AutoCodes – Generic – B1400

B1400 Code - Control Module Supply Circuit 2

Quick Answer

The vehicle control modules or sensors monitor the system voltage to verify the system voltage is within the normal operating range. Common causes include Low battery voltage, Faulty Control Module, Control Module harness is open or shorted. 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: B1400 indicates Control Module Supply Circuit 2.
Common causes: Common causes include Low battery voltage, Faulty Control Module, Control Module harness is open or shorted.
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 19,210

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 Jul 11, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1400 Description

The vehicle control modules or sensors monitor the system voltage to verify the system voltage is within the normal operating range. Damage to components, and incorrect data can occur when the voltage is out of range. The vehicle has multiple Control Modules that will set this Diagnostic Trouble Code (DTC).

OBDII Code B1400 - Control Module Supply Circuit 2 - AutoCodes.com — B1400 Code - Control Module Supply Circuit 2

What does this mean?

What are the Possible Causes of the DTC B1400?

Low battery voltage
Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC B1400?

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 B1400 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 B1400 code?

Need more information on how to fix the B1400 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1400 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1400 Buick — Control Module Supply Circuit 2
B1400 Cadillac — Control Module Supply Circuit 2
B1400 Chevrolet — Control Module Supply Circuit 2
B1400 GMC — Control Module Supply Circuit 2
B1400 Hyundai — SIS Front-Driver Defect
B1400 KIA — SIS Front-Driver Defect

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 B1400 Code

1. What are common symptoms of OBDII code B1400 (Control Module Supply Circuit 2)?

Common symptoms include issues with the vehicle's electrical system, such as difficulty starting the engine or erratic behavior of electronic components.

2. What are possible causes of OBDII code B1400?

Possible causes include a faulty control module, damaged wiring in the supply circuit, loose connections, or a blown fuse related to the circuit.

3. How can I diagnose the cause of OBDII code B1400?

Diagnosing the issue involves using a diagnostic scanner to retrieve the trouble codes, conducting a visual inspection of the wiring and connections, and performing circuit tests to identify the specific problem.

4. Can I still drive my vehicle with OBDII code B1400 present?

It is not recommended to drive the vehicle with this code present, as it can lead to further electrical issues and potential damage to the control module or other components.

5. How can I repair OBDII code B1400?

To repair this code, you may need to replace the faulty control module, repair any damaged wiring, ensure proper connections, and reset the code with a diagnostic scanner after completing the repairs.

6. Are there any DIY tips for fixing OBDII code B1400?

DIY tips include checking for loose or damaged wiring, ensuring proper grounding of the control module, and consulting the vehicle's repair manual for specific troubleshooting steps.

7. Can a blown fuse cause OBDII code B1400?

Yes, a blown fuse in the control module supply circuit can trigger OBDII code B1400, so it's important to check and replace any blown fuses as part of the diagnosis and repair process.

8. How serious is OBDII code B1400?

While OBDII code B1400 may not cause immediate safety concerns, it can lead to electrical malfunctions in the vehicle and should be addressed promptly to prevent further issues.

9. Will OBDII code B1400 cause my check engine light to illuminate?

Yes, OBDII code B1400 will likely trigger the check engine light to illuminate on the dashboard, indicating a problem with the control module supply circuit.

10. Does OBDII code B1400 affect emissions or fuel efficiency?

While OBDII code B1400 itself may not directly impact emissions or fuel efficiency, unresolved electrical issues related to this code can lead to poor performance and potentially affect emissions and fuel efficiency in the long run.