AutoCodes – Generic – U0035

U0035 Code - Vehicle Communication Bus 'A' (-) 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: U0035 indicates Vehicle Communication Bus 'A' (-) 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 4,414

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 U0035 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 U0035 - Vehicle Communication Bus 'A' (-) High - AutoCodes.com — U0035 Code - Vehicle Communication Bus 'A' (-) High

What does this mean?

What are the Possible Causes of the DTC U0035?

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 U0035?

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 U0035 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 U0035 code?

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Need Help with the Code?

Get the U0035 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 U0035 Code

1. What are the common symptoms of OBDII code U0035?

The common symptoms of OBDII code U0035 include communication issues between control modules, warning lights on the dashboard, erratic behavior of vehicle systems, and difficulty starting the vehicle.

2. What are the possible causes of OBDII code U0035?

Possible causes of OBDII code U0035 include damaged wiring or connectors in the communication bus 'A', a faulty control module, issues with the power or ground connections, or a software glitch within the vehicle's system.

3. How can I diagnose OBDII code U0035?

Diagnosing OBDII code U0035 involves using a diagnostic scanner to read the code, checking the communication bus 'A' for any visible damage, inspecting wiring and connectors for continuity, and performing tests to identify the root cause of the communication failure.

4. Can I still drive my vehicle with OBDII code U0035?

It is not recommended to drive your vehicle with OBDII code U0035 present, as it can lead to further electrical issues and potential safety hazards. It is best to address the problem promptly to avoid any complications.

5. How can I repair OBDII code U0035?

Repairing OBDII code U0035 may involve repairing or replacing damaged wiring or connectors, resetting the control modules, checking and fixing any power or ground connection issues, or reprogramming the control modules to resolve the communication problem.

6. Are there any DIY tips for fixing OBDII code U0035?

While some basic troubleshooting steps can be performed by DIY enthusiasts, diagnosing and repairing OBDII code U0035 may require specialized tools and expertise. It is recommended to consult a professional mechanic for accurate diagnosis and repair.

7. How much does it cost to fix OBDII code U0035?

The cost to fix OBDII code U0035 can vary depending on the underlying cause of the issue, the extent of the repairs needed, and the labor rates of the repair shop. It is advisable to obtain multiple quotes from reputable mechanics to compare costs.

8. Can a low battery voltage trigger OBDII code U0035?

Low battery voltage can potentially affect the operation of control modules and communication buses, leading to the triggering of OBDII code U0035. Ensuring a properly charged battery is essential to prevent such issues.

9. Will resetting the OBDII code U0035 make it go away permanently?

Resetting the OBDII code U0035 may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to return. It is crucial to diagnose and repair the root cause of the problem to prevent further occurrences.

10. How can I prevent OBDII code U0035 from reoccurring?

To prevent OBDII code U0035 from reoccurring, regular vehicle maintenance, ensuring proper electrical connections, and addressing any communication issues promptly can help maintain the health of the communication bus 'A' and control modules.