"Index in position 3 exceeds array bounds (must not exceed 1)." for surf function of 2D transient heat transfer

Hi, I'm having a problem with some code based on the time loop for a 2D finite difference transient heat transfer problem. It comes up with the error "Index in position 3 exceeds array bounds (must not exceed 1)." for line 140 (the surf function). Here is the code for the time loop, I know the error must be something I have missed with the start or end of the time loop. Any help would be much appreciated.

for t=1:((t_f/dt))

for i=1:nx % Cold bottom part

T(i,ny,t)=T2;

end

for it=1:100

for i=2:(nx-1)

for j = 2:(ny-1)

if j==1 %PV panel plate

T(i,j,t+1)= (r1*(T(i+1,j,t)-2*T(i,j,t)+T(i-1,j,t)+(-2*T(i,j,t)+2*T(i,j-1,t)+(q*dx)/k2))+T(i,j,t));% plate temperatures

elseif j>=2

if i==1 %Insulated LHS temp

T(i,j,t+1)= r1*(2*T(i+1,j,t)-2*T(i,j,t)+(-2*T(i,j,t)+T(i,j-1,t)+T(i,j+1,t)))+T(i,j,t);

elseif i==nx %Insulated RHS temp

T(i,j,t+1)= r1*(2*T(i-1,j,t)-2*T(i,j,t)+(-2*T(i,j,t)+T(i,j-1,t)+T(i,j+1,t)))+T(i,j,t);

end

end

for j=2:Finlength; %Fin temperatures

if i ==minVal %Fin1

T(i,j,t+1)=alphaaluminium*dt*((T(i+1,j,t)-2*T(i,j,t)+T(i-1,j,t))/(dx^2)+(T(i,j+1,t)-2*T(i,j,t)+T(i,j-1,t))/(dy^2))+T(i,j,t);

elseif i == minVal+minVal %Fin2

T(i,j,t+1)=alphaaluminium*dt*((T(i+1,j,t)-2*T(i,j,t)+T(i-1,j,t))/(dx^2)+(T(i,j+1,t)-2*T(i,j,t)+T(i,j-1,t))/(dy^2))+T(i,j,t);

end

end

if j~=2:Finlength; %

if i~=minVal;

T(i,j,t+1)=alphawax*dt*((T(i+1,j,t)-2*T(i,j,t)+T(i-1,j,t))/(dx^2)+(T(i,j+1,t)-2*T(i,j,t)+T(i,j-1,t))/(dy^2))+T(i,j,t);

end

end

end

end

end

x=linspace(0,platelength,nx);

y=linspace(0,plateheight,ny);

% [x_arr,y_arr] = meshgrid(x,y);

surf(y,x,T(:,:,t+1))

end