1. Remove the clamps and vacuum hose.
2. Apply both suction and pressure to the engine-side hose, and verify that air blows only toward that side.

Air bleeding
Brake pedal inspectionMazda 6 Service Manual: Knock sensor inspection
Note
Perform the following test only when directed.
Resistance Inspection
1. Turn the ignition switch to LOCK.
2. Disconnect the knock sensor connector.
3. Measure the resistance between the knock sensor terminals A and B using an
ohmmeter.
If not as specified, replace the knock sens ...
Mazda 6 Service Manual: Immobilizer system reprogram procedure
Note
When an error occurs during the reprogram procedures, except when
the PCM is replaced, repeat the procedure from Step 1. If you still cannot
reprogram, confirm how many keys can start the engine. Then, perform the key
replacement or addition reprogram procedure according to the val ...