P0201 Injector Circuit Malfunction - Cylinder 1

P0201 points to an injector circuit malfunction on cylinder 1. The fault is electrical or control-circuit focused, though the symptom may feel like a misfire.

Code details

Generic OBD-II · P0

System: Injector
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the injector until the circuit has been checked; an open wire, short, or driver-control issue can set the same code.

Symptoms of P0201

Check-engine light, often with a misfire feel from one cylinder.
Rough idle, hesitation, or a slight loss of power.
Higher fuel use, or in some cases a fuel smell.

Common causes of P0201

A stuck, leaking, clogged, or electrically failed injector.
Injector wiring, connector, or driver-circuit faults.
Low fuel pressure or contamination affecting injector behaviour.

Useful checks before replacing parts

Check injector connector fit, power feed, control circuit, harness routing, and terminal tension at cylinder 1.
Compare injector resistance or current pattern to other cylinders using the correct service procedure.
Review misfire codes and fuel-trim data to separate circuit failure from fuel delivery or mechanical faults.

Related OBD-II codes

These nearby injector entries can help compare wording and pin down the fault area.