changed O2 sensors now engine light is on

[Comin' in Hot]

Yesterday I installed the rear cat delete pipe I bought from Blackened300a. I also installed four new Bosch O2 sensors. Now my engine light is on with two codes.

I don't think the pipes are the problem because the the upstream sensors are throwing the codes.

P2195 O2 sensor signal biased / stuck lean Bank 1 Sensor 1

P2197 O2 sensor signal biased / stuck lean Bank 2 Sensor 1

I have 3 questions:

1. What would cause this?

2.Could they be the wrong O2 sensors?

3. Is it safe to drive my car?

[Comin' in Hot]

I decided im going to the dealer tomorrow to buy 4 motorcraft O2 sensors and I'm going to return the Bosch sensors. I noticed that the Motorcraft website says something about O2 sensors with the green connectors, Mine has them and who knows if the bosch sensors are the right ones.

[Blackened300a]

You have the wrong O2 sensors. The bungs are in the stock locations so there shouldn't be a issue after installing these pipes.

Its safe to drive the car, it will go into a set value which will allow it to drive, just the light will be on.

[Comin' in Hot]

thanks for the reply, I kinda figured it was a sensor problem, I'm going to change them out today with O2 sensors from a dealership.

[RF Overlord]

Before you HUGELY overpay at the dealer, try tascaparts.com or Rock Auto...

[ctrlraven]

Rockauto has them cheap!

[zman]

If you still get a code try inserting spark plug anti foulers into the bungs (Autozone) and then insert the O2's into the anti foulers. This will fool the PCU into thinking you're back to stock.

[Mike M]

Yesterday I installed the rear cat delete pipe I bought from Blackened300a. I also installed four new Bosch O2 sensors. Now my engine light is on with two codes.

I don't think the pipes are the problem because the the upstream sensors are throwing the codes.

P2195 O2 sensor signal biased / stuck lean Bank 1 Sensor 1

P2197 O2 sensor signal biased / stuck lean Bank 2 Sensor 1

I have 3 questions:

1. What would cause this?

2.Could they be the wrong O2 sensors?

3. Is it safe to drive my car?

Where do I buy rear cat delete pipes?

[ctrlraven]

If you still get a code try inserting spark plug anti foulers into the bungs (Autozone) and then insert the O2's into the anti foulers. This will fool the PCU into thinking you're back to stock.
Could of also got the upstream and downstream ones mixed up.

Where do I buy rear cat delete pipes?
Could of bought it from Paul but it's already been sold to the OP.

[tbone]

So Motorcraft O2 sensors are the only ones to get, even though RockAuto lists other ones?

[MOTOWN]

I think motorcraft 02 sensors have a much lower failure rate!

[tbone]

Rock auto only lists the front ones.

[J.bo]

Rock auto only lists the front ones.

True. I saw that myself. So who has the rears at a good price?

[Blackened300a]

If you still get a code try inserting spark plug anti foulers into the bungs (Autozone) and then insert the O2's into the anti foulers. This will fool the PCU into thinking you're back to stock.

You shouldn't have to with this mod. I ran almost 1000 miles without a CEL with this mod installed. Its the O2s that are either mixed up or the wrong ones.

[fastblackmerc]

Ford O2 sensors are the only ones I'd use in my car. There have been too many problems running other make sensors.

[ctrlraven]

You shouldn't have to with this mod. I ran almost 1000 miles without a CEL with this mod installed. Its the O2s that are either mixed up or the wrong ones.
Yep. I had my rear cats deleted for 30-40k miles, ZERO problems. I still have in my original O2 sensors with 161k miles, ZERO problems. I will be changing the front ones though soon cause I know they probably pretty lazy at this point.

If you have a tune or get a tune then the rear O2 sensors are turned off so all you really have to worry about is the Upstream ones.

[tbone]

Yep. I had my rear cats deleted for 30-40k miles, ZERO problems. I still have in my original O2 sensors with 161k miles, ZERO problems. I will be changing the front ones though soon cause I know they probably pretty lazy at this point.

If you have a tune or get a tune then the rear O2 sensors are turned off so all you really have to worry about is the Upstream ones.


GREAT info, thanks! This is just what I wanted to know.

What symptoms do you think happen when they get "lazy"?

[tbone]

I went ahead and ordered the Motorcraft fronts from Rockauto. 128k on my car and time to change them.

[RF Overlord]

A lazy O2 sensor will either not cycle far enough (0V to 1.0V), or not cycle fast enough (at least once per second) or both. This causes the PCM to develop the wrong fuel strategy and can reduce power, reduce economy, or increase emissions (or all three).

[ctrlraven]

GREAT info, thanks! This is just what I wanted to know.

What symptoms do you think happen when they get "lazy"?
See below.


A lazy O2 sensor will either not cycle far enough (0V to 1.0V), or not cycle fast enough (at least once per second) or both. This causes the PCM to develop the wrong fuel strategy and can reduce power, reduce economy, or increase emissions (or all three).
Reduced fuel economy is my reason. My gas mileage can be tracked very well as I drive the same route, (speeds about the same but can vary sometimes :burnout:) and I fill up at the same gas station the same day every week. I've seen a 2 mpg drop as of late.

They're cheap enough to go ahead and just replace.

[Comin' in Hot]

Things got away from me today. I didnt get a chance to work on it. I'm going to call Tasca tomorrow, they have the upper and lower, but they don't list part numbers. I should have them changed out by Sunday if I get home from my business trip on time.

[Comin' in Hot]

Four O2 sensors ordered today from Tasca, great pricing, about 40% off list price, thanks for the info.

[RoyLPita]

Two O2 sensors are all that is needed. The back 2 are catalyst monitors.

[MM_BKK]

The purpose of the rear O2 sensors are to monitor the catalytic effiency to make sure that they're working.

Now that you have deleted the rear cats, I'm not surprised that the CEL came on for those 2 codes as they're suppose to, but sometimes results may vary from car to car.

You will either need to run O2 simulators or get a tune with the rear O2s turn off.

[Blackened300a]

The straight pipes were welded in exactly where the cats were, the O2 bungs are in the same location as stock. There is no reason to shut them off. The wrong O2's have been installed, nobody has ever had a CEL after a rear cat delete.

[MM_BKK]

I believe the front & rear sensors have slightly different connector so you can't mix them up.

So what is the purpose of the rear O2 sensors?

How does the ECM know when the rear cats are no longer working as part of the OBDII system?

[ctrlraven]

The straight pipes were welded in exactly where the cats were, the O2 bungs are in the same location as stock. There is no reason to shut them off. The wrong O2's have been installed, nobody has ever had a CEL after a rear cat delete.
3 years and ZERO CEL after doing this. There are several other members who were stock tuned and did this... no problems for them.

I believe the front & rear sensors have slightly different connector so you can't mix them up.

So what is the purpose of the rear O2 sensors?

How does the ECM know when the rear cats are no longer working as part of the OBDII system?
The rear O2 sensors are just monitors. They serve no real purpose in performance applications which is why DR, Lidio, Zack and Lonnie all turn them off. Mustang tuners turn the rear O2 sensors off in the Mustangs asl well.

[MM_BKK]

You're right. The rear O2's serve no real purpose for performance just like the rear cats or the front cats for that matter.

The cats and rear O2s are there as part of the OBDII Emission compliance requirement. The rear O2s are suppose to monitor how the rear cats are functioning or not functioning. If the rear cats are not functioning and you don't get a CEL code, then that is the abnormally.

I had the same thing happened to me as the OP several years ago where I deleted the rear cats and within 2 days, I got the two same CEL as the OP.

[ctrlraven]

LOL

How is the rear O2 sensors going to monitor the rear cats when they are in FRONT of the rear cats???

If they were such a part of the OBDII Emission compliance requirement, why did you delete them then? lol

They monitor the efficiency of the front cats.

http://i32.photobucket.com/albums/d12/blackened300a/637d2020.jpg
FRONT driver side O2 sensor sits in the exhaust manifold (Green Plug)
FRONT passenger side O2 is before the cat (Green Plug)

REAR Driver side O2 sensor is directly BEFORE the cat or where the cat would be (Blue Plug)
REAR Passenger side O2 sensor is directly BEFORE the cat or where the cat would be (Blue Plug)

I'm not doubting you may or may have not had the same CEL but there has to be some other factor. With having a stock tune the rear O2 sensors must be hooked up, with an aftermarket tune they can be left unplugged or plugged in, won't matter since they are turned off. A main reason why they are turned off is that the rear O2 sensors are only for testing catalyst efficiency.

[ctrlraven]

Actually now that I think about it, witman40 did you install the rear cat delete yourself or have a shop do it?

Double check your exhaust manifold and mid-pipe connection. Also check the PCV elbow to see if it's loose or tight. Have you done a fuel filter change?

P2195 is front passenger side O2 sensor and P2197 is front driver side O2 sensor.

Bank 1 is passenger side
Bank 2 is driver side
Sensor 1 is front
Sensor 2 is back

[tbone]

I got my front sensors today. RockAuto ships OMG FAST!

I heard they are tricky to install because they're hard to get to. True?

[tbone]

PS Motorcraft. Made in Japan.:mad2:

[Marauderjack]

I got my front sensors today. RockAuto ships OMG FAST!

I heard they are tricky to install because they're hard to get to. True?

Driver's side is a little tough but doable!!:argue::mad2:

[Comin' in Hot]

I'm installing the new O2 sensors right now, you guys were right, tasca is great. Four Motorcraft O2 sensors shipped $172.62, thats like $60 less than I paid at Autozone.

[Comin' in Hot]

total time to do all four, 45 minutes including jacking up my car, zip tieing the wiring out of the way, and typing 2 posts on MM.net. not a bad job at all.

[Blackened300a]

total time to do all four, 45 minutes including jacking up my car, zip tieing the wiring out of the way, and typing 2 posts on MM.net. not a bad job at all.

The big question..... Is the CEL off?

[Comin' in Hot]

the CEL is off and I was watching the live data stream on my OBDII scanner and the voltage is now right where it should be

[tbone]

I did the fronts only a few days ago and my issues are gone.

[ctrlraven]

My front O2 sensors are at home waiting for me. I will be changing the fronts tomorrow after work. Any tips on doing them?

[Comin' in Hot]

I used an O2 sensor socket with swiveling head 3/8" drive rachet. The passenger side is easily accessed from under the car. The driver's side is tight, but I first unplugged the sensor under the car and then got it out from the engine compartment. Its tight with the brake lines and steering shaft, but its doable. If that doesn't work you could access it from the driver's front wheel well if the car is jacked up, but it means using about 2 feet of extensions and bending the plastic inner fender away.

[Blackened300a]

the CEL is off and I was watching the live data stream on my OBDII scanner and the voltage is now right where it should be

Excellent, glad it worked out. How do you like the new noise level?

[ctrlraven]

I used an O2 sensor socket with swiveling head 3/8" drive rachet. The passenger side is easily accessed from under the car. The driver's side is tight, but I first unplugged the sensor under the car and then got it out from the engine compartment. Its tight with the brake lines and steering shaft, but its doable. If that doesn't work you could access it from the driver's front wheel well if the car is jacked up, but it means using about 2 feet of extensions and bending the plastic inner fender away.

Thanks for the tips!

[tbone]

+1 Driver's side do from above. Rotate the steering knuckle to get it out of the way as much as possible. I used an open ended wrench. Hard to do but I got it. Passenger side not much better. Part of the transmission housing kept interfering with the end of my wrench.

[ctrlraven]

Got the car jacked up and sprayed some PB Blaster on it and going to let it soak while hot for a little while since only the passenger side has been removed before when I had my exhaust done.

[ctrlraven]

DS is being a pita! lol

[Comin' in Hot]

Excellent, glad it worked out. How do you like the new noise level?

As long as I keep it under 2500 rpms its ok, but if I step on it, its way too loud. My next move is to order new mufflers because the cherrybombs make it sound like a straight through exhaust and I'm waiting to get a ticket.

[ctrlraven]

FINALLY! Done... that is.

Passenger side was of course a breeze since it was removed before. I tried every which way I could from the top engine side to get the drivers side, at one point I finally broke it just a hair loose and then gave up and went under the car. I used my swiveling neck ratchet which has a bend down above the cross-scratch handle, took a hex bit undid the swiveling neck and flipped the handle around and 1/4 turn by 1/4 turn I slowly got the drivers side out.

4 hrs total with a bunch of breaks to sit at the computer, search for tips/tricks and think. I covered the threads in some good high temp nickel anti-seize so they shouldn't be a bear to get out next time.

I took a pic of what 161-162k mile O2 sensors look like, I'll post it up tomorrow.

[Comin' in Hot]

FINALLY! Done... that is.

Passenger side was of course a breeze since it was removed before. I tried every which way I could from the top engine side to get the drivers side, at one point I finally broke it just a hair loose and then gave up and went under the car. I used my swiveling neck ratchet which has a bend down above the cross-scratch handle, took a hex bit undid the swiveling neck and flipped the handle around and 1/4 turn by 1/4 turn I slowly got the drivers side out.

4 hrs total with a bunch of breaks to sit at the computer, search for tips/tricks and think. I covered the threads in some good high temp nickel anti-seize so they shouldn't be a bear to get out next time.

I took a pic of what 161-162k mile O2 sensors look like, I'll post it up tomorrow.

just think, you get to do it again at 320K

[ctrlraven]

just think, you get to do it again at 320K
Oh no, I'll start replacing them every 50-75k miles or pay someone to do it. lol

I don't think I have cursed and cussed so much at a car before like I did tonight.

:lol:

Here is the pic: Drivers (Left), Passenger (Right)
http://i11.photobucket.com/albums/a164/ctrlraven/2011-08-24_23-28-07_970.jpg

[bigmerc'03]

what name brand did you get what are the part numbers you used and where did you get them from and are they 3 wire or 4 wire

[ctrlraven]

what name brand did you get what are the part numbers you used and where did you get them from and are they 3 wire or 4 wire

I went with Motorcraft from www.rockauto.com.

Upstream (Before the 1st set of cats)
MOTORCRAFT Part # DY1040 {#5C5Z9F472BA, XC2Z9F472BA} Heated
XC2F-9F472-BA; Front

Downstream (After 1st set of cats but before 2nd set of cats)
MOTORCRAFT Part # DY1034 {#5W6Z9G444BA, DY1013} Heated
XR3F-9G444-BA; Rear

Fronts are 4 wire and no clue what the rears are since mine are turned off and pay no attention to them. I would assume it is a 4 wire as well.

[tbone]

I guess I was lucky with the driver's side and my open ended wrench. The whole process took me about 1 1/2 hours.

[bigmerc'03]

i chose to go with the Denso 234-4045 Oxygen Sensor for the front car runs better now didn t know the sensors played that big of a part

[bigmerc'03]

Following are the guidelines you can use for replacing the oxygen sensors in your vehicle:
A] The unheated 1 or 2 wire O2 sensors, used in vehicles from mid-1970s through early 1990s should be replaced every 40,000 to 50,000 miles.
B] Heated 3 and 4 wire O2 sensors, used in the vehicles from mid-1980s through mid-1990s should be replaced every 60,000 to 70,000 miles.
C] Newer vehicles made in mid-1990s and later, recommend replacing the oxygen sensors every 100,000 miles.