P0203
Injector Circuit Malfunction — Cylinder 3
An electrical fault has been detected in the cylinder 3 injector circuit — open winding, short to ground or short to supply. This typically disables that injector to protect the driver stage in the ECU; the cylinder runs without fuel and triggers a misfire code as well.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Injector winding failed openCommon
- Wiring or connector faultPossible
Parts involved
- Fuel Injector
- Injector Wiring
P0203 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.