OBD II systems are highly efficient and only illuminate the malfunction indicator light when an emissions failure has occurred that will raise emission levels above 1.5 times the FTP levels.

Question

Quizplus · Accepted Answer

OBD II (On-Board Diagnostics II) systems are designed to monitor vehicle performance and emissions. The malfunction indicator light (MIL), or check engine light, is illuminated when the system detects a problem that could increase emissions beyond 1.5 times the Federal Test Procedure (FTP) standards, indicating a significant emissions failure.

OBD II Systems Are Highly Efficient and Only Illuminate the Malfunction