AutoCodes – Generic – U0048

U0048 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: U0048 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 4,889

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 U0048 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 U0048 - Vehicle Communication Bus 'C' (+) Open - AutoCodes.com — U0048 Code - Vehicle Communication Bus 'C' (+) Open

What does this mean?

What are the Possible Causes of the DTC U0048?

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 U0048?

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 U0048 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 U0048 code?

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Need Help with the Code?

Get the U0048 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 U0048 Code

1. What does the OBDII code U0048 mean?

The U0048 code indicates an open circuit in the Vehicle Communication Bus 'C' (+), which is part of the network system that allows modules to communicate in the vehicle.

2. What are the common symptoms of the U0048 code?

Symptoms may include warning lights on the dashboard (e.g., check engine light), communication errors between vehicle modules, inoperative systems like ABS or traction control, or intermittent electrical issues.

3. What causes the U0048 code to appear?

Common causes include damaged or corroded wiring, loose or disconnected connectors, failed control modules, or water intrusion into the communication bus.

4. Can I still drive my car with the U0048 code?

Driving may still be possible, but critical systems like ABS, traction control, or other safety features might not function properly. Itâ€™s recommended to address the issue promptly.

5. How is the U0048 code diagnosed?

A technician will use a scan tool to check for additional codes, inspect the wiring and connectors associated with Bus 'C', and test the continuity of the communication circuit.

6. What repairs can fix the U0048 code?

Repairs might include repairing or replacing damaged wiring, cleaning corroded connectors, reseating loose connections, or replacing a faulty control module.

7. Can a low battery cause the U0048 code?

Yes, a weak or low battery can disrupt communication between modules and trigger this code. Ensure the battery and charging system are in good condition.

8. Is the U0048 code specific to certain car brands?

No, U0048 is a generic OBDII code, but its exact troubleshooting and repair steps might vary depending on the vehicle make and model.

9. How much does it cost to fix the U0048 code?

Costs can vary widely depending on the cause, ranging from $100 for simple wiring repairs to several hundred dollars if a control module needs replacement.

10. Can I fix the U0048 code myself?

If you're comfortable with basic electrical diagnostics, you can inspect and repair wiring or connectors. For complex issues like module replacement, professional assistance is recommended.