P0121 Honda Accord
Throttle/Pedal Position Sensor A Range/Performance · Powertrain Code · High · Repair: Moderate
What is P0121?
The TPS is reading outside expected parameters for the current conditions.
When the Honda Accord triggers code P0121 (throttle/pedal position sensor a range/performance), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the Honda Accord.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Honda Accord.
Common Causes on Honda Accord
- Worn Throttle Position Sensor (TPS) with dead spots
- Carbon buildup on electronic throttle body causing binding
- Corroded TPS wiring or connector
- Failing electronic throttle body motor
Symptoms
- Check Engine Light on
- Erratic idle speed
- Hesitation or surging during acceleration
- Throttle feels unresponsive or jerky
- Vehicle may enter limp mode
Notes for Honda Accord
Always perform the Honda idle relearn procedure after cleaning or replacing the throttle body — turn ignition on for 2 seconds, off for 10 seconds, repeat, then idle for 10 minutes.