Fuel Tank Inspection: AWD

Level the vehicle.
Complete the "BEFORE SERVICE PRECAUTION". (See BEFORE SERVICE PRECAUTION .)
Drain the fuel. (See FUEL DRAINING PROCEDURE .)
Remove the rear seat cushion. (See REAR SEAT CUSHION REMOVAL/INSTALLATION .)
Remove the service hole cover.
Main side

Fig 1: Removing Service Hole (Main Side) Cover
Courtesy of MAZDA MOTORS CORP.

Sub side

Fig 2: Removing Service Hole (Sub Side) Cover
Courtesy of MAZDA MOTORS CORP.
Disconnect the following parts:
Main side
- Fuel pump unit connector
- Quick release connector (See QUICK RELEASE CONNECTOR REMOVAL/INSTALLATION .)
Sub side
- Fuel gauge sender unit (sub) connector
Remove the floor under cover. (See FLOOR UNDER COVER REMOVAL/INSTALLATION .)
Disconnect the HO2S connector.
Remove the TWC and HO2S as a single unit. (See EXHAUST SYSTEM REMOVAL/INSTALLATION .)
Remove the propeller shaft. (See PROPELLER SHAFT REMOVAL/INSTALLATION .)
Remove the fuel tank, fuel pump unit and fuel gauge sender unit (sub) as a single unit. (See FUEL TANK REMOVAL/INSTALLATION .)
Perform the following procedure to verify the fuel tank airtightness.
1. Plug the fuel pump unit pipe, and ports B and C.
  
  Fig 3: Locating Fuel Pump Unit Pipe And Ports
  Courtesy of MAZDA MOTORS CORP.
2. Apply pressure of 5.9 kPa {44 mmHg, 1.7 inHg} to port A and wait for a while.
3. Verify that there is no change in the pressure and no air leakage from the fuel tank.
- If there is air leakage, replace the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION .)
Remove the port C plug.

Fig 4: Locating Port C Plug
Courtesy of MAZDA MOTORS CORP.
Place the fuel tank in a level position.
Close port A and apply 5.9 kPa {44 mmHg, 1.7 inHg} of pressure to port C, and leave it in this condition momentarily.
Open port A and verify that the pressure decreases from 5.9 kPa {44 mmHg, 1.7 inHg}.
- If it cannot be verified, replace the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION .)
Close port A and apply -2.0 kPa {-15 mmHg, -0.59 inHg} vacuum to port C, and leave it in this condition momentarily.
Open port A and verify that the -2.0 kPa {-15 mmHg, -0.59 inHg} negative pressure condition restores to near positive pressure.
- If it cannot be verified, replace the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION .)
Turn the fuel tank upside down.
Apply pressure of 5.9 kPa {44 mmHg, 1.7 inHg} to port A and wait for a while.

Fig 5: Locating Ports And Plugs
Courtesy of MAZDA MOTORS CORP.
Verify that there is no change in the pressure and no air leakage from the port C.
- If there is air leakage, replace the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION .)