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Home >> Chevy Truck >> 2009 >> Express 3500 V8-6.6L DSL Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> B Code Charts >> B0020

B0020




DTC B0014-B0045

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptors
B0015 01
- Driver Pretensioner Deployment Loop Short to Battery

B0015 02
- Driver Pretensioner Deployment Loop Short to Ground

B0015 04
- Driver Pretensioner Deployment Loop Open Circuit

B0015 0D
- Driver Pretensioner Deployment Loop Resistance Above Threshold

B0015 0E
- Driver Pretensioner Deployment Loop Resistance Below Threshold

B0016 01
- Left Roof Rail Initiator 1 Deployment Loop Short to Battery

B0016 02
- Left Roof Rail Initiator 1 Deployment Loop Short to Ground

B0016 04
- Left Roof Rail Initiator 1 Deployment Loop Open Circuit

B0016 0D
- Left Roof Rail Initiator 1 Deployment Loop Resistance Above Threshold

B0016 0E
- Left Roof Rail Initiator 1 Deployment Loop Resistance Below Threshold

B0019 01
- Passenger Frontal Deployment Loop Stage 1 Short to Battery

B0019 02
- Passenger Frontal Deployment Loop Stage 1 Short to Ground

B0019 04
- Passenger Frontal Deployment Loop Stage 1 Open Circuit

B0019 0D
- Passenger Frontal Deployment Loop Stage 1 Resistance Above Threshold

B0019 0E
- Passenger Frontal Deployment Loop Stage 1 Resistance Below Threshold

B0020 01
- Passenger Frontal Deployment Loop Stage 2 Short to Battery

B0020 02
- Passenger Frontal Deployment Loop Stage 2 Short to Ground

B0020 04
- Passenger Frontal Deployment Loop Stage 2 Open Circuit

B0020 0D
- Passenger Frontal Deployment Loop Stage 2 Resistance Above Threshold

B0020 0E
- Passenger Frontal Deployment Loop Stage 2 Resistance Below Threshold

B0022 01
- Passenger Pretensioner Deployment Loop Short to Battery

B0022 02
- Passenger Pretensioner Deployment Loop Short to Ground

B0022 04
- Passenger Pretensioner Deployment Loop Open Circuit

B0022 0D
- Passenger Pretensioner Deployment Loop Resistance Above Threshold

B0022 0E
- Passenger Pretensioner Deployment Loop Resistance Below Threshold

B0023 01
- Right Roof Rail Initiator 1 Deployment Loop Short to Battery

B0023 02
- Right Roof Rail Initiator 1 Deployment Loop Short to Ground

B0023 04
- Right Roof Rail Initiator 1 Deployment Loop Open Circuit

B0023 0D
- Right Roof Rail Initiator 1 Deployment Loop Resistance Above Threshold

B0023 0E
- Right Roof Rail Initiator 1 Deployment Loop Resistance Below Threshold

B0040 01
- Right Third Row Roof Rail Deployment Loop Short to Battery

B0040 02
- Right Third Row Roof Rail Deployment Loop Short to Ground

B0040 04
- Right Third Row Roof Rail Deployment Loop Open Circuit

B0040 0D
- Right Third Row Roof Rail Deployment Loop Resistance Above Threshold

B0040 0E
- Right Third Row Roof Rail Deployment Loop Resistance Below Threshold

Diagnostic Fault Information





Circuit/System Description

During a side or frontal crash of sufficient force the inflatable restraint sensing and diagnostic module (SDM) will allow current to flow through the deployment loop in order to deploy the air bag module. There are 2 shorting bars used within the module connector which will short together both high and low circuits, when the connector is disconnected. This will prevent unwanted deployment of the inflator module during servicing.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0015 01, B0016 01, B0019 01, B0020 01, B0022 01, B0023 01, B0040 01

The air bag module high and/or low circuit is short to voltage for 120 milliseconds.

B0015 02, B0016 02, B0019 02, B0020 02, B0022 02, B0023 02, B0040 02

The air bag module high and/or low circuit is short to ground for 120 milliseconds.

B0015 04, B0016 04, B0019 04, B0020 04, B0022 04, B0023 04, B0040 04

The air bag module high and/or low circuit is open for 120 milliseconds.

B0015 0D, B0016 0D, B0019 0D, B0020 0D, B0022 0D, B0023 0D, B0040 0D

The air bag module deployment loop resistance is greater than 3.9 ohms for 120 milliseconds.

B0015 0E, B0016 0E, B0019 0E, B0020 0E, B0022 0E, B0023 0E, B0040 0E

The air bag module deployment loop resistance is less than 1.1 ohms for 120 milliseconds.

Action Taken When the DTC Sets

* The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.
* The SDM will store a DTC, however if an event occurs the system will still attempt deployments.

Conditions for Clearing the DTC

* The condition for setting the DTC no longer exists.
* A history DTC will clear once 100 fault-free ignition cycles have occurred.

Diagnostic Aids

* When a harness connector is disconnected, the high control and low control circuits are shorted together by the integral shorting bar. This should be taken into account when testing for faults on these circuits.
* This DTC usually indicates a poor connection or a wiring malfunction between the SDM and the deployment loop.

Reference Information
Schematic Reference

SIR Schematics ([1][2]Air Bag Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

SIR System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information.
Special Tools

J 38715-A Driver and Passenger SIR Load Tool

Circuit/System Testing

Important: When removing the connectors inspect for damage or corrosion. Damage or corrosion to the following requires repair or replacement of the affected component/connector:

* Pretensioner
* Air bag module
* SDM module
* Air bag wiring harness connector
* SDM wiring harness connector

Important: The connector and connector position assurance (CPA) may seat independent of each other. Both the connector and CPA should seat with an audible and/or tactile click. The CPA isolates the shorting-bars within the connector allowing the deployment circuit to operate properly.

1. Verify that the appropriate inflator restraint module connector and CPA are engaged.

• If the above condition is not found, make the appropriate repair.

2. Ignition OFF, disconnect the harness connector at the appropriate inflatable restraint module.
3. With the appropriate load tool adaptor, connect J 38715-A in place of the inflatable restraint module.
4. Ignition ON, with a scan tool, verify the appropriate DTC is set as current.

• If the DTC is not set or is set as history, cycle ignition OFF, disconnect the load tool and adaptor, reconnect the harness connector at the inflator restraint module, and cycle the ignition ON. If the DTC resets after reconnecting the module, replace the inflator restraint module.

5. Ignition OFF, disconnect the load tool and adaptor.
Disconnect the harness connector at the SDM.
6. Ignition ON, test for less than 1 volt between the appropriate high control circuit terminal listed below and ground:

* I/P Module - Stage 1 terminal A1 (light duty)
* I/P Module - Stage 1 terminal A (heavy duty)
* I/P Module - Stage 2 terminal B1
* Left Front Roof Rail Module terminal B
* Right Front Roof Rail Module terminal B
* Right Rear Roof Rail Module terminal B
* Seat Belt Pretensioner - Left terminal A X2
* Seat Belt Pretensioner - Right terminal A X2

• If greater than the specified range, test the control circuit for a short to voltage.

7. Test for less than 1 volt between the appropriate low control circuit terminal listed below and ground:

* I/P Module - Stage 1 terminal A2 (light duty)
* I/P Module - Stage 1 terminal B (heavy duty)
* I/P Module - Stage 2 terminal B2
* Left Front Roof Rail Module terminal A
* Right Front Roof Rail Module terminal A
* Right Rear Roof Rail Module terminal A
* Seat Belt Pretensioner - Left terminal B X2
* Seat Belt Pretensioner - Right terminal B X2

• If greater than the specified range, test the control circuit for a short to voltage.

8. Ignition OFF, test for infinite resistance between the appropriate high control circuit terminal listed below and ground:

* I/P Module - Stage 1 terminal A1 (light duty)
* I/P Module - Stage 1 terminal A (heavy duty)
* I/P Module - Stage 2 terminal B1
* Left Front Roof Rail Module terminal B
* Right Front Roof Rail Module terminal B
* Right Rear Roof Rail Module terminal B
* Seat Belt Pretensioner - Left terminal A X2
* Seat Belt Pretensioner - Right terminal A X2

• If not the specified value, test the control circuit for a short to ground.

9. Test for infinite resistance between the appropriate low control circuit terminal listed below and ground:

* I/P Module - Stage 1 terminal A2 (light duty)
* I/P Module - Stage 1 terminal B (heavy duty)
* I/P Module - Stage 2 terminal B2
* Left Front Roof Rail Module terminal A
* Right Front Roof Rail Module terminal A
* Right Rear Roof Rail Module terminal A
* Seat Belt Pretensioner - Left terminal B X2
* Seat Belt Pretensioner - Right terminal B X2

• If not the specified value, test the control circuit for a short to ground.

10. Test for less then 5 ohms between the following high control circuit terminals listed below:

* I/P Module - Stage 1 terminal A1 at the I/P harness connector and terminal 10 at the SDM harness connector (light duty).
* I/P Module - Stage 1 terminal A at the I/P harness connector and terminal 10 at the SDM harness connector (heavy duty).
* I/P Module - Stage 2 terminal B1 at the I/P harness connector and terminal 6 at the SDM harness connector.
* Left Front Roof Rail Module terminal B at the harness connector and terminal 13 at the SDM harness connector.
* Right Front Roof Rail Module terminal B at the harness connector and terminal 14 at the SDM harness connector.
* Right Rear Roof Rail Module terminal B at the harness connector and terminal 22 at the SDM harness connector.
* Seat Belt Pretensioner - Left terminal A at the X2 harness connector and terminal 25 at the SDM harness connector.
* Seat Belt Pretensioner - Right terminal A at the X2 harness connector and terminal 26 at the SDM harness connector.

• If greater than the specified range, test the control circuit for an open/high resistance.

11. Test for less then 5 ohms between the following low control circuit terminals listed below:

* I/P Module - Stage 1 terminal A2 at the harness connector and terminal 11 at the SDM harness connector (light duty).
* I/P Module - Stage 1 terminal B at the harness connector and terminal 11 at the SDM harness connector (heavy duty).
* I/P Module - Stage 2 terminal B2 at the harness connector and terminal 7 at the SDM harness connector.
* Left Front Roof Rail Module terminal A at the harness connector and terminal 12 at the SDM harness connector.
* Right Front Roof Rail Module terminal A at the harness connector and terminal 15 at the SDM harness connector.
* Right Rear Roof Rail Module terminal A at the harness connector and terminal 23 at the SDM harness connector.
* Seat Belt Pretensioner - Left terminal B at the X2 harness connector and terminal 24 at the SDM harness connector.
* Seat Belt Pretensioner - Right terminal B at the X2 harness connector and terminal 27 at the SDM harness connector.

• If greater than the specified range, test the control circuit for an open/high resistance.

12. If all circuits test normal, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* SIR/SRS Wiring Repairs (Component Tests and General Diagnostics)
* Instrument Panel Inflatable Restraint Module Replacement (Service and Repair)
* Steering Wheel Inflatable Restraint Module Replacement (Service and Repair)
* Steering Wheel Inflatable Restraint Module Coil Replacement (Removal and Replacement)
* Inflatable Restraint Roof Side Rail Module Replacement - Front (Service and Repair)
* Inflatable Restraint Roof Side Rail Module Replacement (without YA2) (Service and Repair)
* Inflatable Restraint Roof Side Rail Module Replacement - Rear (Service and Repair)
* Seat Belt Buckle Pretensioner Replacement (Removal and Replacement)
* Control Module References (Programming and Relearning) for SDM replacement, programming, and setup

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