AutoCodes – GMC – P040B 2015 GMC Sierra

P040B 2015 GMC Sierra Code - Exhaust Gas Recirculation Temperature Sensor 2 Performance

Quick Answer

The Exhaust Gas Recirculation (EGR) temperature sensors are variable resistors that measure the temperature of the exhaust gas at the inlet and outlet of the EGR cooler. Common causes include Faulty Exhaust Gas Recirculation (EGR) Temperature Sensor 2, Exhaust Gas Recirculation Temperature Sensor 2 harness is open or shorted, Exhaust Gas Recirculation Temperature Sensor 2 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: P040B 2015 GMC Sierra indicates Exhaust Gas Recirculation Temperature Sensor 2 Performance.
Common causes: Common causes include Faulty Exhaust Gas Recirculation (EGR) Temperature Sensor 2, Exhaust Gas Recirculation Temperature Sensor 2 harness is open or shorted, Exhaust Gas Recirculation Temperature Sensor 2 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 172

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 Jun 20, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P040B 2015 GMC Sierra Description

The Exhaust Gas Recirculation (EGR) temperature sensors are variable resistors that measure the temperature of the exhaust gas at the inlet and outlet of the EGR cooler. The Engine Control Module (ECM) supplies 5 volts to the EGR temperature sensor signal circuit and a ground for the low reference circuit. When the EGR temperature sensor is cold, the sensor resistance is high. When the EGR temperature increases, the sensor resistance decreases. The ECM detects a higher voltage on the EGR temperature signal circuit with high sensor resistance. With lower sensor resistance, the ECM detects a lower voltage on the EGR temperature signal circuit. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the EGR temperature sensor has not changed greater than a calibrated amount for greater than a calibrated amount of time following a cold start.

OBDII Code P040B 2015 GMC Sierra - Exhaust Gas Recirculation Temperature Sensor 2 Performance - AutoCodes.com — P040B 2015 GMC Sierra Code - Exhaust Gas Recirculation Temperature Sensor 2 Performance

What does this mean?

What are the Possible Causes of the DTC P040B 2015 GMC Sierra?

Faulty Exhaust Gas Recirculation (EGR) Temperature Sensor 2
Exhaust Gas Recirculation Temperature Sensor 2 harness is open or shorted
Exhaust Gas Recirculation Temperature Sensor 2 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P040B 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 P040B 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 P040B 2015 GMC Sierra 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 P040B 2015 GMC Sierra Code

1. What does OBDII code P040B mean on a 2015 GMC Sierra?

Code P040B indicates an issue with the performance of Exhaust Gas Recirculation (EGR) Temperature Sensor 2, which monitors the temperature of gases in the EGR system.

2. What are the common symptoms of code P040B in a 2015 GMC Sierra?

Symptoms may include the check engine light turning on, reduced fuel efficiency, rough idling, decreased engine performance, or increased emissions.

3. What causes the P040B code to appear in a GMC Sierra?

Common causes include a faulty EGR temperature sensor, wiring issues such as shorts or open circuits, excessive carbon buildup in the EGR system, or a malfunctioning EGR valve.

4. Can I drive my 2015 GMC Sierra with a P040B code?

It is possible to drive with this code, but prolonged operation can lead to reduced engine performance, potential damage to the emissions system, and increased pollution.

5. How do I diagnose the P040B code on my GMC Sierra?

Diagnosis involves checking the EGR temperature sensor and its wiring for damage, using a scan tool to monitor sensor readings, and inspecting the EGR system for carbon buildup or blockages.

6. How do I fix the P040B code on a 2015 GMC Sierra?

Repairs may include replacing the faulty EGR temperature sensor, cleaning the EGR system, repairing damaged wiring, or replacing the EGR valve if needed.

7. How much does it cost to repair a P040B code on a GMC Sierra?

The cost of repairs depends on the issue but typically ranges from $100 to $300 for parts and labor, with EGR temperature sensor replacement being the most common fix.

8. Can a dirty EGR system cause the P040B code?

Yes, excessive carbon deposits in the EGR system can interfere with sensor readings and trigger the code.

9. Will resetting the code clear the P040B issue permanently?

Resetting the code may turn off the check engine light temporarily, but the issue will likely reoccur unless the underlying problem is repaired.

10. Is the EGR temperature sensor 2 the same as EGR temperature sensor 1?

No, EGR temperature sensor 2 is a separate sensor and typically monitors a different part of the EGR system. Both sensors work together to ensure proper system operation.