blove

New here. I have a 1999 SE with 98k miles. For the last 3 k, the CEL has been on. At first it would come on and then go off after a while. It has been on steady for a couple of months now. The car seems to run like nothing is wrong. I had autozone read the codes when it first came on. The guy told me that it was an o2 sensor sending a weak signal, but that it was not completely bad. I have had the car less than a year, so I don't know much about it. What i need to know is am i doing damage by driving it this way? Also, what are the symptoms of a bad o2 sensor? I get about 17-18 mpg with a semi heavy foot and 20 mpg when i am soft on the throttle. this is mostly city. i thought a maxima would do better on gas. the car runs great. can anyone give me any info about o2 sensor problems and what it would cost to have replaced? thanks.

catalinoiu

First step, read the codes manually from your ECU. Be careful with the ****, it is very fragile.

I asked another .org member (Zack) how to identify the O2 sensors (our MAX have 4 of them). I will let you know.

The O2 sensors are "consumable" parts like the spark plugs and it is recommended to replaced them anyway around 80-100k miles. If the sensors before CAT are bad then it will probably kill you on gas. There may be other simptoms but I don't know them.

blove

thanks catalinoiu, i looked in my Haynes manual and i noticed one code that reminded me about what the guy at Autozone told me. He said one o2 sensor had a slow response. anybody tell me if it needs to be replaced or can i just keep driving?

Tort

If you are getting an ECU code for the O2 sensor you should replace, obviously something is not right. As far as which one that you have to find out from the code. If you have a little extra money you mind as well do them all. They are all located on the exhaust somewhere. I think 99's are a little different then my 96. I have 3, two on the downpipe and one at the cat.

FLO_BOY

only replace what's broken.
also, if the guy at autozone merely grabbed codes, then he has NO WAY of saying that the O2 sensor is "OK for now and only sending a weak signal"...that's just not possible when you ONLY check the codes.

Also, your fuel economy is suffering because of the bad O2 sensor...you can drive as is, but, you're spending more in gas...just fix it already!!!

hope this helps,
FLO_BOY

blove

thanks flo-boy, but there is a specific code that means the sensor is slow responding.

catalinoiu

I've got no other answer but here is what I know:
Quote:
yeah no problem, on my car which is a 99 with cali emissions, i have 4 . i recently got a engine check code which was P0135 or 0901. Diagnostic Trouble Code 0901 points to a problem with the Front Heated Oxygen Sensor, Right Bank. The right cylinder bank is also called the rear bank. It is cylinders 1,3,5 this is the bank that is closest to the firewall. this means that the front bank is the bank closest to the radiator.
Hope this helps some.

FLO_BOY

that's new to me...can you tell me what code that is?

thanks,
FLO_BOY

bird89sc

hey, i know this isn't exactly the best way to go about this, but how can i loop the o2 sensors to get rid of the check engine light (any resistors required?, etc)? i'm really getting sick of dumping money into this car, no offense to the maxima, but its not like i'm dumping the money into a 67 chevelle or something!