AutoCodes – Generic – U0051

U0051 Code - Vehicle Communication Bus 'C' (-) Open

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: U0051 indicates Vehicle Communication Bus 'C' (-) Open.
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 4,190

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 U0051 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 U0051 - Vehicle Communication Bus 'C' (-) Open - AutoCodes.com — U0051 Code - Vehicle Communication Bus 'C' (-) Open

What does this mean?

What are the Possible Causes of the DTC U0051?

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 U0051?

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 U0051 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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Need Help with the Code?

Get the U0051 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 U0051 Code

1. What are common symptoms of OBDII code U0051?

Common symptoms of code U0051 include issues with the vehicle's communication system, such as difficulty starting the car, loss of power steering, and malfunctioning dashboard displays.

2. What does the code U0051 mean?

OBDII code U0051 indicates a problem with the Vehicle Communication Bus 'C' (-) Open, which means there is an open circuit or break in the communication network within the vehicle.

3. What are possible causes of the Vehicle Communication Bus 'C' (-) Open code?

Possible causes of code U0051 include damaged wiring or connectors in the communication network, faulty control modules, corrosion in the communication bus system, or a malfunctioning communication bus module.

4. How can I diagnose the cause of code U0051?

Diagnosing code U0051 typically involves using a diagnostic scanner to retrieve the trouble codes, inspecting the wiring and connectors in the communication system, checking for corrosion, and testing the control modules for proper functioning.

5. Can I still drive my vehicle with code U0051 present?

It is not recommended to drive your vehicle with code U0051 present, as it can lead to further communication issues within the vehicle, potentially causing safety hazards or malfunctions while driving.

6. How can I repair OBDII code U0051?

Repairing code U0051 may involve repairing or replacing damaged wiring or connectors, cleaning corrosion from the communication bus system, replacing faulty control modules, or resetting the communication bus module.

7. Can a DIY enthusiast fix code U0051?

While some aspects of diagnosing and repairing code U0051 may be within reach for experienced DIY enthusiasts, it is recommended to consult a professional mechanic or technician for accurate diagnosis and repair to ensure the issue is properly resolved.

8. Is OBDII code U0051 related to emissions or engine performance?

No, OBDII code U0051 is not directly related to emissions or engine performance. It pertains to the communication system within the vehicle and does not typically affect emissions or engine operation.

9. Are there any preventive measures to avoid code U0051?

To help prevent code U0051, it is advisable to regularly inspect the wiring and connectors in the vehicle's communication system, avoid water damage to the communication bus components, and address any electrical issues promptly.

10. How long does it typically take to repair code U0051?

The time required to repair code U0051 can vary depending on the specific cause of the issue and the complexity of the repair. Simple fixes like reconnecting loose wires may take a short time, while more involved repairs could take several hours or more.