Drivable briefly; fix soon to protect the catalyst. P0201 is a powertrain code meaning the engine computer has detected an electrical fault — an open or a short — in the fuel-injector control circuit for cylinder 1 only. It points at the number-one injector's coil, its wiring and connector, or the driver inside the PCM, not at fuel quality.
What P0201 means
Each fuel injector is an electrically operated valve. The engine computer (PCM/ECM) fires it by switching the low side of its circuit to ground while battery voltage (VPWR) feeds the high side, so current pulses through the injector coil for a few milliseconds each cycle. A built-in self-check — Ford calls it the comprehensive component monitor — watches the injector driver for cylinder 1 and expects to see the coil's electrical load every time it commands that injector. If the load is missing or the current is out of range because the circuit is open, shorted to ground, or shorted to power, the monitor fails and stores P0201. The code is specific to cylinder 1; the same fault on the other cylinders sets P0202 through P0209, while P0200 is the umbrella "injector circuit" code used when the fault is not tied to one cylinder. Because P0201 is electrical, it implicates the injector solenoid, its connector and harness, or the low-side driver inside the module — not spray pattern or fuel pressure. On many vehicles the test runs continuously, key-on and while running, and can set from a single detected open.
Symptoms
- Cylinder-1 misfire that a scan tool logs as a rising misfire counter on that specific cylinder
- Rough or shaking idle that smooths only slightly as engine speed climbs
- Hard starting or extended cranking, most noticeable when the engine is cold
- Hesitation, stumble, or a clear lack of power under acceleration
- Check-engine light on (often flashing during an active misfire), sometimes with a raw-fuel smell from the exhaust
Common causes
- Open or failed injector-1 solenoid coil (internal winding break) — the most common single cause
- Damaged wiring or a loose, backed-out, or corroded connector at the cylinder-1 injector
- Chafed or broken injector harness rubbing against the engine, bracket, or intake
- Corrosion or water intrusion in the injector connector pins raising circuit resistance
- Open VPWR feed or a failed low-side injector driver for cylinder 1 inside the PCM/ECM (least common)
Severity & driving advice
Severity: Moderate — A dead cylinder-1 injector causes a steady misfire; prolonged driving dumps raw fuel that can overheat and ruin the catalytic converter.
Can I drive? Drivable briefly; fix soon to protect the catalyst.
Diagnostic approach
- Confirm the code and isolate cylinder 1 — Read all stored codes and note whether P0201 appears with a matching misfire code (such as P0301) or with other injector-circuit codes. On Ford the fault flag INJ1_F identifies cylinder 1 in live data. Check the monitor status and freeze-frame so you know whether the fault is currently present or intermittent before probing anything.
- Inspect the cylinder-1 injector connector and harness — Unplug the number-one injector and inspect the connector for spread, corroded, or pushed-out pins and for moisture. Follow the injector harness for chafe points and broken insulation where it passes brackets or the intake. Reseat the connector and perform a wiggle test with the ignition on, watching a live scan-tool data line for the fault dropping in and out.
- Measure injector coil resistance — With the connector off, measure resistance across the two injector terminals. A healthy high-impedance (saturated) port injector typically reads roughly 11-17 ohms at room temperature — confirm the exact figure against the engine's own specification. An infinite / OL reading means an open coil (a definite failure), while a near-zero reading indicates a shorted winding. Compare against a known-good injector on the same engine.
- Test the circuit back to the module — Key on, confirm battery voltage on the VPWR feed side of the injector connector. Check continuity of the control (low-side) wire from the injector connector back to the correct PCM pin, and test that wire for a short to ground and a short to power. Repair any open, high-resistance, or shorted section before condemning the injector or the module.
- Verify the driver and cross-check the injector — With good wiring, back-probe for the injector pulse using a noid light or scope while cranking; no pulse with a confirmed-good circuit points to the low-side driver inside the PCM. As a final cross-check, swap injector 1 with an adjacent cylinder's injector and clear the code — if the fault follows the injector, replace it; if it stays on cylinder 1, the wiring or module is at fault.
Make & model notes
Ford: Ford groups P0201-P0209 as Injector Circuit/Open for cylinders 1-9, with the comprehensive component monitor watching each injector driver in the PCM. On port-injected engines such as the 5.0L F-150 the factory routes diagnosis to Pinpoint Test KG (check the VPWR feed and the INJ control wire); direct-injection 3.5L EcoBoost engines use Pinpoint Test DI, which also checks the injector-return (INJRTN) circuit. Verified against 2011 F-150 factory data.
Toyota: On Toyota and Lexus, P0201 is the cylinder-1 injector circuit, with the ECM switching the injector's low side to ground. Inspect the number-one injector connector and its +B feed, confirm the EFI/injector relay is powered, and measure the injector coil resistance against Toyota's per-engine value before replacing the injector or suspecting the ECM.
FAQ
What does the P0201 code mean?
P0201 means the engine computer has found an electrical problem — an open circuit or a short — in the control circuit for the cylinder-1 fuel injector. Each injector is a small electromagnet the computer switches on and off, and P0201 sets when the self-check for cylinder 1 no longer sees the expected electrical load. It is a wiring and injector-coil fault, not a fuel-quality or spray issue.
Can I drive with a P0201 code?
Only briefly, and gently. If cylinder 1 has stopped firing you will feel a misfire, and the unburned fuel being pushed into the exhaust can overheat and permanently damage the catalytic converter — an expensive part. The engine is also down on power. Get the injector circuit repaired promptly rather than driving on a persistent misfire.
What is the difference between P0201 and P0200?
P0200 is the general "injector circuit" code the computer uses when it detects an injector-circuit fault that it cannot tie to one specific cylinder. P0201 is the cylinder-specific version for cylinder 1, and the related codes P0202 through P0209 cover cylinders 2 through 9. Seeing P0201 tells you exactly which injector circuit to test first.
What usually fixes a P0201 code?
Most often the fix is the cylinder-1 injector itself when its coil has gone open, or a repair to its connector or wiring when a pin is corroded, backed out, or the harness has chafed. Measuring the injector's resistance and checking the circuit back to the computer tells you which. A failed driver inside the PCM is possible but uncommon, so it is confirmed last, after the injector and wiring test good.