AutoCodes – Generic – B1390

B1390 Code - Control Module Supply Circuit 1

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: B1390 indicates Control Module Supply Circuit 1.
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 15,342

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
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B1390 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 B1390 - Control Module Supply Circuit 1 - AutoCodes.com — B1390 Code - Control Module Supply Circuit 1

What does this mean?

What are the Possible Causes of the DTC B1390?

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

How to Fix the DTC B1390?

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

B1390:83 Ambient Light Control Module: Value of Signal Protection Calculation Incorrect
B1390:87 Ambient Light Control Module: Missing Message

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1390 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 B1390 code?

Need more information on how to fix the B1390 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1390 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1390 Buick — Control Module Supply Circuit 1
B1390 Cadillac — Control Module Supply Circuit 1
B1390 Chevrolet — Control Module Supply Circuit 1
B1390 Ford — Ambient Light Control Module
B1390 GMC — Control Module Supply Circuit 1
B1390 Hyundai — Passenger Seat Track Position Sensor Short Or Short To Ground
B1390 KIA — Passenger Seat Track Position Sensor Short Or Short To Ground
B1390 Lincoln — Ambient Light Control Module
B1390 Mercury — Ambient Light Control Module

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 B1390 Code

1. What are the common symptoms of OBDII code B1390?

- Common symptoms of OBDII code B1390 (Control Module Supply Circuit 1) may include issues with starting the vehicle, poor engine performance, and intermittent electrical failures.

2. What can cause OBDII code B1390 to trigger?

- The code B1390 can be triggered by issues such as a faulty control module, damaged wiring or connectors in the supply circuit, or a weak battery.

3. How do I diagnose OBDII code B1390?

- Diagnosing OBDII code B1390 involves using a scan tool to read the code, checking the control module and related wiring for damage, and testing the battery voltage and connections.

4. Can a weak battery cause OBDII code B1390 to appear?

- Yes, a weak or failing battery can cause OBDII code B1390 to appear due to inadequate power supply to the control module.

5. What are some repair tips for fixing OBDII code B1390?

- Repair tips for OBDII code B1390 include repairing or replacing damaged wiring, connectors, or the control module, ensuring a strong battery connection, and clearing the code after repairs are completed.

6. Is it safe to continue driving with OBDII code B1390 present?

- It is not recommended to continue driving with OBDII code B1390 present, as it can lead to potential issues with vehicle performance and electrical systems.

7. Can a DIY enthusiast fix OBDII code B1390 at home?

- Depending on the cause of the code, some DIY enthusiasts may be able to fix OBDII code B1390 at home by following repair guides and using basic tools. However, complex issues may require professional assistance.

8. How much does it typically cost to repair OBDII code B1390?

- The cost to repair OBDII code B1390 can vary depending on the underlying issue, with expenses ranging from a simple wiring repair to replacing the control module. It is advisable to get estimates from auto repair shops.

9. Can a bad alternator cause OBDII code B1390 to appear?

- A bad alternator can indirectly contribute to OBDII code B1390 appearing if it fails to charge the battery properly, leading to insufficient power supply to the control module.

10. Are there any recalls or technical service bulletins related to OBDII code B1390?

- It is recommended to check with the vehicle manufacturer or authorized service centers for any recalls or technical service bulletins related to OBDII code B1390 to see if there are known issues or recommended fixes.