B1990 – Pedal Forward / Rearward Potentiometer Feedback Circuit Failure

The ODBII code B1990 indicates a malfunction in the feedback circuit of the pedal’s forward or rearward potentiometer, which is responsible for detecting the position of the accelerator or brake pedal.

The severity of ODBII code B1990 is moderate.

Common Causes For: B1989 Pedal Position Rearward Switch Circuit Short to Battery

• Faulty pedal position sensor
• Wiring issues (shorts, opens, or corrosion)
• Poor electrical connections
• Malfunctioning powertrain control module (PCM)
• Calibration issues
• Mechanical binding or obstruction in the pedal assembly
• Grounding problems

Common misdiagnosis for B1990 Pedal Forward / Rearward Potentiometer Feedback Circuit Failure

• Faulty accelerator pedal position sensor
• Wiring issues or shorts in the pedal feedback circuit
• Malfunctioning engine control module (ECM)
• Incorrectly calibrated throttle body
• Issues with the brake pedal position sensor
• Problems with the vehicle’s electronic control system
• Faulty connectors or terminals in the pedal circuit

Common Troubleshooting Steps

The OBD-II code B1990 refers to a failure in the pedal forward/rearward potentiometer feedback circuit, which is typically associated with the vehicle’s accelerator or brake pedal position sensors. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues present.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the pedal position sensor. Look for signs of damage, corrosion, or loose connections.
• Ensure that all connectors are securely attached and free of dirt or moisture.
• Test the Potentiometer:
• Use a multimeter to test the resistance of the potentiometer. Check the specifications in the vehicle’s service manual for the correct resistance values.
• Move the pedal through its full range of motion while monitoring the resistance to ensure it changes smoothly and consistently.
• Check Power and Ground:
• Verify that the potentiometer is receiving the correct voltage supply. Use a multimeter to check for power at the connector.
• Ensure that the ground connection is solid and free of corrosion.
• Inspect the Pedal Assembly:
• Check the physical condition of the pedal assembly. Ensure that it moves freely and is not obstructed or damaged.
• Look for any signs of wear or mechanical failure that could affect the potentiometer’s operation.
• Test the Signal Output:
• With the multimeter, check the output signal from the potentiometer while moving the pedal. The output should vary smoothly as the pedal is pressed and released.
• If the output is erratic or does not change as expected, the potentiometer may be faulty.
• Check for Software Updates:
• In some cases, the issue may be related to the vehicle’s software. Check with the manufacturer or a dealership to see if there are any software updates or recalls related to the pedal position sensor.
• Replace the Potentiometer:
• If all tests indicate that the potentiometer is faulty, it may need to be replaced. Ensure that you use a part that meets OEM specifications.
• Clear Codes and Test Drive:
• After making 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.
• Consult a Professional:
• If the issue persists after following 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 troubleshooting steps, you should be able to identify and resolve the issue related to the B1990 code.