P0227 indicates that the Engine Control Module has detected a low voltage condition in the Throttle Position Sensor (TPS) Switch C circuit, meaning the signal from the sensor is weaker than expected.
The sensor or its internal switch can fail, causing an open or high‑resistance condition that drops circuit voltage.
Frayed wires, loose pins, or corrosion can create a high resistance path, resulting in a low voltage reading.
A malfunctioning 5 V reference supply or regulator can cause insufficient voltage to the sensor circuit.
A poor or broken ground connection can raise the circuit voltage drop, triggering the code.
Rarely, the ECM’s input driver or internal circuitry may be defective, but this is usually a last‑resort diagnosis.
It is possible but uncommon. Most P0227 codes are caused by the sensor, its wiring, or a voltage supply issue. The PCM should only be considered after ruling out those components.
The code may clear temporarily, but if the underlying fault remains, the ECM will set the code again, and the vehicle may continue to exhibit symptoms.
No. The throttle body itself is usually fine; the problem is typically isolated to the TPS Switch C sensor or its circuit. Replacing the sensor or repairing the wiring is usually sufficient.
A severely low system voltage can affect sensor readings, but a healthy battery and alternator should maintain the required 5 V reference. If the charging system is weak, verify the reference voltage before concluding the sensor is bad.