AutoCodes – GMC – U18AD GMC

U18AD GMC 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 GMC 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 512

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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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 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 U18AD GMC - Transmission Range Control Module Lost Communication With Electronic Brake Control Module On Chassis Expansion CAN Bus - AutoCodes.com — U18AD GMC 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 GMC?

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 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 U18AD 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 U18AD GMC Code

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

- Common symptoms include transmission shifting issues, illuminated warning lights on the dashboard, and possible loss of communication between the transmission range control module and electronic brake control module.

2. What does the OBDII code U18AD GMC indicate?

- The code U18AD indicates a loss of communication between the Transmission Range Control Module and Electronic Brake Control Module on the Chassis Expansion CAN Bus.

3. What are the possible causes of code U18AD GMC being triggered?

- The code may be triggered by wiring issues, faulty modules, a damaged CAN bus circuit, or a software communication error between the modules.

4. How can I diagnose the U18AD code on my GMC vehicle?

- Diagnosing the U18AD code typically involves using a diagnostic scanner to retrieve the code, checking the connections and wiring between the affected modules, and performing a thorough inspection of the CAN bus circuit.

5. Can I continue driving my vehicle with the U18AD code present?

- It is not recommended to continue driving your vehicle with the U18AD code present, as it may lead to further transmission and brake control issues, compromising safety and overall vehicle performance.

6. How can I repair the U18AD code on my GMC vehicle?

- Repairing the U18AD code may involve repairing or replacing damaged wiring, addressing any module faults, reprogramming the modules, or resetting the communication between the affected modules.

7. Is it necessary to visit a dealership or mechanic for U18AD code repair?

- While it is recommended to seek professional help for diagnosing and repairing the U18AD code, some DIY enthusiasts with advanced automotive knowledge may be able to address the issue themselves with the right tools and resources.

8. Can a software update fix the U18AD code issue?

- In some cases, a software update provided by the manufacturer may resolve the communication error causing the U18AD code. It is advisable to check with a qualified technician for the appropriate software update.

9. How common is the U18AD code in GMC vehicles?

- The U18AD code is not extremely common but may occur in certain GMC vehicles due to various factors affecting the communication between the transmission range control module and electronic brake control module.

10. Will resetting the code using a diagnostic scanner fix the underlying issue?

- Simply resetting the U18AD code using a diagnostic scanner may temporarily clear the code, but it will not fix the underlying communication problem between the affected modules. It is crucial to address the root cause of the issue to prevent it from reoccurring.