AutoCodes – Chevrolet – U18A9 Chevrolet

U18A9 Chevrolet Code - Lost Communication With Transmission Range 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 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: U18A9 Chevrolet indicates Lost Communication With Transmission Range Control Module On Chassis 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 523

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 U18A9 Chevrolet 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 U18A9 Chevrolet - Lost Communication With Transmission Range Control Module On Chassis Expansion CAN Bus - AutoCodes.com — U18A9 Chevrolet Code - Lost Communication With Transmission Range Control Module On Chassis Expansion CAN Bus

What does this mean?

What are the Possible Causes of the DTC U18A9 Chevrolet?

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 U18A9 Chevrolet?

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 U18A9 Chevrolet 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 U18A9 Chevrolet Code

1. What are the common symptoms of OBDII code U18A9 in a Chevrolet related to lost communication with the transmission range control module?

- Common symptoms include transmission shifting issues, engine stalling, and illuminated warning lights on the dashboard.

2. What could be the possible causes triggering OBDII code U18A9 in a Chevrolet for lost communication with the transmission range control module?

- Possible causes may include faulty wiring or connectors, a malfunctioning transmission range control module, or issues with the CAN bus communication system.

3. How can I diagnose the root cause of OBDII code U18A9 in a Chevrolet indicating lost communication with the transmission range control module?

- Diagnosing this issue typically involves performing a thorough inspection of the wiring and connectors, testing the transmission range control module, and checking the CAN bus communication system for faults.

4. What are some repair tips for addressing OBDII code U18A9 in a Chevrolet associated with lost communication with the transmission range control module?

- Repair tips may include repairing or replacing damaged wiring or connectors, testing and potentially replacing the transmission range control module, and ensuring proper communication within the CAN bus system.

5. Can driving with OBDII code U18A9 present in a Chevrolet due to lost communication with the transmission range control module cause further damage?

- Continuing to drive with this code present can potentially lead to more severe transmission issues and may result in further damage, so it is advisable to address the problem promptly.

6. Is it safe to reset the OBDII code U18A9 in a Chevrolet without addressing the underlying issue of lost communication with the transmission range control module?

- Simply resetting the code without addressing the root cause may temporarily clear the warning lights but will not resolve the communication problem and could lead to recurring issues.

7. How much does it typically cost to repair OBDII code U18A9 in a Chevrolet related to lost communication with the transmission range control module?

- Repair costs can vary depending on the specific cause of the issue, but expenses may include parts replacement, labor fees, and diagnostic charges, potentially ranging from a few hundred to over a thousand dollars.

8. Can a DIY enthusiast with automotive knowledge fix OBDII code U18A9 in a Chevrolet caused by lost communication with the transmission range control module?

- While some basic troubleshooting and repairs can be attempted by DIY enthusiasts, diagnosing and fixing issues related to the transmission range control module and CAN bus communication system may require specialized tools and expertise best handled by professional technicians.

9. Are there any recalls or technical service bulletins related to OBDII code U18A9 in Chevrolet vehicles for lost communication with the transmission range control module?

- It is recommended to check with Chevrolet dealerships or online databases for any recalls or technical service bulletins addressing this specific OBDII code and related issues in Chevrolet vehicles.

10. How can regular maintenance help prevent OBDII code U18A9 from occurring in a Chevrolet due to lost communication with the transmission range control module?

- Regular maintenance, including inspections of wiring and connectors, can help identify potential issues early on and prevent the occurrence of communication failures with components like the transmission range control module.