All right... first of all: The idea of returning player colour to vehicles is a good one. Everyone likes player colour (even if it is hard to use well!). You started, and that's very good!
As you may guess, this is not enough... yet!
The original is a render. With player colour, what you do is pixelart, more or less, since you are limited by 2x8 available colours. Result is a mix of render and pixelart. If you want it
not to look like an unholy union of two very different things (and you do), you must either bend the old to match new, or vice versa.
Assuming the render is more or less usable, the task its to make player colour part that matches the remaining parts of render. You have to start with understanding, what rendering a 3d model does. There is detail all over the place, not aligned to pixels. When you see a door, the edge is a mix of door and wall. If you look at the attached picture, the yellow bus has door precisely defined, while the red one's are rather uncertain. Same with wheels and... well, everything.
Assuming I take from your repaint the view with doors, let's see what is there: A huge space of one colour, interrupted only by what you thought is the door. Also, new wheels of pure darkness, on the big area of bright colour. I see three problems here:
1) too big homogenous area
2) mismatched shape of door in original render and your redraw
3) strong (and thus jarring) contrast between wheels and the new bus body
First, door. The original can guide you easily! It has darker pixels in some places. So, let's take what you drew in player colour, and make it darker there. Simple as that
You can check the other views as well and think about this technique. Where the render is darker/brighter, the player colour version might follow for better result.
Second, the wheels. Study the first bus. There isn't just a black circle. There is a ring of pixels around, where the surrounding colour is made a bit darker. The overall shape then seems more circular. And... just look, the render has this too, although there is some chaos mixed in by "misalignment" of model and pixels. What I did in my repaint was the same thing. Darker surroundings.
Third, uniformity of blue area. Well this is always a tough one! So many possibilities. In the end, I decided to add another stripe of secondary colour, and it seems to have worked well.
Finally, I decided that I wasn't satisfied with the top stripe. It appears bright, compared to original colouring. It's easy to see why - once again, there is a strong boundary between "dark" (windows) and "bright" (stripe and lower parts). So, I made this stripe a bit darker. Maybe it helped, maybe not. I am not sure.
Hope this helps somewhat? As you can see, it is always just a matter of: look, think, make it work. The three techniques I detailed are easy to even mindlessly repeat...
