AutoCodes – GMC – U01A1 GMC

U01A1 GMC Code - Lost Communication with Hybrid/EV Battery Interface Control Module 2

Quick Answer

This diagnostic monitors the internal battery communication status between the Hybrid/EV Powertrain Control Module 2 and the Hybrid/EV Battery Interface Control Modules. Common causes include Faulty Hybrid/EV Battery Interface Control Module, Hybrid/EV Battery Interface Control Module harness is open or shorted, Hybrid/EV Battery Interface Control Module 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: U01A1 GMC indicates Lost Communication with Hybrid/EV Battery Interface Control Module 2.
Common causes: Common causes include Faulty Hybrid/EV Battery Interface Control Module, Hybrid/EV Battery Interface Control Module harness is open or shorted, Hybrid/EV Battery Interface Control Module 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 340

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 21, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U01A1 GMC Description

This diagnostic monitors the internal battery communication status between the Hybrid/EV Powertrain Control Module 2 and the Hybrid/EV Battery Interface Control Modules. The diagnostic monitors Hybrid/EV Battery Interface Control Modules data availability whenever this private communications bus is active. The communication network between Hybrid/EV Powertrain Control Module 2 and Hybrid/EV Battery Interface Control Modules is in a daisy-chain architecture. Therefore, a break at any point in the communication bus results in a loss of Hybrid/EV Battery Interface Control Modules communication with the Hybrid/EV Powertrain Control Module 2. If any data is received, the diagnostic will report a pass. If no data is received for greater than 4.5 s, the Hybrid/EV Powertrain Control Module 2 will attempt to initiate the Hybrid/EV Battery Interface Control Modules into a communication mode where the Hybrid/EV Battery Interface Control Modules can perform their own internal communication loop back, bypassing the daisy-chain. If this is the first Hybrid/EV Battery Interface Control Module in the daisy-chain that the Hybrid/EV Powertrain Control Module 2 cannot re-establish communication with, this diagnostic will fail. The Diagnostic Trouble Code (DTC) will be set when the Hybrid/EV Powertrain Control Module 2 has not received data from the Hybrid/EV Battery Interface Control Module 2 for more than 4.5 s.

OBDII Code U01A1 GMC - Lost Communication with Hybrid/EV Battery Interface Control Module 2 - AutoCodes.com — U01A1 GMC Code - Lost Communication with Hybrid/EV Battery Interface Control Module 2

What does this mean?

What are the Possible Causes of the DTC U01A1 GMC?

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

How to Fix the DTC U01A1 GMC?

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 U01A1 GMC 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.

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Information for Specific GMC Models

U01A1 2014 GMC Sierra — Lost Communication with Hybrid/EV Battery Interface Control Module 2
U01A1 2015 GMC Sierra — Lost Communication with Hybrid/EV Battery Interface Control Module 2
U01A1 2016 GMC Sierra — Lost Communication with Hybrid/EV Battery Interface Control Module 2
U01A1 2017 GMC Sierra — Lost Communication with Hybrid/EV Battery Interface Control Module 2
U01A1 2018 GMC Sierra — Lost Communication with Hybrid/EV Battery Interface Control Module 2

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 U01A1 GMC Code

What does the OBDII code U01A1 mean for a GMC vehicle?

The U01A1 code indicates a loss of communication with the Hybrid/EV Battery Interface Control Module 2, which manages key battery functions in hybrid or electric GMC vehicles.

What are the common symptoms of the U01A1 code?

Symptoms may include a check engine light, reduced hybrid or EV performance, inability to charge the battery, or limited vehicle drivability.

What causes the U01A1 code to appear in a GMC vehicle?

Common causes include faulty wiring or connectors, issues with the Hybrid/EV Battery Interface Control Module 2, a failed control module, or network communication problems.

How can I diagnose the U01A1 code?

Start by inspecting the wiring and connectors for damage or corrosion, check the CAN bus network for communication issues, and use a scan tool to verify the moduleâ€™s data and functionality.

Can I drive my GMC with the U01A1 code active?

Driving may be possible, but it is not recommended as it could lead to further damage or reduced performance of the hybrid or EV system.

How do I fix the U01A1 code in my GMC vehicle?

Repairs may include replacing or repairing damaged wiring, cleaning or reconnecting connectors, updating module software, or replacing the Hybrid/EV Battery Interface Control Module 2 if it has failed.

How much does it cost to repair the U01A1 code on a GMC vehicle?

Repair costs can vary widely, ranging from $100 for basic wiring repairs to over $1,000 if the control module needs to be replaced.

Can a software update fix the U01A1 code?

Yes, in some cases, a software update for the control module may resolve the communication issues causing the U01A1 code.

What tools are needed to troubleshoot the U01A1 code?

You will need a professional scan tool capable of reading GMC-specific codes, a multimeter for testing wiring, and potentially an oscilloscope for analyzing CAN bus signals.

Is the U01A1 code specific to GMC hybrid and EV vehicles?

Yes, the U01A1 code is specific to GMC hybrid and electric vehicles that utilize a Hybrid/EV Battery Interface Control Module 2.