AutoCodes – Generic – U1301

U1301 Code - High 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: U1301 indicates High 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 36,818

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 Nov 27, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U1301 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 U1301 - High Voltage On Class 2 Serial Data Circuit - AutoCodes.com — U1301 Code - High Voltage On Class 2 Serial Data Circuit

What does this mean?

What are the Possible Causes of the DTC U1301?

Repair other code first

How to Fix the DTC U1301?

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 U1301 code is combined with other codes, fix other codes first.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U1301 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 U1301 code?

Need more information on how to fix the U1301 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1301 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U1301 Buick — High Voltage On Class 2 Serial Data Circuit
U1301 Cadillac — High Voltage On Class 2 Serial Data Circuit
U1301 Chevrolet — High Voltage On Class 2 Serial Data Circuit
U1301 GMC — High Voltage On Class 2 Serial Data Circuit
U1301 Pontiac — High Voltage On Class 2 Serial Data Circuit
U1301 Saturn — High 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 U1301 Code

1. What does OBDII code U1301 mean?

Code U1301 indicates a high voltage condition on the Class 2 Serial Data Circuit, which is used for communication between vehicle modules.

2. What are common symptoms of code U1301?

Symptoms may include warning lights on the dashboard (like the Check Engine Light), erratic or non-functioning gauges, communication issues between modules, or intermittent electrical problems.

3. What causes code U1301 to be triggered?

Potential causes include a short to voltage in the Class 2 data circuit, a faulty control module, damaged wiring, or poor electrical connections.

4. Can a weak battery cause code U1301?

Yes, a weak or failing battery can cause voltage irregularities that might trigger this code.

5. How do I diagnose code U1301?

Start by inspecting the wiring and connectors in the Class 2 data circuit for damage or corrosion. Use a scan tool to check for additional codes and perform continuity tests on the circuit.

6. Can code U1301 cause drivability issues?

Yes, depending on the affected modules, this code can result in erratic performance, communication failures, or loss of functionality in critical vehicle systems.

7. Is a faulty module a common cause of code U1301?

While possible, a faulty module is less common than damaged wiring or poor connections. Always rule out wiring issues before replacing a module.

8. How can I resolve code U1301?

Repair or replace damaged wiring, clean corroded connectors, and ensure proper grounding. If necessary, replace a faulty module after confirming it as the root cause.

9. Can code U1301 clear itself?

In rare cases, the code may clear temporarily if the issue is intermittent, but the underlying problem must be resolved to prevent its recurrence.

10. Is driving with code U1301 safe?

Driving may be unsafe if critical systems are affected, such as the ABS or power steering. Itâ€™s best to address the issue promptly to avoid further complications.