AutoCodes – Generic – U18D3

U18D3 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 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 1,630

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

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?

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 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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Information for Specific Makes

U18D3 Buick — Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus
U18D3 Cadillac — Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus
U18D3 Chevrolet — Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus
U18D3 GMC — Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus

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 Code

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

The common symptoms of OBDII code U18D3 include difficulty shifting gears, transmission not engaging properly, illuminated transmission warning light, and possible limp mode operation.

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

The possible causes of OBDII code U18D3 include faulty transmission range selector control module, damaged wiring or connectors in the CAN bus system, software issues, or a malfunctioning powertrain control module (PCM).

3. How can I diagnose OBDII code U18D3?

Diagnosing OBDII code U18D3 typically involves using a diagnostic scanner to retrieve the code, checking the transmission range selector control module for faults, inspecting the wiring and connectors for damage, and performing a CAN bus communication test.

4. Can I still drive my vehicle with OBDII code U18D3?

It is not recommended to drive your vehicle with OBDII code U18D3, as it can lead to further damage to the transmission system. It is best to address the issue promptly to avoid potential safety hazards.

5. How can I repair OBDII code U18D3?

Repairing OBDII code U18D3 may involve replacing the faulty transmission range selector control module, repairing damaged wiring or connectors, updating software, or reprogramming the PCM. It is recommended to consult a qualified mechanic for proper diagnosis and repair.

6. Is OBDII code U18D3 a serious issue?

OBDII code U18D3 should be addressed promptly as it can affect the proper functioning of the transmission system. Ignoring this code may result in transmission failure or other serious drivability issues.

7. Can a DIY enthusiast fix OBDII code U18D3?

While some basic checks like inspecting wiring and connectors can be done by a DIY enthusiast, diagnosing and repairing OBDII code U18D3 may require specialized tools and expertise. It is advisable to seek professional help for accurate diagnosis and repair.

8. Will resetting the fault codes make OBDII code U18D3 disappear?

Simply resetting the fault codes may temporarily clear OBDII code U18D3, but the issue will likely reoccur if the underlying problem is not addressed. It is important to diagnose the root cause of the code and perform the necessary repairs.

9. How much does it cost to repair OBDII code U18D3?

The cost to repair OBDII code U18D3 can vary depending on the specific cause of the issue, the labor rates of the repair shop, and the cost of any necessary parts. It is recommended to obtain multiple quotes from different mechanics to compare prices.

10. Can extreme weather conditions trigger OBDII code U18D3?

Extreme weather conditions, especially those that can cause damage to wiring or connectors, may contribute to triggering OBDII code U18D3. It is important to ensure that the electrical components are properly protected to prevent weather-related issues.