What does Error Code P2138 mean?
Moderate Issue
DTC Code P2138 indicates a correlation issue between Accelerator Pedal Position (APP) Sensor 1 and Sensor 2. This code is triggered when the Engine Control Module (ECM) detects a discrepancy greater than 10% between the signals of the two sensors or when both sensors exceed 5% of the learned minimum position.
What are the symptoms of Error Code P2138?
- Engine Light ON: The check engine light or service engine soon warning light illuminates, indicating a potential issue with the accelerator pedal position sensor.
- Reduced Engine Power: The vehicle may experience reduced engine power, which can be linked to the accelerator pedal position sensor not providing accurate readings.
- Unresponsive Throttle: The throttle may become unresponsive or exhibit delayed response, potentially due to a discrepancy between the signals from the two accelerator pedal position sensors.
- Erratic Acceleration: The vehicle may experience erratic acceleration, which can be associated with the correlation issue between the two sensors.
What causes Error Code P2138?
- The accelerator pedal position sensor may be malfunctioning, leading to incorrect readings and triggering the error code.
- An open or shorted harness in the accelerator pedal position sensor can disrupt the signal transmission, causing a correlation error.
- Poor electrical connections in the accelerator pedal position sensor circuit can result in intermittent or faulty signals.
- A defective Engine Control Module (ECM) might misinterpret sensor data, leading to a correlation error between the two sensors.
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How to fix Error Code P2138?
- Initial Code Verification: Verify the presence of DTC P2138 using a diagnostic scanner. Ensure no other codes are present that might affect the diagnosis.
- Visual Inspection: Inspect the accelerator pedal assembly and wiring for any visible damage, corrosion, or loose connections. Pay special attention to the connectors and harness.
- Check Sensor Voltage: Using a multimeter, measure the voltage output from both Accelerator Pedal Position Sensor 1 and Sensor 2. Compare the readings to the manufacturer's specifications.
- Sensor Correlation Test: With the ignition on, slowly depress the accelerator pedal and monitor the voltage outputs from both sensors. Ensure the voltage changes smoothly and correlates between the two sensors.
- Inspect Related Components: Check the throttle body and related components for any issues that might affect the sensor readings, such as carbon buildup or mechanical obstructions.
- Review Related Codes: Consider the related codes provided, such as P2135 and P2136, which may indicate issues with voltage correlation between different sensors. Investigate these if present.
- Replace Faulty Components: If any sensor or wiring issues are identified, replace the faulty components. Clear the codes and perform a test drive to ensure the issue is resolved.