AutoCodes – GMC – P30B4 2015 GMC Sierra

P30B4 2015 GMC Sierra Code - NOx Sensor 1 Signal Message Counter Incorrect

Quick Answer

Control modules connected to the serial data circuits monitor the communication during normal vehicle operation. Common causes include Faulty NOx Sensor 1, NOx Sensor 1 harness is open or shorted, NOx Sensor 1 circuit poor electrical connection. 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: P30B4 2015 GMC Sierra indicates NOx Sensor 1 Signal Message Counter Incorrect.
Common causes: Common causes include Faulty NOx Sensor 1, NOx Sensor 1 harness is open or shorted, NOx Sensor 1 circuit poor electrical connection.
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 159

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 Sep 29, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P30B4 2015 GMC Sierra Description

Control modules connected to the serial data circuits monitor the communication during normal vehicle operation. Operating information and commands are exchanged among the control modules. Each module on the serial data circuit maintains a transmit error counter and a receive error counter. The counter values increase with detected errors and decrease with error-free messages. The Diagnostic Trouble Code (DTC) will be set when the NOx Sensor 1 Signal Message Counter is Incorrect.

OBDII Code P30B4 2015 GMC Sierra - NOx Sensor 1 Signal Message Counter Incorrect - AutoCodes.com — P30B4 2015 GMC Sierra Code - NOx Sensor 1 Signal Message Counter Incorrect

What does this mean?

What are the Possible Causes of the DTC P30B4 2015 GMC Sierra?

Faulty NOx Sensor 1
NOx Sensor 1 harness is open or shorted
NOx Sensor 1 circuit poor electrical connection

How to Fix the DTC P30B4 2015 GMC Sierra?

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 P30B4 2015 GMC Sierra 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 P30B4 2015 GMC Sierra code?

Need more information on how to fix the P30B4 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 P30B4 2015 GMC Sierra Code

1. What does the OBDII code P30B4 mean on a 2015 GMC Sierra?

The code P30B4 indicates an issue with the NOx Sensor 1, specifically that its signal message counter is incorrect or not functioning as expected.

2. What are the symptoms of the P30B4 code on a GMC Sierra?

Common symptoms include the check engine light turning on, reduced engine performance, increased fuel consumption, and possible limp mode activation.

3. What causes the P30B4 code to appear?

This code is typically caused by a faulty NOx sensor, wiring or connector issues, software glitches in the engine control module (ECM), or contamination of the sensor.

4. Can I drive my 2015 GMC Sierra with the P30B4 code?

While it may be possible to drive the vehicle, it is not recommended as it can lead to decreased performance, higher emissions, and potential damage to the emissions system.

5. How do I diagnose the P30B4 code on my GMC Sierra?

Diagnosing this code involves checking the NOx sensor for proper operation, inspecting the wiring and connectors for damage or corrosion, and using a scan tool to verify sensor data and ECM communication.

6. How do I fix the P30B4 code on a 2015 GMC Sierra?

Repairs may include replacing the faulty NOx sensor, repairing damaged wiring or connectors, or updating the ECM software if a firmware issue is detected.

7. How much does it cost to fix the P30B4 code on a GMC Sierra?

The cost can vary, but replacing a NOx sensor typically ranges from $300 to $700, including parts and labor. Additional costs may apply if wiring repairs or ECM updates are needed.

8. Can a bad NOx sensor damage other parts of my truck?

Yes, a faulty NOx sensor can cause improper emissions system operation, potentially leading to damage in components like the catalytic converter or diesel particulate filter (DPF).

9. How can I prevent the P30B4 code from recurring?

Regular maintenance, proper fuel quality, and timely repairs of emissions-related components can help prevent this code from recurring.

10. Does the P30B4 code require reprogramming the ECM?

In some cases, the ECM may need to be reprogrammed or updated if the issue is related to a software glitch. A professional diagnosis can determine if this is necessary.