AutoCodes – Mercury – U012D Mercury

U012D Mercury Code - Lost Communication With Generator Control Module

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Generator Control Module, Generator Control Module harness is open or shorted, Generator 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: U012D Mercury indicates Lost Communication With Generator Control Module.
Common causes: Common causes include Faulty Generator Control Module, Generator Control Module harness is open or shorted, Generator 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 567

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 31, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U012D 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 periodic message from the Generator Control Module has not been received.

OBDII Code U012D Mercury - Lost Communication With Generator Control Module - AutoCodes.com — U012D Mercury Code - Lost Communication With Generator Control Module

What does this mean?

What are the Possible Causes of the DTC U012D Mercury?

Faulty Generator Control Module
Generator Control Module harness is open or shorted
Generator Control Module circuit poor electrical connection

How to Fix the DTC U012D 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 U012D 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.

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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 U012D Mercury Code

1. What are the common symptoms of OBDII code U012D in a Mercury vehicle?

- Common symptoms include issues with the charging system, dimming lights, battery draining quickly, and the battery warning light illuminating on the dashboard.

2. What can cause the OBDII code U012D "Lost Communication With Generator Control Module" in a Mercury?

- Possible causes include a faulty generator control module, damaged wiring or connectors, a weak battery, or a software communication issue.

3. How can I diagnose the OBDII code U012D in my Mercury?

- Diagnosis involves using a professional OBDII scanner to retrieve the code, checking the wiring and connectors for any damage, testing the generator control module, and ensuring the battery is in good condition.

4. Is it safe to continue driving my Mercury with the U012D trouble code?

- It is not recommended to drive your vehicle with this code, as it can lead to potential charging system failure and unexpected stalling on the road.

5. Can I repair the U012D code in my Mercury by simply resetting the fault code?

- Resetting the fault code may temporarily clear the warning light, but it will not fix the underlying issue causing the communication problem with the generator control module.

6. How much does it typically cost to repair the U012D code in a Mercury?

- The cost of repair can vary depending on the exact cause of the communication failure, but it may involve replacing the generator control module, repairing wiring, or addressing battery issues. Costs can range from a few hundred to over a thousand dollars.

7. Are there any DIY repair tips for addressing the U012D code in my Mercury?

- DIY repair tips include checking for loose or damaged wiring, ensuring the battery connections are secure, and consulting the vehicle's service manual for specific troubleshooting steps.

8. Can a mechanic easily fix the U012D code in my Mercury, or does it require specialized expertise?

- A mechanic with experience in diagnosing and repairing electrical issues in vehicles should be able to effectively address the U012D trouble code in your Mercury.

9. Will fixing the U012D code improve the overall performance and reliability of my Mercury?

- Yes, addressing the communication problem with the generator control module can help restore proper charging system functionality, ensuring your Mercury operates smoothly and reliably.

10. Is the U012D code specific to Mercury vehicles, or can it occur in other car makes and models?

- While the U012D code is associated with Mercury vehicles, similar communication issues with the generator control module can occur in other car makes and models as well.