AutoCodesGeneric – U0009

U0009 Code - High Speed CAN Communication Bus (-) Shorted To Bus (+)

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
U0009 indicates High Speed CAN Communication Bus (-) Shorted To Bus (+).
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.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 24,996
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Mar 29, 2020
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Code U0009 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 U0009 - High Speed CAN Communication Bus (-) Shorted To Bus (+) - AutoCodes.com
U0009 Code - High Speed CAN Communication Bus (-) Shorted To Bus (+)

What are the Possible Causes of the DTC U0009?

  • 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 U0009?

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 U0009 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 U0009 code?

Need more information on how to fix the U0009 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0009 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

  • U0009 Ford — High Speed CAN Communication Bus (-) Shorted To Bus (+)
  • U0009 Lincoln — High Speed CAN Communication Bus (-) Shorted To Bus (+)
  • U0009 Mercury — High Speed CAN Communication Bus (-) Shorted To Bus (+)
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 U0009 Code

1. What are the common symptoms of OBDII code U0009?

- Common symptoms include intermittent or complete loss of communication between modules on the high-speed CAN bus, dashboard warning lights, and potential drivability issues.

2. What could be causing the OBDII code U0009 to trigger?

- The code U0009 may be triggered by a short circuit between the high-speed CAN bus positive and negative wires, damaged wiring harness, faulty control modules, or water intrusion in the wiring system.

3. How can I diagnose the OBDII code U0009?

- Diagnosis involves inspecting the wiring harness for damage, checking for water intrusion, testing the high-speed CAN bus communication using a diagnostic scan tool, and checking for loose connections.

4. Can I drive my vehicle with the OBDII code U0009?

- It is not recommended to drive your vehicle with the U0009 code present, as it can lead to communication issues between critical modules, potentially affecting the vehicle's performance and safety.

5. How can I repair the OBDII code U0009?

- Repairing the U0009 code involves locating and repairing any short circuits in the high-speed CAN bus wiring, replacing damaged wiring harnesses, ensuring proper connections, and clearing the code with a diagnostic scan tool.

6. Is it possible to prevent the OBDII code U0009 from recurring?

- To prevent the U0009 code from recurring, it is essential to perform regular inspections of the wiring harness, avoid water exposure to the wiring system, and ensure all electrical connections are secure.

7. Can a DIY enthusiast fix the OBDII code U0009 at home?

- While diagnosing the U0009 code may be possible for experienced DIY enthusiasts with the necessary tools, repairing the high-speed CAN bus wiring or modules may require professional expertise to ensure proper repairs.

8. Will the OBDII code U0009 cause permanent damage to my vehicle if left unaddressed?

- Ignoring the U0009 code can lead to further communication issues between modules, potential drivability problems, and even permanent damage to sensitive electronic components in the vehicle.

9. What are the potential risks of driving with the OBDII code U0009 unresolved?

- Driving with the U0009 code unresolved can pose safety risks due to potential loss of critical communication between modules, affecting vital functions such as ABS, airbags, and engine management systems.

10. How long does it typically take to repair the OBDII code U0009?

- The repair time for the U0009 code can vary depending on the extent of the wiring damage and the complexity of the repair, ranging from a few hours to a full day in some cases.

Discuss the causes and fixes for U0009 OBDII Code

  • EL COCHE IVA POR LA AUTO PISTA Y SEPARO A LOS DE MINUTOS VOLVIÓ A PONERSE EN MARCHA AL 1 KM. SE VOLVIÓ A PARAR LE DI AL ARRANQUE Y SE PUSO EN MARCHA Y NO SE PARO MAS PERO LA LUZ DE CHECK MOTOR ESTA ENCENDIDA LE HICE UN CHEQUEO CON EL OBD. Y SALE EL ERROR U0009 High Speed CAN Communication Bus(-) shorted to Bus (+)

  • Que modelo y año es su vehiculo?

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