AutoCodes – Buick – U0115 Buick

U0115 Buick Code - Lost Communication with Engine Control Module 'B'

Quick Answer

Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Engine Control Module 'B', Engine Control Module 'B' harness is open or shorted, Engine Control Module 'B' 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: U0115 Buick indicates Lost Communication with Engine Control Module 'B'.
Common causes: Common causes include Faulty Engine Control Module 'B', Engine Control Module 'B' harness is open or shorted, Engine Control Module 'B' 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 534

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 Mar 30, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0115 Buick Description

Modules connected to the 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 modules. The modules 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 module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Engine Control Module 'B' has not been received.

OBDII Code U0115 Buick - Lost Communication with Engine Control Module 'B' - AutoCodes.com — U0115 Buick Code - Lost Communication with Engine Control Module 'B'

What does this mean?

What are the Possible Causes of the DTC U0115 Buick?

Faulty Engine Control Module 'B'
Engine Control Module 'B' harness is open or shorted
Engine Control Module 'B' circuit poor electrical connection

How to Fix the DTC U0115 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 U0115 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 U0115 Buick Code

1. What does the OBDII code U0115 mean on a Buick?

The U0115 code indicates the vehicle's communication network has lost contact with the Engine Control Module 'B' (ECM-B), meaning the module isn't responding to other systems.

2. What are common symptoms of the U0115 code in a Buick?

Symptoms may include the Check Engine Light turning on, reduced engine performance, difficulty starting the engine, or the vehicle going into limp mode.

3. What causes the U0115 code in a Buick?

Common causes include faulty wiring or connectors in the communication network, a failed ECM-B, low battery voltage, or issues with the power or ground supply to the module.

4. How do you diagnose the U0115 code on a Buick?

Diagnosis typically involves inspecting the wiring and connectors for damage, checking for proper power and ground at the ECM-B, and verifying communication on the CAN bus network using a scan tool.

5. Can the U0115 code be caused by a dead battery?

Yes, a dead or weak battery can disrupt communication between modules and trigger the U0115 code.

6. Is it safe to drive a Buick with the U0115 code?

Driving with the U0115 code may not be safe as it can lead to reduced engine performance or limp mode, potentially causing unexpected driving issues.

7. How do you fix the U0115 code on a Buick?

Repairs may include fixing or replacing damaged wiring or connectors, reprogramming or replacing the ECM-B, or addressing power and ground supply issues.

8. Can a faulty ECM-B cause the U0115 code?

Yes, a malfunctioning ECM-B can fail to communicate with other modules, triggering the U0115 code.

9. How much does it cost to fix the U0115 code on a Buick?

The cost varies depending on the specific issue but can range from $100 for wiring repairs to over $1,000 if the ECM-B needs replacement and reprogramming.

10. Can the U0115 code clear itself on a Buick?

The code may clear temporarily if the issue is intermittent, but the underlying problem needs to be addressed to prevent it from reappearing.