AutoCodes – Cadillac – U1023 Cadillac

U1023 Cadillac Code - Lost Communications With Hybrid Control Module

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Faulty Hybrid Control Module (HCM), Hybrid Control Module harness is open or shorted, Hybrid 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: U1023 Cadillac indicates Lost Communications With Hybrid Control Module.
Common causes: Common causes include Faulty Hybrid Control Module (HCM), Hybrid Control Module harness is open or shorted, Hybrid 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 462

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 Apr 22, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1023 Cadillac Description

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for the state of health monitoring/node alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module node alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a Diagnostic Trouble Code (DTC) U1023 is set.

OBDII Code U1023 Cadillac - Lost Communications With Hybrid Control Module - AutoCodes.com — U1023 Cadillac Code - Lost Communications With Hybrid Control Module

What does this mean?

What are the Possible Causes of the DTC U1023 Cadillac?

Faulty Hybrid Control Module (HCM)
Hybrid Control Module harness is open or shorted
Hybrid Control Module circuit poor electrical connection

How to Fix the DTC U1023 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 U1023 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 U1023 Cadillac Code

1. What does the OBDII code U1023 for Cadillac mean?

The code U1023 indicates a communication problem between the vehicle's onboard computer system and the hybrid control module.

2. What are the common symptoms of U1023 code in a Cadillac?

Common symptoms of the U1023 code include the hybrid system not engaging properly, reduced fuel efficiency, and potential drivability issues.

3. What are some common causes of the U1023 code in a Cadillac?

Common causes of the U1023 code include faulty wiring connections, a defective hybrid control module, software issues, or a problem with the onboard network communication system.

4. How can I diagnose the U1023 code in my Cadillac?

Diagnosing the U1023 code typically involves using a diagnostic scanner to retrieve the code, checking for any other related codes, inspecting wiring connections, and testing the hybrid control module for faults.

5. Can I continue driving my Cadillac with the U1023 code present?

It is not recommended to continue driving your Cadillac with the U1023 code present, as it may lead to further damage to the hybrid system or affect the vehicle's overall performance.

6. How can I repair the U1023 code in my Cadillac?

Repairing the U1023 code may involve repairing or replacing faulty wiring connections, replacing the hybrid control module, updating software, or addressing any underlying communication system issues.

7. Can I reset the U1023 code in my Cadillac using an OBDII scanner?

Resetting the U1023 code with an OBDII scanner is possible, but it is recommended to diagnose and repair the underlying issue first to prevent the code from reappearing.

8. Are there any DIY tips for fixing the U1023 code in my Cadillac?

While some simple checks like inspecting wiring connections can be done DIY, diagnosing and repairing the U1023 code may require advanced diagnostic tools and technical knowledge best handled by a professional mechanic.

9. How much does it typically cost to repair the U1023 code in a Cadillac?

The cost of repairing the U1023 code in a Cadillac can vary depending on the underlying issue, parts needed for replacement, and labor costs. It is best to consult with a mechanic for an accurate estimate.

10. Can the U1023 code in a Cadillac be prevented?

Preventing the U1023 code involves regular vehicle maintenance, checking for any warning signs of communication issues, and addressing any related problems promptly to avoid more severe issues with the hybrid control module.