Technician A says that a vehicle may have stored DTCs even if the MIL is not illuminated. Technician B says that all DTCs will illuminate the MIL. Which technician is correct?
A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B

Question

Quizplus · Accepted Answer

Technician A is correct. A vehicle may have stored Diagnostic Trouble Codes (DTCs) even if the Malfunction Indicator Lamp (MIL) is not illuminated. The MIL will only illuminate for certain codes that are considered emissions-related or safety-related, but there may be other codes stored in the system that do not trigger the MIL. Technician B is incorrect because not all DTCs will cause the MIL to illuminate.

Technician a Says That a Vehicle May Have Stored DTCs