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DTC codes / U06xx · Network communication / U0683

U0683Lost Communication With Throttle/Pedal Position Sensor/Switch F

U0683 is a network communication fault indicating that a control module has lost contact with the throttle or pedal position sensor or switch designated as 'F'. The computer detects this when the expected data message from that sensor or switch stops arriving on the vehicle's communication bus within the required time window.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaNetwork communication

Symptoms you may notice

  • The check engine light or a dedicated powertrain warning lamp illuminates on the dashboard.
  • The engine may enter limp mode, limiting throttle response or idle speed.
  • The accelerator pedal may feel unresponsive or the engine may hesitate when pressed.
  • A message such as 'Service Electronic Throttle' or 'Reduced Engine Power' may appear on the driver information display.
  • Often no symptoms besides the warning light, especially if the fault is intermittent.

Common causes, most likely first

  1. A faulty throttle or pedal position sensor or switch 'F' that is not transmitting data.
  2. Damaged, corroded, or loose wiring or connectors in the circuit between the sensor and its control module.
  3. A failed or intermittently failing control module that is supposed to relay or receive the sensor data.
  4. A communication bus fault, such as a shorted or open data line, that disrupts messages from the sensor.
  5. Low system voltage or a weak battery causing modules to drop offline intermittently.
  6. Water intrusion or physical damage to the sensor or its connector.
  7. Aftermarket electronic accessories improperly tapped into the throttle or pedal wiring.

How to diagnose and fix it

  1. Verify battery voltage and charging system output, as low voltage can cause spurious communication codes.
  2. Inspect the throttle body and accelerator pedal sensor connectors for corrosion, loose pins, or damaged wiring.
  3. Use a scan tool to check for communication with the throttle/pedal sensor module and review live data for sensor 'F'.
  4. Perform a wiggle test on the harness while watching live data to expose intermittent connection faults.
  5. Check the communication bus integrity with a digital multimeter or oscilloscope to rule out data line faults.
  6. If wiring and voltage are good, substitute a known-good sensor or switch 'F' and recheck communication.
  7. Clear the code and perform a road test to confirm the fault does not return before releasing the vehicle.

What Most Technicians Miss on U0683

  • This code often sets because a control module was temporarily starved of voltage during engine cranking, not because the sensor itself has failed.
  • A poor ground connection at the throttle body or pedal assembly can mimic a failed sensor 'F' and is frequently overlooked during diagnosis.
  • Aftermarket remote starters or alarm systems tapped into the pedal wiring are a common hidden cause of lost communication on this circuit.
  • The code does not always mean the sensor is dead; a single dropped message on a noisy bus can set it, and it may never return after clearing.
  • Some vehicles use a redundant sensor 'F' only for monitoring, so the engine may run normally while the code is stored, leading owners to ignore a real wiring fault.

Can I keep driving with U0683?

You can usually drive the vehicle to a repair shop if the engine runs and throttle response is normal, but avoid heavy acceleration or highway merging if the pedal feels unresponsive. If the engine enters limp mode or the throttle sticks, stop safely and have the vehicle towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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