P2138 2018 GMC Sierra Code - Accelerator Pedal Position Sensor 1-2 Correlation
Quick Answer
The P2138 diagnostic trouble code (DTC) for a 2018 GMC Sierra refers to an issue with the correlation between Accelerator Pedal Position Sensor 1 and Sensor 2. Common causes include Faulty Accelerator Pedal Position Sensor 1 or Sensor 2, Wiring or connection issues between the sensors and the engine control module, Corrosion or damage to sensor connectors. 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 2018 GMC Sierra indicates Accelerator Pedal Position Sensor 1-2 Correlation.
- Common causes
- Common causes include Faulty Accelerator Pedal Position Sensor 1 or Sensor 2, Wiring or connection issues between the sensors and the engine control module, Corrosion or damage to sensor connectors.
- 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 P2138 2018 GMC Sierra Description
The P2138 diagnostic trouble code (DTC) for a 2018 GMC Sierra refers to an issue with the correlation between Accelerator Pedal Position Sensor 1 and Sensor 2. In simpler terms, this means that the signals from these two sensors do not match up as expected, which can lead to a variety of performance issues in the vehicle. The Accelerator Pedal Position Sensor is responsible for communicating the position of the accelerator pedal to the engine control module, which then determines how much fuel to inject and how to adjust other parameters for optimal performance. When there is a correlation issue between these sensors, the engine may not respond correctly to driver inputs, leading to poor acceleration, rough idling, and potential safety concerns.
Common Causes of P2138 2018 GMC Sierra
- Faulty Accelerator Pedal Position Sensor 1 or Sensor 2.
- Wiring or connection issues between the sensors and the engine control module.
- Corrosion or damage to sensor connectors.
- Issues with the engine control module.
- Mechanical issues affecting the sensors' ability to function properly.
Symptoms of P2138 2018 GMC Sierra
- Reduced acceleration or lack of response when stepping on the gas pedal.
- Rough idling or stalling at idle.
- Inconsistent or jerky acceleration.
- Illumination of the Check Engine Light on the dashboard.
- Reduced fuel efficiency.
How to Fix P2138 2018 GMC Sierra
- Perform a thorough inspection of the Accelerator Pedal Position Sensors and wiring harness for any visible damage or corrosion.
- Test the sensors using a multimeter to check for proper resistance values and signal output.
- Replace any faulty sensors or wiring harness components as needed.
- Clear the DTC from the vehicle's computer using a diagnostic scanner.
- Perform a test drive to ensure that the issue has been resolved and that the sensors are now correlating properly.
Cost to Fix P2138 2018 GMC Sierra
The cost of repairing a P2138 code on a 2018 GMC Sierra can vary depending on the specific cause of the issue and the labor rates in your area. Generally, replacing the Accelerator Pedal Position Sensor can cost between $100 and $200, while labor costs can range from $80 to $150 per hour. Overall, you can expect to pay anywhere from $200 to $400 for parts and labor to address this issue. It's recommended to consult with a trusted mechanic or repair shop for a more accurate estimate based on your vehicle's specific needs.
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Frequently Asked Questions about P2138 2018 GMC Sierra Code
1. What does the OBDII code P2138 mean on a 2018 GMC Sierra?
P2138 indicates a correlation issue between the Accelerator Pedal Position (APP) Sensor 1 and Sensor 2, meaning the signals from the two sensors do not match as expected.
2. What are the common symptoms of code P2138 in a 2018 GMC Sierra?
Symptoms may include reduced engine power mode, hesitation during acceleration, throttle response issues, or the illumination of the check engine light.
3. What causes the P2138 code in a 2018 GMC Sierra?
Common causes include a faulty accelerator pedal position sensor, damaged wiring or connectors, a failing throttle body, or issues with the vehicle's powertrain control module (PCM).
4. How does the accelerator pedal position sensor work in a 2018 GMC Sierra?
The APP sensor monitors the position of the accelerator pedal and sends two separate signals to the PCM to ensure proper throttle control and safety redundancy.
5. Can I drive my 2018 GMC Sierra with the P2138 code active?
While the truck may still run, driving with P2138 active is not recommended as it can lead to unsafe conditions, such as sudden loss of throttle response or reduced power mode.
6. How do you diagnose the P2138 code on a 2018 GMC Sierra?
Diagnosis typically includes scanning for other codes, inspecting the APP sensor and its wiring for damage, checking the throttle body operation, and testing the voltage signals from the APP sensors.
7. How do you fix the P2138 code on a 2018 GMC Sierra?
Repairs may involve replacing the accelerator pedal assembly, repairing damaged wiring or connectors, cleaning or replacing the throttle body, or updating/replacing the PCM.
8. Is the P2138 code specific to the accelerator pedal?
While the APP sensor is the most common cause, the issue can also stem from the throttle body, wiring, or PCM, so a thorough diagnosis is essential.
9. How much does it cost to repair the P2138 code on a 2018 GMC Sierra?
Costs vary but typically range from $150 to $400, depending on whether the issue is the APP sensor, wiring, or throttle body.
10. Can a dirty throttle body cause the P2138 code on a 2018 GMC Sierra?
Yes, a dirty or malfunctioning throttle body can cause signal discrepancies, leading to the P2138 code. Cleaning or replacing the throttle body may resolve the issue.
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