Quote:
Originally Posted by Tcoat
Even the keyed Twins are operating the same as the button ones. It just feels old school to put a key in a slot. Both are actually just a control that sends a signal to the modules that electronically unlock the steering and tell the starter to spin. The key is not working like switch and directly sending power to the starter.
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Yes, and with these push-button start cars, the ECU actually sends the 12 volt signal to the starter solenoid circuit after all of the checks are made such as the clutch switch, the park position or neutral safety switch on an automatic transmission car, the passive auto immobilizer circuit, the minimum operating voltage check, etc. if and when those pass the self check, which happens in milliseconds, THEN the solenoid will finally get the 12 volt signal it needs to energized the contacts to the starter motor.
One key thing, the minimum operating voltage check is there to protect the ECU from an under-voltage condition. If the ECU doesn't detect the minimum voltage as it gets the signal from the push-button for a start cycle, in order to protect itself, it will not attempt to energized the starter solenoid circuitry. Very low voltage on modern vehicles is equally, if not, even worse than high voltage conditions.
This explains why I often see issues such as someone leaving their vehicle parked for weeks at a time with a failing battery and coming back to start it up to find a dead battery. After the battery has been recharged or replaced, they start having strange electrical issues. Low voltage conditions for extended periods is normally the cause of these strange issues.