P0220 indicates a malfunction in the electrical circuit for the 'B' (secondary) channel of the throttle position sensor or accelerator pedal position sensor. Modern vehicles use dual-channel systems for safety redundancy, so if the computer detects an out-of-range voltage or signal drop on this specific circuit, it triggers this code to prevent unsafe acceleration. It almost always points to an electrical wiring issue or a failing sensor rather than a mechanical failure.
Corroded, frayed, or loose wiring and connectors in the sensor circuit are the most common cause, disrupting the signal voltage to the computer.
The sensor mounted on the throttle body can develop internal electrical failures or dead spots, causing an erratic or out-of-range signal on the B circuit.
The sensor assembly on the accelerator pedal can fail internally, sending an incorrect voltage signal to the engine computer.
Heavy carbon deposits around the throttle plate can cause it to bind mechanically, resulting in sensor readings that do not match the computer's expected values.
An internal failure in the powertrain control module's reference voltage or ground circuit is possible, but it is extremely rare.
It is not recommended. The vehicle will likely enter limp mode, restricting speed and acceleration, and could stall unexpectedly, creating a safety hazard.
Modern electronic throttle systems use two separate sensors (A and B) for redundancy. The 'B' circuit is the secondary channel; if its signal disagrees with the primary channel, the system assumes a fault and restricts engine power to prevent unintended acceleration.
Not necessarily. While the throttle body or pedal sensor can fail, damaged wiring or corroded connectors are equally common causes and are much less expensive to repair.
Usually, no. Replacing the engine computer is a common misdiagnosis for this code. The problem is almost always a bad sensor, dirty throttle body, or damaged wiring. PCM failure is highly unlikely and should only be considered after all other components are thoroughly tested.