OBD-II trouble code
P0201: Injector Circuit/Open - Cylinder 1
The engine computer detected an electrical fault in the fuel injector control circuit for cylinder 1 — usually the wiring, connector, or injector coil. Cylinder 1 may lose fuel and misfire, so diagnose it promptly.
Quick facts
- System
- Powertrain
- Category
- Fuel Injectors
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $50 – $1,500
- DIY difficulty
- Intermediate DIY
Browse every code in P0200–P0299, or start from the full code library.
What does P0201 mean?
The engine control module (ECM) opens each fuel injector by pulsing its control circuit — battery voltage feeds one side of the injector while the ECM switches the ground on the other side for a precise number of milliseconds. The ECM watches the electrical feedback on that circuit, and when the voltage or current doesn't match what it commanded, it sets an injector-circuit code. P0201 means the fault is on the circuit for the cylinder 1 injector specifically.
Because the code is already isolated to one cylinder, diagnosis is targeted. On most inline engines, cylinder 1 is at the front of the engine, closest to the accessory belt and timing components. On a V-configuration engine, cylinder 1 is on Bank 1 by definition, but its physical location varies by manufacturer, so confirm the layout in the engine service information.
"Circuit/Open" is an electrical description. The circuit check starts at the wiring and the connector: a broken or chafed wire, a corroded or backed-out pin at the injector, or a poor ground. The cylinder 1 injector's own coil can also fail open. An injector that never gets pulsed leaves cylinder 1 without fuel, so P0201 typically appears with a cylinder 1 misfire (P0301) and the rough running and reduced power that come with a dead cylinder.
Common causes
- Broken, chafed, or shorted wiring to the cylinder 1 injector
- Corroded, loose, or backed-out connector pins at the cylinder 1 injector
- Open or shorted coil winding inside the cylinder 1 injector
- Poor ground or a bad shared power feed affecting the injector
- Blown injector fuse or open supply feed — worth a minute to check, though a fuse normally feeds several injectors, so P0201 standing alone makes it unlikely
- Rarely, a failed cylinder 1 injector driver inside the ECM/PCM
Symptoms
- Check engine light on, sometimes flashing if cylinder 1 is dead
- Rough idle and engine shaking
- Loss of power and hesitation on acceleration
- A cylinder 1 misfire (often a companion P0301)
- Raw-fuel smell or increased fuel consumption
- Hard starting in some cases
Diagnostic steps
- 1.Confirm the code is P0201 and note any companion codes, especially a cylinder 1 misfire (P0301).
- 2.Locate the cylinder 1 injector and inspect its connector and wiring for corrosion, chafing, or backed-out pins; wiggle-test while watching live data.
- 3.Measure the cylinder 1 injector's coil resistance with the key off and compare it to specification and to the other injectors. An open or out-of-spec reading condemns the injector.
- 4.Confirm the ECM is pulsing the circuit. On a port-injected engine with low-voltage saturated injectors, a noid light at the cylinder 1 connector does this directly. A direct injector is opened from a booster voltage — Bosch's HDEV 5.2 data sheet specifies a 65 V booster supply, and the Bosch CY335 is rated to 65 V — and Underhood Service describes driver voltage in a window of about 30–120 V. Do not test it with a 12 V port-injector noid light. Use the scan tool's injector output test. Keep the key off while probing the boost side.
- 5.Check the power feed and ground for the injector, and swap-test with a known-good injector if resistance is borderline. Relieve fuel pressure before unseating any injector — a port rail holds pressure for a long time after shutdown — and treat a direct-injection or diesel injector as a replace-not-swap item, since those need new seals and often a correction code after fitting.
- 6.If the wiring, fuse, ground, and injector all test good but the drive pulse is missing, suspect the injector driver in the ECM/PCM.
Repair cost
$50 – $1,500
A repaired wire or connector at the cylinder 1 injector is the low end of the printed bracket. A failed injector driver in the control module, which then has to be programmed, is the high end. Use the bracket to plan the job, then price the injector, the harness repair, and the labor time in the service information for this vehicle. The bracket is not a quoted price. Prove the circuit before the module is replaced.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with fuel injector replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.