Aces High Bulletin Board
General Forums => The O' Club => Topic started by: ozrocker on December 04, 2011, 11:22:50 AM
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I own a 00 Ford Expedition, 5.4 (330 CUI) V8. My Check Engine light was intermittenly on-off
for a few months. Recently staying on. I was getting a fault code for the Differential Feedback Control
Sensor. Average price $135.00. I took off top intake cover to access module, looked around a bit.
Was nice to discover that 1 of 2 1/4" vacuum lines had a small tear near connector.
Replaced both lines for $2.88 Vs. a $135.00 Sensor. No more "Check Engine"
Take that Murphy :)
:cheers: Oz
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Don't worry.....your car will eventually refuse to start when the DPFE sensor shorts it's reference voltage to ground.
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Common thing for the Ford ones to fail. But even when it fails, truck will run.
I even had electric plug disconnected while I went to parts store.
:cheers: Oz
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It won't run in about 50% of dpfe sensor failures.
As general manager of blue streak electronics, I did troubleshooting on at least 60 vehicles in which the car would not run if the sensor was plugged in because it was shorting the reference voltage to ground.........and the technician now wanted me to ship him another replacement ecu for the perfectly working ecu we sent him.
About 20% of those cases had the regulator burned out because it was trying to shove reference voltage straight to ground.
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That's all good and fine. Mine happens to not be in the 50%, so once again
Murphy- FU :)
:cheers: Oz
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I own a 00 Ford Expedition, 5.4 (330 CUI) V8. My Check Engine light was intermittenly on-off
for a few months. Recently staying on. I was getting a fault code for the Differential Feedback Control
Sensor. Average price $135.00. I took off top intake cover to access module, looked around a bit.
Was nice to discover that 1 of 2 1/4" vacuum lines had a small tear near connector.
Replaced both lines for $2.88 Vs. a $135.00 Sensor. No more "Check Engine"
Take that Murphy :)
:cheers: Oz
some of the older 5.4's, and 4.6's used to have a problem with egr passages in the throttle body clogging up, filled with carbon. they would trip this code. if you cleared the CEL, it can take 2 days, to a couple of weeks for the code to reset if that wasn't the only problem.
one problem with those sensors, is that they get moisture in them.
i worked at a place for about 6 months.....couldn't get outta there fast enough. i had gotten myself in a bit of trouble, due to some unfiltered words leaving my verbal dispersion orifice. i think they were concerning the intelligence of the mechanics there....the ones that thought that just because they knew how to hook up a MODIS they knew how to diagnose a car. i was hired there as the diag. tech. i was busy, so an f250 was given to the smartest mechanic there. he pulled the dreaded p0401(i think that's the most common code on fords.), assumed a DPFE sensor, and replaced it, shipped the truck, feeling all proud of himself.
it came back in 2 days CEL on, same code. i got it this time. he kept coming over, telling me it must be a defective part, bla bla bla. it wasn't. it was blocked passages. i got myself in a little more trouble that day. it seemed i had forgotten to wear my verbal filtering device again. :devil
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It won't run in about 50% of dpfe sensor failures.
As general manager of blue streak electronics, I did troubleshooting on at least 60 vehicles in which the car would not run if the sensor was plugged in because it was shorting the reference voltage to ground.........and the technician now wanted me to ship him another replacement ecu for the perfectly working ecu we sent him.
About 20% of those cases had the regulator burned out because it was trying to shove reference voltage straight to ground.
in my nearly 30 years, i've NEVER seen a DPFE sensor prevent a vehicle from starting. or the old style of egr position sensor either. i've replaced more than my share of them too.
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Well.....I saw 60 in a two year period.
You have to remember that I was the sole technical support for products sold by standard motor products and Blue Streak and diagnosed hundreds of cars per week with problems that most technicians run into only 5 or 6 times in thier entire career.
I was usually brought these issues by our vendors (pep boys, auto zone, all the big chains) after the customer had purchased multiple ecus and still had the same issue.
Remember also that the reference voltage as sent to three wire sensors is divined by the same power supply that runs the entire ecu so that any grounding of said three wire sensor reference voltage is also making the voltage that runs the ecu short to ground.
Now a two wire sensor reference voltage power supply is designed to resist to ground and grounding of that type of sensor line will only result in the readings the ecu interprets to be maximum in one direction.
That said, I probably had many hundreds of 1996 jeep grand cherokees, 1996 dodge caravans, and 1996 dodge durangos during that same period.
1996 is a nightmare year for any dodge/jeep electrical diagnostician.
Fords issues were mainly with the dpfe sensor itself and o2 sensors shorting which causes the driver for the O2 sensor heater circuit to burn out.........or send 12v back up to the ecu through either a sensor ground, signal return, or 5v reference line.
Fords are much more fun to diagnose than either chrysler or GM.
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Well.....I saw 60 in a two year period.
You have to remember that I was the sole technical support for products sold by standard motor products and Blue Streak and diagnosed hundreds of cars per week with problems that most technicians run into only 5 or 6 times in thier entire career.
I was usually brought these issues by our vendors (pep boys, auto zone, all the big chains) after the customer had purchased multiple ecus and still had the same issue.
Remember also that the reference voltage as sent to three wire sensors is divined by the same power supply that runs the entire ecu so that any grounding of said three wire sensor reference voltage is also making the voltage that runs the ecu short to ground.
Now a two wire sensor reference voltage power supply is designed to resist to ground and grounding of that type of sensor line will only result in the readings the ecu interprets to be maximum in one direction.
That said, I probably had many hundreds of 1996 jeep grand cherokees, 1996 dodge caravans, and 1996 dodge durangos during that same period.
1996 is a nightmare year for any dodge/jeep electrical diagnostician.
Fords issues were mainly with the dpfe sensor itself and o2 sensors shorting which causes the driver for the O2 sensor heater circuit to burn out.........or send 12v back up to the ecu through either a sensor ground, signal return, or 5v reference line.
Fords are much more fun to diagnose than either chrysler or GM.
bolded.....THAT is the problem. no one at any of those chains should be allowed to do more than change a tire.
so oc course you're gonna get this stuff from them. most have trouble figuring their way out of a wet paper bag with a knife.
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bolded.....THAT is the problem. no one at any of those chains should be allowed to do more than change a tire.
so oc course you're gonna get this stuff from them. most have trouble figuring their way out of a wet paper bag with a knife.
Which reminds me....
If you are ever stuck in a room with no doors or windows but you do have a mirror and table simply look into the mirror to see what you saw. Take the saw, cut the table in half. Stick the two halves together to make a whole and climb through it.
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in my nearly 30 years, i've NEVER seen a DPFE sensor prevent a vehicle from starting. or the old style of egr position sensor either. i've replaced more than my share of them too.
Maybe he meant very popular FPDM?
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The chains are where the ECU's and other sensors are purchased for places such as independants, dealerships, and electrical specialists.
I only supported a couple of pep boys mechanics because they are watched by management to not get in over thier heads and instead concentrate on the gravy.
Diagnosis does not pay unless you are an electrical specialist shop and have properly communicated with the customer what fixing his car may entail.
I charge $160 per labor hour.
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bolded.....THAT is the problem. no one at any of those chains should be allowed to do more than change a tire.
so oc course you're gonna get this stuff from them. most have trouble figuring their way out of a wet paper bag with a knife.
just a week ago i had my brakes done at sears auto center because my mechanic doesnt work weekends... said brake job has now shattered and my mechanic has said that it looked like a grenade went off inside the drum brake housing...
just to show you never go to chains...
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just a week ago i had my brakes done at sears auto center because my mechanic doesnt work weekends... said brake job has now shattered and my mechanic has said that it looked like a grenade went off inside the drum brake housing...
just to show you never go to chains...
that sounds almost as if a retaining spring was left off.
pretty sad that they couldn't competently handle something as simple as a brake job.
the place i mentioned that i worked where i kept getting in trouble for my lack of verbal filtering.........i could tell ya some horror stories about the brake pads they used there. i had to friggin burnish them after each brake job. i ain't burnished a brake pad for 20 effing years, till i went there.
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I still grind the proper arc into brake shoes.
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Actually when I disconnected (electric And vacuum)the DPFE , I noticed NO difference
whatsoever in the idling or revving. Maybe it's just a Joisey thing eh CAP :D
And myself, I won't even call or go in a Pepboys.
:cheers: Oz
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Actually when I disconnected (electric And vacuum)the DPFE , I noticed NO difference
whatsoever in the idling or revving. Maybe it's just a Joisey thing eh CAP :D
And myself, I won't even call or go in a Pepboys.
:cheers: Oz
nah. there is no vacuum there.
what that sensors purpose is, is to tell the computer if egr gases are flowing properly, and how much. it does this, by those hoses. on the tube to the valve, there's an oriface. on each side of that oriface, there's one of those tubes connected. the oriface creates a pressure differential. hence the name "delta pressure feedback sensor". this differential is converted to a voltage. at idle, most of these should show about 1.5v, slowly rising as the valve opens. most i've dealt with top out around 4.7v.
most often these sensors go bad, due to moisture from the exhaust system getting into them. you can actually remove the sensor, and tap the hose connectors on the counter, and see the water come out. i was tlking with another tech today.....he's so old, i feel young. he's never seen a dpfe sensor stop a car from running either.
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I've seen about 60.
The difference is that every car I saw was there for an engine management issue.
No brake jobs, no timing belts.......just pure diagnosis for 12 hours a day for 3 years.
If you saw the 15 to 35 cars a day I was seeing at that period of my life, you would also have diagnosed and found just as many.........because the sensor was the problem.
Nowadays, I finish cars in which others have gotten in over thier head.
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I've seen about 60.
The difference is that every car I saw was there for an engine management issue.
No brake jobs, no timing belts.......just pure diagnosis for 12 hours a day for 3 years.
If you saw the 15 to 35 cars a day I was seeing at that period of my life, you would also have diagnosed and found just as many.........because the sensor was the problem.
Nowadays, I finish cars in which others have gotten in over thier head.
you don't seem to understand. at pretty much every shop i've worked at, i have been the diagnostic guy. i got them all. they didn't come to me after someone couldn't figure them out(most of the time), but rather they came to me FIRST. hence, they got diagnosed properly the first time. the other stuff was given to others first, if i was diagnosing. if i was doing a "grunt" job, and a diagnosis came in, then i was pulled off of it to do the fun job.
but i must not be as uber as you....most i've ever done in a day, is 11. that just came about a month and a half ago, so that was 11 with a couple running problems, normal grunt work, customer intake, make the estimate, sell the job, price and order the parts, do the job, then customer care when they came to get their cars.
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OK......so how many defective DPFE sensors have you diagnosed in your lifetime?
Me? At least 200 if not more.
Of those, 60 would not run or communicate with a scan tool.
Might have something to do with the water intrusion you mentioned and the corrosion that results from that.
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OK......so how many defective DPFE sensors have you diagnosed in your lifetime?
Me? At least 200 if not more.
Of those, 60 would not run or communicate with a scan tool.
Might have something to do with the water intrusion you mentioned and the corrosion that results from that.
over a hundred. each and every one of them had water in them. customers were/are always amazed that water comes out of them.
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Me? I'm no trained mechanic. A backyard one, starting with my Grandpa
when I was 6.
I've diagnosed 1. Like I said, I was getting a bad code for the sensor.
You seem , even starting at 1st reply, to have an animosity about me
getting away with a 3 buck repair on an overpriced, unneeded sensor.
I'm happy for you that you've diagnosed over 200.
Good Luck with your endeavor for 200 more. :rolleyes:
:cheers: Oz
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Me? I'm no trained mechanic. A backyard one, starting with my Grandpa
when I was 6.
I've diagnosed 1. Like I said, I was getting a bad code for the sensor.
You seem , even starting at 1st reply, to have an animosity about me
getting away with a 3 buck repair on an overpriced, unneeded sensor.
I'm happy for you that you've diagnosed over 200.
Good Luck with your endeavor for 200 more. :rolleyes:
:cheers: Oz
personally, i think it's pretty cool that you got it that easy. :aok
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Hopefully no more diagnostic specialist duties.
I'm burned out from Blue Streak where needed 3 people to do my former duties (might have something to do with having worked 12+ hours a day for 6 or 7 days a week).
My duties as a toyota/lexus master technician weren't so much fun either when you realize that guys who can diagnose are outearned by parts replacers with zero skill because diagnosis does not pay at the dealership level.
If I ever consider dealership work again as a technician, I will claim that listening to heavy metal music has made it impossible for me to ferret out squeeks and rattles (NVH) and that I know nothing about electrical diagnosis but excel at brakes, services, and alignments.
I'm considering letting a Z car shop in california recruit me as that shop has the kind of action I enjoy most though my current job (unusual part time job) is interesting and will see me tomorrow at Kennedy Space Center's shuttle landing facility runway to assist in attemptiing a world record standing mile run of over 270mph.
These guys interest me but moving from south florida to california is a pretty big undertaking.
http://www.zcargarage.com/
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pin 90(bn/wh)=v-ref
pin 65(bn/lg)=signal return.
sensor shares a common ground with the tps and a few other sensors.
(http://i200.photobucket.com/albums/aa135/1LTCAP/dpfewiring.png)
unless i'm missing something, if this sensor shorts to ground, it will at most conduct full reference voltage to pin 65, thus convincing the ecu that there is full egr flow. it will not create damage on pin 90, as it's already supplying 5v constantly.
so basically 5v will go straight through the dpfe sensor, and land on pin 65 which will then read 5v, and the ecu will trip a code for high voltage.
tell me what i'm missing. prove me wrong.
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You are referencing shorting to Vref to signal return.
I was referencing Vref shorted to ground............You know........that third wire you failed to mention.
You also forget that the regulator that provides this reference voltage also powers the ecu itself..........so.....shorti ng it ground will render the ecu non-powered.
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You are referencing shorting to Vref to signal return.
I was referencing Vref shorted to ground............You know........that third wire you failed to mention.
You also forget that the regulator that provides this reference voltage also powers the ecu itself..........so.....shorti ng it ground will render the ecu non-powered.
again, unless i'm missing something.......vref is already grounded, otherwise no voltage would flow through the resistor to the signal return line.
save me some time and show me in a schematic how what you say is possible is so.
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again, unless i'm missing something.......vref is already grounded, otherwise no voltage would flow through the resistor to the signal return line.
save me some time and show me in a schematic how what you say is possible is so.
LOL......Vref is not "grounded".
Yes, you were missing something.
If Vref were grounded, the two sensors in your diagram would never see 5v.
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For the record I've diagnosed probably 500 bad DPFE sensors (Due to P0401/P0402 codes) in my career and when I worked at Ford for 14 months I fixed about 100 of them which had brand new aftermarket DPFE sensors installed by replacing the brand new aftermarket DPFE with a Motorcraft DPFE sensor. Then the customer would usually get mad at me because Autozone would claim that their DPFE sensor failed due to water in the exhaust and refuse to give them a refund! <facepalm>
Icepac you claim that 50% of cars with DPFE failures will not run and this is flat out false. I did run into a few old ford pickups that had an actual EGR sensor mounted on the EGR valve that had shorted out and killed the reference circuit as well but this was not a DPFE sensor. Of the hundreds of DPFE sensors I've replaced I never ran into one which prevented the vehicle from running.
I'm not saying that it isn't possible but based on what you've described you only see the "worst of the worst" but what you see in no way reflects 50% of the DPFE failures.. no even close.
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actually, it is not possible. 5v will not short a ecu. the vref is in fact grounded. the voltage travels through a resistor to ground. the signal return reads the varying voltage, which is changed through the pressure, through the resistor.
once again, i could be missing something, but i've been through the diagrams(can't find any internal circuit diagrams for the units anymore), talked with techs with loads more experience than myself, and they all say the same thing.
tigger.....if i'm not mistaken, the only way that shorting the dpfe would prevent a car from running, would be if it took signal away from the tps, cts, and possibly the iats?
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Then cap's description of "grounded" includes every single electonic unit that uses power.
It's just not true.
Grounding Vref and having it not affect an ecu only applies to two wire sensor which are resisted to sensor ground from the 5v feed.........or 8v in the case of many chryslers which feature both 5v and 8v reference voltage lines.
In those cases, you will see the reference voltage being lower depending on how much resistence there is.
In a 3 wire sensor, the regulator works to keep the Vref at a constant 5v relative to sensor ground.
Like I said before, I've rebuilt thousands of ford ecus as well as supported all of the products of Standard Motor Products and Blue Streak.
This includes dpfe sensors and the ecus we receive when a mechanic with a bad DPFE sensor sends it in to us.
The reasons I was diagnosing these is a bit different from Tiggers experience because I was brought in after technicians had already spent considerable time diagnosing and had already thrown an ecu at the problem as if it were a magic bullet that would fix thier woes.
I did no brakes or anything else but diagnose electrical issues related to the products that blue streak and standard motor products sells.
In the case of shorted to ground dpfe and other sensors, we either saw an ecu that had no errors and tested good or found the 5v regulator burned out because it was trying to push 5v direct to ground.
I know the runtime algorithms and ecus down to each and every component.
Hell.....I wrote the test proceedures on the newer ford ecus as well as many sensors for standard and blue streak.
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Then cap's description of "grounded" includes every single electonic unit that uses power.
It's just not true.
Grounding Vref and having it not affect an ecu only applies to two wire sensor which are resisted to sensor ground from the 5v lead.define "affect an ecu"
In those cases, you will see the reference voltage being lower depending on how much resistence there is.reference voltage is always the same. hence the term reference voltage. it gives the ecu something to reference against.
In a 3 wire sensor, the regulator works to keep the Vref at a constant 5v relative to sensor ground.it doesn't have to do as you describe here. if it did, then we'd always be looking for a 5v signal on the signal return. the 5v to the sensor in this situation is a constant 5v. the changes the current flow to ground based on pressure, and this is what signal return reads.
Like I said before, I've rebuilt thousands of ford ecus as well as supported all of the products of Standard Motor Products and Blue Streak.
This includes dpfe sensors and the ecus we receive when a mechanic with a bad DPFE sensor sends it in to us.
In the case of shorted to ground dpfe and other sensors, we either saw an ecu that had no errors and tested good or found the 5v regulator burned out because it was trying to push 5v direct to ground.
I the runtime algorithms and ecus down to each and every component.
Hell.....I wrote the test proceedures on the newer ford ecus as well as many sensors for standard and blue streak.show us some of the procedures you wrote.
Both of you are working from an experience disadvantage as compared to me. possibly....but........ :rofl :rofl
i'm honestly starting to think you've mixed this up with something else. you've got a guy that has always been the one to get the diagnostic nightmares in any shop he's worked at for nearly 30 years, and another guy that's apparently gotten the same, including working for a dealer, which would give him more experience than me on those things.
in all of my years, i have never once had to replace an ecu due to a dpfe failure. nor have i had a dpfe failure stop a car from running. i've seen maf, tps, cts and maps do this though.
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Basic physics is on my side.
Your huge output of posts on each and every automotive subject does make you always correct......I just get fed up with refuting what basic physics and experience tells me is untrue and stop posting while you continue to pour out posts.
in all of my years, i have never once had to replace an ecu due to a dpfe failure. nor have i had a dpfe failure stop a car from running. i've seen maf, tps, cts and maps do this though.
How can you say that?
In your diagram, both the DPFE sensor and the throttle position sensor share both the Vref and the sensor ground.
So what makes it possible for the throttle position sensor to cause a non-run situation while the DPFE can never cause the same no-run situation?
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Basic physics is on my side.
Your huge output of posts on each and every automotive subject does make you always correct......I just get fed up with refuting what basic physics and experience tells me is untrue and stop posting while you continue to pour out posts.
How can you say that?
In your diagram, both the DPFE sensor and the throttle position sensor share both the Vref and the sensor ground.
So what makes it possible for the throttle position sensor to cause a non-run situation while the DPFE can never cause the same no-run situation?
because without input from the tps, the ecu will often times have trouble knowing how to run the engine. the dpfe is not necessary to run, and therefore with or without input from it, the engine will continue to run, unaffected. i also mentioned that it was on older eec4 systems i'd seen the tps stop an engine from running.
i did not say i am always right. i asked you to prove me wrong, and you have not done that as yet.
oh yea......my output of posts will NEVER make me right. that's done with the grey matter between my ears. :aok
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Please name me a car that won't run without a TPS signal.
Please tell me how a short to ground on the Vref that is divined from the same power supply as the one that runs the ecu will allow the unit to function.
You can't and I am not interested in reading a multi-post smokescreen.
You are arguing beyond your depth.
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could you two just get a ruler and an interested woman to settle this contest please? If you can't find an interested one I think Kim Kardashian is available
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Please name me a car that won't run without a TPS signal.
Please tell me how a short to ground on the Vref that is divined from the same power supply as the one that runs the ecu will allow the unit to function.
You can't and I am not interested in reading a multi-post smokescreen.
You are arguing beyond your depth.
2.3 turbo coupe t-bird.
the ecu runs on 12v. the 5v regulator drops the voltage down to 5v for the various sensor v-references. hence, it cannot short out the computer.
i can and i just did.
not yet i'm not. :aok
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could you two just get a ruler and an interested woman to settle this contest please? If you can't find an interested one I think Kim Kardashian is available
:neener:
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You're tall enough for her. Well you're human, I think. Okay we'll settle for sentient.