The Best Why Is My Check Engine Light On But No Codes Ideas. Sometimes, a problem may occur in the engine or emissions system that triggers the check engine light to flash but does not leave a permanent code. There are several possible causes for this, including sensor issues, damaged wiring, exhaust system problems, misfires, software or calibration issues, and hidden emissions problems.

A weak battery can cause the check engine light to come on even if there are no codes. So, if your check engine light is off but you get an error code, use an obd2 scanner to check what the problem might be. Web the easiest way to reset the check engine light is to use your compatible code scanner.

