What is the difference between P0264 and P0265?

They are the low and high versions of the same cylinder 2 injector circuit fault. P0264 means the circuit read low, which typically points at a short to ground or a shorted injector coil. P0265 means the circuit stayed high, which typically points at an open circuit — a broken wire or an open injector winding — or a short to battery voltage.

Should I replace the injector right away?

Test before you buy. Measure the cylinder 2 injector's coil resistance — an open reading condemns it, but a normal reading means the fault is in the harness or connector. Broken wires, backed-out pins, and corroded terminals cause this code often enough that skipping the wiring check risks paying for a part you did not need.

Can I keep driving with P0265?

Only as far as necessary to reach a shop. A dead cylinder pushes raw air and unburned fuel into the exhaust, which can overheat and destroy the catalytic converter — a far more expensive repair. Drive gently, avoid hard acceleration, and stop driving if the check engine light is flashing.

Could a recent repair have caused this?

It happens more often than people expect. Intake manifold, valve cover, and head gasket jobs all require moving the injector harness, and a pinched wire, an unseated connector, or a pin pushed back during reassembly will produce exactly this code. If the light came on shortly after service, inspect the connectors and harness routing in that area first.

OBD-II trouble code

P0265: Cylinder 2 Injector Circuit High

The engine computer saw the cylinder 2 fuel injector control circuit stay high — usually an open circuit or a wire shorted to battery voltage. Cylinder 2 typically stops firing, so address it before the catalytic converter is damaged.

Medium severityPowertrainFuel InjectorsDo not drive

Quick facts

System: Powertrain
Category: Fuel Injectors
Severity: Medium severity
Drivable: No — stop driving until repaired
Repair cost range: $50 – $1,500
DIY difficulty: Intermediate DIY

What does P0265 mean?

The engine control module (ECM) fires each injector by pulling its control wire to ground for a measured number of milliseconds while battery voltage feeds the other side. During that pulse, the ECM expects the control wire to drop to near zero volts. P0265 sets when the ECM commands the cylinder 2 injector on and the circuit stays high instead — or, on some manufacturers, when sensed current is out of range high.

A circuit that refuses to pull down points to one of two conditions. Either it is open — a broken wire, a backed-out or disconnected connector pin, or an injector coil that has burned open — so there is no path for the ECM to sink current through. Or the control wire is shorted to battery voltage, which holds it high regardless of what the driver commands. Either way the injector cannot be controlled and cylinder 2 does not get its fuel.

Before working on anything, confirm which cylinder is number 2 on your specific engine. On an inline engine it is the second from the front. On a V engine, numbering varies by manufacturer — some alternate across banks, others number down one bank first — so check the cylinder-numbering diagram rather than assuming. With cylinder 2 unfueled, expect a rough idle, shaking, reduced power, and usually a companion P0302 misfire code. A sustained misfire dumps raw air and unburned mixture into the exhaust and can overheat the catalytic converter, so this is not a code to leave alone.

Common causes

Open or broken control wire between the ECM and the cylinder 2 injector
Disconnected, backed-out, or corroded pin in the cylinder 2 injector connector
Open coil winding inside the cylinder 2 injector
Control wire chafed and shorted to a battery-voltage wire
Blown fuse or open power feed on the injector supply side
Rarely, a failed cylinder 2 injector driver inside the ECM/PCM

Symptoms

Check engine light on, sometimes flashing when cylinder 2 is dead
Rough idle and pronounced engine shake
Cylinder 2 misfire, commonly with a companion P0302
Loss of power and hesitation on acceleration
Raw fuel smell or unburned fuel odor from the exhaust
Hard starting or extended crank in some cases

Diagnostic steps

1.Confirm P0265 and note companion codes, especially P0302 for a cylinder 2 misfire or P0264 for the paired low-circuit fault.
2.Look up the cylinder-numbering diagram for your specific engine and locate cylinder 2 before disassembling anything.
3.Inspect the cylinder 2 injector connector and pigtail for backed-out pins, corrosion, and broken or brittle wires.
4.Unplug the injector and measure its coil resistance. An infinite or very high reading indicates an open winding and condemns the injector.
5.Check for battery voltage at the injector's power feed terminal with the key on — no voltage points at a blown fuse or an open supply wire rather than the injector.
6.Check continuity of the control wire from the injector connector back to the ECM pin with both ends disconnected; an open confirms a broken harness.
7.Check the control wire for a short to battery voltage, then use a noid light or a scan tool injector test to confirm the ECM produces a drive pulse. No pulse with good wiring and a good injector points at the ECM driver.

Repair cost

$50 – $1,500

Repairing a broken wire or a corroded connector is often $75-$250. A single fuel injector runs $60-$400 in parts plus 0.5-3 hours of labor depending on accessibility — a port injector on top of the intake is quick, while direct-injection or lower-intake injectors take longer. A failed ECM injector driver is uncommon and runs $500-$1,500 with programming. Diagnosis alone is typically $75-$150.

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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.