O2 Sensor

[Metallman56]

my sensor is a ac delco denso. is that bad?

[gectek]

no, thats what they normally are, but i would just double check the code you are getting, then check the wiring harness and maybe put some dielectric grease in the conn.

there may be secondary voltage leaking from the spark plug wires, make sure they arent laying on the O2 wires

[Metallman56]

as far as the code, i've checked it atleast 5 times. same cold. o2 low volt. i think its code # 183. or something real close to that.

i made my own wiring harness to replace the other one thinking that could be the problem. nope.

i'll check the wires tonight. but i doubt its the case, cause i've replaced wires sinse the light has been on.

[gectek]

then maybe its time to look at a scan tool to make sure it is getting the low voltage, and also hook up a meter to check and make sure it is getting the normal voltage supply and that there isnt excessive resistance in the wiring, that would cause low voltage also...just a few thoughts

[gectek]

also the DTC for sensor 1 bank 1(which is the upstream) is P0131 for sensor low voltage. ther isnt a P018x in the DTC list AFAIK...so on that note lets look at the cause of the code, which is

CONDITIONS FOR SETTING THE DTC
The DTC will set if either of the following conditions are present for up to 50 seconds :
The HO2S 1 signal voltage remains below 175 mV during Closed Loop operation.
The HO2S 1 signal voltage remains below 600 mV during power enrichment (PE) mode.

so there are 2 reasons.

your only options for fixing it are replace the sensor, check wiring for a short to ground, check PCM harness to make sure it is ok...or replace PCM. also about the wiring, if you just make a harness, it might be affecting the sensor, having maybe too much resist in the wiring. also check for any damaged or questionable wiring, the wrong fuel pressure, the evap canister purging at the wrong time or all the time, an exhaust leak or any other obstruction in the exhaust to keep the O2 from getting a good clean air reading, or a contaminated one. those are the only options. and those are directly from the manufacturer.

[Sprucegagt]

Originally Posted by Metallman56

as far as the code, i've checked it atleast 5 times. same cold. o2 low volt. i think its code # 183. or something real close to that.

i made my own wiring harness to replace the other one thinking that could be the problem. nope.

i'll check the wires tonight. but i doubt its the case, cause i've replaced wires sinse the light has been on.

I think you mean this code:

P0138 - Heated Oxygen Sensor (HO2S) Circuit High Voltage Bank 1 Sensor 2

not this:

P0183 - Fuel Temperature Sensor Circuit High Voltage.

Now the Bank 1 Sensor 2 O2 is the one located after the catalytic converter. Have you been working on it or the one located in your headers?

[Metallman56]

its the one before the cat.

[gectek]

have u ever tried replacing the one behind the cat? just a thought, and spruce has the same idea i do

[Metallman56]

no, but its easy to do. is it the same size as the one in front of the cat?

[Sprucegagt]

It's the same sensor.

[Metallman56]

sweet, i'll give it a try.

yeah, i'm not 100% what exact code it is. all it says is something like o2 band 1 low volt. so thats all i know.

[gectek]

whoa wait a minute, when i got my upstream it was alot different than the one after the cat...not sure y though, but it didnt have the flowerlooking shield on it and it was a denso ac delco, the other i think is a bosch downstream, they are both genuine GM no aftermarket, also the harnesses are different lengths, so have fun with that

and one of the codes i gave u was for the upstream O2, the code for the rear is P0137...thats the rear sensor low voltage, so those are the only 2 it could be if it was low voltage

[coupe]

Dude, check fuse #47, under hood fuse box.

Mine was blown all this time and didnt even know it.

will this work with my 96' GAGT 3.1?

http://cgi.ebay.com/ebaymotors/NTK-N...spagenameZWD1V

ive been getting really bad mpg and i was thinking i would start here...

NTK a junk brand?

[coupe]

Are you throwing a code?

nope, i just bought the car a couple months ago, 170,000 on the body and 60,000 on the engine, The plugs/wires are brand new and about a month ago i put on a CAI with a 3 or 4" K&N. (mpg sucked before cai) i just took a quick look at the o2 by the cat.. looks ancient, prob has never been changed... i guess im not sure if this will help my crap mpg but i guess i need a starting point...

Ive heard that a bad o2 might not set of a ses...

Also, any idea where this other o2 is?

thank.

I found the other o2.. it looks pretty new... i dont know

[lvemy3100]

yes an o2 sensor can be bad (not working correctly) but not throw a code.... this would most likely result in decreased MPG and performance

how important is that lower o2 sensor (next to the cat)?... that one looks pretty old..

[coupe]

IMO, not that important if at all.