AutoCodes – Generic – U0025

U0025 Code - Low Speed CAN Communication Bus (-) Low

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: U0025 indicates Low 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 10,594

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 U0025 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 U0025 - Low Speed CAN Communication Bus (-) Low - AutoCodes.com — U0025 Code - Low Speed CAN Communication Bus (-) Low

What does this mean?

What are the Possible Causes of the DTC U0025?

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 U0025?

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 U0025 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 U0025 code?

Need more information on how to fix the U0025 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0025 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 U0025 Code

1. What are the common symptoms of OBDII code U0025 (Low Speed CAN Communication Bus (-) Low)?

- Common symptoms include issues with the vehicle's communication systems, such as problems with the instrument cluster, warning lights, and other electronic components.

2. What are the possible causes of the U0025 code?

- The U0025 code is typically caused by wiring or connection issues in the Low Speed CAN communication network, faulty control modules, or a malfunctioning CAN bus.

3. How can I diagnose the U0025 code?

- To diagnose the U0025 code, you will need a diagnostic scanner capable of reading OBDII codes. You may also need to inspect the wiring harness, connectors, and control modules related to the Low Speed CAN network.

4. Can a DIYer repair the U0025 code issue?

- While some DIYers may be able to address wiring or connection issues causing the U0025 code, diagnosing and repairing faults in the CAN bus system may require advanced diagnostic tools and expertise, so professional help is recommended.

5. What are some repair tips for fixing the U0025 code?

- Repair tips for the U0025 code may include checking and repairing any damaged wiring or connectors, ensuring proper grounding, and resetting the fault codes after addressing the root cause of the issue.

6. Is it safe to continue driving with the U0025 code present?

- It is not recommended to drive the vehicle with the U0025 code present, as it may lead to further communication failures in critical systems, potentially affecting the vehicle's performance and safety.

7. Can weather conditions affect the occurrence of the U0025 code?

- Extreme weather conditions, such as severe cold or heat, can sometimes exacerbate wiring and connection issues that trigger the U0025 code, so it's essential to keep the vehicle well-maintained in all conditions.

8. How much does it typically cost to repair the U0025 code?

- The cost of repairing the U0025 code can vary depending on the underlying cause of the issue, the labor rates of the repair shop, and the need for replacement parts. It's advisable to obtain estimates from multiple service providers.

9. Will resetting the fault codes make the U0025 code disappear permanently?

- Resetting the fault codes without addressing the root cause of the U0025 code will only clear the code temporarily. The issue causing the fault code will likely trigger it again until properly repaired.

10. Can a dead battery cause the U0025 code to appear?

- A dead or low battery voltage can sometimes trigger communication errors and fault codes like U0025. Ensuring the battery is in good condition and properly charged is essential for diagnosing and repairing this code.