AutoCodes – Chevrolet – U18A4 Chevrolet

U18A4 Chevrolet Code - Lost Communication With Hybrid/EV Battery DC Charging Communications Gateway Module On High Voltage Energy Management CAN Bus

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 DC Charging Communications Gateway Module, Hybrid/EV Battery DC Charging Communications Gateway Module harness is open or shorted, Hybrid/EV Battery DC Charging Communications Gateway 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: U18A4 Chevrolet indicates Lost Communication With Hybrid/EV Battery DC Charging Communications Gateway Module On High Voltage Energy Management CAN Bus.
Common causes: Common causes include Faulty Hybrid/EV Battery DC Charging Communications Gateway Module, Hybrid/EV Battery DC Charging Communications Gateway Module harness is open or shorted, Hybrid/EV Battery DC Charging Communications Gateway 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 2,006

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 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18A4 Chevrolet 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 Diagnostic Trouble Code (DTC) will set a supervised periodic message that includes the transmitter device availability that has not been received.

OBDII Code U18A4 Chevrolet - Lost Communication With Hybrid/EV Battery DC Charging Communications Gateway Module On High Voltage Energy Management CAN Bus - AutoCodes.com — U18A4 Chevrolet Code - Lost Communication With Hybrid/EV Battery DC Charging Communications Gateway Module On High Voltage Energy Management CAN Bus

What does this mean?

What are the Possible Causes of the DTC U18A4 Chevrolet?

Faulty Hybrid/EV Battery DC Charging Communications Gateway Module
Hybrid/EV Battery DC Charging Communications Gateway Module harness is open or shorted
Hybrid/EV Battery DC Charging Communications Gateway Module circuit poor electrical connection

How to Fix the DTC U18A4 Chevrolet?

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 U18A4 Chevrolet 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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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 U18A4 Chevrolet Code

1. What are common symptoms of OBDII code U18A4 in a Chevrolet related to lost communication with the Hybrid/EV Battery DC Charging Communications Gateway Module?

- Common symptoms include loss of power to the hybrid/EV components, inability to charge the battery, and warning lights on the dashboard related to the hybrid system.

2. What are some potential causes of the U18A4 code in a Chevrolet?

- Possible causes include a faulty Hybrid/EV Battery DC Charging Communications Gateway Module, issues with the high voltage energy management CAN bus, wiring problems, or a malfunction in the communication network.

3. How can I diagnose the U18A4 code in my Chevrolet?

- Diagnosing this code typically involves using a professional OBDII scanner capable of reading hybrid system codes, checking the wiring connections, inspecting the Hybrid/EV Battery DC Charging Communications Gateway Module, and verifying the high voltage energy management CAN bus.

4. Is it safe to continue driving my Chevrolet with the U18A4 code present?

- It is not recommended to drive the vehicle with the U18A4 code active, as it may lead to further damage to the hybrid/EV components and compromise the safety and performance of the vehicle.

5. How can I repair the U18A4 code in my Chevrolet?

- Repairing the U18A4 code typically involves addressing the root cause of the communication loss, which may require replacing the Hybrid/EV Battery DC Charging Communications Gateway Module, repairing wiring issues, or resetting the communication network.

6. Can I reset the U18A4 code in my Chevrolet using an OBDII scanner?

- Resetting the U18A4 code with an OBDII scanner is possible after the underlying issue has been resolved. However, it is important to ensure that the problem causing the code is fixed before clearing it to prevent it from reoccurring.

7. What are some preventative maintenance tips to avoid the U18A4 code in a Chevrolet?

- Regularly checking the hybrid/EV system components, monitoring the high voltage energy management system, and addressing any warning lights or unusual behavior promptly can help prevent issues leading to the U18A4 code.

8. Can a DIY enthusiast repair the U18A4 code in a Chevrolet, or is professional assistance necessary?

- Repairing the U18A4 code may require specialized knowledge and tools related to hybrid/EV systems. In most cases, seeking professional assistance from a certified technician familiar with hybrid vehicles is recommended for accurate diagnosis and repair.

9. Are there any recalls or technical service bulletins related to the U18A4 code in Chevrolet vehicles?

- It is advisable to check with the manufacturer or authorized service centers for any recalls or technical service bulletins related to the U18A4 code in Chevrolet vehicles, as they may provide valuable information and assistance in addressing the issue.

10. How can I prevent future occurrences of the U18A4 code in my Chevrolet after it has been repaired?

- To prevent future instances of the U18A4 code, it is essential to follow the manufacturer's recommended maintenance schedule for the hybrid/EV system, address any related warning signs promptly, and have the vehicle inspected regularly by a qualified technician.