Check engine light does not light?

[mss5413]

Hey guys,I have had my 240 for 4 years and have never seen the Check engine light come on. I have had the car to the dealership twice before and they have found codes in the computer such as a MAF sensor malfunction the first time and an injector leak the second time.How do I know that the dealership is not lying to me even though they gave me a receipt and the paperwork for the service and how do I know for sure that the malfunction lamp or the self-diagnostic system is working properly? When I disconnect the MAF sensor or the coolant sensor, or O2 sensor for a couple of seconds I still have not seen the light come on? Can this be a problem? Thanks for all of your responses!

[onosqv]

Ok, Put your car ignition to ON but don't crank the engine. If the check engine lights, it is working properly. It's probably not from the way you described.

SOOOOO, either check your codes - 240sx.org -> FAQ's -> ECU/ECM check lights link

orrrr

pull out your cluster and change the bulb: http://www.lsauto.com/install.asp

If it still doesn't light up, well, then your SOL, hahahaha.

[mss5413]

Yes it does light in the on position when the engine is off and goes off when the engine is running. But I don't understand how the dealership could still find codes in the computer. And why would it not light with a sensor disconnected?

[onosqv]

Yes it does light in the on position when the engine is off and goes off when the engine is running. But I don't understand how the dealership could still find codes in the computer. And why would it not light with a sensor disconnected?

Well, in that case, the only way you can verify is to pull codes yourself. It does seem strange that they pulled codes w/o the light being on. But from what I can tell, you engine light is working fine.

Just disconnecting the sensor for a short while, I'm not sure if that will throw a code or not, maybe if you left it disconnected a little longer.

Pull the codes yourself. Easy as that.

[nyckanny]

its possible they didnt actually pull any codes, if u know what i mean... wink wink

[mss5413]

Thanks guysLike you say the dealership could I been givin me BS, I won't really know for sure, but I am thinking about getting the $30 decoder from http://www.etoolcart.com. It states that it works for nissan 240sx from 89-95 and mine is a 1993 so I may be wasting my money but what is $30 compared to $80 at the shop for just retreving a DTC. I have around 130k miles on my engine and have not serviced a fuel injector yet, could that hold true according to what the dealership told me about an injector leak?When I get the car back I plan to run the car for a couple of minutes and then pull the spark plugs to check for a wet plug and also I plan to inspect my AIV for carbon buildup. I know AIV has nothing to do with the injectors but I have had to clean my throttle body probably once every 4 months.

[Ubernoober]

You don't need to spend a dime to pull codes from a 93.On the great intarweb is the FSM for our cars. Download it and it describes exactly how to get the blink codes and also how to decode them. Done and done.

Also, you can have a code without a check engine light. If the problem is brief enough or intermittent it doesn't seem to pop the light. I have an ongoing knock-sensor code that never lights the CE light.