WOMS
B code body Medium severity

B1989 Pedal Position Rearward Switch Circuit Short to Battery

The OBD2 code B1989 indicates a malfunction in the pedal position rearward switch circuit, specifically a short circuit to the battery, which means the circuit is receiving an unintended voltage from the battery,...

Definition

The OBD2 code B1989 indicates a malfunction in the pedal position rearward switch circuit, specifically a short circuit to the battery, which means the circuit is receiving an unintended voltage from the battery, potentially affecting the vehicle's electronic systems related to the accelerator pedal

Common causes

  • Shorted wiring or connectors
  • Faulty pedal position sensor
  • Corroded or damaged connectors
  • Grounding issues
  • Malfunctioning electronic control unit (ECU)
  • Improper installation or adjustment of the pedal assembly

Common misdiagnoses

  • Faulty accelerator pedal position sensor
  • Wiring issues or shorts in the harness
  • Malfunctioning engine control module (ECM)
  • Incorrectly installed or damaged pedal assembly
  • Issues with the brake pedal position switch
  • Faulty throttle body or electronic throttle control system
  • Corroded or loose electrical connections

Troubleshooting steps

  1. 1. Understand the Code

    The B1989 code typically relates to the pedal position sensor or switch that detects the position of the accelerator pedal. A short to battery means that the circuit is receiving voltage when it shouldn't be

  2. 2. Visual Inspection

    Wiring and Connectors: Inspect the wiring harness and connectors associated with the pedal position sensor. Look for frayed wires, corrosion, or loose connections

  3. 3. Pedal Position Sensor

    Check the sensor itself for any physical damage or signs of wear

  4. 4. Check for Related Codes

    Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

  5. 5. Test the Pedal Position Sensor

    Voltage Test: With the ignition on (engine off), use a multimeter to check the voltage at the pedal position sensor connector. Compare the readings to the specifications in the vehicle’s service manual

  6. 6. Resistance Test

    Measure the resistance of the sensor across its terminals to ensure it falls within the specified range

  7. 7. Inspect the Circuit

    Continuity Test: Perform a continuity test on the wiring between the pedal position sensor and the engine control module (ECM) to ensure there are no breaks or shorts in the circuit

  8. 8. Ground Check

    Ensure that the ground connection for the pedal position sensor is secure and functioning properly

  9. 9. Check for Shorts

    Short to Battery: Use a multimeter to check for a short circuit in the wiring. Disconnect the sensor and check the resistance between the signal wire and battery voltage. A low resistance indicates a short

  10. 10. Inspect for Pinched Wires

    Look for any areas where the wiring may be pinched or damaged, causing a short to battery

  11. 11. Test the ECM

    If all other components check out, the issue may lie with the engine control module (ECM). Check for any software updates or known issues with the ECM related to the pedal position sensor

  12. 12. Clear Codes and Test Drive

    After performing repairs or replacements, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  13. 13. Seek Professional Help

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these steps, you should be able to identify and address the cause of the B1989 code effectively