To open, pull the remote fuel-filler lid release.
To close, press the fuel-filler lid until it locks securely.

Fuel-Filler Lid and Cap
Fuel-Filler CapMazda 6 Owners Manual: Intermittent rear wiper relay inspection
1. Connect the connector to the intermittent rear wiper relay.
2. Connect the negative battery cable.
3. Measure the voltage at the intermittent rear wiper relay using voltmeter.
When inspecting terminal D for continuity, disconnect the intermittent
rear wiper relay connector.
4. If the ...
Mazda 6 Owners Manual: Contact Authorized Mazda Dealer and Have Vehicle Inspected
If any of the following warning lights or the indicator light turns on/flashes,
the system may have a malfunction. Contact an Authorized Mazda Dealer to have your
vehicle inspected.
...