AutoCodes – Generic – U0026

U0026 Code - Low Speed CAN Communication Bus (-) High

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: U0026 indicates Low Speed CAN Communication Bus (-) High.
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 8,299

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 U0026 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 U0026 - Low Speed CAN Communication Bus (-) High - AutoCodes.com — U0026 Code - Low Speed CAN Communication Bus (-) High

What does this mean?

What are the Possible Causes of the DTC U0026?

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 U0026?

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 U0026 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 U0026 code?

Need more information on how to fix the U0026 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0026 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 U0026 Code

1. What does the OBDII code U0026 mean?

U0026 indicates a fault in the Low-Speed Controller Area Network (CAN) communication bus (-) line, typically signaling a high voltage issue or disruption in communication.

2. What are the symptoms of the U0026 code?

Symptoms may include warning lights on the dashboard (e.g., ABS, traction control), intermittent or complete loss of communication with certain modules, or erratic vehicle behavior.

3. What causes the U0026 code to appear?

Common causes include damaged or corroded wiring, loose or faulty electrical connections, malfunctioning control modules, or a short circuit in the CAN bus system.

4. Can I drive with the U0026 code active?

While the vehicle may still be drivable, it's not recommended as it could lead to further issues or reduced functionality of critical systems like ABS or traction control.

5. How do I diagnose the U0026 code?

Start by visually inspecting the CAN bus wiring and connections for damage or corrosion. Use a scan tool to check for other related codes and test the continuity and resistance of the CAN bus system.

6. What tools are needed to fix the U0026 code?

Youâ€™ll likely need a diagnostic scan tool, multimeter, wiring diagram, and possibly replacement wires or connectors if damage is found.

7. How much does it cost to repair the U0026 code?

Costs vary depending on the root cause. Simple repairs like fixing a loose connection might cost under $100, while replacing a faulty module could exceed $500.

8. Which modules are affected by the U0026 code?

Modules connected to the Low-Speed CAN bus, such as the body control module (BCM), ABS module, or other secondary systems, may be affected.

9. Can a low battery cause the U0026 code?

Yes, a low or failing battery can cause communication errors in the CAN bus system, potentially triggering the U0026 code.

10. How is the U0026 code typically fixed?

Repairs may include repairing or replacing damaged wiring, cleaning corroded connectors, ensuring proper grounding, or replacing a malfunctioning module.