One problem related to service engine light on has been reported for the 1998 Chevrolet Astro. The most recently reported issues are listed below.
Diagnostic system was defective and didn't provide warning that the engine was overheating. The book states the service engine soon light comes on to indicate that there is a problem and service is required. Malfunctions often will be indicated by the system before any problem is apparent. This system is also designed to assist your service technician in correctly diagnosing any malfunction. None of this worked on the van.