AutoCodes – Buick – U1024 Buick

U1024 Buick Code - Lost Communications With Transmission 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 Transmission Control Module (TCM), Transmission Control Module harness is open or shorted, Transmission 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: U1024 Buick indicates Lost Communications With Transmission Control Module.
Common causes: Common causes include Faulty Transmission Control Module (TCM), Transmission Control Module harness is open or shorted, Transmission 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 498

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code U1024 Buick 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) U1024 is set.

OBDII Code U1024 Buick - Lost Communications With Transmission Control Module - AutoCodes.com — U1024 Buick Code - Lost Communications With Transmission Control Module

What does this mean?

What are the Possible Causes of the DTC U1024 Buick?

Faulty Transmission Control Module (TCM)
Transmission Control Module harness is open or shorted
Transmission Control Module circuit poor electrical connection

How to Fix the DTC U1024 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 U1024 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.

Need more information about the U1024 Buick code?

Need more information on how to fix the U1024 Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1024 Buick code diagnosed by a professional: Find a repair shop in your area

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 U1024 Buick Code

1. What does the OBDII code U1024 mean on a Buick?

U1024 indicates a loss of communication between the Engine Control Module (ECM) and the Transmission Control Module (TCM), which can affect vehicle performance.

2. What are common symptoms of the U1024 code in a Buick?

Symptoms may include the transmission staying in a single gear (limp mode), harsh shifting, dashboard warning lights like the check engine light, or reduced engine performance.

3. What causes the U1024 code in a Buick?

Common causes include damaged wiring or connections, a faulty Transmission Control Module (TCM), a malfunctioning Engine Control Module (ECM), or network communication issues on the CAN bus.

4. Can a weak battery cause the U1024 code in a Buick?

Yes, a weak or failing battery can cause voltage drops, leading to communication problems between modules and triggering the U1024 code.

5. How do you diagnose the U1024 code on a Buick?

Diagnosis involves using an OBDII scanner to confirm the code, visually inspecting wiring and connectors, testing the CAN bus network, and checking module power and ground connections.

6. Is it safe to drive a Buick with the U1024 code?

Driving with the U1024 code is not recommended, as it can lead to unpredictable transmission behavior or further damage to critical components.

7. How do you fix the U1024 code in a Buick?

Repairs may include fixing or replacing damaged wiring, reconnecting loose connectors, reprogramming or replacing the TCM or ECM, and ensuring proper CAN bus communication.

8. Does the U1024 code always mean the TCM is bad?

No, the U1024 code doesnâ€™t always indicate a bad TCM. It could result from wiring issues, a failing ECM, or network communication faults.

9. What tools are needed to troubleshoot the U1024 code on a Buick?

Youâ€™ll need an OBDII scanner with CAN bus monitoring capabilities, a multimeter for electrical testing, and wiring diagrams for your specific Buick model.

10. Can a software update fix the U1024 code in a Buick?

In some cases, a software update may resolve communication issues between the ECM and TCM if the problem is due to outdated programming.