AutoCodes – Buick – U18B5 Buick

U18B5 Buick Code - Lost Communication With Hybrid Powertrain Control Module On Chassis Expansion CAN Bus

Quick Answer

Devices connected to the Chassis high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Hybrid Powertrain Control Module, Hybrid Powertrain Control Module harness is open or shorted, Hybrid Powertrain 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: U18B5 Buick indicates Lost Communication With Hybrid Powertrain Control Module On Chassis Expansion CAN Bus.
Common causes: Common causes include Faulty Hybrid Powertrain Control Module, Hybrid Powertrain Control Module harness is open or shorted, Hybrid Powertrain 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 619

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 U18B5 Buick Description

Devices connected to the Chassis high speed General Motor Local Area Network (GMLAN) 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 Motor Control Modules and the Hybrid Powertrain Control Module 1 are all internal to the Power Inverter Module. Communication diagnostics for the serial data, including device power and ground as well as the wakeup circuits for Motor Control Modules and the Hybrid Powertrain Control Module 1 are all diagnosed from external sources only to the Power Inverter Module connector because any circuit fault condition within the Power Inverter Module will cause a complete replacement.The Diagnostic Trouble Code (DTC) will set a supervised periodic message that includes the transmitter device availability that has not been received.

OBDII Code U18B5 Buick - Lost Communication With Hybrid Powertrain Control Module On Chassis Expansion CAN Bus - AutoCodes.com — U18B5 Buick Code - Lost Communication With Hybrid Powertrain Control Module On Chassis Expansion CAN Bus

What does this mean?

What are the Possible Causes of the DTC U18B5 Buick?

Faulty Hybrid Powertrain Control Module
Hybrid Powertrain Control Module harness is open or shorted
Hybrid Powertrain Control Module circuit poor electrical connection

How to Fix the DTC U18B5 Buick?

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 U18B5 Buick 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 U18B5 Buick Code

1. What are the common symptoms of OBDII code U18B5 in a Buick related to lost communication with the hybrid powertrain control module on the chassis expansion CAN bus?

- Common symptoms may include a hybrid system warning light on the dashboard, loss of hybrid system functionality, and potential drivability issues.

2. What are some possible causes of OBDII code U18B5 in a Buick indicating a communication problem with the hybrid powertrain control module?

- Possible causes may include faulty wiring or connectors in the CAN bus system, a malfunctioning hybrid powertrain control module, or issues with the vehicle's software.

3. How can I diagnose the source of the communication problem leading to OBDII code U18B5 in my Buick?

- Diagnosing the issue may involve checking the wiring and connectors in the CAN bus system, testing the hybrid powertrain control module for functionality, and using a diagnostic scan tool to pinpoint the communication failure.

4. Is it safe to continue driving my Buick if OBDII code U18B5, indicating lost communication with the hybrid powertrain control module, is present?

- It is recommended to avoid driving the vehicle if possible, as continued operation with communication issues in the hybrid powertrain control module can lead to further damage or safety risks.

5. What are some repair tips for addressing OBDII code U18B5 in a Buick related to the hybrid powertrain control module communication problem?

- Repair tips may include checking and repairing any damaged wiring or connectors, resetting the hybrid powertrain control module, and updating the vehicle's software to resolve communication issues.

6. Can a DIY enthusiast fix OBDII code U18B5 in a Buick caused by lost communication with the hybrid powertrain control module?

- While some basic troubleshooting steps can be performed by DIY enthusiasts, diagnosing and repairing communication issues with the hybrid powertrain control module may require specialized tools and expertise.

7. How much can I expect to pay for professional repairs related to OBDII code U18B5 in a Buick involving the hybrid powertrain control module?

- The cost of professional repairs can vary depending on the exact cause of the communication issue, but it is advisable to budget for diagnostic fees, parts replacement, and labor costs.

8. Are there any recalls or technical service bulletins related to OBDII code U18B5 in Buick vehicles experiencing communication problems with the hybrid powertrain control module?

- It is recommended to check with Buick's authorized service centers or visit the National Highway Traffic Safety Administration (NHTSA) website for any relevant recalls or technical service bulletins regarding this issue.

9. How long does it typically take to resolve OBDII code U18B5 in a Buick due to lost communication with the hybrid powertrain control module?

- The repair time can vary depending on the complexity of the issue, availability of parts, and the technician's workload, but resolving communication problems with the hybrid powertrain control module may take a few hours to a day.

10. Is it important to address OBDII code U18B5 promptly in a Buick to prevent further damage or complications?

- Yes, it is crucial to address communication issues indicated by OBDII code U18B5 promptly to prevent potential damage to the hybrid powertrain system and ensure the vehicle's safe operation.