AutoCodes – GMC – U18D3 GMC

U18D3 GMC Code - Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Transmission Range Control Module, Transmission Range Control Module harness is open or shorted, Transmission Range 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: U18D3 GMC indicates Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus.
Common causes: Common causes include Faulty Transmission Range Control Module, Transmission Range Control Module harness is open or shorted, Transmission Range 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 1,205

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 09, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18D3 GMC Description

Devices connected to the 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 a supervised periodic message that includes the transmitter device availability that has not been received.

OBDII Code U18D3 GMC - Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus - AutoCodes.com — U18D3 GMC Code - Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus

What does this mean?

What are the Possible Causes of the DTC U18D3 GMC?

Faulty Transmission Range Control Module
Transmission Range Control Module harness is open or shorted
Transmission Range Control Module circuit poor electrical connection

How to Fix the DTC U18D3 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 U18D3 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 U18D3 GMC Code

1. What are common symptoms of OBDII code U18D3 GMC?

The common symptoms of code U18D3 GMC include issues with shifting gears, transmission malfunctions, and the transmission being stuck in one gear.

2. What are possible causes of OBDII code U18D3 GMC?

Possible causes of code U18D3 GMC include a faulty transmission range selector control module, damaged wiring or connectors, a malfunctioning CAN bus, or software issues.

3. How can I diagnose OBDII code U18D3 GMC?

Diagnosing code U18D3 GMC involves using a scan tool to retrieve the code, checking for any other related codes, inspecting the transmission range selector control module, testing the wiring and connectors, and verifying communication on the CAN bus.

4. Can I continue driving with OBDII code U18D3 GMC?

It is not recommended to continue driving with code U18D3 GMC as it can lead to further transmission damage and safety hazards. It's best to address the issue promptly.

5. How can I repair OBDII code U18D3 GMC?

Repairing code U18D3 GMC may involve replacing the transmission range selector control module, repairing damaged wiring or connectors, reprogramming the module, or addressing any CAN bus communication issues.

6. Are there any DIY tips for fixing OBDII code U18D3 GMC?

While some basic checks like inspecting for loose connectors or damaged wires can be done DIY, it's recommended to seek professional help for diagnosing and repairing code U18D3 GMC due to the complexity of transmission systems.

7. How much does it cost to fix OBDII code U18D3 GMC?

The cost of fixing code U18D3 GMC can vary depending on the underlying issue, parts needed for repair, and labor costs. It's best to consult a mechanic for an accurate estimate.

8. Can a bad battery cause OBDII code U18D3 GMC?

A weak or failing battery can potentially cause communication issues on the CAN bus, which may trigger code U18D3 GMC. It's advisable to ensure the battery is in good condition as part of the diagnostic process.

9. Is code U18D3 GMC a serious problem?

Code U18D3 GMC should be addressed promptly as it can affect the proper functioning of the transmission system, leading to drivability issues and potential safety concerns.

10. How long does it take to fix OBDII code U18D3 GMC?

The repair time for code U18D3 GMC can vary depending on the exact cause of the issue and the complexity of the repair. Some fixes may be quick, while others might require more time for diagnosis and replacement of components.