Oh My: D slipping, OD blink, check engine lamp, P0720 P0721 P0174 codes

[kraex]

hello everybody, this is my second post - the first one was saying hello

I would like to ask you for help. I spend several days reading the forum,
read many topics but still have not
been lucky with my explorer problem. Maybe I have missed something. Hope you will help.
In Poland reparing explorers is a little problem because it is not common car here. So usually I have to
help mechanic with the informtions, materials etc.


I will try to describe what is happening.
My ford have actually 150 000 km. Recently I have problems with my automatic transmission.

The ford goes ok in 1,2,P,N,R and 4x4, only at D it is wrong.
All this is in D position: driving cold car after more or less 2 km the transmission goes something like to N position
rpms go high, a second later there is hard "knock" like the trans try to catch the gear - and again it starts to "slip"

sorry maybe the description is not perfect, my english is not so good - I try to do my best

So all this happens especially between 40 and 60 km, but also above this.

The check engine lamps appears and also D warning lamp is blinking.

Turning off the acu does not help.
I also have following obd codes:

P0720 - output speed sensor ckt fault
P0721 - output speed sensor performance
P0174 - system to lean (bank 2)

my ford is 1997 sohc 4l 4x4 with 5 gear automatic transmission


What I have try to do so far:

I have check the resistance at TSS and OSS sensors
and also replace OSS sensor for test - still the same


TSS I measured between 2 and 3 pin like on the picture below (but not on this blue place but in the slot of course)

the resistance is

tss - 78,1 ohm when cold
tss - 90 ohm after driving






for oss sensor (no.15 on the picture yes?) :

oss - 398 ohm

I have also checked above resistances in my friend's explorer and there are the same so I think sensors are ok?

The atf is ok clear and fresh, also the level is correct.
I still believe this is maybe electronic problem and the transmission goes crazy?
But maybe I am wrong? What else should I check?

Any help would be great. Thank you very much in advanced.

ps. So now I drive only using 2 position (only up to 60km/h and I have made in this way about 1000 km so far)

 

[ultimohero]

Hey. I dont have an anwser, but I am having the same exact problem. I have been having this problem for months now almost a year. I dont know if anyone has messaged you personally with a solution but if you solved the problem or have any advise for me please let me know. Thanks

 

[BrooklynBay]

The transmission going into neutral shows that there is a loss of hydraulic pressure. It could be a failing EPC solenoid, bad valve body gaskets or loose valve body bolts. The last code which indicates a lean mixture could be a vacuum leak from a hose or intake manifold gaskets. Bad spark plugs could cause this too.

 

[ultimohero]

The Valvebody gasket and loose valve bolts would mean you would have to remove and rebuild right? Im gonna try to get the sensoor checked tomorrow. I have a friend with a wrecked navigator, do you know if I could use that trans on my 4.0?

 

[BrooklynBay]

You would have to remove the valve body to get to the gasket. The Lincoln Navigator uses a different transmission (4R100).

 

[ultimohero]

ok thanks. Someone told me that i could change the tailshaft and use it. I was only cincidering it because its almost free. I have built engines before ut never went into a trans. do you think someone like me could do what was neseceary to fix the problem? Im confident in my work, but somtimes a pro is always better.

 

[BrooklynBay]

Check the sticky thread called the 5R55E valve body rebuild diary for more information.

 

[ultimohero]

Thanks. Thats the most help I have gotten in a while. I guess Ill spend a little more time up here than I had expected. lolThanks

 

[kraex]

thanks for replies to everybody

ultimohero - do you have exactly the same things like me? The same error codes?

 

[kraex]

Ok - I have solved my problem.

The reason was somewhere in one wire going from oss sensor to the pcm.
I have put new wire and that's it.
It is going now as smooth as in the past!

The total cost of this repair about 2$ (for new wire and 2 connectors)
I do not talk about the time it took me to solve this but it does not matter.


Strange how such transmissions behave if they do not have all inputs/outputs signals from/to computer.
It is very easy sometimes think that the problem is for example in the transmission itself.
So now no more slipping in D!
It works perfect. Great to be able to drive faster than 60 km/h again

Thanks.

 

[BrooklynBay]

Thanks for the update!

 

[ultimohero]

I borrowed a scanner and this is what I found. The scanner I used dosent tell you error codes, but gives short messages. It found one code. It said "Speed Sensor Error". I haven't even started the Explorer in a few months. I went out there and started it and it had no errors found. I put it into reverse and it went backwards with no problems. Then I put it into drive and it sat still and the O/D light came on. I tested it then and it told me speed sensor error. I shifted it into 1 and it moves a little then started slipping again. so I shifted into 2 and parked it back where it was. Does this sound like it could be the same thing as yours?

 

[kraex]

Probably the bad speed sensor should give you such "slipping" symptoms.
(I have slipping when I have no signal from output shaft sensor OSS.

If the error says vehicle speed sensor VSS (and I think your code reader says about it) this should the one on the transmission. First try to replace or borrow from other user this sensor.

So your problem can be as simple as replacing the dead speed sensor.
I would start from this point

 

[ultimohero]

Thanks! Im gonna try that my next day off