P0220: Throttle/Pedal Position Sensor/Switch B Circuit Malfunction

What does P0220 actually mean?

Many electronic throttle bodies carry two independent position sensors so the computer can cross check them for safety. This code covers the general circuit for the second sensor, sensor B, and sets when its signal is missing, out of range or does not track sensor A correctly. It is an electronic drive-by-wire fault rather than anything to do with the mechanical throttle plate itself.

The code sits in the throttle position sensing area and is reported by the comprehensive component monitor. It names the circuit or the condition where the computer saw a reading outside its expected range. It does not name a failed part, and several genuinely different faults set this same code, which is the whole reason the causes below are ordered rather than listed.

What people usually notice

• Reduced power mode
• Rough or unstable idle
• Hesitation when pressing the pedal
• Check engine light
• Throttle feels disconnected from the pedal

Why does P0220 set?

The causes below are ordered by how often they turn out to be the answer, cheapest and most common first. That order matters more than the list itself: the expensive component named in the code text is very rarely the first thing to replace, and working down from the top is what stops a throttle position sensing fault becoming an expensive guess.

Corroded or loose connector at the throttle body is the one to rule out before anything else. This connector is exposed to engine bay heat and is the easiest thing to check first.

The order worth checking on P0220

Start with freeze frame. Throttle position at the moment of the fault shows whether it happened at idle, part throttle or wide open throttle. That snapshot is taken at the instant the code set, and it is the single most useful piece of evidence you have, which is also why clearing the code before reading it is such a costly habit.

This code is diagnosed by watching values change rather than by reading the number again, so the tool has to stream live data and hold freeze frame. Live comparison of sensor A and sensor B voltage while sweeping the pedal shows exactly where the two disagree.

The order worth working in

• 1. Corroded or loose connector at the throttle body: This connector is exposed to engine bay heat and is the easiest thing to check first.
• 2. Chafed wiring between the computer and the throttle body: Wires routed near moving throttle linkage can wear through over time.
• 3. Failed sensor B element inside the throttle body assembly: The dual sensors are usually sold only as part of a complete throttle body unit.
• 4. Contamination inside the throttle body housing affecting the sensors: Carbon and oil vapor buildup inside the housing can interfere with the sensor readings.
• 5. Failed accelerator pedal position sensor module: On drive-by-wire pedals, the pedal itself contains a sensor pair and can fail as a unit.

Is it safe to drive with P0220?

The car is usually drivable in a reduced power mode, but throttle response can feel abrupt or very limited, so treat it as a get-home condition only.

This is a severity 2 of 4 code. It will not usually strand you, but it will fail an emissions test while it is present, and the underlying fault rarely gets cheaper by being left alone.

What does it cost to ignore P0220?

The computer limits engine power to protect against a runaway throttle when it cannot verify sensor B, so ignoring this code leaves the car stuck in reduced power mode.

There is also the diagnostic cost of waiting. Freeze frame data, pending code history and the readiness monitor state all describe the fault as it was when it set, and all of it is lost the moment somebody clears the code to make the lamp go out.