AutoCodes – Lincoln – U0004 Lincoln

U0004 Lincoln Code - High Speed CAN Communication Bus (+) Low

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: U0004 Lincoln indicates High Speed CAN Communication Bus (+) Low.
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 1,156

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 U0004 Lincoln 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) U0004 sets when a High Speed Controller Area Network (HS-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 U0004 Lincoln - High Speed CAN Communication Bus (+) Low - AutoCodes.com — U0004 Lincoln Code - High Speed CAN Communication Bus (+) Low

What does this mean?

What are the Possible Causes of the DTC U0004 Lincoln?

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 U0004 Lincoln?

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 U0004 Lincoln 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 U0004 Lincoln code?

Need more information on how to fix the U0004 Lincoln code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0004 Lincoln 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 U0004 Lincoln Code

1. What are common symptoms of the U0004 OBDII code in a Lincoln vehicle?

- Common symptoms include intermittent or complete loss of communication with various control modules, malfunction indicator light (MIL) illumination, and potential drivability issues.

2. What can cause the U0004 code to trigger in a Lincoln car?

- The U0004 code is typically triggered by a low voltage condition on the High Speed CAN Communication Bus (+) circuit, often due to damaged wiring, loose connections, or faulty control modules.

3. How can I diagnose the U0004 code in my Lincoln vehicle?

- To diagnose the U0004 code, you will need a professional OBDII scanner to read the code, inspect the wiring and connectors for damage, check control modules for proper operation, and perform a thorough electrical system check.

4. Can I still drive my Lincoln with the U0004 code present?

- It is not recommended to drive your vehicle with the U0004 code present, as it can lead to potential safety hazards and further damage to the vehicle's control systems.

5. What are some repair tips for fixing the U0004 code in a Lincoln car?

- Repair tips include checking and repairing any damaged wiring or connectors, ensuring proper ground connections, replacing faulty control modules, and clearing the code to see if it returns.

6. Is the U0004 OBDII code specific to Lincoln vehicles only?

- No, the U0004 code is a generic OBDII code related to High Speed CAN Communication Bus issues and can be found in various vehicle makes and models, not limited to Lincolns.

7. How much does it typically cost to repair the U0004 code in a Lincoln car?

- Repair costs for the U0004 code can vary depending on the exact cause of the issue, but expect to pay for diagnostic fees, parts replacement, and labor, which can range from a few hundred to over a thousand dollars.

8. Can a DIY enthusiast fix the U0004 code issue in a Lincoln vehicle?

- While some basic troubleshooting steps can be performed by a DIY enthusiast, diagnosing and repairing the U0004 code may require specialized tools and expertise, making it more suitable for professional mechanics.

9. Will resetting the OBDII system clear the U0004 code in my Lincoln?

- Resetting the OBDII system may temporarily clear the U0004 code, but if the underlying issue is not addressed and fixed, the code is likely to return upon driving the vehicle again.

10. How urgent is it to address the U0004 code in a Lincoln car?

- It is recommended to address the U0004 code as soon as possible to prevent potential safety risks and further damage to the vehicle's communication systems.