2004 Toyota Sevilla P0122 Fault: How to Diagnose and Fix Throttle Position Sensor Issue
My 2004 Toyota Sevilla occasionally shows the check engine light with code P0122. The car runs smoothly, has no misfires, and delivers strong performance—fuel efficiency is consistently between 23.5 and 24.9 MPG. The warning light appears intermittently; it sometimes stays off for hours or comes back shortly after. I've already cleaned the throttle position sensor (TPS) with electronic cleaner, and it remained off for about 225 miles. However, the light still reappears periodically. I'm concerned that if the TPS were faulty, the car would show symptoms when hot—yet no such issues occur. Given this behavior, should I replace the throttle position sensor? The P0122 code indicates a problem with the throttle position sensor signal, typically related to low or inconsistent voltage readings.
To determine whether the issue is caused by low or no voltage, review the freeze frame data from the OBD2 scan. A faulty connection could be responsible—check the electrical connector for tightness, corrosion, and physical damage. Gently wiggle the wires to see if the code reappears; this can help identify a loose or corroded wire. The throttle position sensor (TPS) is an inexpensive component that's easy to replace. If replacing it, always perform the TPS relearn procedure after installation: 1. Turn the ignition to RUN/ON position. 2. Wait 1 minute. 3. Turn the ignition to LOCK/OFF position. 4. Wait 15 seconds. This ensures proper sensor calibration and helps prevent recurring P0120/P0122 codes after replacement.