P0272 Code: Cylinder 4 Contribution/Balance

What the P0272 code means

The computer compares the crankshaft acceleration each cylinder produces. On diesels it adjusts the amount each injector delivers to balance the engine, which is called fuel correction per cylinder. If cylinder 4 needs a correction outside the limit, or keeps contributing differently from the others, the P0272 code is stored.

On diesels, the contribution of each cylinder can also be checked with a return flow test. You disconnect the injector return lines and collect the fuel from each one in a container over a fixed time with the engine at idle. An injector that returns far more than the others has an internal leak and does not spray cylinder 4 properly.

Cylinder numbering depends on the manufacturer. On most inline engines, cylinder 1 is the one closest to the timing belt or chain. On V engines, the odd and even numbered cylinders are usually on different banks. Confirm the numbering in the service manual before you take anything apart.

P0272 code symptoms

• Check engine light on.
• Shaking engine or rough idle.
• Loss of power.
• Black or white smoke on a diesel, or misfires on a gasoline engine.
• High fuel use or a smell of fuel.

Likely causes of the P0272 code

1. Injector 4 worn or clogged. This is the most frequent cause on high mileage diesels.
2. Injector 4 leaking or dripping, which delivers too much fuel and makes smoke.
3. Low compression in that cylinder from valves, rings or the head gasket.
4. Contaminated fuel that damages the injectors.
5. Injector codes not programmed after an injector was replaced without coding it. This is common on diesels.

How to diagnose the P0272 code step by step

1. Confirm the cylinder with the scan tool, using misfire counters or, on a diesel, the fuel correction values per cylinder.
2. Read the fuel corrections of all the injectors at hot idle. The affected one is usually far apart from the rest.
3. Do the injector return flow test on a diesel. An injector with much more return than the others has an internal leak.
4. Measure the compression of the cylinder to rule out a mechanical problem.
5. If an injector was changed, check that its calibration code was programmed (IMA, QR or C2I depending on the brand).
6. Clear the codes and reproduce the condition to confirm the repair.

How to fix the P0272 code

• Clean or replace the affected injector. On a diesel, have it done at an injection shop.
• Program the new injector into the computer when the manufacturer requires it.
• Repair the mechanical cause if compression is low.
• Change the fuel filter and check for water.
• Clear the codes and confirm the repair with a road test.

Technical reference data

• High impedance gasoline injector: 11 to 18 ohms.
• Low impedance injector: 2 to 5 ohms.
• Typical supply: 12 volts from a relay or from the computer. The computer switches the ground to open the injector.
• Piezoelectric common rail diesel injectors are not tested with an ohmmeter in the same way. Follow the manufacturer procedure.
• Typical fuel correction on a diesel: within plus or minus 2 to 3 mm3 per injection.
• These are reference values only. Check the manufacturer data for your engine.

Brand-specific notes

On common rail diesels, the injectors carry a calibration code that has to be written into the computer when they are replaced. Without that step, contribution and balance codes appear.

P0272 on Toyota

The D-4D common rail diesel injectors carry a calibration code that must be written into the computer on replacement.

P0272 on Nissan

The dCi common rail diesel injectors carry a calibration code that must be written into the computer on replacement.

P0272 on Ford

The TDCi common rail diesel injectors carry a calibration code that must be written into the computer on replacement.

P0272 on Volkswagen

The TDI common rail diesel injectors carry a calibration code that must be written into the computer on replacement.

P0272 on Hyundai

The CRDi common rail diesel injectors carry a calibration code that must be written into the computer on replacement.

Frequently asked questions about P0272