The following are known Gecko Codes for FIFA 15 on Nintendo Wii (Wii).

Miscellaneous

Wii Remote/Nunchuk Button Activator [Bully@Wiiplaza]
28135400 YYYYZZZZ
http://geckocodes.org/index.php?arsenal=2

Profile Modifiers

All Overall Bonuses Completed [Bully@Wiiplaza]
C21A0C48 00000007
2C1B0001 40820028
38600005 907F63D8
38600014 907F1398
907F4D98 3860001E
907F0038 38600023
907F2798 807F0038
60000000 00000000

City Population Modifier [Bully@Wiiplaza]
C21E4C1C 00000003
3FA0XXXX 63BDXXXX
93A4A8EC 93A4A8F0
60000000 00000000

Stadium Match

Home Team: Goals Modifier [Bully@Wiiplaza]
C228CA44 00000002
3800XXXX 90046F3C
60000000 00000000

Away Team: Goals Modifier [Bully@Wiiplaza]
C241D648 00000002
3800XXXX 90037294
60000000 00000000

Goals Multiplier [Bully@Wiiplaza]
045EBFC8 3805XXXX
Sets the amount of goals added to a team's score after scoring

Home Team: Players Amount Modifier [Bully@Wiiplaza]
C22683CC 00000003
2C1F0000 4082000C
3980000X 918300C8
800300C8 00000000

Away Team: Players Amount Modifier [Bully@Wiiplaza]
C22683D0 00000003
2C1F0001 4082000C
3980000X 918300C8
7C1E0000 00000000
Video: http://www.youtube.com/watch?v=TpJSQfBfT00

Red Cards Don't Count [Bully@Wiiplaza]
047360B0 60000000
Players are not sent off the court for getting red cards

Players Sent Off Amount Modifier [Bully@Wiiplaza]
047360AC 3803XXXX
FFFF = Default (- 1)
The amount of players which have to leave the field when someone of the team receives a red card

Time Control [Bully@Wiiplaza]
046CA5A0 38040001
046CA544 7C00E214
046CA5A8 60000000
046CA548 60000000
28135400 F9FF0600
046CA5A0 3800270F
046CA544 3800270F
046CA5A8 901D0008
046CA548 901D000C
E0000000 80008000
Press 1 + B to finish half time, otherwise the match timer is frozen
Video: http://www.youtube.com/watch?v=ijBVrSAf3W8

Timer Speed Modifier [Bully@Wiiplaza]
046CA5A0 3804000X
Don't use with "Time Control"

Manager Mode

Infinite Transfer Points [Bully@Wiiplaza]
C2385004 00000002
39800063 91830000
80630000 00000000

Infinite Budget [Bully@Wiiplaza]
C2385024 00000002
3D807FFF 91830004
80630004 00000000

Maximum Club Upgrades [Bully@Wiiplaza]
C23513C0 00000003
38800012 908304E0
908304E8 908304EC
908304F0 00000000
Video: http://www.youtube.com/watch?v=AGngjDdmcJs

Streets to Stadiums

Infinite Experience Points [Bully@Wiiplaza]
C2397B34 00000002
38000066 9016004C
60000000 00000000
Allows you to level up your player as much as you want

All Attributes Maxed Out [Bully@Wiiplaza]
04397AC4 38000063
Enter "attribute" screen and confirm without doing anything to save the modified stats (it will have taken effect the next time you check)
Video: http://www.youtube.com/watch?v=S6V1CMhBla4

Hit the Streets

Home Team: Power-Up Meter Modifier [Bully@Wiiplaza]
C25F12D0 00000003
2C1EFFFF 4082000C
3D80LLLL 918371CC
C02371CC 00000000

Away Team: Power-Up Meter Modifier [Bully@Wiiplaza]
C24884E0 00000003
2C1E0001 4082000C
3D80LLLL 918371CC
901D003C 00000000

Power-Ups Last Forever [Bully@Wiiplaza]
04005F0E 60000000

Power-Up Meter Never Decreases [Bully@Wiiplaza]
045F1174 60000000
045F0E84 60000000
045F0EA4 60000000

Placeholders

*YYYY & ZZZZ Values*
Button mask & button values
Button calculator:
http://www.geckocodes.org/index.php?arsenal=2

*SS Values*
ASCII letters converted to hexadecimal

*X Values*
Decimal converted to hexadecimal

*LLLL Values*
Decimal with places from 0 to 1 converted to Float

*PPPPPPPP Values*
00000015 = Power Shot
00000016 = Super Speed
00000017 = Side Shot
00000018 = Sliding Tackle
00000019 = Super Shoulder
0000001A = Gladly Big
0000001B = Shock Wave