If you are facing issues with your vehicle and your diagnostic tool is showing the B1390 DTC code, it is essential to understand what it means and how to troubleshoot it. In this article, we will provide a detailed explanation of the B1390 Diagnostic Trouble Code, its potential causes, and possible solutions to resolve the issue. So, let’s dive in and explore the world of B1390!
The B1390 code is an OBD-II diagnostic trouble code that relates to the body control module (BCM) in your vehicle. It indicates a malfunction in the front power window motor feedback circuit. The BCM monitors the feedback from the power window motor and if it detects any abnormalities, it sets the B1390 code, illuminating the check engine light (CEL) and triggering a diagnostic alert.
Faulty Power Window Motor: The most common cause of the B1390 code is a faulty power window motor. When the motor fails to provide the expected feedback to the BCM, it triggers the code.
Wiring or Connector Issues: Damaged or loose wiring connections, as well as faulty connectors between the power window motor and the BCM, can result in the B1390 code.
BCM Malfunction: In some cases, a malfunctioning BCM itself could be the root cause of the B1390 code. The BCM may fail to interpret the feedback from the power window motor accurately, triggering the code.
When the B1390 code is present in your vehicle, you may experience one or more of the following symptoms:
It is important to note that these symptoms can vary depending on the vehicle make, model, and year.
To properly diagnose the B1390 code, a professional-level OBD-II scan tool is required. Here are the steps involved in diagnosing the issue:
Scan for Codes: Connect the OBD-II scan tool to the vehicle’s diagnostic port and retrieve any stored codes, specifically focusing on the B1390 code.
Inspect Power Window Motor and Wiring: Visually inspect the power window motor and its associated wiring. Look for any signs of damage, loose connections, or corrosion.
Test Power Window Motor: Use a multimeter to test the power window motor’s circuits and verify if it is providing the necessary feedback signals as per the manufacturer’s specifications.
Check BCM Functionality: If the power window motor and its wiring are in good condition, it’s time to inspect the BCM. Test the BCM using the manufacturer-approved diagnostic procedures to ensure its proper functioning.
Once you have diagnosed the cause of the B1390 code, you can proceed with the appropriate repairs. Here are the possible solutions:
Replace Power Window Motor: If the power window motor is found to be faulty, it should be replaced with a new one. Make sure to choose a quality motor from a reliable source.
Repair or Replace Wiring and Connectors: In case damaged or loose wiring connections or faulty connectors were the cause, repair or replace them as necessary. Ensure proper insulation and secure connections.
Replace BCM: If the BCM is determined to be the culprit, it should be replaced with a new or refurbished unit. Follow the manufacturer’s guidelines for proper programming and installation.
A1: It is generally safe to drive the vehicle with the B1390 code, but it is recommended to address the issue as soon as possible to prevent further damage and inconvenience.
A2: Yes, diagnosing the B1390 code requires a professional-level OBD-II scan tool and a multimeter to perform accurate tests and readings.
A3: While experienced DIYers may attempt to fix the B1390 code, it is recommended to consult a professional mechanic or automotive technician to ensure proper diagnosis and repair.
The B1390 DTC code indicates a problem with the front power window motor feedback circuit, controlled by the BCM. By understanding the possible causes and following the diagnostic and repair steps outlined in this article, you can effectively troubleshoot and resolve the B1390 code issue. Remember to prioritize safety and seek professional help when needed.
Meet Sam Mitchell, your experienced and reliable guide in the complex world of car fault codes. With a robust career spanning over 15 years as a professional car mechanic, John has the skills, knowledge, and practical experience to help you navigate car fault issues with confidence.
