O2 sensor location on 1997 f150 ford 4,6

The O2 Sensor is mounted to the side of the exhaust system. There are two sensors. One is located as near as practical to the engine, physically on the exhaust manifold -- the manifold is the piping that carries the exhaust from the cylinders to the muffler and out the tail pipe. You will find the first O2 Sensor where all of the individual manifold pipes blend into one pipe that then carries the exhaust toward the back of the car or truck. The other sensor is located immediately after the Catalytic Converter (CAT). The sensors are easily identified because they have wires connected to them. The only reason to have wires connected to the exhaust system is to support the O2 Sensors.

Why are you asking?

I have a check engin light on and had it checked and was told the 02 sensor needs replaced.

Well Lynn,

You have 2 O2 sensors on your truck. Both are located in the Y-pipe just after the exhuast manifolds.

First locate both sensors, then figure out where they plug into the harness at. It shouldnt be more than 30" away from the sensor, just follow the wires. They are usually connected at the back of the engine..

Next take the truck out for a nice drive (about 10-20min), to get the truck up to operating temp, and get the O2 sensors working. They have to reach

600*F before they start signalling the computer, and your truck has to run a certain amount of time before they start working...

Then take the truck home and leave it running. Pull each sensor loose (one at a time), and check for a varying voltage signal on the grey/light blue striped wire for the right sensor, and red/black striped wire for the left sensor. If that checks out then do this..

On those same two connectors, switch your voltmeter over to OHMS. Then put your positive and negative lead between the red wire and yellow/light blue striped wire on the left sensor, and between the red and the red/white striped wire on the right sensor. You should have between 3 and 30ohms resistance in both heaters. If not replace the sensor (s) with the high or low resistance..

Basically if one isnt signalling, or the heater is shorted in one of them, then that is the one that needs replaced.. Which bank is it saying has the problem? Bank 1 or 2?

After you identify which sensor is giving you problems, then you need to figure out why.. Have you used any octane boosters lately? Had any engine work done lately in which silicone gasket maker was used? Burning any oil? The list goes on for this part, but that gives you an idea of what can make these fail prematurely..

Ford Tech

You have to find out WHICH sensor needs to be replaced. Ford Tech says you have two, one on each manifold. I suggest you have at least two, one on each manifold, and one after the CAT. In any case, you can troubleshoot the sensors as Ford Tech describes, or you can pull codes and let the computer tell you which sensor seeks your attention. I would pull codes ...

(At this point, we really don't need to discuss the total number of sensors and I may regret bringing that topic into the discussion. What we need to know in order to provide the best information on where to look next is the code(s).) Once the code(s) is(are) known, then we will be able to say precisely where the sensor is that is asking for your time and money.

On Mon, 26 Feb 2007 09:11:51 -0600, Ford Tech rearranged some electrons to form:

Are you sure there aren't four?

EVTM only showed 2 sensors. I dont think ford used an after cat sensor on the prior 2000 MY trucks..

Ford Tech

On Thu, 01 Mar 2007 15:39:55 -0600, Ford Tech rearranged some electrons to form:

I think your database is wrong. My 98 F150 has four.

GRRR, damn Ford manuals not puttin everything together.. I got extremely curious since you said you had 4 on your truck. SO I went to lookin, and the

2 (only two I thought it had) are on 24-4 in the EVTM, but upon further checking, I found 2 more on 24-7 of the EVTM..

So you are correct, there are 4 in the system.. Too damn many if you ask me.. All they need is ONE in front of the cat, and ONE behind it.. LOL I mean jesus thats about $600.00 to replace all 4 of them....

But alas, I should have looked further back in the EVTM, and I would have noticed the other two... And then I wouldnt be writing this.. LOL

On Thu, 01 Mar 2007 21:12:28 -0600, Ford Tech rearranged some electrons to form:

That's what it is. There are two cats, at least on the V8.

Well, I guess that's the difference between looking at it on a computer, and working on the vehicle.