Diagnosing cylinder pressure sensor gain and offset

A method, comprising:

• determining a reference in-cylinder pressure for a cylinder of an engine based on an ambient pressure measured at a location external to the engine and an air intake system;
• measuring an actual in-cylinder pressure of the cylinder of the engine with a cylinder pressure sensor while the engine is keyed on and a crankshaft of the engine is not rotating;
• determining an offset of the cylinder pressure sensor based on the reference in-cylinder pressure and the actual in-cylinder pressure;
• comparing the offset of the cylinder pressure sensor to a threshold offset;
• providing an offset error notification responsive to the offset of the cylinder pressure sensor being greater than the threshold offset;
• and
• determining a gain of the cylinder pressure sensor while the engine is keyed on, the crankshaft of the engine is rotating, and the engine is not firing.

A system, comprising:

• a cylinder pressure sensor configured to be communicably coupled to a cylinder of an engine and structured to measure an actual in-cylinder pressure of the cylinder while the engine is keyed on and the crankshaft of the engine is not rotating;
• and
• a controller configured to be communicably coupled to the engine and the cylinder pressure sensor, the controller structured to:
• determine an offset of the cylinder pressure sensor based on a reference in-cylinder pressure and the actual in-cylinder pressure, wherein the reference in-cylinder pressure is based on an ambient pressure measured at a location external to the engine and an air intake system, and wherein the offset of the cylinder pressure sensor is determined while the engine is keyed on and a crankshaft of the engine is not rotating;
• compare the offset of the cylinder pressure sensor to a threshold offset;
• provide an offset error notification responsive to the offset of the cylinder pressure sensor being greater than the threshold offset;
• and
• determine a gain of the cylinder pressure sensor responsive to the offset of the cylinder pressure sensor being less than the threshold offset, wherein the gain is determined while the engine is keyed on, the crankshaft of the engine is rotating, and the engine is not firing.