AutoCodes – Mercury – U0074 Mercury

U0074 Mercury Code - Control Module Communication Bus 'B' Off

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. 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: U0074 Mercury indicates Control Module Communication Bus 'B' Off.
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 696

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 U0074 Mercury Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U0074 Mercury - Control Module Communication Bus 'B' Off - AutoCodes.com — U0074 Mercury Code - Control Module Communication Bus 'B' Off

What does this mean?

What are the Possible Causes of the DTC U0074 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 U0074 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 U0074 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 U0074 Mercury code?

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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 U0074 Mercury Code

1. What are common symptoms of OBDII code U0074 in a Mercury vehicle?

- Common symptoms include the Check Engine light illuminating on the dashboard, poor acceleration, rough idling, and possible transmission shifting issues.

2. What does the OBDII code U0074 for Control Module Communication Bus 'B' Off mean in a Mercury?

- This code indicates a communication problem between various control modules in the vehicle, often leading to a loss of data exchange.

3. What are the possible causes of the U0074 code in a Mercury?

- The U0074 code can be triggered by issues such as faulty control modules, damaged wiring or connectors, a software glitch, or a problem with the communication network.

4. How can I diagnose the U0074 code in my Mercury?

- Diagnosing the U0074 code typically involves using a professional OBDII scanner to retrieve the specific details of the code and then inspecting the communication network, control modules, and related components for any faults.

5. Is it safe to continue driving with the U0074 code present in my Mercury?

- It is generally not recommended to drive with the U0074 code active, as it can lead to further communication issues between vital vehicle systems and potentially cause more serious problems.

6. How can I repair the U0074 code in my Mercury?

- Repairing the U0074 code involves addressing the root cause, which may include replacing faulty control modules, repairing damaged wiring, updating software, or resetting the communication network.

7. Can a DIY enthusiast fix the U0074 code issue in a Mercury?

- While some basic troubleshooting steps can be performed by a DIY enthusiast, resolving the U0074 code often requires advanced diagnostic tools and technical expertise, so seeking professional help is advisable.

8. Will resetting the OBDII system clear the U0074 code in my Mercury?

- Resetting the OBDII system may temporarily clear the code, but if the underlying issue causing the U0074 code is not addressed, it is likely to reappear once the system detects the problem again.

9. How much does it typically cost to repair the U0074 code in a Mercury?

- The cost of repairing the U0074 code can vary depending on the specific cause of the issue, but it may range from a few hundred to over a thousand dollars, considering parts and labor.

10. Can extreme weather conditions trigger the U0074 code in a Mercury?

- Yes, extreme weather conditions such as severe cold or heat can sometimes affect the communication network in a vehicle, potentially leading to the U0074 code being triggered.