Bank 1, Sensor 1 (upstream, firewall) O2 replacement

[CSVT_2004]

Not very likely. See all the P0420/P0430 discussions in the regular troubleshooting forum.

However, a faulty upstream sensor, left unattended, will cause excess fuel to be dumped into the precat and will ruin it, causing a P0420/P0430 after the upstream sensor is replaced.

Steve

I've read through them, and just did again. Mil elim's seem like denying a problem. Do you think this would be an appropriate course of action.

- Chemical cleaning of UIM, fuel lines and tank. ( Something like Berryman's)
- O2 Sensor replacement
- Headers

It would be headers right, iirc from the threads for the upper bank sensors? Bank 1 sensor 1..... P0420

 

[SoopaCooga]

yes, 2 crow-foot sockets (I think that's what they're called) that allow for alot more room to manuver a ratchet, as opposed to using a traditional O2 socket and wrench. it worked great.

Crows feet FTW!

It would be headers right, iirc from the threads for the upper bank sensors? Bank 1 sensor 1..... P0420

ProjectSHO89 is right. P0420 could result from a faulty sensor but does not indicate - by itself - a faulty sensor. My preferred method for getting rid of P0420? MIL eliminators. Am I denying a problem? Yes, I am. I don't want to buy new pre-cats. I don't even want to run with pre-cats.

 

[WHEELSPIN]

I did mine yesterday, and I followed all the steps except for using the o2 sensor socket. All I did was bend my 22mm wrench (box end) and slid the o2 plug through it, got it on the sensor and got it off that way. Way easier than sticking the socket in there and then the wrench, its way to cramped.

 

[val30]

o2 sensor

o2 sensor

i have an auto 2.5 i found the easyest way was to use a good quality 22mm crows foot with a knuckle bar took me more time finding the correct tool than doing it

 

[98 Contour]

Just did both my upstream sensors last night. I just wanted to say this was an excellent write up. I read through a few times before starting, and everything went surprisingly well. I recommend using an offset O2 socket for the rear sensor, it worked very well. The whole job took me less than an hour.

 

[elraido]

Very good write up. I also recommend a off set 02 sensor. Made things easier than what I thought it would be....while you have the coil pack off, I would suggest changing spark plugs since it opens it up a lot.

 

[98csvt69]

Get someone with small hands in there. I replaced all 4 sensors before i was a member of the sight so i had not a clue to what i was doing and the top 2 were a pain but not that bad cuz iv got small arms and hands!

 

[WETODID]

Does this code have a reduce to 70% performance or effiency default error loop like other fords?

 

[paulschott]

Fixed 1131 code.

Fixed 1131 code.

Just replace the bank 1 upper a couple of days ago. Needed to remove the coil pack and loosen the wire harness and move it back. Used an open end wrench cause there wasn't enough room for the socket to fit. One half turn and it came out by hand. The new one went in easily by hand and only needed about 3/4 turn to tighten it. A few scrapes and cuts but better than the mechanic @ $90 per hour.