AutoCodes – Generic – U2621

U2621 Code - Battery Energy Control Module Lost Communication With Hybrid/EV Battery Interface Control Module 9

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Hybrid/EV Battery Interface Control Module 9, Hybrid/EV Battery Interface Control Module 9 harness is open or shorted, Hybrid/EV Battery Interface Control Module 9 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: U2621 indicates Battery Energy Control Module Lost Communication With Hybrid/EV Battery Interface Control Module 9.
Common causes: Common causes include Faulty Hybrid/EV Battery Interface Control Module 9, Hybrid/EV Battery Interface Control Module 9 harness is open or shorted, Hybrid/EV Battery Interface Control Module 9 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 1,288

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 Jun 18, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U2621 Description

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device.
The scan tool does not communicate the Hybrid/EV Battery Interface Control Modules 9 on Battery Energy Control Module dedicated bus.
The Diagnostic Trouble Code (DTC) will set when there is no temperature report message from Hybrid/EV Battery Interface Control Modules 9 to Battery Energy Control Module within 4s.

OBDII Code U2621 - Battery Energy Control Module Lost Communication With Hybrid/EV Battery Interface Control Module 9 - AutoCodes.com — U2621 Code - Battery Energy Control Module Lost Communication With Hybrid/EV Battery Interface Control Module 9

What does this mean?

What are the Possible Causes of the DTC U2621?

Faulty Hybrid/EV Battery Interface Control Module 9
Hybrid/EV Battery Interface Control Module 9 harness is open or shorted
Hybrid/EV Battery Interface Control Module 9 circuit poor electrical connection
Faulty Battery Energy Control Module

How to Fix the DTC U2621?

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 U2621 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 U2621 code?

Need more information on how to fix the U2621 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U2621 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U2621 Buick — Battery Energy Control Module Lost Communication With Hybrid/EV Battery Interface Control Module 9
U2621 Cadillac — Battery Energy Control Module Lost Communication With Hybrid/EV Battery Interface Control Module 9
U2621 Chevrolet — Battery Energy Control Module Lost Communication With Hybrid/EV Battery Interface Control Module 9
U2621 GMC — Battery Energy Control Module Lost Communication With Hybrid/EV Battery Interface Control Module 9

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 U2621 Code

1. What are the common symptoms of OBDII code U2621?

The common symptoms of code U2621 include a check engine light illuminated on the dashboard, reduced hybrid or electric vehicle performance, and potential issues with starting the vehicle.

2. What causes the OBDII code U2621 to appear?

This code typically appears when there is a communication failure between the Battery Energy Control Module and the Hybrid/EV Battery Interface Control Module 9. This communication failure can be caused by wiring issues, a faulty control module, or a software glitch.

3. How serious is OBDII code U2621?

Code U2621 should be addressed promptly as it can impact the performance and efficiency of the hybrid or electric vehicle. Ignoring this code may lead to further complications and potential damage to the vehicle's components.

4. Can I still drive my vehicle with OBDII code U2621?

It is not recommended to drive the vehicle with code U2621 present, as it can affect the overall performance and safety of the vehicle. It is advisable to have the issue diagnosed and repaired as soon as possible.

5. How can I diagnose OBDII code U2621?

Diagnosing code U2621 requires a professional OBDII scanner to retrieve the specific fault codes. Additionally, a thorough inspection of the wiring, connectors, and control modules involved in the communication system is necessary.

6. Can I repair OBDII code U2621 on my own?

While some DIY enthusiasts may attempt to diagnose and repair code U2621, it is recommended to seek assistance from a qualified mechanic or dealership with experience in hybrid or electric vehicle systems to ensure proper diagnosis and repair.

7. How much does it cost to repair OBDII code U2621?

The cost of repairing code U2621 can vary depending on the underlying cause of the communication failure. It may range from a simple wiring repair to replacing a control module. Getting a diagnostic assessment from a professional is the best way to determine the cost.

8. Will resetting the fault codes make OBDII code U2621 disappear?

Resetting the fault codes may temporarily clear the check engine light, but if the underlying issue causing code U2621 is not addressed, the code is likely to reappear. It is important to diagnose and repair the root cause of the problem.

9. Is OBDII code U2621 specific to certain vehicle makes and models?

Code U2621 related to Battery Energy Control Module communication issues is commonly found in hybrid and electric vehicles. However, the specific make and model of the vehicle can determine the exact components involved and the diagnostic process required.

10. How can I prevent OBDII code U2621 from appearing in the future?

Regular maintenance and inspections of the hybrid or electric vehicle's communication systems can help prevent code U2621 from reoccurring. Keeping the vehicle's components in good condition and addressing any issues promptly can help maintain optimal performance.