p0121
Moderate
Toyota · SUVs
Throttle/Pedal Position Sensor A Circuit Range/Performance
Quick Answer
Error code P0121 on your Toyota SUVs means: Throttle/Pedal Position Sensor A Circuit Range/Performance. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Dirty throttle body causing erratic throttle plate movement
  2. Faulty throttle position sensor (TPS) built into the throttle body
  3. Damaged wiring or connector to the throttle body
  4. Carbon buildup on the throttle plate preventing smooth operation
  5. Failed electronic throttle body motor
How to Fix It
1
Clean the throttle body bore and plate with throttle body cleaner
2
Use a scan tool to monitor TPS voltage while slowly opening the throttle and check for dropouts or jumps
3
Inspect the throttle body wiring harness and connector for damage or corrosion
4
Perform a throttle body relearn procedure after cleaning
5
Replace the throttle body assembly if the TPS output is erratic after cleaning
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Throttle body assembly
Throttle body cleaner
Throttle body gasket
Wiring repair connector
Related Error Codes
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