I have the dreaded SES p1040 code. I was going to install the 02 simulator today. The SES comes and goes. At any rate got under the car and saw that this mesh kinda wire is detached. Anyone know what is this? Can this be the reason for the code?

 

I have that wire too...I wonder what it's for?

 

Well mine is detached. Is yours detached??

 

you mean yours isn't connected to the cat bolts? mine is connected to the cat...

 

Thats why it is dangling. It is not connected. And there is not much for me to be able to put it back. I am going to replace it with another wire..I am just wondering if that is the reason why I have the P0140 code...

 

maybe that's used as a ground.

 

Mine looks nearly identical to yours, Zippin. And my exhaust is similarly rusted.

 

When my muffler cracked into two I saw that and the mechanic said its just a ground strap or something. Doesnt cause any codes that i know of but he just reattached mine.

 

Thats what I thought also. Oh well, I am going to install the 02 simulator now

 

it is a ground strap for something but i don't know what. I have an 02 and i dont have an o2 sensor right before the cat so it cant be to ground it for me. well i went on alldata at work it is is a ground for the exhaust system huh go figure

 

its just a ground for the exhaust, one would think, how much electricty can run thru ur exhaust. well not much,its mainly just transfered thru all the random metal parts in our cars. but its like all those fancy grounding kits, grounding everything basicly makes things work more efficently. however small the differences may be. hence why many of us have detacted ones and notice no difference.

i hope that made sence.

 

If I remember correctly, it is the ground that provides rust prevention for the exhaust system.

 

its a ground, but not for the exhuast, exhaust doesnt need electricity. It helps the O2 sensors and all that stuff works better.

 

yea its a ground, my mechanic snipped it and said its not needed.

 

Mine is gone

Guess you don't need it

 

WOW! I cant believe this thread came up! One day I was in the car driving through a parkinglot when I heard a snap! When I looked under the car I saw that and ignored it. A couple of weeks ago I heard rattling and thought that the left shock was broken (its some what broken, and its origonal @ about 60,000 Miles, time to change!). My dad figured out that the "B" pipe (the pipe between the cat and muffler) broke loose and was hitting the bracket on every bump. Well we welded it, but I guess the next step is to fix that wire.

 

Got a coupon in the mail for an oil change for $15.99. No disposal fee or anything....I figured I would spend the extra $.75 and save my self the hassle of getting dirty and hauling oil around...So I take it in and my "ground strap" is broken...The other 2 maximas in the shop also needed ground straps.....I told em not to worry about it, they reluctantly agreed with me..You can probably weld it back into place, but is there really a voltage spike or any fragile electronics flowing through your exhaust anyways?

 

The wire is to 'ground' the exhaust so that the o2 sensor works properly. Most times the manifold is grounded by the exhaust studs, but not always.
Remember that the pipes are isolated by rubber mountings and there are no other grounding points.

 

If that is the case, then the o2 sensor might have gone bad due to the wire not grounding??

 

The o2 sensors have its own grounds on the wiring harness(es).

 

http://store.racinglab.com/hoteaexgrsy.html

These are usually not necessary. I think engine grounding is more effective.

 

on the not needed comments. My Porsche mechanic neighbor told me it's a leftover from the days when O2 sensors had only one wire. I cut mine off a long time ago.

O2 sensors go bad cause they suck and Nissan's ECU criteria is too narrow.

 

O2 sensor wiring has 1 signal wire and 2 heater wires. Grounding happens before the sensor connector at the main harness and through the sensor case and through exhaust.

Loose (floating) ground could potentially cause a wrong signal voltage sent to ECM if the ground is floating since the reference GND is absent...

I would fix that wire first and clear the code and see if it comes back. If it does, the first thing to look at is the sensor itself...