What is the reason for not hearing the self-test sound when turning the key?
2 Answers
Self-test itself does not produce any sound, at most you may hear about 1 second of fuel pump pressurization noise. Therefore, the sound you previously heard might be due to unfastened seat belts or improperly closed doors. Here is relevant information about vehicle self-test: Silent self-test: The self-test is the ECU's detection of various sensor signals in cold state to determine if they are normal, which does not generate any sound. Self-test process: Many indicator lights on the dashboard will illuminate, automatically turning off after a few seconds, while malfunctioning indicators will remain lit to alert the driver. Check items: Common indicator lights typically include door alerts, handbrake alerts, seat belt alerts, engine self-test, lubrication oil condition check, ABS system check, etc.
I remember my old sedan also made no self-check sound when turning the key, which felt really unsettling, like the car was on strike. The self-check sound is actually a little reminder before the car starts, telling us that the system is checking its own status. Possible reasons? Most of the time, it's a battery issue—like the battery being too low on charge or old and failing, unable to provide enough power for the system to make the sound. Also, a blown fuse is another common factor, like a broken guard in the circuit. Additionally, poor contact in the ignition switch or a malfunction in the ECU (that little computer module) can also silence the sound. It's recommended to first check the battery's condition or replace a new fuse. If you're unsure, quickly consult a professional to avoid disrupting daily commutes. In short, though it's a minor issue, it relates to the car's health—address it promptly, and everything will be fine.
