AutoCodes – Generic – U18AD

U18AD Code - Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis 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 Electronic Brake Control Module (EBCM), Electronic Brake Control Module harness is open or shorted, Electronic Brake 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: U18AD indicates Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis Expansion CAN Bus.
Common causes: Common causes include Faulty Electronic Brake Control Module (EBCM), Electronic Brake Control Module harness is open or shorted, Electronic Brake 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 505

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 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18AD 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 U18AD - Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis Expansion CAN Bus - AutoCodes.com — U18AD Code - Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis Expansion CAN Bus

What does this mean?

What are the Possible Causes of the DTC U18AD?

Faulty Electronic Brake Control Module (EBCM)
Electronic Brake Control Module harness is open or shorted
Electronic Brake Control Module circuit poor electrical connection

How to Fix the DTC U18AD?

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 U18AD 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 U18AD code?

Need more information on how to fix the U18AD code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U18AD code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U18AD Buick — Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis Expansion CAN Bus
U18AD Cadillac — Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis Expansion CAN Bus
U18AD Chevrolet — Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis Expansion CAN Bus
U18AD GMC — Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis 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 U18AD Code

1. What are the common symptoms of OBDII code U18AD?

The common symptoms of code U18AD include the transmission not shifting properly, the vehicle going into limp mode, and warning lights such as the check engine light or transmission warning light illuminating on the dashboard.

2. What does the OBDII code U18AD indicate?

Code U18AD indicates that there is a communication problem between the Transmission Range Control Module and the Electronic Brake Control Module on the Chassis Expansion CAN Bus.

3. What are the possible causes of OBDII code U18AD?

Possible causes of code U18AD include damaged wiring or connectors between the Transmission Range Control Module and Electronic Brake Control Module, a faulty Transmission Range Control Module, a faulty Electronic Brake Control Module, or issues with the CAN bus communication network.

4. How can I diagnose OBDII code U18AD?

Diagnosing code U18AD involves checking the wiring and connectors between the Transmission Range Control Module and Electronic Brake Control Module, testing the modules for proper functionality, and inspecting the CAN bus network for any faults.

5. How can I repair OBDII code U18AD?

Repairing code U18AD may involve repairing or replacing damaged wiring and connectors, replacing a faulty Transmission Range Control Module or Electronic Brake Control Module, or addressing any issues with the CAN bus communication network.

6. Can I continue driving my vehicle with OBDII code U18AD?

It is not recommended to continue driving your vehicle with code U18AD present, as it can lead to transmission issues and potentially affect the safety and performance of the vehicle. It is best to address the problem promptly.

7. How much does it typically cost to repair OBDII code U18AD?

The cost of repairing code U18AD can vary depending on the specific cause of the issue, the extent of the repairs needed, and the labor rates of the repair shop. It is advisable to get a diagnostic and repair estimate from a qualified mechanic.

8. Is OBDII code U18AD a common issue in certain vehicle makes and models?

Code U18AD can be more common in vehicles that use the Chassis Expansion CAN Bus system for communication between modules. It is always recommended to check with the manufacturer or a dealership for any known issues related to this code in specific vehicle models.

9. Can a DIY enthusiast repair OBDII code U18AD at home?

While some basic diagnostics like checking wiring and connectors can be done at home, repairing code U18AD may require specialized tools and knowledge. It is advisable to consult with a qualified mechanic for proper diagnosis and repair of this code.

10. Will resetting the OBDII system clear code U18AD?

Resetting the OBDII system may temporarily clear the code, but if the underlying issue causing code U18AD is not addressed, the code is likely to return. It is important to diagnose and repair the root cause of the problem to prevent the code from reappearing.