2001 F150 Supercrew, 70,000 miles -

Check engine light is on, diagnostic is P0135 - oxygen sensor, bank 1, sensor 1. My understanding is that this is the first sensor down from the manifold on the passenger side. Of all the 02 sensors, looks like this is the worst one to have a problem with, how do I get to it?

I have seen from other threads that the problem is likely to be wiring, connectivity, etc and I have checked some of that, but I am having problems even getting to the wiring harness. Is there a trick to getting at this sensor and related wiring?

Thanks in advance,
Jollym0n

 

I have a 98 4.6 & the easiest way I found was to just get under the truck, wasn't hard at all I didn't think, they both had sufficent room to work on, give that a try if you havn't already

 

normally you need a socket with a slot in the side to accept the wire harness. About $8 for the socket at auto parts stores. Some stores will loan the socket on a deposit returned basis.

 

you don't really need that special socket. just get a 7/8 open end wrench, and just climb under the truck. you may have to warm the truck up, so that the treads will loosen up, but don't get it too hot, as you will be working on the exhaust. oh yeah, make sure you snap the wiring harnest back into the grove on the engine block. this keeps it from hanging on the exhaust and melting.

 

on my 97 they were easily accesible and so were the connections. I found out that mine didn't need the extended harness both originals were the same length. I used a propane torch to heat up the bungs since they were a bit rusty and man did it help. Had them out in about 30 minutes total.

 

7/8" wrench works OK ?
I never tried it, I just paid a few dollars and got the flexhead O2 wrench.
It is a 22mm wrench with a fixed position "open-end" on one side, and a pivot head "open-end" on the other. Allows for a quick alignment to the HO2S for any of the 4.

If a regular open end wrench works, that is kind of cool, I would have thought for at least one of them, it would not have, due to the angle that you need to take.

 

I wound up removing the trans dipstick tube for the passenger side front sensor(01 5.4 SCab). That made it easier for my old fat stubby fingers. Once I had it broken loose with a wrench I just used a pair of channel locks to spin it out.

Sscully,

Where did you find the O2 wrench at? All I've seen is those big fat sockets.

 

Wow all this work. Glad I have a 4.6. Once heated up it was a breeze getting up there. No problems at all.

 

ChiDiver,
It is the H&D Tools flexhead HO2S wrench.
I got mine from www.toolsource.com
Part Number : FHWO2-22 : $ 37.99

At the time this is the only place I had found them, they might be at more places now.

2 shots of it :
https://www.f150online.com/galleries...2028-86557.jpg

https://www.f150online.com/galleries...2028-86558.jpg

You can see how the fixed side head is off-set both from the knuckle direction, but also is off set to one side of the wrench as well.

 

7/8 open end, and a small flat tip screwdriver to release the harnes clip. the passenger side is easily accessed from the wheel well. but it's better under the truck, more visibility.