I have 2 codes P1151 (lack of HO2S21 switches - sensor indicates lean) and PO153 (O2 sensor circuit slow response - Bank 2 sensor 1). What is the likely cause (O2 sensor or fuel supply)? Are O2 sensors covered under the 8 year, 130000km emission warranty? I have a 97, F150, 4x4, ext, auto with 105000km.

Thanks

 

Both of your codes are for the front O2 on the driver's side. Does your engine run well? No misfiring? If so I'd be inclined to try replacing the O2.

 

Try replacing your fuel filter if you havnt done it in a while (or at all) I have one with 98k miles and the sensors started going haywire. I replaced the fuel filter and it fixed the problem.

A clogged filter causes the sensors to act up.


Just a thought.

 

Just pull the sensors out and clean them with electrical motor cleaner and a tooth brush and they will be alright.

 

Replace the 02 sensor on the drivers side. (primary, first one), Been doing this for many a year, and have never seen a sensor 'cleaned'.

My .002

(don't mean to **** in anyone's wheaties), just speaking from LOTS of experience............

 

The engine runs rough occassionally, but has done so since new. The dealer refused to increase the idle RPM as they said it was factory set. I have changed the O2 sensor, but still get both codes. I have not detected any airleaks or other problems. However, I do hear a hissing (vacuum bleeding off?) from the EGR valve when the engine is turned off. Could this be a problem? It is a closed unit so I am unable to move the diaphragm by hand to see if it is ok. Are they hard t replace - that is the fitting from the exhaust looks quite corroded and aam not sure I want to mess with it?

Thanks

 

Are you replacing the 02 with 'ford factory, (i.e. proper), replacement?
I don't know how many times I"ve been burned by aftermarket, (spoze to be da right ones), 02 sensors.
Seriously. If it's a 'replacement' from the local parts house, the chances of it being the correct one, are about one in a hundred. Kind of like running champion spark plugs in a ford. Not a good thing.

Ooops, off subject.

Has the pcm been reflashed to the latest/greatest update?
Have you monitored the long and short fuel trim, and see what the baro reading is on freeze frame?

There is a bunch of stuff that I, (as a technician), would want to see/know before actually throwing parts at the vehicle.

The noise you hear (after engine shutdown), is a normal noise. Nothing to be alerted about.
If you had a lean concern, you'd see it in not only codes being set, but your short and long fuel trims would be out of whack. (maybe not enough to flag a code, but out of whack).
I'd suggest taking it to maybe a different dealership and having them take a crack at it.

My .002............again............

 

The O2 sensor was a Ford part. How would I check the fuel trim as the only codes I am getting are 0153 and 1151.

Thanks

 

You'd have to have access to a scan tool that can read live data.
(i.e. NGS/WDS, upper line snapon/matco scan tools/meters.

That's why I suggest taking it to a ford dealer to have it checked out.

(plus the warranty)...........

 

I'm getting the same codes on my 97 F-150. The check engine light stays on most the time and it does hesitate sometimes but other times it runs great and the light will go out for a period of time. I have not changed any O2 sensors out but I have changed the fuel filter, air filter, spark plugs and PCV valve out. I'm not sure exactly where the O2 sensors are and the cost of them in. Can some one tell me where exactly they are and possibly the cost of one? thanks
Great site.

 

Do yourself a favor before you just go shotgunning parts at your vehicle.
Have the codes read, and vehicle properly diagnosed.
You could spend literally hundreds, (and maybe thousands if you got really carried away), replacing parts that you don't need on your truck.

It's a matter of which came first, the chicken or the egg. Granted, I've installed many an 02 sensor, in my lifetime at the dealership, but at least 50%, (rough estimate), are NOT 02 sensor problems. The 02 sensor is the end result of something else amiss. (maf sensor/intake leaks, etc, etc, etc).

In either case, again, have it diagnosed first.

For what it's worth, the primary 02 sensors, (the ones that give the feedback to the pcm for actual fuel control), are located just aft of the exhaust manifolds, and in front of the cats. The 02 sensors behind the cats are for emissions monitoring only. (cat efficiency).

I'll get off my soap box now.
OH yeah, prices on 02 sensors.........I'd guesstimate around 80-100 bucks dealer cost.............guesstimate.

Highly recommend NOT going aftermarket on the 02 sensors. Ford is pretty vehicle/engine specific as to what fits what. You could be building in a driveability concern by going aftermarket.

 

thanks for the info drag79stang

 

No problem.
I just wish I had a dime/nickel/whatever, for every time I"ve had to 'find the problem', after some customer has replaced every sensor/gasket/part on a vehicle, and THEN brings it into me to diagnose.
Then you're fighting whether or not the parts they used are causing the problem before you can even find the real concern.

Good luck. Have fun.

 

All I know is that I have had o2 sensor code issuses before on my 97 f150 and I would pull them out.....spray them down with electrical motor cleaner.....reinstall them and bingo, no more 02 codes.
Go figure.

 

Did you clean all of the O2 sensors or just the ones in the exhaust maniflods? Was you truck running smoothly or was it rough after it warmed up. Thanks