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Engine-Codes – GMC – P2122 2018 GMC Sierra

P2122 2018 GMC Sierra Code - Accelerator Pedal Position Sensor 1 Circuit Low Voltage

Quick Answer

The P2122 diagnostic trouble code (DTC) in a 2018 GMC Sierra indicates a problem with the Accelerator Pedal Position Sensor 1 Circuit, specifically low voltage. Common causes include Faulty accelerator pedal position sensor, Wiring or connector issues in the sensor circuit, Corrosion or damage to sensor components. 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
P2122 2018 GMC Sierra indicates Accelerator Pedal Position Sensor 1 Circuit Low Voltage.
Common causes
Common causes include Faulty accelerator pedal position sensor, Wiring or connector issues in the sensor circuit, Corrosion or damage to sensor components.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P2122 2018 GMC Sierra Description

The P2122 diagnostic trouble code (DTC) in a 2018 GMC Sierra indicates a problem with the Accelerator Pedal Position Sensor 1 Circuit, specifically low voltage. This sensor is responsible for sending signals to the engine control module (ECM) regarding the position of the accelerator pedal, which in turn adjusts the fuel delivery and ignition timing to control the vehicle's speed and performance. When the voltage from the sensor falls below the expected range, it can lead to issues with engine performance and drivability.

OBDII Code P2122 2018 GMC Sierra - Accelerator Pedal Position Sensor 1 Circuit Low Voltage
P2122 2018 GMC Sierra Code - Accelerator Pedal Position Sensor 1 Circuit Low Voltage

Common Causes of P2122 2018 GMC Sierra

  1. Faulty accelerator pedal position sensor
  2. Wiring or connector issues in the sensor circuit
  3. Corrosion or damage to sensor components
  4. ECM software or hardware problems
  5. Electrical issues such as a low battery voltage or poor ground connections

Symptoms of P2122 2018 GMC Sierra

  1. Hesitation or lack of response when pressing the accelerator pedal
  2. Reduced power output or difficulty maintaining speed
  3. Rough idling or irregular engine performance
  4. Stalling or difficulty starting the engine
  5. Vehicle entering limp mode or displaying a reduced engine power warning

How to Fix P2122 2018 GMC Sierra

  1. Begin by conducting a thorough inspection of the accelerator pedal position sensor and its wiring harness for any visible damage or corrosion.
  2. Use a multimeter to test the voltage output of the sensor and compare it to the manufacturer's specifications. If the voltage is too low, the sensor may need to be replaced.
  3. Check the wiring harness and connectors for any signs of wear or poor connections. Repair or replace any damaged components as needed.
  4. Clear the DTC from the ECM using an OBD-II scanner and perform a test drive to ensure the issue has been resolved.
  5. If the problem persists, seek professional assistance to diagnose more complex electrical or ECM-related issues.

Cost to Fix P2122 2018 GMC Sierra

The cost of repairing a P2122 code on a 2018 GMC Sierra can vary depending on the specific cause of the issue. In general, replacing the accelerator pedal position sensor can range from $100 to $300, while addressing wiring or connector problems may add additional labor costs. Overall, the total repair bill could amount to $200 to $500, including parts and labor. It's important to note that diagnostic time and labor rates at auto repair shops can fluctuate based on location and other factors, so it's advisable to obtain quotes from multiple sources before proceeding with the repair.

What does this mean?

Tech Notes for P2122 2018 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 P2122 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code P2122 in a 2018 GMC Sierra?

- Common symptoms include poor acceleration, reduced engine power, and the illumination of the Check Engine light.

2. What does the OBDII code P2122 for Accelerator Pedal Position Sensor 1 Circuit Low Voltage indicate in a 2018 GMC Sierra?

- This code indicates that there is a low voltage condition detected in the circuit of the accelerator pedal position sensor.

3. What are the potential causes of OBDII code P2122 in a 2018 GMC Sierra?

- Potential causes include a faulty accelerator pedal position sensor, damaged wiring or connectors in the sensor circuit, or issues with the vehicle's electronic control module.

4. How can I diagnose the cause of OBDII code P2122 in my 2018 GMC Sierra?

- Diagnosing the issue involves checking the accelerator pedal position sensor for proper operation, inspecting the sensor wiring and connectors for damage, and scanning the vehicle's computer for related trouble codes.

5. Can I still drive my 2018 GMC Sierra with OBDII code P2122?

- It is not recommended to drive with this code present, as it can lead to reduced performance and potential safety issues. It is best to address the problem promptly.

6. How can I repair OBDII code P2122 in my 2018 GMC Sierra?

- Repair involves replacing the faulty accelerator pedal position sensor, repairing any damaged wiring or connectors, and clearing the trouble codes from the vehicle's computer.

7. Are there any DIY tips for addressing OBDII code P2122 in a 2018 GMC Sierra?

- While basic inspections can be done, it is recommended to have a qualified mechanic diagnose and repair the issue to ensure proper resolution.

8. Will resetting the trouble codes fix OBDII code P2122 in a 2018 GMC Sierra?

- Resetting the codes may temporarily turn off the Check Engine light, but if the underlying issue is not addressed, the code is likely to reappear.

9. How much does it typically cost to fix OBDII code P2122 in a 2018 GMC Sierra?

- The cost can vary depending on the specific cause of the issue and labor rates, but it may involve expenses for sensor replacement, wiring repairs, and diagnostic fees.

10. Can weather conditions affect OBDII code P2122 in a 2018 GMC Sierra?

- Extreme weather conditions, such as excessive heat or moisture, can potentially impact sensor performance and contribute to the occurrence of this code.

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