P0266

Cylinder 2 Contribution/Balance

Fuel injection / cylinder balance Generic OBD-II High

What it means

P0266 means the ECM has detected that cylinder 2 isn't contributing its expected share of power compared with the other cylinders. That imbalance usually comes from a weak or leaking fuel injector or from low compression on that cylinder. The engine runs rough and down on power, and a persistent weak cylinder can eventually damage the catalytic converter.

High

Can I keep driving? Driveable but rough — cylinder 2 isn't pulling its weight, so expect a misfire-like miss; extended driving with a weak cylinder can stress the catalytic converter.

Real-world scan data

Seen in

1,062

scans in the past year

Found in

0.2%

of scans

0.3%

of scans that found faults

Appears alongside · share of P0266 scans

P0263in 73.9% of scans

P0269in 73.3% of scans

P0272in 73.3% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Rough idle or noticeable vibration
Hesitation and reduced power
Possible increased fuel consumption

Common causes

Most likely first

Weak, clogged, or leaking cylinder-2 fuel injectorLikely
Low compression on cylinder 2 (valve, ring, or head-gasket issue)Common
Injector wiring or connector fault on cylinder 2Common
Fuel delivery problem (pressure or restriction)Less often
Faulty ECM (least likely)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data and check cylinder-balance / contribution PIDs to confirm cylinder 2.
Test the cylinder-2 injector — resistance, and swap or flow-test if possible.
Run a compression (and leak-down) test on cylinder 2 to rule out a mechanical cause.
Inspect the injector wiring and connector for damage.
Replace or clean the injector, or repair the mechanical fault. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0266?+

Only briefly. A weak cylinder runs rough and, if it becomes a full misfire, unburned fuel can overheat the catalytic converter. Get it diagnosed soon.

Can I just clear P0266?+

It returns within a few drive cycles until cylinder 2's injector or compression problem is fixed.

Read & clear P0266 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX