FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Hummer >> 2009 >> H3 L5-3.7L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> B Code Charts >> B0101

B0101




DTC B0100, B0101, B0102, B0103, B0104, or B0105

Diagnostic Instructions

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

DTC Descriptors
DTC B0100
- Electronic Front End Sensor 1 Performance

DTC B0101
- Discard Electronic Front End Sensor 1

DTC B0102
- Incorrect Electronic Front End Sensor 1 Installed

DTC B0103
- Electronic Front End Sensor 2 Performance

DTC B0104
- Discard Electronic Front End Sensor 2

DTC B0105
- Incorrect Electronic Front End Sensor 2 Installed

Diagnostic Fault Information





Circuit/System Description

The inflatable restraint electronic frontal sensor (EFS) utilizes a unidirectional 2-wire circuit. The EFS modulates current on the interface to send ID, state of health (SOH), and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the EFS. When the ignition is turned ON and input power from the SDM is first detected, the EFS will respond 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 EFS continually communicates status messages to the SDM, which determines if a fault is present in the EFS circuit. When a fault is detected, the SDM resets the EFS twice by removing and reapplying power. If the fault is still present, the SDM will set a diagnostic trouble code (DTC).

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0100 and B0103
* A valid ID message is not received within 5 seconds of the EFS being powered up.
* Status message is not received.
* The SDM has failed twice to reset the EFS.

B0102 and B0105
* The SDM has received an ID message from the EFS that does not match the ID stored in the SDM memory.
* When 2 EFS resets are attempted without the correct identification being detected by the SDM.

B0101 and B0104

Will set when the SDM has received a NOK (Not OK) message from the EFS.

Action Taken When the DTC Sets

* The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.
* The SDM attempts to reset the EFS.

Conditions for Clearing the DTC

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

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

Circuit/System Testing

Important: Refer to SIR Service Precautions (Technician Safety Information).


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


* Front end sensor

* SDM module

* Front end sensor wiring harness connector

* SDM wiring harness connector


1. Ignition OFF, disconnect the harness connector at the SDM and the appropriate front end sensor.
2. Ignition ON, test for less than 1-volt between the front end sensor signal circuit terminal B and ground.

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

3. Ignition ON, test for less than 1-volt between the front end sensor low reference circuit terminal A and ground.

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

4. Test for infinite resistance between the front end sensor signal circuit terminal B and ground.

• If less than the specified value, test the circuit for a short to ground.

5. Test for less than 1 ohm between the front end sensor signal circuit terminals listed below:

* Right front end sensor terminal B and SDM harness connector terminal 37.
* Left front end sensor terminal B and SDM harness connector terminal 36.

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

6. Test for less than 1 ohm between the front end low reference circuit terminals listed below:

* Right front end sensor terminal A and SDM harness connector terminal 39.
* Left front end sensor terminal A and SDM harness connector terminal 38.

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

7. If all circuits test normal, replace the appropriate front end sensor.
8. Reconnect all SIR components. Ignition ON, verify the DTC does not set as current.

• If the DTC resets as current , replace the SDM.

Repair Instructions

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

* Inflatable Restraint Front End Sensor Replacement (Inflatable Restraint Front End Sensor Replacement)
* SIR/SRS Wiring Repairs (Component Tests and General Diagnostics)
* Control Module References (Programming and Relearning) for SDM replacement, setup, and programming

pro multis Credits:Operation CHARM About Operation CHARM