AutoCodes – Ford – U0004 Ford

U0004 Ford 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 Ford 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 3,573

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 Ford 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 Ford - High Speed CAN Communication Bus (+) Low - AutoCodes.com — U0004 Ford Code - High Speed CAN Communication Bus (+) Low

What does this mean?

What are the Possible Causes of the DTC U0004 Ford?

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 Ford?

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 Ford 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 Ford code?

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

Need Help with the Code?

Get the U0004 Ford 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 Ford Code

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

- Common symptoms include issues with the vehicle's transmission, engine performance, and the malfunction indicator light (MIL) being illuminated.

2. What are the possible causes of the U0004 code in a Ford vehicle?

- The code may be triggered by a fault in the High Speed CAN Communication Bus (+) circuit, such as damaged wiring, loose connections, or a defective control module.

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

- Diagnosing the code typically involves using a professional OBDII scanner to retrieve the specific fault codes and then conducting a thorough inspection of the High Speed CAN Communication Bus (+) circuit.

4. Can I drive my Ford vehicle with the U0004 code present?

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

5. What are some repair tips for resolving the U0004 code in a Ford vehicle?

- Repair tips may include checking and repairing any damaged wiring, ensuring all connections are secure, and replacing any faulty control modules related to the High Speed CAN Communication Bus (+) circuit.

6. Is it possible to reset the U0004 code in a Ford vehicle without repairs?

- While you can clear the code with an OBDII scanner, it is crucial to address the underlying issue causing the code to prevent it from reoccurring.

7. Are there any recalls related to the U0004 code in Ford vehicles?

- It is advisable to check with Ford or the National Highway Traffic Safety Administration (NHTSA) for any recalls or technical service bulletins related to the U0004 code in your specific vehicle model.

8. Can weather conditions affect the triggering of the U0004 code in a Ford vehicle?

- Extreme weather conditions, such as temperature fluctuations or moisture, can potentially impact the High Speed CAN Communication Bus (+) circuit and contribute to the code being triggered.

9. How much does it typically cost to repair the U0004 code in a Ford vehicle?

- The cost of repairing the U0004 code can vary depending on the specific cause of the issue, but it may involve labor costs for diagnosis and repair, as well as the cost of any necessary parts.

10. How can I prevent the U0004 code from appearing in my Ford vehicle in the future?

- Regular maintenance, including inspecting wiring and connections, keeping the vehicle's systems in good condition, and addressing any issues promptly, can help prevent the recurrence of the U0004 code.