AutoCodes – Generic – B133B

B133B Code - Reverse Gear Status Not Plausible

Quick Answer

The Human Machine Interface Control Module receives a signal from the Human Machine Interface Control Module Bypass Module indicating reverse gear status. Common causes include Faulty Body Control Module (BCM), Body Control Module harness is open or shorted, Body Control Module 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: B133B indicates Reverse Gear Status Not Plausible.
Common causes: Common causes include Faulty Body Control Module (BCM), Body Control Module harness is open or shorted, Body Control Module 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 1,522

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 Dec 12, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code B133B Description

The Human Machine Interface Control Module receives a signal from the Human Machine Interface Control Module Bypass Module indicating reverse gear status. The reverse gear status is used to determine when to activate the rearview camera display. The Human Machine Interface Control Module also receives another reverse gear status message via serial data. The Human Machine Interface Control Module compares the two serial data messages to verify the plausibility of the messages. The Diagnostic Trouble Code (DTC) will be set when the Human Machine Interface Control Module has determined the reverse message states do not match and are therefore not plausible.

OBDII Code B133B - Reverse Gear Status Not Plausible - AutoCodes.com — B133B Code - Reverse Gear Status Not Plausible

What does this mean?

What are the Possible Causes of the DTC B133B?

Faulty Body Control Module (BCM)
Body Control Module harness is open or shorted
Body Control Module circuit poor electrical connection
Faulty Human Machine Interface Control Module

How to Fix the DTC B133B?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B133B 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 B133B code?

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Information for Specific Makes

B133B Buick — Reverse Gear Status Not Plausible
B133B Cadillac — Reverse Gear Status Not Plausible
B133B Chevrolet — Reverse Gear Status Not Plausible
B133B GMC — Reverse Gear Status Not Plausible

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.