Diagnostic trouble code P0201 indicates that the powertrain control module (PCM) has detected a malfunction in the electrical circuit for the cylinder 1 fuel injector. This could be due to an open circuit, a short to ground or voltage, or high resistance in the injector or its wiring. The code sets when the PCM sees an unexpected voltage or current condition on the injector control circuit.
The injector itself may have an internal open or short circuit, or be mechanically stuck, causing incorrect electrical readings.
Damaged, chafed, or broken wires between the PCM and the injector connector can interrupt the circuit or cause a short to power or ground.
Corrosion, bent pins, or a loose connector at the cylinder 1 injector can create high resistance or intermittent contact.
The transistor that controls the injector ground circuit may have failed, though this is rare and should only be considered after ruling out all other causes.
Driving with a cylinder 1 injector circuit fault can cause misfires, poor performance, and potential catalytic converter damage. It is best to address the issue promptly.
No. A wiring issue or poor connection can mimic a bad injector. Always inspect the circuit and connector before replacing the injector to avoid unnecessary expense.
The code may clear if the fault is intermittent, but it will return if the underlying problem is not fixed. The PCM runs the injector circuit test continuously.
PCM failure is a rare cause of this code. Many shops and DIYers mistakenly replace the PCM when the real issue is a bad injector, wiring, or connector. Exhaust all other diagnostics first.