P0272
Cylinder 4 Contribution/Balance
Fuel injection / cylinder balance
Generic OBD-II
High
What it means
P0272 means cylinder 4 isn't contributing its fair share of power compared with the other cylinders. The ECM watches how evenly each cylinder pulls and flags cylinder 4 as weak. A worn or clogged injector is the usual cause, though low compression or a wiring fault can be behind it too. The engine runs rough and down on power, but a single weak cylinder won't stop it from starting.
High
Can I keep driving? Usually drivable but rough — cylinder 4 isn't pulling its weight, so expect a rough idle and lost power. Fix it before it fouls or damages the converter.
Common symptoms
What you'll notice
- Check-engine light on
- Rough idle or noticeable vibration
- Reduced power and hesitation
- Occasional misfire feel from cylinder 4
Common causes
Most likely first
- Weak, clogged, or failing injector on cylinder 4Likely
- Low compression on cylinder 4 (valve or ring wear)Common
- Wiring or connector fault at the cylinder 4 injectorCommon
- Fuel delivery or intake issue affecting cylinder 4Less often
- Failed engine control module (ECM) (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and compare cylinder contribution/balance readings with a scan tool.
- Test the cylinder 4 injector electrically and swap it with a neighboring cylinder to see if the imbalance follows.
- Inspect the injector connector and wiring for damage or corrosion.
- Run a compression or leak-down test on cylinder 4 if the injector checks out.
- Address fuel-delivery or intake faults; clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0272?+
Short-term, yes, but a weak cylinder makes the engine run rough and can wash fuel into the exhaust, risking converter damage. Repair it soon.
Can I just clear P0272?+
It returns once the ECM re-measures cylinder 4 falling short. The injector or mechanical cause has to be fixed.
Related codes
Often seen with P0272
Read & clear P0272 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX