OBD · Engine sensors
P0121 Throttle position sensor range or performance
What this code means
P0121 is a generic OBD code shared by all manufacturers since 2001 for petrol and 2004 for diesel. It relates to: engine sensors. The code tells you what the ECU measured as abnormal, not necessarily which part to replace.
Most common causes
- Intake air leak#1
A hiss at idle with an unstable idle often means a split hose or intake gasket.
How to read this code
An OBD scanner plugged into the 16-pin socket under the steering wheel reads and clears codes. Bluetooth models cost £20 to £40. Clearing a code without fixing the fault is pointless: it comes back.
Related problems
Frequently asked questions
What does code P0121 mean?
P0121: Throttle position sensor range or performance. P0121 is a generic OBD code shared by all manufacturers since 2001 for petrol and 2004 for diesel. It relates to: engine sensors. The code tells you what the ECU measured as abnormal, not necessarily which part to replace.
Can I drive with code P0121?
Fix soon. Drive gently and as little as possible. The fault can get worse and damage other parts.
How to read this code
An OBD scanner plugged into the 16-pin socket under the steering wheel reads and clears codes. Bluetooth models cost £20 to £40. Clearing a code without fixing the fault is pointless: it comes back.