P0261 Code Meaning and Next Steps

First checks take 10 to 20 minutes for the first checks. No special tools are usually needed for the first checks.

Can you keep driving?

Stop driving if any of these apply

!The check-engine light is flashing.
!The engine is shaking badly, stalling, or struggling to accelerate.

If the light is steady and the vehicle still drives normally: Maybe, but only for a very short distance if the engine still runs smoothly.

What to check first

Step-by-step checks

1
Free - no tools
Inspect the injector connector and harness for looseness, corrosion, or heat damage
2
Free - no tools
Compare cylinder 1 balance or misfire data if scan data is available
3
Basic tool needed
Look for recent service work that may have left the connector loose or the harness pinched
4
Basic tool needed
If the injector was swapped with a known-good cylinder, see whether the fault moved with it
5
Basic tool needed
Keep clear of hot exhaust and moving engine parts while inspecting the area

If the code returns

-If the problem follows the injector, replacement becomes more likely than wiring repair.
-If the code returns after connector work, revisit the control circuit and continuity checks.
-If cylinder 1 still misfires after injector checks, test compression and ignition next.

Background

What this code means

P0261 is a generic OBD-II injector circuit code for cylinder 1.

A fault on cylinder 1 can come from the injector, the harness, the connector, or the ECU driver side of the circuit.

A cylinder-specific misfire or rough idle can show up when the injector circuit is not working correctly.

Diagnosis

Common causes

Most common

Injector circuit wiring fault

A damaged wire can keep cylinder 1 from firing correctly.

Common

Loose or corroded connector

A poor connection can make the fault intermittent.

Common

Failed injector

The injector may be stuck open, stuck closed, or electrically open.

Possible

Driver circuit issue

The ECU output may not be commanding the injector normally.

Avoid these mistakes

What not to do

xDo not keep driving if the engine is shaking badly or the check-engine light is flashing.
xDo not replace injector or solenoid parts before checking the connector, wiring, and fuel supply side.

Parts

Parts that may need replacing

PartTypical costNotes

Fuel injector$80-$300Relevant when the injector itself is confirmed bad.

Connector pigtail repair$15-$90Worth checking if the plug or pins are damaged.

Injector wiring repair$20-$160Useful if the harness has an open, short, or heat damage.

Related OBD codes

P0260

P0260 usually means injector circuit malfunction for cylinder 2.

P0262

P0262 usually means injector circuit malfunction for cylinder 3.

P0301

P0301 means cylinder 1 is misfiring.

Source notes

Generic OBD-II (SAE J1979 / ISO 15031-5). P0261 was expanded around common injector circuit faults, including wiring issues, connector problems, and injector failure.

This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.

This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.

Last reviewed: 2026-04-10

Reference: Open reference

P0261 - P0261 Usually Means Injector Circuit Malfunction for Cylinder 1