OBD-II Generic Error Code P0120: How to Fix It
Medium 30 minutes to 1 hour Medium Severity
Verified June 2026
- Error Code
- P0120
- Brand
- OBD-II Generic
- Product Type
- automotive
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 30 minutes to 1 hour
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Tools You'll Need
- OBD2 scanner
- Multimeter
- Electrical contact cleaner
- Torx or Phillips screwdriver set
- Safety glasses
How to Fix Error Code P0120
-
Inspect the TPS Connector and Wiring
Disconnect the battery before unplugging any sensors to avoid short circuits. -
Test the TPS with a Multimeter
-
Check for Vacuum Leaks
Wear safety glasses when using a smoke machine. -
Replace the Throttle Position Sensor
Do not overtighten screws, as it can damage the sensor housing. -
Clear the Error Code and Test Drive
If the engine runs erratically, do not drive the vehicle; seek professional help.
Parts You May Need
Throttle position sensor
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Throttle body gasket (if applicable)
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Throttle position sensor
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Throttle body gasket (if applicable)
Check Price on Amazon
Throttle position sensor
Check Price on Amazon
Throttle body gasket (if applicable)
Check Price on Amazon
Throttle position sensor
Check Price on Amazon
Throttle body gasket (if applicable)
Check Price on Amazon
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When to Call a Professional
If you've replaced the TPS and wiring but the code persists, or if you're not comfortable working with electrical systems, consult a certified mechanic. Issues like a faulty engine control module (ECM) or throttle body may require specialized equipment.Frequently Asked Questions
Can I drive with a P0120 code?
It is not recommended. The vehicle may experience poor acceleration, stalling, or limp mode, which is unsafe in traffic. Get it diagnosed and fixed as soon as possible.
What are common symptoms of a bad TPS?
Common symptoms include hesitation during acceleration, rough idle, inconsistent engine jerking, and the check engine light turning on.
How much does it cost to fix P0120?
A TPS replacement costs between $80 and $200 including parts and labor, depending on the vehicle. DIY replacement is cheaper (around $20–$60 for the sensor).
Can a dirty throttle body cause P0120?
Yes, a dirty throttle body can affect TPS voltage readings. Cleaning the throttle body and the TPS area may fix the issue. Use a throttle body cleaner and a soft brush.
Is P0120 the same for all car brands?
Yes, P0120 is a generic OBD-II code, meaning it has the same definition for all vehicles. However, the location and type of TPS may vary by make and model.