1. Disconnect the brake fluid level sensor connector from the master cylinder.
2. Inspect for continuity according to fluid level between the brake fluid level sensor terminals.

If not as indicated in the table, replace the reserve tank.

Brake Switch InspectionInput/Turbine Speed Sensor Inspection [FS5 A EL]
CAUTION:
Water or foreign objects entering the connector can cause a poor connection
or corrosion. Be sure not to drop water or foreign objects on the connector
when disconnecting it.
On-Vehicle Inspection
1. Perform the following procedures.
a. Remove the battery cover..
b. ...
Air Fuel Ratio (A/F) Sensor Inspection [Mzr 2.0, Mzr 2.5]
A/F Sensor Inspection
1. Connect the M-MDS to the DLC-2.
2. Switch the ignition to ON.
3. Warm up the engine to normal operating temperature.
4. Access the following PIDs using the M-MDS..
VSS (Vehicle speed)
RPM (Engine speed)
O2S11 (A/F sensor output current)
...
Check Valve (One Way) Inspection [Mzr 2.3 Disi Turbo]
1. Disconnect the vacuum hose connected between the check valve and the purge
solenoid valve from the purge solenoid valve..
2. Disconnect the vacuum hose connected between the check valve (one-way) and
the intake manifold from the intake manifold..
3. Blow through the check valve (one-way) ...