P0201 means the ECU has detected an electrical fault — typically an open circuit — in the wiring or driver circuit for cylinder 1’s fuel injector, which usually means that injector is receiving no signal at all rather than an inconsistent or partial one. This is a more absolute failure than the ignition-side causes covered in our P0304 guide — a circuit-open injector typically means that cylinder isn’t firing at all rather than misfiring intermittently.
What Does P0201 Mean?
Each cylinder’s fuel injector is commanded to open for a precisely timed interval by the ECU’s injector driver circuit. P0201 specifically means the ECU can’t detect the expected electrical signal in cylinder 1’s injector circuit — most often because the circuit is open somewhere between the ECU and the injector, rather than the injector itself being clogged or mechanically stuck.
Because this is a circuit-detection fault rather than a fuel-delivery-quality issue, it commonly produces a harder, more consistent symptom than a partially clogged injector would — see our P0300 and P0301 guides for the broader misfire family this code sits alongside, distinguished by being specifically electrical/circuit-based rather than covering the full range of possible misfire causes.
Common Symptoms
- A noticeable, consistent misfire on cylinder 1 specifically, often rougher than an intermittent fuel-quality-related misfire.
- Rough idle, sometimes pronounced given that one cylinder is contributing little to nothing.
- Reduced power under acceleration.
- Check engine light on, potentially flashing if the resulting misfire is severe enough to be classified as active and damaging.
Common Causes, Most Likely First
- A disconnected or poorly seated injector connector — worth checking first, especially if any recent engine work was done near that cylinder.
- Damaged or corroded wiring in the injector circuit.
- A failed injector itself, with an internal open circuit in its own windings.
- A failed injector driver circuit within the ECU itself, less common but possible, particularly if multiple injector circuits show faults simultaneously.
How to Diagnose It
- Check the injector connector for cylinder 1 — confirm it’s fully seated and undamaged.
- Test circuit continuity and resistance at the injector and along its wiring with a multimeter, comparing against manufacturer specification.
- Swap the injector with an adjacent cylinder’s injector if wiring checks out fine — if the fault follows the swapped injector, that confirms the injector itself rather than the wiring.
- Check for the same fault on other cylinders if this one resolves easily, since a pattern across multiple injectors points toward a shared wiring harness or ECU-side issue.
Never work under a vehicle supported only by a jack. Use axle stands on firm, level ground, chock the wheels that stay down, and leave the car in gear or Park with the handbrake on. A jack lifts; stands hold.
Possible Fixes
| Cause | Fix | Typical cost |
|---|---|---|
| Disconnected/loose connector | Reseat the connector | $0 |
| Damaged wiring | Repair the affected section | $80 – $250 |
| Failed injector | Replace the injector | $150 – $400 |
| Failed ECU driver circuit | Repair or replace the ECU | $400 – $1,200 |
Can I Drive With P0201?
For short trips only, with caution — a consistently misfiring cylinder dumps unburned fuel into the exhaust and catalytic converter, similar to the concern covered in our P0300 guide, and continued driving risks converter damage the longer it continues. If the check engine light is flashing, treat that as the more urgent version of this fault.
When to See a Mechanic
Promptly — mention that it’s specifically an injector circuit code for cylinder 1 rather than a general misfire, since that detail lets a shop start with connector and wiring checks rather than a broader investigation. More in our engine problems section.
Frequently Asked Questions
What does P0201 mean?
An electrical fault — typically an open circuit — in the wiring or driver circuit for cylinder 1’s fuel injector, usually meaning that injector receives no signal at all rather than a partial one.
Is P0201 the same as a regular misfire code?
It’s related but more specific — P0201 points at an electrical circuit fault for that injector specifically, while a general misfire code like P0301 can have many possible causes including ignition, fuel, or mechanical issues.
Can a loose connector cause P0201?
Yes, commonly — a disconnected or poorly seated injector connector is one of the most common and cheapest-to-fix causes, especially after recent engine work near that cylinder.
Is it safe to drive with a P0201 code?
For short trips only, with caution — a consistently misfiring cylinder can damage the catalytic converter the longer it continues, so it’s worth addressing promptly.
How much does it cost to fix P0201?
Often $150–$400 for an injector or wiring repair, though it can run higher if an ECU-side driver circuit fault turns out to be the cause.
