"service engine soon light question?

Question

Here's my question-I have 2004 Nissan Sentra /94 thousand miles. For about 6 months the "service engine soon" light has been on th dash. I have routine serviced several times(oil change, coant, etc) since it came on. There is nothing wrong with the car. I cant get this darned ligh to go out, and I cant it smoged with it on. help! I tried disconnecting the battery, that didnt work-any sugestions wlcome

Answer 1

On most vehicles, the "Service Engine Soon^ light is ONLY A REMINDER that a recommended routine maintenance is needed. When you got your engine serviced, they should have reset the light. It should tell you in your owners manual how to do it under "Service" or "Maintenance" or something like that.



You should have no problem getting your smog test with this light on. It does not have anything to do with emissions.

Answer 2

It can mean anything from you are very low on oil and better get some added or an oil change soon or it can mean that your oxygen sensor(s) for your emissions system need replacing. This is a stupid design concept, putting emergency and non-emergency items in the same warning light. Anyway, check your oil level. See if you need more oil. If that's not it, it's probably the oxygen sensor(s). Some places (repair shops) will do the diagnostics for no charge, hoping you will have the sensor(s) replaced by them. It can run $350 to $450 to have this done. You can't pass the emissions test without good sensors in place. A dealer will charge you for the diagnostics but will put that charge toward the repair.

Answer 3

There is simply no way around this. You can erase the code with a scan tool. But if the problem still exists, it will come back on. If you think you can erase it and run it down for a smog check, think again. The computer runs several "readiness monitors" before it gives an "all clear" to the smog inspector. They can tell if you've recently erased the codes.



Take it to an auto parts store, find out what trouble code is stored in the computer and get it fixed. You cannot scam the smog checkers. They've seen every trick in the book.

Answer 4

That light only comes on for emission system problems or false readings sent by faulty sensors in the emission control system. It has nothing to do with routine maintenance. If after a thorough testing of all emission control devices and switches checks out OK, or if the problem parts have been replaced and the light still comes on; then the computer needs to be reset by battery disconnection. If it cannot be reset, then the computer itself may need to be replaced.

Answer 5

That is cause your PCM still holds juice while you disconnect the battery. Try this. Disconnect the battery, press on the brake. To make double sure press on the horn for 5 seconds. This will clear that light. But that light is on for emissions which means it could be easy as a loose gas cap to a misfire in your engine. Service engine soon.

Answer 6

well disconnecting the battery just erases codes, but if the code keeps on reading it won't go out. Something is going on such as a bad O2 sensor, thats probably what it is. have you had decreased fuel eco etc? just get an obd2 code scanner and find out; they're easy to use and some places let you use them for free.

Answer 7

such systems can be reset, usually by depressing a series of buttons on your radio. check your owners manual for the procedure, or check online if you do not have the owners manual for the car..i do not have a nissan, but in my chev i need to tell the computer in the car that my car has been serviced and do so thru the radio buttons...the mechanic should be doing this for you whenever he changes oil, or services anything on car...ask before you pay.