# 2005 SER service engine soon light still on



## sptt (Mar 23, 2011)

Hello,

I just replaced my rear precat which was pretty bad (and $$$) and rattling loudly but my SES light is still on (I have reset and cleared memory twice. One before and one after oil change). I read somewhere it is prbbly the egr valve in this model. Car has 98K. Will codes tell me what needs replaced or just that it is an emissions issue. Car sounds great. Mileage is back to normal. This has 3 O2 #3"#94# I believe. Two precat and one cat converter. Altima SER 2005. It's also a Calif car.

Thanks,

SP


----------



## sptt (Mar 23, 2011)

*No bites...*

Anywhere you all suggest I repost this? Thanks


----------



## smj999smj (Jan 1, 2006)

Trouble codes give you a point to start and "may" tell you the part that failed, but that needs to be confirmed with testing. For example, you may get an O2 sensor code, which may be caused by a failed O2 sensor, but it could also be triggered by a very lean condition (ie low fuel pressure, vacuum leak) or a very rich condition (ie bad fuel pressure regulator) or even a circuit issue (ie open or shorted wire, poor connection in a harness connector). There are several hundred things that could cause a trouble code to set, so someone telling you it is "probably" something is about as "shot in the dark" as it gets! Most parts stores will retrieve your codes for no charge, being that your vehicle is OBD II compliant. So, the best place to start is to see what stored codes exist and post them!


----------

