AutoCodes – GMC – P2BAB GMC

P2BAB GMC Code - NOx Exceedance - Incorrect EGR Flow

Quick Answer

The selective catalytic reduction system reduces oxides of nitrogen (NOx) emissions by injecting a metered amount of diesel exhaust fluid or reductant into the exhaust gas stream entering the diesel particulate filter (DPF). Common causes include Faulty NOx Sensors, NOx Sensors harness is open or shorted, NOx Sensors 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: P2BAB GMC indicates NOx Exceedance - Incorrect EGR Flow.
Common causes: Common causes include Faulty NOx Sensors, NOx Sensors harness is open or shorted, NOx Sensors 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 1,446

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 01, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P2BAB GMC Description

The selective catalytic reduction system reduces oxides of nitrogen (NOx) emissions by injecting a metered amount of diesel exhaust fluid or reductant into the exhaust gas stream entering the diesel particulate filter (DPF). Within the selective catalytic reduction catalyst, the reductant reacts with the NOx to form nitrogen, carbon dioxide, and water vapor. Upstream and downstream NOx sensors provide the Engine Control Module (ECM) with engine-out and tailpipe-out NOx levels.
The ECM uses the 2 NOx sensors to control exhaust NOx levels. The NOx sensor measures the amount of NOx and oxygen in the exhaust system. The first NOx sensor is located at the outlet of the turbocharger and monitors the engine out NOx. The second NOx sensor is located in the DPF that monitors NOx levels exiting the DPF. The ECM varies the amount of reductant added by varying the reductant injector duty cycle in response to changes in engine exhaust out NOx levels.

OBDII Code P2BAB GMC - NOx Exceedance - Incorrect EGR Flow - AutoCodes.com — P2BAB GMC Code - NOx Exceedance - Incorrect EGR Flow

What does this mean?

What are the Possible Causes of the DTC P2BAB GMC?

Faulty NOx Sensors
NOx Sensors harness is open or shorted
NOx Sensors circuit poor electrical connection
Fualty Diesel Particulate Filter (DPF)

How to Fix the DTC P2BAB 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2BAB 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 P2BAB GMC code?

Need more information on how to fix the P2BAB GMC 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 P2BAB GMC Code

1. What does the OBDII code P2BAB GMC indicate?

The P2BAB code on a GMC vehicle points to NOx Exceedance due to Incorrect EGR Flow.

2. What are common symptoms of the P2BAB GMC code?

Common symptoms include rough idling, reduced engine performance, and increased fuel consumption.

3. What can cause the P2BAB GMC code to trigger?

The code is often triggered by a dysfunctional Exhaust Gas Recirculation (EGR) valve or a clogged EGR system.

4. How can I diagnose the cause of the P2BAB code on my GMC?

To diagnose the issue, perform a visual inspection of the EGR components, check for vacuum leaks, and test the EGR valve functionality.

5. What are some repair tips for addressing the P2BAB code?

Repair tips include cleaning or replacing the EGR valve, clearing any obstructions in the EGR system, and ensuring proper vacuum supply to the EGR valve.

6. Can driving with the P2BAB code unresolved cause further damage to my GMC vehicle?

Continuing to drive with the P2BAB code can lead to increased emissions, reduced fuel efficiency, and potential damage to the catalytic converter.

7. Is it safe to temporarily reset the P2BAB code using an OBDII scanner?

While you can reset the code temporarily, it is essential to address the underlying issue promptly to prevent long-term damage to the vehicle.

8. Does the P2BAB code on a GMC always require professional repair?

Depending on your mechanical skills, you may be able to address the issue yourself by cleaning or replacing the EGR components. However, professional help may be needed for complex repairs.

9. How long does it typically take to repair the P2BAB GMC code?

The repair time can vary based on the exact cause of the issue. Simple fixes like cleaning the EGR valve may take a few hours, while more complex repairs could require a day or more.

10. Can a P2BAB GMC code be prevented in the future?

Regular maintenance, such as cleaning the EGR system during tune-ups, using high-quality fuel, and driving your GMC responsibly, can help prevent the recurrence of the P2BAB code.