Here's why:
* Low Oil Pressure: The most direct cause. When oil is very low or extremely dirty (from being overdue for a change), it doesn't lubricate the engine properly. This leads to low oil pressure. The engine's computer detects this low pressure and illuminates the check engine light as a warning to prevent catastrophic engine damage.
* Oil Sensor Issues: While less likely to be the primary cause, severely degraded oil can clog or damage the oil pressure sensor itself, leading to inaccurate readings and triggering the check engine light.
* Related Damage: Prolonged driving with low or dirty oil can cause damage to other engine components, triggering the check engine light due to those secondary problems (e.g., increased wear on bearings, damage to the crankshaft). The check engine light doesn't pinpoint the *cause* but rather alerts you to a problem.
In short, if your Grand Caravan's check engine light came on and your oil change is significantly overdue, that's a very strong indicator that the overdue oil change is at least a contributing factor, if not the primary cause. You should have the oil changed immediately and get the car diagnosed by a mechanic to identify the specific problem and address any resulting damage. Ignoring it could lead to very expensive engine repairs.
