The "service engine soon" light on a Dodge Grand Caravan indicates a problem in the engine or emissions sensors. Before bringing the vehicle in for service, the owner should check for a loose or missing gas cap. AllPar explains that if this is the problem, closing the cap causes the light to turn off within several miles.
One of the most common triggers of the "service engine soon" light is a faulty oxygen sensor. This sensor monitors the vehicle's emissions and communicates that information to the engine. Functional oxygen sensors monitor the vehicle's emissions and help the engine run efficiently. A vehicle with a faulty oxygen sensor automatically fails its annual inspection.
Other common causes of an activated "service engine soon" light include damaged hoses, cracked gaskets, battery problems and electrical problems in the vehicle's computer. Many problems indicated by the engine light require inexpensive components available at automotive parts stores. Most stores also have computers that read and interpret the code generated by the engine light. Automotive repair shops and dealerships also offer this service.
About.com expert Matthew Wright explains that the "service engine soon" light typically goes on and stays on until the problem disappears. Vehicles with activated lights are safe to drive. However, a flashing engine service light indicates misfiring in the engine. Cars with flashing service lights require immediate service. Running the vehicle in this condition harms the engine and sometimes ruins it.