My car my nissian sentra 2005 has a check engine light on and two days ago it did not want to start. now it does start

diagnostic scrambler ???? What's that or what do you think it is ? Most tech's call it a diagnostic scan tool . Cranks but won't start , what's missing ? Fuel , spark , engine compression ? Do you know how to test for these thing's ?
No Start Diagnostic Basics EricTheCarGuy

THE CHECK ENGINE LIGHT COMES ON WHEN THE COMPUTER DETECTS A PROBLEM. YOU NEED TO HAVE THE CODES READ. THAT GIVES YOU A GOOD PLACE TO START.

Unfortunately, replacing a sensor only fixes the problem about half the time. The code means the computer is not getting a signal from the sensor, not that the sensor has failed.
The problem could be in the wiring, or the part that the sensor gets the signal from.

Broken bulb can happen

Have a fuel pressure leak down test performed, the check valve in the fuel pump may have failed and this causes longer cranking times.

im not a pro but most cars now days are preset and the adjustment screws are covered and have to be drilled out, so they are tamper proof and only pro's know where to drill,, the old stuff 70's and 80's screws were in plain sight

I had that exact problem on my 03 sentra gxe 1.8L , turned out to be the alternator had died and it was trying to use the battery. Are you having any electrical problems? Because when this was going on with me, the lights would barely work inside and outside the car - new alternator and battery and its been fine ever since

Looks like a common problem on lots of GM vehicles. You should watch this video before fixing your problem, which is in the
Secondary Air Injection System:

How to test an electric air pump P0410 case study

First of all have you done obd2 scan test for codes?

is the engine turning very fast and making an uncommon noise . if it is then you more than likely have a broken timing belt . if this is not the case then you need to check for spark .