Скачать или смотреть Why Is My Check Engine Light On But No Codes Are Displayed

The Check Engine Light can be triggered without showing diagnostic trouble codes (DTCs) due to several factors, including pending or manufacturer-specific codes, communication errors between control modules, scan tool limitations, electrical issues like low battery voltage or poor grounds, and transient faults in systems such as EVAP. Basic scanners may miss codes stored in non-powertrain modules or fail to detect faults that haven’t matured. Diagnosing the issue involves checking battery and ground connections, using a more advanced or OEM-specific scan tool to access all modules and live data, reviewing Technical Service Bulletins (TSBs), and inspecting components like the gas cap and wiring. If these steps don't reveal the cause, professional diagnostics are recommended to test CAN bus integrity, perform module-level analysis, and identify faults not visible to DIY tools.

00:00 - Intro: The Mystery of the Check Engine Light with No Codes
00:42 - Reason 1: Pending Trouble Codes
01:06 - Reason 2: Manufacturer-Specific (Hidden) Codes
01:27 - Reason 3: Module Communication Errors & CAN Bus Faults
02:13 - Reason 4: Electrical and Intermittent System Faults
02:49 - Explaining Different Code Types (Active, Pending, Stored)
03:28 - How to Diagnose the Problem: A Step-by-Step Guide
04:16 - When to Consult a Professional Mechanic
04:42 - Summary of Diagnostic Steps
05:18 - FAQ: Can a weak battery cause this?
05:40 - FAQ: Is it safe to drive with the light on?