A power voltage of 5 V is applied to the brake vacuum
sensor power terminal (terminal No. 3) from the engine-ECU (terminal No. 127) and earthed to
the engine-ECU (terminal No. 130) from the brake vacuum sensor (terminal No. 2).
The sensor signal is inputted to the engine-ECU (terminal No. 128) from the brake
vacuum sensor output terminal (terminal No. 1).
The brake vacuum sensor converts the vacuum pressure
in the brake booster into a voltage signal and inputs the signal to the engine-ECU.
In response to the signal, the engine-ECU controls the AS&G system.
2 seconds later after the ignition switch has been in “ON” position
or the engine has started up.
The brake vacuum sensor output voltage is 4.5 V or more for 2 seconds.
The brake vacuum sensor output voltage is 0.2 V or less for 2 seconds.
Failed brake vacuum sensor
Open or shorted brake vacuum sensor circuit, harness damage, or connector damage