Does a circuit code mean the injector is clogged?

No. P0203 is about the electrical circuit, not fuel flow. A clogged injector that still has correct resistance would not set this code.

What is the correct resistance for a fuel injector?

Port injectors typically measure 10 to 18 ohms. Direct injection injectors are usually 1 to 5 ohms. Always check the spec for your specific engine.

Will the car run if I just clear this code?

The code will return almost immediately. Clearing it without fixing the fault only delays the repair and risks catalytic converter damage from the ongoing misfire.

Codes › P0203

P0203: The fuel injector circuit for cylinder 3 has a fault

Injector Circuit Malfunction -- Cylinder 3

High severityCan you keep driving?

Drive with caution. A non-firing injector causes a misfire. If the light is flashing, stop and get the car towed. Driving with a misfire sends raw fuel into the catalytic converter.

What it means

P0203 means the PCM detected an electrical fault in the fuel injector circuit for cylinder 3. The PCM measures current flow when it fires each injector. If the return signal is missing or wrong, it sets this code. A related cylinder 3 misfire code (P0303) is almost always stored at the same time. This is a circuit electrical fault, meaning the problem may be the injector itself, the wiring, or the connector rather than a clogging or fuel delivery issue.

Common causes

Damaged wiring between PCM and cylinder 3 injectorChafing against the block, heat shield, or other components breaks the circuit.
Failed cylinder 3 injector coilMeasure the injector resistance. Out-of-spec reading confirms a bad solenoid.
Corroded cylinder 3 injector connectorPins oxidized from heat and humidity break the signal path without visibly damaging the injector.
PCM driver failure for cylinder 3Last resort diagnosis. Only consider after wiring and injector checks come back normal.

What it costs

Wiring or connector repair$80 to $250
Fuel injector replacement (single)$150 to $400 installed
PCM diagnosis and replacement$500 to $1,200

Symptoms

Check engine light on, steady or flashing
Rough idle and vibration
Power loss under acceleration
P0303 misfire code likely also stored
Fuel economy reduction

What to do next

Use a multimeter to measure injector resistance at the harness connector. Compare the reading against the spec for your vehicle. If it is out of range, the injector is faulty. If it reads normal, the fault is in the wiring between the injector and the PCM. Trace the harness carefully, looking for melted insulation or a pinched wire near engine mounts.

Lewis shows misfire event counts per cylinder so you can verify cylinder 3 is the source before disconnecting anything. Download Lewis.

Related codes

FAQ

Does a circuit code mean the injector is clogged?: No. P0203 is about the electrical circuit, not fuel flow. A clogged injector that still has correct resistance would not set this code.
What is the correct resistance for a fuel injector?: Port injectors typically measure 10 to 18 ohms. Direct injection injectors are usually 1 to 5 ohms. Always check the spec for your specific engine.
Will the car run if I just clear this code?: The code will return almost immediately. Clearing it without fixing the fault only delays the repair and risks catalytic converter damage from the ongoing misfire.