AutoCodes – GMC – B1155 GMC

B1155 GMC Code - SDM Calibration Mismatch

Quick Answer

When the ignition switch is turned to RUN position, Instrument Panel Cluster (IPC) sends two messages over the class 2 serial data line containing identification information. Common causes include Faulty Sensing and Diagnostic Module (SDM), Sensing and Diagnostic Module (SDM) harness is open or shorted, Sensing and Diagnostic Module (SDM) circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B1155 GMC indicates SDM Calibration Mismatch.
Common causes: Common causes include Faulty Sensing and Diagnostic Module (SDM), Sensing and Diagnostic Module (SDM) harness is open or shorted, Sensing and Diagnostic Module (SDM) circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 428

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 19, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B1155 GMC Description

When the ignition switch is turned to RUN position, Instrument Panel Cluster (IPC) sends two messages over the class 2 serial data line containing identification information. The first message contains serial data keying information, and the second message contains a partial Vehicle Identification Number (VIN). The Sensing and Diagnostic Module (SDM) compares these messages to the information stored in memory. The Diagnostic Trouble Code (DTC) B1155 sets when either message does not match information stored in SDM. DTC B1155 sets along with DTC B1159 or DTC B1160 depending on the message that does not match. If SDM does not receive the serial data keying message, DTC B1159 will be set without DTC B1155. If SDM does not receive a partial VIN message, DTC B1160 will be set without DTC B1155. Messages are sent only at POWER-ON.

OBDII Code B1155 GMC - SDM Calibration Mismatch - AutoCodes.com — B1155 GMC Code - SDM Calibration Mismatch

What does this mean?

What are the Possible Causes of the DTC B1155 GMC?

Faulty Sensing and Diagnostic Module (SDM)
Sensing and Diagnostic Module (SDM) harness is open or shorted
Sensing and Diagnostic Module (SDM) circuit poor electrical connection

How to Fix the DTC B1155 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

If DTCs B1155, B1159, and B1160 are all set, the Sensing and Diagnostic Module (SDM) is receiving both incorrect messages.
If DTCs B1155 and B1159 are set, SDM is receiving the wrong message from Standard Body Module (SBM).
If DTCs B1155 and B1160 are set, SDM is receiving the wrong message from Powertrain Control Module (PCM).
If DTC B1159 sets alone, SDM did not receive a message from SBM.
If DTC B1160 sets alone, SDM did not receive a message from PCM.
If DTCs B1159 and B1160 are set without DTC B1155, SDM did not receive messages from SBM or PCM.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1155 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B1155 GMC code?

Need more information on how to fix the B1155 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1155 GMC code diagnosed by a professional: Find a repair shop in your area

Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service

Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.

Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1155 GMC Code

1. What is OBDII code B1155 GMC?

The B1155 GMC code refers to an SDM (Sensing and Diagnostic Module) Calibration Mismatch error.

2. What are common symptoms of B1155 GMC code?

Common symptoms of B1155 GMC code include the airbag warning light illuminating on the dashboard and potential issues with the vehicle's airbag system.

3. What can cause the B1155 GMC code to trigger?

The B1155 GMC code is triggered when there is a discrepancy between the calibration data in the SDM and other modules in the vehicle, often due to a previous repair or replacement of components in the airbag system.

4. How serious is the B1155 GMC code?

The B1155 GMC code is a serious issue as it relates to the proper functioning of the airbag system. It is important to address this code promptly to ensure the safety features of the vehicle are working correctly.

5. How can I diagnose the B1155 GMC code?

Diagnosing the B1155 GMC code typically requires a professional scan tool to communicate with the SDM and other modules in the vehicle to identify the calibration mismatch.

6. Can I repair the B1155 GMC code on my own?

Repairing the B1155 GMC code often requires specialized knowledge and tools. It is recommended to have a qualified technician diagnose and repair this issue to ensure proper functioning of the airbag system.

7. What are some possible repair tips for the B1155 GMC code?

Repairing the B1155 GMC code may involve recalibrating the SDM, updating software, or replacing faulty components in the airbag system. It is crucial to follow manufacturer guidelines for proper repair procedures.

8. Is it safe to drive with the B1155 GMC code present?

It is not recommended to drive with the B1155 GMC code present, as it indicates a potential issue with the airbag system. Driving with this code can compromise the safety of the vehicle occupants in the event of a collision.

9. How much does it typically cost to repair the B1155 GMC code?

The cost of repairing the B1155 GMC code can vary depending on the underlying cause and the necessary repairs. It is advisable to consult with a professional technician for an accurate estimate.

10. Can the B1155 GMC code be cleared without fixing the underlying issue?

Clearing the B1155 GMC code without addressing the calibration mismatch can temporarily turn off the warning light, but the issue will likely reoccur. It is essential to address the root cause of the problem to ensure the airbag system functions properly.