Check Engine Light On? A Practical OBD-II Diagnostic Workflow

A scan code is a starting point, not a parts order. Follow this repeatable workflow to turn a check-engine light into a focused diagnosis.

A scan code is a starting point, not a parts order. Follow this repeatable workflow to turn a check-engine light into a focused diagnosis.
Oil level can fall without a puddle. Compare external evidence, exhaust behavior, operating conditions, and measured usage before choosing a repair.