module, refer to «Inflatable Restraint Steering Wheel Module Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) . When removing the I/P module, refer to «Inflatable Restraint Instrument Panel Module Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) .
5. Place the inflator module with the vinyl trim cover facing up and away from the surface on a work bench, floor or deployment fixture.
6. Clear an area on the floor approximately 1.85 m (6 ft) in diameter for deployment of the inflator module. If possible, use a paved, outdoor location free of activity. Otherwise, use an area free of activity on the shop floor. Make sure you have sufficient ventilation.
7. Make sure no loose or flammable objects are in the area.
8. When deploying a steering wheel module, place the steering wheel module in the center of the cleared area.
9. When deploying an I/P module, refer to the following instructions: Place the J 39401-B (2) in the center of the cleared area. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) . Fill the deployment fixture (2) with water or sand. Mount the I/P module (1) in the deployment fixture (2) with the vinyl/plastic trim facing up. To mount, use 4 M 6 bolts (6), nuts (8), and washers (7) to properly secure the I/P module (1) to the deployment fixture (2). Tighten all fasteners prior to deployment.
10. Inspect the J 38826 and the appropriate pigtail adapter for damage. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) . Replace as needed.
11. Short the 2 SIR deployment harness leads (1) together using one banana plug seated into the other.
12. Connect the appropriate pigtail adapter (2) to the SIR deployment harness (1).
13. Extend the SIR deployment harness and adapter to full length from the deployment fixture.
14. Connect the inflator module (1) to the adapter (2) on the SIR deployment harness (3).
15. Clear the area of people.
16. Separate the 2 banana plugs on the SIR deployment harness.
17. Place a 12 V minimum/2 A minimum power source, i.e. vehicle battery, near the shorted end of the SIR deployment harness.
18. Connect the SIR deployment harness wires to the power source. Inflator module deployment will occur when contact is made.
19. Disconnect the SIR deployment harness from the power source.
20. Seat 1 banana plug into the other in order to short the deployment harness leads.
21. If the inflator module did not deploy, disconnect the adapter and discontinue the procedure. Contact the Technical Assistance Group for further assistance. Otherwise, proceed to the following steps.
22. Put on a pair of shop gloves.
23. Disconnect the pigtail adapter from the inflator module as soon as possible.
24. Dispose of the deployed inflator module through normal refuse channels.
25. Wash hands with a mild soap.

Deployment Inside Vehicle - Vehicle Scrapping Procedures

Deploy the inflator modules inside of the vehicle when destroying the vehicle or when salvaging the vehicle for parts. This includes but is not limited to the following situations

1. The vehicle has completed its useful life.
2. Irreparable damage occurs to the vehicle in a non-deployment type accident.
3. Irreparable damage occurs to the vehicle during a theft.
4. The vehicle is being salvaged for parts to be used on a vehicle with a different VIN as opposed to rebuilding as the same VIN.

1. Turn OFF the ignition.
2. Remove the ignition key.
3. Put on safety glasses.
4. Remove all loose objects from the front seats.
5. Disconnect the inflatable restraint steering wheel module connector (2) located to the left of the steering column.
6. Cut the steering wheel module harness connector out of the vehicle, leaving at least 16 cm (6 in) of wire at the connector.
7. Strip 13 mm (0.5 in) of insulation from each of the connector wire leads.
8. Cut two 6.1 m (20 ft) deployment wires from a 0.8 mm (18 gage) or thicker multi-strand wire. Use these wires to fabricate the deployment harness.
9. Strip 13 mm (0.5 in) of insulation from both ends of the wires cut in the previous step.
10. Twist together one end from each of the wires in order to short the wires. Deployment wires shall remain shorted, and not connected to a power source until you are ready to deploy the inflator module.
11. Twist together two connector wire leads, the high circuits from both stages of the steering wheel module, to one set of deployment wires. Refer to «SIR Connector End Views»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system__sir-connector-end-views) in order to determine the correct circuits.
12. Inspect that the connection is secure.
13. Bend flat the twisted connection.
14. Secure and insulate the connection using electrical tape.
15. Twist together two connector wire leads, the low circuits from both stages of the steering wheel module, to one set of deployment wires. Refer to «SIR Connector End Views»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system__sir-connector-end-views) in order to determine the correct circuits.
16. Inspect that the connection is secure.
17. Bend flat the twisted connection.
18. Secure and insulate the connection using electrical tape.
19. Connect the deployment harness to the steering wheel module connector.
20. Route the deployment harness out of the vehicle's driver side.
21. Disconnect the inflatable restraint I/P module connector (1) located under the instrument panel extension (3).
22. Cut the I/P module harness connector out of the vehicle, leaving at least 16 cm (6 in) of wire at the connector.
23. Strip 13 mm (0.5 in) of insulation from each of the connector wire leads.
24. Cut two 6.1 m (20 ft) deployment wires from a 0.8 mm (18 gage) or thicker multi-strand wire. These wires will be used to fabricate the deployment harness.
25. Strip 13 mm (0.5 in) of insulation from both ends of the wires cut in the previous step.
26. Twist together one end from each of the wires in order to short the wires.
27. Twist together two connector wire leads, the high circuits from both stages of the I/P module, to one set of deployment wires. Refer to «SIR Connector End Views»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system__sir-connector-end-views) in order to determine the correct circuits.
28. Inspect that the connection is secure.
29. Bend flat the twisted connection.
30. Secure and insulate the connection using electrical tape.
31. Twist together two connector wire leads, the low circuits from both stages of the I/P module, to one set of deployment wires. Refer to «SIR Connector End Views»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system__sir-connector-end-views) in order to determine the correct circuits.
32. Inspect that the connection is secure.
33. Bend flat the twisted connection.
34. Secure and insulate the connection using electrical tape.
35. Connect the deployment harness to the I/P module connector.
36. Route the deployment harness out of the vehicle's passenger side.
37. Stretch the driver side deployment harnesses to full length.
38. Stretch the passenger side deployment harnesses to full length.
39. Completely cover the windshield and front door window openings with a drop cloth.
40. Place a power source, 12 V minimum/2 A minimum, i.e. vehicle battery, near the shorted ends of the passenger side deployment harnesses.
41. Separate the ends of the I/P module deployment harness wires.
42. Connect the I/P module deployment harness wires to the power source in order to deploy the I/P module.
43. Disconnect the I/P module deployment harness wires from the power source.
44. Twist together one end of each wire of the I/P module on the passenger side deployment harness in order to short the wires.
45. Move the power source, 12 V minimum/2 A minimum, i.e., a vehicle battery, near the shorted ends of the driver side deployment harnesses.
46. Separate the ends of the steering wheel module deployment harness wires.
47. Connect the steering wheel module deployment harness wires to the power source in order to deploy the steering wheel module.
48. Disconnect the steering wheel module deployment harness wires from the power source.
49. Twist together one end of each wire of the steering wheel module on the driver side deployment harness in order to short the wires.
50. Remove the drop cloth from the vehicle.
51. Disconnect all harnesses from the vehicle.
52. Discard the harnesses.
53. Scrap the vehicle in the same manner as a non-SIR equipped vehicle.
54. If one or more of the inflator modules did not deploy, perform the following steps to remove the undeployed modules from the vehicle: «Inflatable Restraint Steering Wheel Module Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system) «Inflatable Restraint Instrument Panel Module Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/airbag/#supplemental-inflatable-restraint-system)
55. Contact the Technical Assistance Group for further assistance.

Scheme 11

The supplemental inflatable restraint (SIR) system supplements the protection offered by the occupant's seat belt system (2). The SIR system may contain several inflator modules located throughout the vehicle, i.e. steering wheel module (1) and instrument panel (I/P) module. Each inflator module has a deployment loop that is controlled by the sensing and diagnostic module (SDM) mounted inside the vehicle. The SDM determines the severity of a collision with the assistance of various sensor inputs. When the SDM detects a collision of sufficient force it will process the information provided by the sensors to further support air bag deployment. The SDM performs continuous diagnostic monitoring of the SIR system electrical components. Upon detection of a circuit malfunction, the SDM will set a DTC and inform the driver by requesting the instrument panel cluster (IPC) to turn the AIR BAG indicator ON. The steering column (1) and knee bolsters (3) are designed to absorb energy and compress during frontal collisions in order to limit leg movement and decrease the chance of injury to the driver and passenger.

Frontal SIR System Description

The frontal SIR system consists of the following components

1. AIR BAG indicator located on the instrument panel cluster (IPC)
2. Driver and passenger knee bolsters
3. Inflatable restraint front end sensor
4. Inflatable restraint I/P module
5. Inflatable restraint I/P module disable switch
6. Inflatable restraint seat position sensors (SPS) (left/right)
7. Inflatable restraint sensing and diagnostic module (SDM)
8. Inflatable restraint steering wheel module
9. Inflatable restraint steering wheel module coil
10. Inflatable restraint wiring harnesses
11. Steering wheel and column

A frontal collision of sufficient force will deploy the frontal air bags. The SDM contains a sensing device that converts vehicle velocity changes to an electrical signal. In the event of a frontal collision, the SDM receives a signal from the front end sensor which assists the SDM in determining the severity of some frontal collisions. The SDM contains a microprocessor that performs calculations using the measured accelerations. The SDM compares these calculations to a value stored in memory. When the generated calculations exceed the stored value, the SDM will cause current to flow through the frontal deployment loops deploying the frontal air bags. Once the air bags are inflated they quickly deflate through the air bag vent holes. After the air bags have deployed, the SDM sets a diagnostic trouble code (DTC) and requests the instrument panel cluster (IPC) to turn the AIR BAG indicator ON. The SDM, I/P module, steering wheel module, steering wheel module coil, seat belt pretensioners and the connecting wires makeup the frontal deployment loops. The SDM continuously monitors the deployment loops for malfunctions and requests the IPC to turn the AIR BAG indicator ON if a fault is detected.

Inflatable Restraint Sensing and Diagnostic Module (SDM)

The sensing and diagnostic module (SDM) is a microprocessor and the control center for the SIR system. The SDM contains internal sensors along with several external sensors, if equipped, mounted at various locations on the vehicle. In the event of a collision, the SDM performs calculations using the signals received from the internal and external sensors. The SDM compares the results of the calculations to values stored in memory. When these calculations exceed the stored value, the SDM will cause current to flow through the appropriate deployment loops to deploy the air bags. The SDM records the SIR system status when a deployment occurs and requests the instrument panel cluster (IPC) to turn the AIR BAG indicator ON. The SDM performs continuous diagnostic monitoring of the SIR system electrical components and circuitry when the ignition is turned ON. If the SDM detects a malfunction, a DTC will be stored and the SDM will request the IPC to turn the AIR BAG indicator ON. In the event that ignition 1 voltage is lost during a collision, the SDM maintains a 23-volt loop reserve (23 VLR) for deployment of the air bags. It is important to note, when disabling the SIR system for servicing or rescue operations to allow the 23 VLR to dissipate, which could take up to 1 minute.

Inflatable Restraint Seat Position Sensors (SPS)

The seat position sensor (SPS) is used to determine the proximity of a front driver or passenger seat position with respect to the frontal air bag. The SPS interfaces with the SDM. The state of the SPS allows the SDM to disable stage 2 of the frontal air bag for a front seat that is forward of a forward/rearward point in seat track travel. The SPS is a Hall effect sensor that is mounted on the seat track of both the driver and passenger seats. The seat track includes a metal bracket that shunts the SPS magnetic circuit creating two states of seat position. The shunted state represents a rearward seat position. The non-shunted state represents a forward position. The SPS provides two current ranges, one range for the shunted state and a second range for a non-shunted state. These two states are inputs to the sensing and diagnostic module (SDM). State 1 (shunted) being the rearward threshold and state 2 (non-shunted) being the forward threshold. When the SDM receives input from a SPS that state 1 threshold is reached (seat is rearward) the SDM will not disable stage 2 deployment, if required by the deployment sensors. When state 2 threshold is reached (seat is forward) the SDM will disable stage 2 deployment on the side the seat is forward. The SDM monitors the SPS circuit and if a fault is detected the SDM will set codes B0083 or B0084 and defaults to disabling stage 2 frontal deployment. This will only default on the side of the vehicle the sensor has a fault. It's important to understand that the SPS is secondary to the manual I/P module disable switch. If the I/P module disable switch is in the disable mode the passenger air bag will not deploy regardless of the SPS status.

AIR BAG Indicator

The AIR BAG indicator, located on the instrument panel cluster (IPC) is used to notify the driver of SIR system malfunctions and to verify that the SDM is communicating with the IPC. When the ignition is turned ON, the SDM is supplied with ignition 1 voltage and requests the IPC to flash the AIR BAG indicator 7 times. While flashing the indicator, the SDM conducts test on all SIR system components and circuits. If no malfunctions are detected the SDM will communicate with the IPC through the class 2 serial data circuit and request the IPC to turn the AIR BAG indicator OFF. The SDM provides continuous monitoring of the air bag circuits by conducting a sequence of checks. If a malfunction is detected the SDM will store a diagnostic trouble code (DTC) and request the IPC to turn the AIR BAG indicator ON. The presence of a SIR system malfunction could result in non-deployment of the air bags. The AIR BAG indicator will remain ON until the malfunction has been repaired.

Single Stage Inflator Modules (Heavy Duty)

Single stage inflator modules contain a housing, inflatable air bag, initiating device, canister of gas generating material and, in some cases, stored compressed gas. The initiator is part of the inflator module deployment loop. When the vehicle is involved in a collision of sufficient force, the SDM will cause current to flow through the deployment loops to the initiator. Current passing through the initiator ignites the material in the canister producing a rapid generation of gas and the release of compressed gas, if present. The gas produced from this reaction rapidly inflates the air bag. Once the air bag is inflated it quickly deflates through the air bag vent holes.

Each inflator module is equipped with a shorting bar located on the connector of the module. The shorting bar shorts the inflator module deployment loop circuitry to prevent unwanted deployment of the air bag when it is disconnected.

Dual Stage Inflator Modules (Light Duty)

Dual stage inflator modules contain a housing, inflatable air bag, two initiating devices, canister of gas generating material and, in some cases, stored compressed gas. The two initiators are part of the inflator module deployment loop. The inflator modules have two stages of deployment, which varies the amount of restraint to the occupant according to the collision severity. For moderate frontal collisions the inflator modules deploy at less than full deployment which consists of stage 1 of the inflator module. For more severe frontal collisions a full deployment is initiated which consists of stage 1 and stage 2 of the inflator module. When the vehicle is involved in a collision of sufficient force, the SDM will cause current to flow through the deployment loops to the initiator. Current passing through the initiator ignites the material in the canister producing a rapid generation of gas and the release of compressed gas, if present. The gas produced from this reaction rapidly inflates the air bag. Once the air bag is inflated it quickly deflates through the air bag vent holes.

Each dual stage inflator module is equipped with a shorting bar located on the connector(s) of the module. The shorting bar shorts the inflator module deployment loop circuitry to prevent unwanted deployment of the air bag when it is disconnected.

Inflatable Restraint Steering Wheel Module Coil

The steering wheel module coil is attached to the steering column and is located under the steering wheel. The steering wheel module coil consists of two or more current-carrying coils. The coils allow the rotation of the steering wheel while maintaining continuous electrical contact between the driver deployment loop and the steering wheel module. Four coil wires are used for the steering wheel module deployment loop. Additional coil wires are used for accessories attached to the steering wheel depending on the vehicle model. The steering wheel module coil connector is located near the base of the steering column. The connector contains a shorting bar that shorts the steering wheel module coil deployment loop circuitry to prevent unwanted deployment of the air bag when it is disconnected.

Inflatable Restraint Front End Sensor

The front end sensor is equipped on vehicles to supplement the SIR system performance. The front end sensor is electronic and is not part of the deployment loops, but instead provides input to the SDM. The front end sensor can assist in determining the severity of some frontal collisions. The SDM uses the input from the front end sensor to assist in determining the severity of a frontal collision further supporting air bag deployment. If the SDM determines a deployment is warranted, the SDM will cause current to flow through the deployment loops deploying the frontal air bags.

Inflatable Restraint I/P Module Disable Switch (Heavy Duty)

The instrument panel (I/P) module disable switch is a manual 2-position key switch located inside the vehicle. The I/P module disable switch allows the vehicle operator the ability to enable or disable the I/P module (passenger frontal air bag). The vehicle operator must disable the I/P module if a rear-facing child seat is installed in the front passenger seat. The I/P module disable switch interfaces with the sensing and diagnostic module (SDM) to request the enabling or disabling of the I/P module. The occupants are notified of the enabling or disabling of the I/P module via the I/P module disable switch ON/OFF indicators located on the I/P module disable switch.

Inflatable Restraint Wiring Harnesses

The wiring harnesses connect the sensing and diagnostic module (SDM), inflator modules, front end sensor, seat belt pretensioners, seat position sensors (SPS), and the class 2 serial data circuit together using weather pack connectors. SIR system connectors are yellow in color for easy identification. When repairing SIR system wiring harnesses, follow the proper testing and wiring repair procedures outlined in this manual.

Steering Wheel and Column

The steering wheel and column are designed to absorb energy when driver contact is made with the steering wheel or inflated air bag. In a frontal collision the driver may contact the steering wheel directly or load the steering wheel and column through the inflated air bag. When the driver applies load to the air bag or steering wheel the column will compress downward absorbing some of the impact, helping to reduce bodily injuries to the driver. The steering wheel and column must be inspected for damage after a collision.

Driver and Passenger Knee Bolsters

The knee bolsters are designed to help restrain the lower torsos of front seat occupants by absorbing energy through the front seat occupants' upper legs. In a frontal collision the front seat occupants legs may come in contact with the knee bolsters. The knee bolsters are designed to crush or deform absorbing some of the impact, which helps to reduce bodily injuries. The driver and passenger knee bolsters are located in the lower part of the instrument panel and must be inspected for damage after a collision.

Special Tools

Special Tools Illustration Tool Number/ Description J 38715-A SIR Driver/Passenger Load Tool J 38826 SIR Deployment Harness J 39401-B SIR Deployment Fixture

See also:
• SIR Special Tool Caution
• Scan Tool Does Not Power Up
• Diagnostic Trouble Code (DTC) List
• DTC B1000
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Circuit Testing
• Wiring Repairs
• Power Seat Systems Connector End Views
• Programming Theft Deterrent System Components
• Checking Aftermarket Accessories
• Diagnostic System Check - Instrument Cluster
• Diagnostic System Check - Engine Electrical
• SIR Caution
• Lifting and Jacking the Vehicle
• SIR Inflator Module Handling and Storage Caution
• Fastener Notice
• Steering Wheel Replacement
• Inflatable Restraint Steering Wheel Module Coil Centering
• Operational and Functional Checks
• SIR Inflator Module Disposal Caution
• SIR Deployed Inflator Modules Are Hot Caution
• SIR Inflatable Module Deployment Outside Vehicle Caution
• SIR Disabling and Enabling Zones
• Diagnostic System Check - SIR
• Symptoms - SIR
• Diagnostic Trouble Code (DTC) List
• DTC B0012, B0013, B0014, B0016, B0017, or B0018
• SIR Connector End Views
• SIR Service Precautions
• SIR Zone Identification Views