Engine-CodesGMC – P2138 2015 GMC Sierra

P2138 2015 GMC Sierra Code - Accelerator Pedal Position Sensor 1-2 Correlation

Quick Answer

The P2138 diagnostic trouble code (DTC) for a 2015 GMC Sierra refers to an issue with the Accelerator Pedal Position Sensor 1-2 correlation. Common causes include Faulty accelerator pedal position sensors, Wiring issues or poor electrical connections, ECM software or hardware problems. 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
P2138 2015 GMC Sierra indicates Accelerator Pedal Position Sensor 1-2 Correlation.
Common causes
Common causes include Faulty accelerator pedal position sensors, Wiring issues or poor electrical connections, ECM software or hardware problems.
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.
Table of contents Created and updated by William Orellana on Sep 14, 2024
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Code P2138 2015 GMC Sierra Description

The P2138 diagnostic trouble code (DTC) for a 2015 GMC Sierra refers to an issue with the Accelerator Pedal Position Sensor 1-2 correlation. This code indicates that there is a discrepancy between the signals sent by the two accelerator pedal position sensors in the vehicle. In modern vehicles, there are typically two accelerator pedal position sensors for redundancy and safety reasons. These sensors are responsible for sending signals to the engine control module (ECM) to determine how much fuel and air should be delivered to the engine based on the driver's input.

OBDII Code P2138 2015 GMC Sierra - Accelerator Pedal Position Sensor 1-2 Correlation
P2138 2015 GMC Sierra Code - Accelerator Pedal Position Sensor 1-2 Correlation

Common Causes of P2138 2015 GMC Sierra

  1. Faulty accelerator pedal position sensors.
  2. Wiring issues or poor electrical connections.
  3. ECM software or hardware problems.
  4. Water or debris intrusion affecting sensor operation.
  5. Mechanical issues with the accelerator pedal assembly.

Symptoms of P2138 2015 GMC Sierra

  1. Poor acceleration or lack of response when pressing the accelerator pedal.
  2. Rough idling or stalling when coming to a stop.
  3. Check Engine Light illuminated on the dashboard.
  4. Vehicle going into limp mode, limiting speed and performance.
  5. Inconsistent throttle response or surging while driving.

How to Fix P2138 2015 GMC Sierra

  1. Begin by connecting a diagnostic scanner to the vehicle's OBD-II port to retrieve the trouble codes and confirm the P2138 code.
  2. Inspect the wiring and connectors associated with the accelerator pedal position sensors for any damage or corrosion. Repair or replace as needed.
  3. Test the accelerator pedal position sensors using a multimeter to ensure they are sending consistent signals to the ECM.
  4. If the sensors are found to be faulty, replace them with new OEM parts to ensure proper operation.
  5. Clear the trouble codes from the ECM's memory and perform a test drive to verify that the issue has been resolved.

Cost to Fix P2138 2015 GMC Sierra

The typical repair costs for addressing a P2138 code on a 2015 GMC Sierra can vary depending on the specific cause of the issue. In general, the cost of replacing the accelerator pedal position sensors and addressing any wiring or connector issues can range from $200 to $500. This estimate includes parts and labor, but it's important to note that prices may vary based on the location of the repair shop, the vehicle's make and model, and the specific rates charged for diagnosis and labor. It's recommended to consult with a trusted mechanic or dealership for a more accurate estimate based on your individual circumstances.

Tech Notes for P2138 2015 GMC Sierra









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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 P2138 2015 GMC Sierra Code

What does OBDII code P2138 mean for a 2015 GMC Sierra?

Code P2138 indicates a problem with the correlation between Accelerator Pedal Position Sensor 1 and Sensor 2, suggesting inconsistent signals from the pedal sensors.

What are the symptoms of code P2138 on a 2015 GMC Sierra?

Common symptoms include reduced engine power, the check engine light turning on, and difficulty accelerating or hesitation during throttle input.

What causes code P2138 on a 2015 GMC Sierra?

Typical causes include a faulty accelerator pedal position sensor, damaged wiring or connectors, or electrical issues such as corrosion or shorts.

Can I drive my 2015 GMC Sierra with code P2138 active?

While it may be possible to drive, the vehicle may enter "limp mode," reducing power and performance. Driving with this code is not recommended, as it could worsen underlying issues.

How is code P2138 diagnosed on a 2015 GMC Sierra?

Technicians typically use a scan tool to monitor live data from the pedal position sensors, inspect wiring and connectors for damage, and test the sensors for proper function.

How do I fix code P2138 on a 2015 GMC Sierra?

Repairs may include replacing the accelerator pedal position sensor, repairing or replacing damaged wiring, or cleaning corroded connectors.

What does "correlation" mean in the context of code P2138?

"Correlation" refers to the expected relationship between signals from Sensor 1 and Sensor 2 in the accelerator pedal position sensor. When these signals don’t align, the code is triggered.

Can cleaning the accelerator pedal position sensor fix code P2138?

Cleaning the sensor may help if dirt or debris is affecting its performance, but often replacement is needed if the sensor itself is faulty.

Is code P2138 a common issue for the 2015 GMC Sierra?

Yes, this code can occur frequently in GM vehicles, including the Sierra, due to issues with the pedal position sensors or related wiring.

How much does it cost to fix code P2138 on a 2015 GMC Sierra?

Repair costs can range from $100 to $300, depending on whether the accelerator pedal assembly needs replacement or just wiring repairs.

Discuss the causes and fixes for P2138 2015 GMC Sierra OBDII Code

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