Parts
$80–400 throttle body assembly
P0222 — Throttle Position Sensor B Circuit Low
CAUTIONIs it safe to drive? Driveable at very low speeds but the ECU has lost one of its two throttle position signals — expect reduced power mode (limp mode) and unpredictable throttle response.
What P0222 means
On drive-by-wire (electronic throttle) systems, there are two TPS sensors (A and B) in the throttle body that work as a redundant pair — one reads 0.5–2.5V and the other reads inversely 2.5–4.5V. This code means the B sensor is reading below its valid range.
Most likely causes (in order)
- Faulty electronic throttle body (most common on drive-by-wire — the dual-sensor unit fails as an assembly, $80–400)
- Short to ground on the TPS B signal wire
- Loose or corroded throttle body connector
- Damaged wiring harness
- ECU fault (rare — rule out sensor and wiring first)
Symptoms you might notice
- Limp mode — reduced RPM and power
- Rough or unstable idle
- Throttle unresponsive or erratic
- Traction control and stability control may disable
- Accelerator pedal feels unresponsive
What to check first
On drive-by-wire systems, sensors A and B should read inversely — when A goes up, B goes down. Check both live on a scan tool simultaneously: if both read low or both read the same direction, the wiring is suspect. If they diverge correctly but B is below spec, the throttle body sensor has failed and typically the entire throttle body assembly is replaced.
Repair cost & difficulty
Labor
0.5–1.5 hr
Difficulty
Moderate