P0121Medium urgency

Throttle Position Sensor Circuit Range/Performance

Engine · Throttle Control

⚠️ Drive with caution — throttle response may be erratic.

What this means

The throttle position sensor (TPS) signal is outside expected range or inconsistent. A faulty TPS causes hesitation, surging, and unpredictable acceleration.

Likely causes

Faulty throttle position sensorMost common
Dirty or worn throttle bodyCommon
Wiring harness issueCommon

Estimated repair cost

TPS replacement$75 – $250

Throttle body cleaning$75 – $200

Throttle body replacement$200 – $600

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Frequently asked questions

What does P0121 mean?

The throttle position sensor (TPS) signal is outside expected range or inconsistent. A faulty TPS causes hesitation, surging, and unpredictable acceleration.

Is P0121 serious?

Drive with caution — throttle response may be erratic.

How much does it cost to fix P0121?

Repair costs for P0121 range from $75 – $250 depending on the root cause and your vehicle.

Can I drive with P0121?

You can drive short distances but should have it repaired within 1-2 weeks to prevent further damage.