AutoCodes – Generic – U1305

U1305 Code - High Or Low Voltage On Class 2 Serial Data Circuit

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Repair other code first. 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: U1305 indicates High Or Low Voltage On Class 2 Serial Data Circuit.
Common causes: Common causes include Repair other code first.
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 14,545

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 May 16, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U1305 Description

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. In addition to this, Node Alive messages are transmitted by each module on the class 2 serial data circuit about once every 2 seconds. When the module detects one of the following conditions on the class 2 serial data circuit for approximately 3 seconds, the setting of all other class 2 serial communication Diagnostic Trouble Code (DTC) is inhibited and a DTC will set.

OBDII Code U1305 - High Or Low Voltage On Class 2 Serial Data Circuit - AutoCodes.com — U1305 Code - High Or Low Voltage On Class 2 Serial Data Circuit

What does this mean?

What are the Possible Causes of the DTC U1305?

Repair other code first

How to Fix the DTC U1305?

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 does this mean?

Code Tech Notes

In most cases, the P1305 code is combined with other codes, fix other codes first.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U1305 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 U1305 code?

Need more information on how to fix the U1305 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1305 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U1305 Buick — High Or Low Voltage On Class 2 Serial Data Circuit
U1305 Cadillac — High Or Low Voltage On Class 2 Serial Data Circuit
U1305 Chevrolet — High Or Low Voltage On Class 2 Serial Data Circuit
U1305 GMC — High Or Low Voltage On Class 2 Serial Data Circuit
U1305 Infiniti — Around View Monitor Control Unit Configuration Unfinish
U1305 Nissan — Around View Monitor Control Unit Configuration Unfinish
U1305 Pontiac — High Or Low Voltage On Class 2 Serial Data Circuit

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 U1305 Code

1. What are the common symptoms of OBDII code U1305?

- Common symptoms include issues with communication between vehicle modules, intermittent or complete loss of communication on the data bus, and various warning lights on the dashboard.

2. What are the possible causes of OBDII code U1305?

- Possible causes include damaged wiring or connectors in the Class 2 serial data circuit, faulty modules on the data bus, low or high voltage issues, or a malfunctioning PCM.

3. How can I diagnose OBDII code U1305?

- Diagnosis involves using a scan tool to communicate with the vehicle's PCM and other modules to identify the source of the communication error. Checking for loose connections or damaged wiring is also crucial.

4. Can OBDII code U1305 be triggered by a dead battery?

- Yes, a dead or low battery voltage can cause communication issues on the Class 2 serial data circuit, potentially triggering code U1305.

5. How can I repair OBDII code U1305?

- Repair steps may include repairing or replacing damaged wiring, ensuring secure connections, checking and replacing faulty modules, and resetting the fault code with a scan tool after repairs are made.

6. Will OBDII code U1305 prevent my vehicle from starting?

- In some cases, code U1305 can lead to starting issues if the communication error affects critical systems. It's important to address the underlying cause promptly.

7. Can extreme weather conditions trigger OBDII code U1305?

- Yes, extreme temperatures or moisture can affect the electrical connections and components in the data bus, potentially leading to code U1305.

8. Is it safe to drive with OBDII code U1305 present?

- It is not recommended to drive with unresolved communication issues in the vehicle's data bus, as it can impact the functionality of various systems and compromise safety.

9. How long does it take to fix OBDII code U1305?

- The repair time for code U1305 varies depending on the cause of the issue. Simple fixes like reconnecting loose wires may take a short time, while diagnosing and repairing more complex issues can be time-consuming.

10. Can a DIY enthusiast fix OBDII code U1305 at home?

- DIY enthusiasts with knowledge of automotive electrical systems may be able to diagnose and repair simple causes of code U1305, but complex issues may require professional assistance.