AutoCodes – Mercury – U0028 Mercury

U0028 Mercury Code - Vehicle Communication Bus 'A' Bus Off

Quick Answer

The Restraint Control Module (RCM) supplies the stability/traction control system with accelerometer data over a dedicated Controller Area Network (CAN). Common causes include Faulty Restraint Control Module (RCM), Restraint Control Module (RCM) harness is open or shorted, Restraint Control Module (RCM) 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: U0028 Mercury indicates Vehicle Communication Bus 'A' Bus Off.
Common causes: Common causes include Faulty Restraint Control Module (RCM), Restraint Control Module (RCM) harness is open or shorted, Restraint Control Module (RCM) 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 730

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 U0028 Mercury Description

The Restraint Control Module (RCM) supplies the stability/traction control system with accelerometer data over a dedicated Controller Area Network (CAN). If the RCM detects a fault with communications with the dedicated CAN circuits, it sets Diagnostic Trouble Code (DTC) U0028. The RCM does not request the Instrument Panel Control (IPC) to illuminate the airbag warning indicator if DTC U0028 is set.

OBDII Code U0028 Mercury - Vehicle Communication Bus 'A' Bus Off - AutoCodes.com — U0028 Mercury Code - Vehicle Communication Bus 'A' Bus Off

What does this mean?

What are the Possible Causes of the DTC U0028 Mercury?

Faulty Restraint Control Module (RCM)
Restraint Control Module (RCM) harness is open or shorted
Restraint Control Module (RCM) circuit poor electrical connection
Faulty Antilock Brake System (ABS) Module

How to Fix the DTC U0028 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 U0028 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 U0028 Mercury code?

Need more information on how to fix the U0028 Mercury code? Get Access to Factory Service Manuals

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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 U0028 Mercury Code

1. What are common symptoms of OBDII code U0028 in a Mercury vehicle?

- Common symptoms include loss of communication with various control modules, erratic behavior of electronic components, and warning lights on the dashboard.

2. What can cause the Vehicle Communication Bus 'A' Bus Off code U0028 in a Mercury?

- Possible causes include a faulty communication module, damaged wiring or connectors, software issues, or a problem with the vehicle's network architecture.

3. How can I diagnose the U0028 code in my Mercury?

- Diagnosis typically involves using a professional OBDII scanner to retrieve the code, checking for other related codes, inspecting wiring and connectors, and performing network communication tests.

4. Can a DIY enthusiast repair the U0028 code in a Mercury?

- While basic troubleshooting like checking connections and fuses can be done by DIYers, repairing the underlying cause of the code often requires specialized equipment and expertise, best left to professionals.

5. Is it safe to drive with OBDII code U0028 present in a Mercury?

- It is not recommended to drive with the U0028 code active, as it can lead to unreliable communication between critical vehicle systems, potentially affecting safety and performance.

6. How much does it cost to repair the Vehicle Communication Bus 'A' Bus Off code in a Mercury?

- Repair costs can vary significantly depending on the underlying issue. It is advisable to get a professional diagnosis to determine the exact cause and associated repair expenses.

7. Are there any preventive measures to avoid the U0028 code in a Mercury?

- Regular maintenance, including checking and addressing any communication system issues promptly, can help prevent the occurrence of the U0028 code in a Mercury vehicle.

8. Can a weak battery trigger the U0028 code in a Mercury?

- Yes, a weak or failing battery can cause voltage fluctuations that may disrupt communication on the vehicle bus network, potentially triggering the U0028 code.

9. Will resetting the code make it go away permanently in a Mercury?

- Resetting the code may temporarily clear the warning, but if the underlying issue causing the U0028 code is not addressed, it is likely to reappear once the system detects the problem again.

10. How long does it take to repair the U0028 code in a Mercury?

- The repair time for the U0028 code can vary depending on the specific cause and complexity of the issue. It is best to consult with a professional technician for an accurate estimate of repair time.