P2138 2018 GMC Sierra Code - Accelerator Pedal Position Sensor 1-2 Correlation
Quick Answer
The Accelerator Pedal Assembly contains 2 Accelerator Pedal Position (APP) sensors. Common causes include Faulty Accelerator Pedal Position Sensor, Accelerator Pedal Position Sensor harness is open or shorted, Accelerator Pedal Position 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
- P2138 2018 GMC Sierra indicates Accelerator Pedal Position Sensor 1-2 Correlation.
- Common causes
- Common causes include Faulty Accelerator Pedal Position Sensor, Accelerator Pedal Position Sensor harness is open or shorted, Accelerator Pedal Position 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.
Code P2138 2018 GMC Sierra Description
Both the APP sensors 1 and 2 signal percentages increase as the pedal is depressed, from approximately 0 percent at rest to above 95 percent when fully depressed.
The Diagnostic Trouble Code (DTC) will be set when the ECM detects that APP sensor 1 and APP sensor 2 disagree greater than 10 percent for less than 1 s or the ECM detects that both APP sensor 1 and APP sensor 2 are 5 percent greater than the learned minimum position for less than 1 s.
What are the Possible Causes of the DTC P2138 2018 GMC Sierra?
- Faulty Accelerator Pedal Position Sensor
- Accelerator Pedal Position Sensor harness is open or shorted
- Accelerator Pedal Position Sensor circuit poor electrical connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P2138 2018 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 P2138 2018 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.
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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.
Discuss the causes and fixes for P2138 2018 GMC Sierra OBDII Code
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