P0201 – Injector Circuit Malfunction – Cylinder 1

What does P0201 mean?

The fuel injector control circuit for cylinder 1 has an electrical malfunction. This code refers to the circuit — the wiring, connector, or injector solenoid — rather than to the spray pattern or flow rate of the injector itself.

What causes P0201?

Listed from most to least common:

1. 1Failed injector solenoid (open or shorted internally)
2. 2Damaged wiring to the injector
3. 3Corroded or loose connector
4. 4Poor ground or supply voltage to the injector
5. 5Failed injector driver circuit inside the ECM (less common)

Code breakdown

Common symptoms

• Check engine light on, often alongside a P0301 misfire code
• Rough idle and vibration
• Loss of power
• Hard starting
• Poor fuel economy
• Fuel smell from unburned fuel in the exhaust

How to diagnose

1. 1Inspect the injector connector and wiring for damage, corrosion, or heat exposure.
2. 2Measure injector resistance and compare against specification — most port injectors fall in a predictable range, and an open or shorted reading confirms failure.
3. 3Verify voltage supply reaches the injector with the key on.
4. 4Use a noid light or scope to confirm the ECM is sending a pulse to the injector.
5. 5Swap the injector with a neighboring cylinder. If the code follows the injector, the injector is faulty; if it stays, the fault is in the wiring or ECM.

A non-firing injector means cylinder 1 receives no fuel, causing a misfire that can damage the catalytic converter. Address promptly.

Common fixes and estimated costs

Costs are rough US estimates including parts and labor. Actual pricing varies significantly by vehicle, region, and shop rates.

Good to know

Check the resistance and wiring before assuming the injector is bad. If the ECM pulse is present and injector resistance is within spec, the problem is more likely a connector or ground issue than the injector itself.

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