Engine Control System - Trouble Shooting - No Codes - 4.2L: Symptoms: Notes

NOTE: Before proceeding with any symptom diagnosis, perform PRELIMINARY INSPECTION .

NOTE: If PCM displays data but engine fails to start, see NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 4.2L BRAVADA, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article.