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Engine-Codes – Generic – B1390

B1390 Code - Control Module Supply Circuit 1

Quick Answer

The B1390 code refers to an issue with the Control Module Supply Circuit 1. Common causes include Faulty Wiring: Damaged or corroded wiring in the control module supply circuit can trigger the B1390 code, Blown Fuse: A blown fuse in the circuit can disrupt the power supply to the control module, Loose Connections: Loose or poor connections within the circuit can cause intermittent power supply issues. 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 Faulty Wiring: Damaged or corroded wiring in the control module supply circuit can trigger the B1390 code, Blown Fuse: A blown fuse in the circuit can disrupt the power supply to the control module, Loose Connections: Loose or poor connections within the circuit can cause intermittent power supply issues.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code B1390 Description

The B1390 code refers to an issue with the Control Module Supply Circuit 1. This code indicates that there is a problem with the power supply to a specific control module in the vehicle. Control modules are essential components in modern vehicles, as they help regulate various systems such as the engine, transmission, ABS, and more. When the supply circuit to a control module is compromised, it can lead to malfunctions in the corresponding system, affecting the vehicle's performance and overall functionality.

OBDII Code B1390 - Control Module Supply Circuit 1
B1390 Code - Control Module Supply Circuit 1

Common Causes of B1390

  1. Faulty Wiring: Damaged or corroded wiring in the control module supply circuit can trigger the B1390 code.
  2. Blown Fuse: A blown fuse in the circuit can disrupt the power supply to the control module.
  3. Loose Connections: Loose or poor connections within the circuit can cause intermittent power supply issues.
  4. Defective Control Module: A malfunctioning control module itself can cause the supply circuit to fail.

Symptoms of B1390

  1. Check Engine Light: The most common symptom associated with the B1390 code is the illumination of the check engine light on the dashboard.
  2. Unresponsive Controls: The affected control module may become unresponsive, leading to issues with controlling certain systems in the vehicle.
  3. Reduced Performance: The vehicle may experience reduced performance or efficiency due to the compromised control module supply circuit.
  4. Electrical Issues: Electrical problems such as random electrical failures or fluctuations in the affected system may occur.

How to Fix B1390

  1. Diagnose the Issue: Use a diagnostic scanner to retrieve the B1390 code and pinpoint the specific control module and circuit affected.
  2. Inspect Wiring: Thoroughly inspect the wiring in the supply circuit for any damage, corrosion, or loose connections. Repair or replace as needed.
  3. Check Fuses: Inspect and replace any blown fuses in the circuit.
  4. Test Control Module: Test the affected control module to determine if it is functioning correctly. Replace if necessary.
  5. Clear Codes: After completing the repairs, clear the diagnostic trouble codes and test the vehicle to ensure the issue has been resolved.

Cost to Fix B1390

The cost of repairing the B1390 code can vary depending on the specific cause of the issue and the extent of the repairs needed. On average, the repair costs for this issue can range from $100 to $500, including parts and labor. However, it's important to note that the actual cost can be higher or lower based on factors such as the location of the repair, the vehicle's make and model, and the mechanic's labor rates. It's recommended to consult with a professional mechanic to get an accurate estimate for your specific situation.

What does this mean?

Tech Notes for B1390

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

Need more information about the B1390 code?

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

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

Code B1390 Information for Specific Makes

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.

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