AutoCodes – Mercury – U0018 Mercury

U0018 Mercury Code - Medium Speed CAN Communication Bus (-) Shorted To Bus (+)

Quick Answer

Multiplexing is a method of sending 2 or more signals simultaneously over a single circuit. Common causes include Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s), Check for more codes, Faulty Control Module. 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: U0018 Mercury indicates Medium Speed CAN Communication Bus (-) Shorted To Bus (+).
Common causes: Common causes include Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s), Check for more codes, Faulty Control Module.
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 660

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 Mar 29, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0018 Mercury Description

Multiplexing is a method of sending 2 or more signals simultaneously over a single circuit. Multiplexing allows 2 or more electronic modules (nodes) to communicate over a twisted wire pair [data (+) and data (-)] network. The information or messages that can be communicated on these wires consists of commands, status or data. Multiplexing reduces the weight of the vehicle by reducing the number of redundant components and electrical wiring. The vehicle has 4 module communication networks connected to the DLC, located under the instrument panel. The communication networks are: HEV High Speed Controller Area Network (HS-CAN), High Speed Controller Area Network (HS-CAN), Medium Speed Controller Area Network (MS-CAN) and Infotainment Controller Area Network (I-CAN). The Diagnostic Trouble Code (DTC) U0018 sets when a Medium Speed Controller Area Network (MS-CAN) fault was present at a point in time. The fault is not currently present since the module is communicating with the scan tool.

OBDII Code U0018 Mercury - Medium Speed CAN Communication Bus (-) Shorted To Bus (+) - AutoCodes.com — U0018 Mercury Code - Medium Speed CAN Communication Bus (-) Shorted To Bus (+)

What does this mean?

What are the Possible Causes of the DTC U0018 Mercury?

Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s)
Check for more codes
Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC U0018 Mercury?

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 U0018 Mercury 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 U0018 Mercury code?

Need more information on how to fix the U0018 Mercury code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0018 Mercury code diagnosed by a professional: Find a repair shop in your area

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 U0018 Mercury Code

1. What are common symptoms of a U0018 OBDII code in a Mercury?

- Common symptoms include intermittent or complete loss of communication with various control modules, the illumination of the check engine light, and potential transmission shifting issues.

2. What can cause the U0018 code to appear in a Mercury?

- The U0018 code typically indicates a short circuit between the Medium Speed CAN communication bus positive and negative lines, which can be caused by damaged wiring, loose connections, or faulty control modules.

3. How do I diagnose the U0018 code in my Mercury?

- Diagnosing the U0018 code involves inspecting the CAN bus wiring for damage, checking for loose connections, and using a diagnostic scanner to communicate with the affected control modules to identify the specific issue.

4. Can a U0018 code be triggered by a faulty control module in a Mercury?

- Yes, a faulty control module can cause the U0018 code to appear if it is shorting the Medium Speed CAN communication bus positive and negative lines. Replacing the faulty module may be necessary to resolve the issue.

5. Are there any repair tips for fixing the U0018 code in a Mercury?

- Repair tips for the U0018 code include carefully inspecting the wiring harness for damage, ensuring all connections are secure, and using a multimeter to check for continuity and shorts in the CAN bus circuit.

6. Is it safe to drive my Mercury with a U0018 code present?

- It is not recommended to drive your Mercury with a U0018 code present, as it can lead to communication issues between various control modules and potentially affect the vehicle's performance and safety systems.

7. How much does it typically cost to repair a U0018 code in a Mercury?

- The cost of repairing a U0018 code in a Mercury can vary depending on the underlying cause of the issue, but it may involve replacing damaged wiring, repairing connections, or replacing faulty control modules, which can range from a few hundred to a few thousand dollars.

8. Can a DIY enthusiast fix a U0018 code in a Mercury?

- Depending on the individual's skill level and access to tools, a DIY enthusiast may be able to diagnose and repair a U0018 code in a Mercury by following repair manuals, online guides, and utilizing diagnostic equipment.

9. Will resetting the OBDII code clear the U0018 code in a Mercury?

- Resetting the OBDII code may temporarily clear the U0018 code, but if the underlying issue causing the code is not addressed, it is likely to reappear once the vehicle is driven and the system detects the fault again.

10. How urgent is it to address a U0018 code in a Mercury?

- It is recommended to address a U0018 code in a Mercury as soon as possible to prevent potential communication issues between control modules, performance issues, and further damage to the vehicle's electrical system.