I've disconnected my battery before and didn't have to enter a security code, is this a D1 thing?

 

It depends on how long the battery was discconected.

 

Actually part of it depends on how good the small radio battery is, if it has failed, your radio will not be able to hold the code when the main battery has been disconnected.

 

I want to remove the sensor because i cannit aford all the expensive parts and repairs
The light must be off to get smogged
and the car runs perfect
it is a disco 2

 

Just because turn the light off does NOT mean it will pass inspection.
Even with the light off the codes will still be there and it will not pass.
Get the codes read, tell us what they are and we can help you fix the problems so that you can pass inspection.
May not be as bad as you think.

 

I was just jokin about the battery.

 

They won't be fooled by a non-working Check Engine Light. I suggest going to a parts store, like Autozone and they will read the code for free. Not all parts stores do this, but Autozone for sure does, many others probably do as well. Write it down and let us know what it is. It could be a simple error like an Oxygen Sensor which is really common. All the goofing around and energy spent to get around the inspection, you'd be ahead if you had to buy a $140 O2 sensor or another sensor, and fix the root problem (and your vehicle will perform better with the emissions working correctly which will pay for itself with fuel savings). And, if that's what it turns out to be, O2 sensors are on sale this month at Roverparts.com.

 

you can fool the emissions tech by taking out the light but you can't fool his computer when he hooks it up

 

yes you really can't "trick" the OBD II emissions test, it will communicate with the vehicles computer and require a "good response" even if you were able to disconnect the battery to turn the CEL off the computer would still provide a "not ready" state and you will still fail the emissions test. there are only two ways to get around this the first which I and everyone else on here would agree would be to fix whatever is throwing a code, the second is to actually make modifications to the sensors (or sensor wiring) to actually change the reading that is provided and put it in the correct range. in order to do this you would need to know what is causing the light, what the reading is currently and what the reading should be, then you would need a pretty good understanding of electronics to figure out how to bring the signal into the proper range (like what resistors or diodes, or whatever you would need to provide the correct reading) I would suggest the easy route which would be just to fix the problem! it may be a bit more expensive but as stated in previous replies not only will you prevent damaging your truck you will also save money in fuel costs!

also as you stated before that your truck runs great, well the OBD II system is not only there to let you know something is wrong it is also designed to help prevent newer (96 and on) vehicles from producing higher levels of emissions "before" they actually start to do it. I hope that makes sense!

 

most places you cant even do this because they will turn just the ignition on first to make sure the light actually works!