P0221 means Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance. Throttle or pedal position sensor B is reading a value that does not agree with what the computer expects, or with sensor A. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0221 means
Most vehicles built in the last two decades use electronic throttle control instead of a throttle cable: the accelerator pedal carries two or three position sensors, and the throttle body has a motor and two position sensors of its own. The computer compares the redundant sensors constantly, and any disagreement triggers reduced-power mode as a safety measure. Older engines with a throttle cable control idle with a separate idle air control valve.
P0221 symptoms
- Reduced power or limp mode
- Throttle response limited
- Check engine light
- Stalling on some vehicles
Common causes of P0221
- Worn or failing sensor
- Throttle body carbon buildup
- Poor connection causing a voltage drop
How to diagnose P0221
- Compare sensor A and B readings on a scan tool through the throttle range
- Check reference voltage and ground at the connector
- Inspect the connector and harness
Can you drive with P0221?
Use caution; the engine may go into reduced power suddenly.
P0221 tips
Carbon buildup can make the throttle plate sit slightly open; clean the throttle body and perform an idle relearn before replacing parts.
Will P0221 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0221 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0121 | Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance |
| P0220 | Throttle/Pedal Position Sensor/Switch B Circuit |
| P2135 | Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation |
Guides that help
When it is more than a sensor
Throttle and idle codes are fixed at the throttle body, the pedal, a sensor or a leak. If those check out and the engine still runs poorly, a compression test separates a control problem from a worn engine; compare engines by code on our engines page.
Shipping is a flat $80.00 per order to US addresses, with 15-day free returns. Questions? Ask a parts specialist.