AutoCodes – GMC – U1815 GMC

U1815 GMC Code - Lost Communication With Drive Motor Control Module 1 On Bus B

Quick Answer

Devices connected to the powertrain high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Drive Motor Control Module 1, Drive Motor Control Module 1 harness is open or shorted, Drive Motor Control Module 1 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: U1815 GMC indicates Lost Communication With Drive Motor Control Module 1 On Bus B.
Common causes: Common causes include Faulty Drive Motor Control Module 1, Drive Motor Control Module 1 harness is open or shorted, Drive Motor Control Module 1 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 429

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 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1815 GMC Description

Devices connected to the powertrain 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 Diagnostic Trouble Code (DTC) will set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U1815 GMC - Lost Communication With Drive Motor Control Module 1 On Bus B - AutoCodes.com — U1815 GMC Code - Lost Communication With Drive Motor Control Module 1 On Bus B

What does this mean?

What are the Possible Causes of the DTC U1815 GMC?

Faulty Drive Motor Control Module 1
Drive Motor Control Module 1 harness is open or shorted
Drive Motor Control Module 1 circuit poor electrical connection

How to Fix the DTC U1815 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 U1815 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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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 U1815 GMC Code

1. What are common symptoms of OBDII code U1815 GMC (Lost Communication With Drive Motor Control Module 1 On Bus B)?

- Common symptoms include issues with vehicle performance, such as loss of power, hesitation during acceleration, and potential stalling.

2. What are possible causes of OBDII code U1815 GMC?

- Possible causes include faulty wiring or connections, a malfunctioning drive motor control module, issues with the bus communication network, or a software glitch.

3. How can I diagnose the cause of OBDII code U1815 GMC?

- Diagnosing this code typically involves using a diagnostic scanner to retrieve the specific details of the communication fault and conducting a thorough inspection of the wiring and connections related to the drive motor control module.

4. Can a DIYer repair OBDII code U1815 GMC?

- While some DIYers may be able to address simple wiring or connection issues, resolving this code often requires advanced diagnostic tools and expertise. It is recommended to consult a professional technician for proper diagnosis and repair.

5. Are there any repair tips for fixing OBDII code U1815 GMC?

- Repair tips may include checking and repairing any damaged wiring, ensuring proper connections, updating software if necessary, and resetting the fault codes after completing the repairs.

6. Is it safe to continue driving with OBDII code U1815 GMC present?

- It is not recommended to continue driving with this code present, as it can lead to further damage or safety risks. It is best to have the issue diagnosed and repaired as soon as possible.

7. How much does it cost to repair OBDII code U1815 GMC?

- The cost of repairing this code can vary depending on the specific cause of the communication fault. It is advisable to obtain diagnostics from a professional technician to get an accurate estimate.

8. Can weather conditions affect OBDII code U1815 GMC?

- Extreme weather conditions, such as moisture or temperature fluctuations, can potentially impact the electrical connections and components related to the drive motor control module, leading to communication faults.

9. Will disconnecting the battery reset OBDII code U1815 GMC?

- Disconnecting the battery may reset the fault code temporarily, but it will not address the underlying issue causing the communication fault. It is essential to diagnose and repair the root cause to prevent the code from reoccurring.

10. Is OBDII code U1815 GMC specific to GMC vehicles?

- While the U1815 code is specific to GMC vehicles, similar codes related to lost communication with control modules can be found in other vehicle makes and models.