AutoCodes – GMC – P2456 GMC

P2456 GMC Code - Diesel Particulate Filter Differential Pressure Sensor Circuit Intermittent

Quick Answer

The diesel exhaust aftertreatment system consists of an underhood pre-catalytic converter and an underbody catalyst converter. Common causes include Faulty Diesel Particulate Filter (DPF) Pressure Sensor, Diesel Particulate Filter Pressure Sensor harness is open or shorted, Diesel Particulate Filter Pressure Sensor 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: P2456 GMC indicates Diesel Particulate Filter Differential Pressure Sensor Circuit Intermittent.
Common causes: Common causes include Faulty Diesel Particulate Filter (DPF) Pressure Sensor, Diesel Particulate Filter Pressure Sensor harness is open or shorted, Diesel Particulate Filter Pressure Sensor 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 1,590

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jul 28, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P2456 GMC Description

The diesel exhaust aftertreatment system consists of an underhood pre-catalytic converter and an underbody catalyst converter. The underbody catalyst converter also consists of the main Diesel Oxidation Catalyst and the coated Diesel Particulate Filter (DPF). One of the main purposes of the DPF is to collect particulates from the engine exhaust in order to minimize discharge of soot to the atmosphere. The soot particles accumulate in the channels of the DPF and are burned off at regular intervals through a process called regeneration. This prevents the DPF from clogging. The Engine Control Module (ECM) commands the DPF regeneration after calculating various vehicle conditions such as DPF pressure difference, exhaust gas temperature, engine oil quality, engine speed, etc. Excessive accumulation of the soot in the DPF can cause a drop in the engine performance. During regeneration, additional fuel is injected via multiple post injections in order to increase the exhaust gas temperature. During this period, the DPF temperature is raised to approximately 600°C (1112°F) and the accumulated soot is oxidized or burned off into carbon dioxide (CO2). The Diagnostic Trouble Code (DTC) will be set when the ECM detects an implausible DPF differential pressure sensor signal.

OBDII Code P2456 GMC - Diesel Particulate Filter Differential Pressure Sensor Circuit Intermittent - AutoCodes.com — P2456 GMC Code - Diesel Particulate Filter Differential Pressure Sensor Circuit Intermittent

What does this mean?

What are the Possible Causes of the DTC P2456 GMC?

Faulty Diesel Particulate Filter (DPF) Pressure Sensor
Diesel Particulate Filter Pressure Sensor harness is open or shorted
Diesel Particulate Filter Pressure Sensor circuit poor electrical connection
Diesel particulate filter pressure sensor connecting hose is loose, cracked, or missing
Faulty Engine Control Module (ECM)

How to Fix the DTC P2456 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 P2456 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.

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Need more information on how to fix the P2456 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 P2456 GMC Code

1. What are the common symptoms of OBDII code P2456 in a GMC vehicle?

Symptoms may include the check engine light illuminating, reduced engine performance, increased fuel consumption, and potential regeneration issues with the diesel particulate filter.

2. What are the possible causes of the Diesel Particulate Filter Differential Pressure Sensor Circuit Intermittent code in a GMC?

Common causes include a faulty differential pressure sensor, wiring or connector issues, exhaust system leaks, clogged DPF, or a malfunctioning powertrain control module.

3. How serious is the P2456 code in a GMC vehicle?

While the vehicle may still be operable with this code, it is important to address it promptly to prevent potential long-term damage to the diesel particulate filter and ensure optimal engine performance.

4. Can I continue driving my GMC with the P2456 code present?

It is generally not recommended to drive the vehicle for an extended period with this code active, as it can lead to increased emissions, reduced fuel efficiency, and potential performance issues.

5. How can I diagnose and repair the P2456 code in my GMC?

Diagnosis typically involves inspecting the differential pressure sensor, checking for wiring issues, and verifying the condition of the diesel particulate filter. Repair may involve sensor replacement, addressing wiring faults, cleaning or replacing the DPF, or reprogramming the PCM.

6. Will resetting the check engine light make the P2456 code go away permanently?

Simply clearing the code without addressing the underlying issue will not permanently resolve the problem. It is important to diagnose the root cause and perform the necessary repairs to prevent the code from reoccurring.

7. Can a DIY enthusiast fix the P2456 code in a GMC, or is professional assistance required?

Depending on your skill level and access to tools, DIY repair may be possible for simpler tasks like sensor replacement or checking for loose connections. However, complex issues such as DPF cleaning or PCM reprogramming may require professional assistance.

8. Are there any maintenance tips to prevent the P2456 code from appearing in the future?

Regularly servicing your vehicle, using high-quality diesel fuel, and driving at highway speeds periodically to aid DPF regeneration can help prevent issues that trigger the P2456 code.

9. How long does it typically take to repair the P2456 code in a GMC?

The repair time can vary based on the specific cause of the code and the complexity of the fix. It could range from a quick sensor replacement to a more involved DPF cleaning or repair, potentially taking a few hours to a full day.

10. Is it safe to ignore the P2456 code and continue driving my GMC?

While the vehicle may still be driveable with this code, ignoring it can lead to decreased fuel efficiency, potential engine damage, and emission control system issues. It is advisable to address the problem as soon as possible.