Engine

P0275 — Cylinder 5 Contribution/Balance Fault

Severity: medium Drive with care, to a shop

What P0275 means

The engine control module compares how much each cylinder contributes to engine output, usually by watching crankshaft speed changes. P0275 is set when cylinder 5 is noticeably weaker than the rest. The cause can be fuel delivery, spark, cylinder mechanical condition or the wiring that controls them.

Symptoms

  • Check Engine light on
  • Rough or uneven idle
  • Hesitation or loss of power
  • Worse fuel economy
  • Engine vibration or a misfire feeling

Possible causes

  1. Faulty or clogged fuel injector on cylinder 5
  2. Worn spark plug or failing ignition coil on cylinder 5
  3. Damaged, corroded or loose wiring or connectors to the injector or coil
  4. Low compression in cylinder 5 (valves, rings, head gasket)
  5. Vacuum leak or fuel delivery problem affecting one cylinder
  6. Rarely, an ECM fault or software issue

How to diagnose

  1. Scan all codes and freeze frame data, and look for misfire codes (P0300–P0308)
  2. Inspect the wiring and connectors for the cylinder 5 injector and coil
  3. Swap the coil (and plug) with a neighboring cylinder and see if the fault follows
  4. Inspect the spark plug for gap, wear, fouling, oil or fuel
  5. Test the injector: coil resistance, control signal, and operation by sound or scope
  6. Run a compression or leak-down test on cylinder 5
  7. Check for vacuum leaks and fuel pressure
  8. If all is good, check ECM power and grounds and look for software updates

Common fixes

  • Replace the spark plug and/or ignition coil on cylinder 5
  • Clean or replace the cylinder 5 fuel injector
  • Repair the wiring or connectors
  • Do the needed engine mechanical repair (valves, rings, head)
  • Update or replace the ECM (last resort)

Questions and answers

What does P0275 mean?

The ECM found that cylinder 5 produces less power than the other cylinders. The usual causes are the injector, spark plug, coil or wiring, and less often a mechanical problem.

Can I drive with P0275?

Briefly and under light load, yes. If the check engine light is flashing, stop driving, because the misfire can damage the catalytic converter.

How can I quickly find the cause of P0275?

Swap the cylinder 5 coil and plug with a neighbor's. If the fault moves, it's ignition. If not, check the injector and compression.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.