P0290 Code: Cylinder 10 Contribution/Balance

What the P0290 code means

The computer compares how much each cylinder accelerates the crankshaft. On diesels it corrects the amount of fuel each injector delivers so the engine runs balanced (per-cylinder fuel quantity correction). If cylinder 10 needs a correction outside the allowed limit, or keeps contributing differently from the rest, the computer stores the P0290 code.

On diesels, each cylinder contribution 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 for a fixed time with the engine idling. An injector that returns much more than the others has an internal leak and is not spraying cylinder 10 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 cylinders are usually on different banks. Confirm the numbering in the service manual before you take anything apart.

P0290 code symptoms

• Check engine light on.
• Engine shaking or a rough idle.
• Loss of power.
• Black or white smoke (diesel) or misfires (gas engine).
• High fuel use or a smell of fuel.

Likely causes of the P0290 code

1. Worn or clogged injector 10. The most common cause on high-mileage diesels.
2. Injector 10 leaking or dripping. It delivers too much fuel and produces smoke.
3. Low compression in that cylinder. Valves, piston rings or the head gasket.
4. Contaminated fuel that damages the injectors.
5. Injector codes not programmed after an injector was replaced without being coded (common on diesels).

How to diagnose the P0290 code step by step

1. Confirm the cylinder with the scan tool (misfire counters, or per-cylinder fuel quantity corrections on a diesel).
2. Read the fuel quantity corrections for all the injectors at hot idle. The affected one is usually far apart from the others.
3. Run the injector return flow test (diesel). An injector with much more return flow 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 replaced, check that its calibration code was programmed (IMA, QR or C2I depending on the brand).
6. Clear the codes and recreate the condition to confirm the repair.

How to fix the P0290 code

• Clean or replace the affected injector (on a diesel, at an injection specialist).
• Program the new injector into the computer when the manufacturer requires it.
• Repair the mechanical cause if the compression is low.
• Change the fuel filter and check for water in the fuel.
• Clear the codes and verify on a road test.

Technical reference data

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

Brand-specific notes

On common rail diesels (Toyota D-4D, Nissan dCi, Ford TDCi, Volkswagen TDI, Hyundai CRDi), the injectors carry a calibration code that must be written into the computer when they are replaced. Without that step, contribution and balance codes like the P0290 code show up.

Frequently asked questions about P0290