P0275 indicates that the powertrain control module has detected an imbalance in the contribution of cylinder 5 during the engine’s power stroke. The module compares the expected torque from each cylinder and flags cylinder 5 when its contribution deviates beyond a calibrated threshold.
A stuck‑open, stuck‑closed, or leaking injector will deliver too much or too little fuel, causing a contribution imbalance.
Insufficient fuel pressure or a blocked fuel line to cylinder 5 can starve the cylinder, reducing its torque output.
A weak or missing spark prevents proper combustion, leading to a contribution mismatch.
Reduced compression or valve train issues lower the cylinder’s ability to produce power.
Corroded, broken, or high‑resistance circuits can interrupt the control signals, mimicking a component failure.
Rare; a defective PCM may misinterpret sensor data and set the code, but this is only considered after all other causes are ruled out.
PCM replacement is rarely required. The code is almost always caused by a fuel injector, ignition component, fuel delivery, or mechanical issue in cylinder 5. Only after all those items test good should a PCM fault be considered.
Yes. A fouled or worn spark plug in cylinder 5 can prevent proper combustion, leading the PCM to detect a contribution imbalance.
Clearing the code only turns off the light temporarily. The underlying fault will cause the code to return unless the root cause is repaired.
Driving with a cylinder contribution fault can increase emissions, reduce fuel economy, and potentially cause catalyst damage if the misfire persists. Prompt diagnosis is recommended.