AutoCodes – Cadillac – U1815 Cadillac

U1815 Cadillac 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 Cadillac 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 414

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 Cadillac 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 Cadillac - Lost Communication With Drive Motor Control Module 1 On Bus B - AutoCodes.com — U1815 Cadillac 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 Cadillac?

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 Cadillac?

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 Cadillac 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 Cadillac Code

What are common symptoms of the OBDII code U1815 in a Cadillac?

Common symptoms include loss of communication with the drive motor control module, illuminated warning lights on the dashboard, and possible drivability issues.

What are some possible causes of the U1815 code in a Cadillac?

Possible causes may include a faulty drive motor control module, wiring issues, poor electrical connections, or a software malfunction.

How can I diagnose the U1815 code in my Cadillac?

Diagnosis typically involves checking the wiring connections, inspecting the drive motor control module, testing the communication lines, and using a diagnostic scanner to retrieve specific fault codes.

Is it safe to continue driving with the U1815 code present in a Cadillac?

It is not recommended to drive with the U1815 code present, as it can affect the performance and safety of the vehicle. It is best to have the issue diagnosed and repaired as soon as possible.

Can I repair the U1815 code in my Cadillac myself?

While some DIY enthusiasts may attempt to diagnose and repair the issue, it is recommended to seek professional help for proper diagnosis and resolution of the U1815 code.

How much does it typically cost to fix the U1815 code in a Cadillac?

The cost of fixing the U1815 code can vary depending on the exact cause of the issue, labor rates, and parts needed for the repair. It is advisable to get a few quotes from reputable mechanics or dealerships.

Are there any preventive measures to avoid the U1815 code in a Cadillac?

Routine maintenance, such as checking the electrical connections and keeping the vehicle's software up to date, can help prevent the occurrence of the U1815 code in a Cadillac.