Engine-CodesChevrolet – P1278 Chevrolet

P1278 Chevrolet Code - Accelerator Pedal Position Sensor 1 Circuit High Voltage

Quick Answer

The P1278 Chevrolet code indicates an issue with the Accelerator Pedal Position Sensor 1 Circuit High Voltage. Common causes include Faulty accelerator pedal position sensor, Wiring or connection issues in the sensor circuit, ECM malfunction. 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
P1278 Chevrolet indicates Accelerator Pedal Position Sensor 1 Circuit High Voltage.
Common causes
Common causes include Faulty accelerator pedal position sensor, Wiring or connection issues in the sensor circuit, ECM malfunction.
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 10, 2024
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Code P1278 Chevrolet Description

The P1278 Chevrolet code indicates an issue with the Accelerator Pedal Position Sensor 1 Circuit High Voltage. This sensor is responsible for monitoring the position of the accelerator pedal and sending signals to the engine control module (ECM) to adjust fuel delivery and ignition timing accordingly. When the sensor detects a high voltage in the circuit, it means that the signal being sent to the ECM is outside of the expected range, which can lead to various performance issues in the vehicle.

OBDII Code P1278 Chevrolet - Accelerator Pedal Position Sensor 1 Circuit High Voltage
P1278 Chevrolet Code - Accelerator Pedal Position Sensor 1 Circuit High Voltage

Common Causes of P1278 Chevrolet

  1. Faulty accelerator pedal position sensor
  2. Wiring or connection issues in the sensor circuit
  3. ECM malfunction
  4. Corrosion or damage to sensor connectors
  5. Electrical issues such as shorts or open circuits

Symptoms of P1278 Chevrolet

  1. Poor acceleration or lack of response when pressing the accelerator
  2. Rough idling or irregular engine speed
  3. Reduced fuel efficiency
  4. Engine stalling or hesitation during acceleration
  5. Check Engine Light illuminated on the dashboard

How to Fix P1278 Chevrolet

  1. Begin by conducting a thorough inspection of the accelerator pedal position sensor and its wiring for any visible damage or corrosion.
  2. Use a multimeter to test the sensor's voltage output and compare it to the manufacturer's specifications to determine if it falls within the acceptable range.
  3. If the sensor is faulty, replace it with a new one and ensure proper installation and calibration.
  4. Check the wiring and connections for any signs of wear or damage, repairing or replacing as needed.
  5. Clear the diagnostic trouble codes from the ECM and perform a test drive to verify that the issue has been resolved.

Cost to Fix P1278 Chevrolet

The cost of repairing a P1278 Chevrolet code related to the Accelerator Pedal Position Sensor 1 Circuit High Voltage can vary depending on the specific cause of the issue and the labor rates at the auto repair shop. On average, the parts for this repair can range from $50 to $200, while labor costs can be between $100 and $300. However, it's important to note that these are rough estimates, and actual costs may differ based on the location, vehicle make and model, and the extent of the repair needed. It's recommended to get a detailed quote from a trusted mechanic before proceeding with the repair.

When is the Code Detected?

The Engine Control Module (ECM) detected a voltage below 0.2 volts or above 4.25 volts on the APP signal

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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.

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