P0201: Cylinder 1 Injector Circuit/Open
P0201 means the engine computer found an electrical fault, most often an open circuit (a break in the wiring path), in the fuel injector circuit for cylinder 1. That cylinder can misfire and the engine may run rough or lose power, so get it checked soon rather than driving on it for long.
You can drive, but get it checked soon
The engine may run on the remaining cylinders, but cylinder 1 misfires and power drops. Diesel and direct injection engines can also go into limp mode (reduced power to protect the engine). Keep driving to a minimum, and stop if the engine runs very rough or the check engine light flashes.
What it means
The engine control module (the car's main computer) monitors the electrical output that fires each fuel injector. For cylinder 1, it reports P0201 when the circuit does not complete, as if a wire were cut or a connector unplugged. On GM vehicles an open circuit is flagged at an impedance (electrical resistance) of 200 kΩ or more. Direct injection and diesel engines can turn on the warning light on the first trip, while some port-injected engines need two trips. Ford port injection reports a fault bit that covers an open circuit, a short to ground and a short to voltage alike. Ford diesels use this code only for an open circuit and report shorts as P0261 or P0262. On direct injection engines the affected injector is switched off, so cylinder 1 misfires. The check engine light comes on, and the fault counts as emissions-relevant.
Likely causes
- Loose, corroded or damaged connector at the cylinder 1 injectorVery likely
A loose or corroded connector, or a broken or pushed-back pin, interrupts the circuit, and this is the most common cause.
- Open injector coilPossible
If the coil inside the injector is broken, current cannot flow and the module sees an open circuit.
- Open or chafed wire between module and injectorPossible
Heat or rodents can damage the wiring and break the circuit.
- Missing injector power supply (fuse or relay)Less likely
A blown fuse or failed relay cuts power to the injectors, but this usually affects several cylinders at once rather than only cylinder 1.
- Faulty driver stage in the engine moduleLess likely
The part of the computer that switches the injector can fail, though this is uncommon.
What you may notice
- Check engine light on
- Misfire and rough running, often with misfire code P0301
- Loss of power
- Rough idle
- Possible limp mode on diesel and direct injection engines
What to check, cheapest first
- 1Read all stored codes and note whether P0301, P0300 or other injector codes (such as P0261 or P0262) appear with P0201. · you can do it
- 2Inspect the cylinder 1 injector connector for looseness, corrosion, moisture or a pushed-back or broken pin, and reseat it firmly. · you can do it
- 3Look at the visible wiring to the cylinder 1 injector for chafing, heat damage or rodent chewing. · you can do it
- 4Check the injector fuse and relay. If several cylinders show injector faults, suspect the supply first. · you can do it
- 5Measure the injector coil resistance and test the wire between the module and injector for continuity. · mechanic
- 6If the injector and wiring test good, test the module's driver output for cylinder 1 before replacing the module. · mechanic
Related codes
Frequently asked questions
Can I drive with P0201?+
Only briefly and with care. Cylinder 1 misfires, power drops, and some engines go into limp mode. Have it fixed soon.
Can a loose gas cap cause P0201?+
No. P0201 is an electrical fault in the injector circuit. A loose gas cap causes evaporative system codes, not this one.
Will P0201 pass an emissions test?+
No. The check engine light is on and the code is emissions-relevant, so the vehicle should be repaired before testing.
Can I fix P0201 myself?+
Sometimes. Reseating or cleaning a bad connector is a DIY job. Testing the injector coil and wiring is harder. Repair time ranges from half an hour to about four hours.
Written with the help of AI from the public OBDex definition (CC0). Each make may use the code differently. Updated: 2026-11-10