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Auto mechanics - Please lend me your ear
September 28, 2018, 07:48 PM
bigdealAuto mechanics - Please lend me your ear
My 2001 Ford F150 threw a
P0156 O2 Sensor Circuit Malfunction B2S2 error code the other day. Since then the 'Check Engine' light has come on and gone off a few times. It's current on. Researching this online it appears an o2 sensor, or its wiring, may be creating a problem.
So here's my questions...
1 - Can an o2 sensor fail intermittently?
2 - What would you suggest I do to diagnose this issue?
Thank you in advance for your input.
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Guns are awesome because they shoot solid lead freedom. Every man should have several guns. And several dogs, because a man with a cat is a woman. Kurt Schlichter
September 28, 2018, 08:03 PM
sigcrazy7Yes, it can fail intermittently if it is going. You can diagnose the sensor; however, most people would diagnose the wiring, but replace the sensor, especially on a sensor that old. By the time you go through the trouble of pulling it, I'd just put a new one in. B2S2 would mean bank 2, sensor 2.
Demand not that events should happen as you wish; but wish them to happen as they do happen, and you will go on well. -Epictetus September 28, 2018, 08:27 PM
egregorequote:
1 - Can an o2 sensor fail intermittently?
Yes.
Such a code is almost always the sensor. It takes a scan tool starting around $2000 to show a data display with sensor outputs. You can visually inspect your wiring for chafing, rubbing or burning through, chewed by rats, etc., but this doesn't happen often; Ford does almost too good of a job at securing their wiring. If the sensor (you have four of them) is original, I'd just put one in. They "only" cost in the $50-$70 range. "B2S2" stands for Bank 2, Sensor 2. Bank 2 on a Ford V8 is the driver's side, Sensor 2 is the one
downstream of or behind the catalytic converter.
I am surprised that oxygen sensors last as long as they do. They don't start putting out a signal until they reach some 600°, are obviously blasted by hot exhaust all the time, and to get them up to that temperature as quickly as possible there is a heating element in them.
September 28, 2018, 08:29 PM
MattWReplace the O2 sensor and be done.
September 28, 2018, 08:58 PM
bigdealquote:
Originally posted by egregore:
quote:
1 - Can an o2 sensor fail intermittently?
Yes.
Such a code is almost always the sensor. It takes a scan tool starting around $2000 to show a data display with sensor outputs. You can visually inspect your wiring for chafing, rubbing or burning through, chewed by rats, etc., but this doesn't happen often; Ford does almost too good of a job at securing their wiring. If the sensor (you have four of them) is original, I'd just put one in. They "only" cost in the $50-$70 range. "B2S2" stands for Bank 2, Sensor 2. Bank 2 on a Ford V8 is the driver's side, Sensor 2 is the one
downstream of or behind the catalytic converter.
I am surprised that oxygen sensors last as long as they do. They don't start putting out a signal until they reach some 600°, are obviously blasted by hot exhaust all the time, and to get them up to that temperature as quickly as possible there is a heating element in them.
Excellent feedback. Thank you. One additional question. I read in the information on a Bosch replacement o2 sensor that the useful life of the part is 100k miles. Since my truck has 140k on it, should I just go ahead and replace both downstream sensors now, or replace the driver's side now and just play wait and see with the passenger side?
Oh, and Rockauto has the Bosch o2 sensor for $27, so the cost to replace these is negligible with me turning the wrench.
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Guns are awesome because they shoot solid lead freedom. Every man should have several guns. And several dogs, because a man with a cat is a woman. Kurt Schlichter
September 28, 2018, 09:03 PM
bdylanI'm a wait and see guy on emissions hardware. You'll get a code when it's time.
September 28, 2018, 09:37 PM
GreymannIf no noticeable wire damage or bad connector, change the sensor. If it's rusted on and doesn't want to loosen what I have done is heat up the sensor with a mini butane torch then put a candle on the threads. The wax will usually work better than penetrant oils to help break it loose, but you may have repeat heat and wax.
September 28, 2018, 10:43 PM
Jaywendland1981Do not get a Bosch. Find a motorcraft sensor. Other brands don't always read as fast as Ford's pcms would like them to. Then you will have the light come on for a different code. Replacing them all is not really necessary, couldn't hurt but I would replace them as they fail.
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September 28, 2018, 10:50 PM
bigdealquote:
Originally posted by Jaywendland1981:
Do not get a Bosch. Find a motorcraft sensor. Other brands don't always read as fast as Ford's pcms would like them to. Then you will have the light come on for a different code. Replacing them all is not really necessary, couldn't hurt but I would replace them as they fail.
Interesting. The Bosch sensors rate much better (substantially so) on Amazon reviews than the Motorcraft sensors do. Rockauto also showed the Bosch sensors as a customer favorite over their other options. Price difference was only a couple bucks, so I doubt that was a motivating factor.
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Guns are awesome because they shoot solid lead freedom. Every man should have several guns. And several dogs, because a man with a cat is a woman. Kurt Schlichter
September 28, 2018, 11:01 PM
VoshterkoffEveryone online loved Denso for my Toyota, got them at RockAuto for half of what NAPA wanted. Of course my sensor 2 code didn't stop coming back until I replaced sensor 1. Keep that in mind if the code comes back.
September 28, 2018, 11:21 PM
jimmy123xquote:
Originally posted by bigdeal:
quote:
Originally posted by Jaywendland1981:
Do not get a Bosch. Find a motorcraft sensor. Other brands don't always read as fast as Ford's pcms would like them to. Then you will have the light come on for a different code. Replacing them all is not really necessary, couldn't hurt but I would replace them as they fail.
Interesting. The Bosch sensors rate much better (substantially so) on Amazon reviews than the Motorcraft sensors do. Rockauto also showed the Bosch sensors as a customer favorite over their other options. Price difference was only a couple bucks, so I doubt that was a motivating factor.
I've driven Fords exclusively for the past 20 years or so pretty much. I've found that the motorcraft parts are always top quality. If you current sensor has lasted 17 years, I'd be inclined to replace it with another motorcraft part.
September 29, 2018, 05:15 AM
Black92LXquote:
Originally posted by jimmy123x:
quote:
Originally posted by bigdeal:
quote:
Originally posted by Jaywendland1981:
Do not get a Bosch. Find a motorcraft sensor. Other brands don't always read as fast as Ford's pcms would like them to. Then you will have the light come on for a different code. Replacing them all is not really necessary, couldn't hurt but I would replace them as they fail.
Interesting. The Bosch sensors rate much better (substantially so) on Amazon reviews than the Motorcraft sensors do. Rockauto also showed the Bosch sensors as a customer favorite over their other options. Price difference was only a couple bucks, so I doubt that was a motivating factor.
I've driven Fords exclusively for the past 20 years or so pretty much. I've found that the motorcraft parts are always top quality. If you current sensor has lasted 17 years, I'd be inclined to replace it with another motorcraft part.
Agreed. Lots of Fords in 20 years myself and all sensors get the motorcraft replacement.
Most parts outside of brakes get motorcraft for that matter.
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September 29, 2018, 05:23 AM
egregoreThe oxygen sensors
downstream of the cats perform a different function than the upstream ones. The upstreams are the ones that actually monitor and adjust the air/fuel ratio. The downstreams are for monitoring the efficiency - or health, if you will - of the cats.
September 29, 2018, 07:18 AM
shovelheadUse O.E. replacements, you will be further ahead.
Just an FYI, those reviews of Bosch sensors are probably left for Amazon just after they were installed, not after they were in place for 50-75k miles. They are probably rating them on initial fit and starting up the vehicle and the check engine light not illuminating immediately. Real world usage may be different.
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————————--Ignorance is a powerful tool if applied at the right time, even, usually, surpassing knowledge(E.J.Potter, A.K.A. The Michigan Madman)
September 29, 2018, 07:47 AM
92fstechquote:
posted September 29, 2018 07:18 AM Hide Post
Use O.E. replacements, you will be further ahead.
This. I've had all kinds of problems with high quality non OE brand parts... especially anything like a sensor that needs to interact with the computer. For sensors these days, I always buy AC Delco for GMs, Motorcraft for Fords. And I won't touch a Chrysler with a 10 foot pole. These policies have saved me a lot of headache over the years
.
As to the OPs question....visually inspect the wiring as well as you can. If it looks ok, change the sensor. 9/10 it'll solve your problem. I wouldn't mess with the other ones until they start throwing codes. They can be a real bear to get out on older vehicles...rusted in place and all that. And the downstream ones don't really do anything for you besides monitoring your catalytic converter performance. Having one go bad isn't going to hurt your truck.
September 29, 2018, 09:46 AM
blueyeWhen I replaced the coil packs on my Chevy Trailblazer I used AC Delco parts. All repair shops around me use factory parts whenever possible. Less returns as opposed to aftermarket parts.
September 29, 2018, 10:52 AM
RileyOEM parts for this.
If it's not a deal breaker, as in in the truck is still operable with a CEL, then I'd just replaced the failed one. The only caveat being if you have to remove a bunch of stuff to get to them, then you may be time ahead to do them all. Probably not on O2 sensors.
Lots of penetrating oil and warm up the truck a touch before trying to unscrew it.
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Expectations are premeditated disappointments. September 29, 2018, 11:25 AM
Edmondquote:
Originally posted by egregore:
The oxygen sensors downstream of the cats perform a different function than the upstream ones. The upstreams are the ones that actually monitor and adjust the air/fuel ratio. The downstreams are for monitoring the efficiency - or health, if you will - of the cats.
That's what I always thought.
Has a catalytic converter problem been ruled out?
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September 29, 2018, 02:47 PM
walker77quote:
Originally posted by blueye:
All repair shops around me use factory parts whenever possible.
I find that hard to believe.
September 29, 2018, 03:02 PM
jimmy123xquote:
Originally posted by walker77:
quote:
Originally posted by blueye:
All repair shops around me use factory parts whenever possible.
I find that hard to believe.
It's not, the good aftermarket brands we used to use 10-20 years ago, that were great quality, are so hit and miss with quality now since they've outsourced everything to China and other places. That nobody wants to be wasting free labor, to change out a part that you already changed out for free (warranty), to make an extra $10 in parts sales. It just does not make sense. You can't charge the customer if the O2 sensor you changed a month ago, is throwing a code and you have to replace it again.