AutoCodes – GMC – U1305 GMC

U1305 GMC 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 GMC 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 6,360

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

What does this mean?

What are the Possible Causes of the DTC U1305 GMC?

Repair other code first

How to Fix the DTC U1305 GMC?

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 GMC 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 GMC code?

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

Need Help with the Code?

Get the U1305 GMC 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 U1305 GMC Code

1. What are the common symptoms of OBDII code U1305 in a GMC vehicle?

- Common symptoms include intermittent or total loss of communication with various control modules, erratic behavior of electrical systems, and warning lights on the dashboard.

2. What are the possible causes of OBDII code U1305 in a GMC vehicle?

- The code U1305 can be caused by issues such as loose or corroded wiring connections, a faulty Class 2 serial data circuit, a malfunctioning control module, or a damaged communication network.

3. How can I diagnose the OBDII code U1305 in my GMC vehicle?

- Diagnosis typically involves checking the wiring harness and connectors for signs of damage, testing the voltage on the Class 2 serial data circuit, and using a scan tool to communicate with the different control modules in the vehicle.

4. Can a DIY enthusiast repair the OBDII code U1305 issue in a GMC vehicle?

- Depending on the root cause, DIY enthusiasts may be able to address the issue by checking and repairing wiring connections, replacing damaged components, or resetting the communication network using a scan tool.

5. Is it safe to continue driving with the OBDII code U1305 present in a GMC vehicle?

- It is not recommended to continue driving with the U1305 code active, as it can lead to further electrical system malfunctions and potential safety hazards. It is best to address the issue promptly.

6. How much does it typically cost to repair the OBDII code U1305 in a GMC vehicle?

- The cost of repairing the U1305 code can vary depending on the underlying cause. Simple fixes like repairing wiring connections may be relatively inexpensive, while replacing a control module or fixing a complex communication network issue can be more costly.

7. Can extreme weather conditions affect the occurrence of OBDII code U1305 in a GMC vehicle?

- Yes, extreme weather conditions such as extreme heat or cold can sometimes exacerbate electrical issues leading to the U1305 code. It is important to keep the vehicle well maintained to prevent such issues.

8. Are there any preventive measures to avoid encountering the OBDII code U1305 in a GMC vehicle?

- Regular maintenance, including checking and cleaning wiring connections, ensuring proper grounding, and addressing any electrical issues promptly, can help prevent the occurrence of the U1305 code in a GMC vehicle.