TROUBLE CODES

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#1
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MAKE:MITISHIBUSHI
MODEL:MONTERO SPORT 4WD
YEAR:2000
MILES:165K
ENGINE:3.O L
DESCRIBE ISSUE.I WAS DRIVING DOWN THE HIGHWAY NOTICED A SLIP IN THE TRANSMISSION THEN NOTICED THE AUTOTRANS LIGHT ON THE DASHBOARD CAME ON SO I IMMEDIATELY PULLED OFF THE HIGHWAY INTO A GAS STATION AND SMOKE CAME OUT FROM UNDER THE FRONT FOR A FEW MINUTES.
I CHECKED THE TRANS. LEVEL AND IT WAS NORMAL THEN CHECKED THE COLOR, TEXTURE AND SMELL ALL THREE SEEMED NORMAL. I LEFT THE VEHICLE THERE FOR A WEEK. DROVE IT 20MILES HOME.WHILE DRIVING HOME IT SEEMED TO START OFF IN 2ND GEAR THEN SHIFT TO 3RD BUT NOT INTO 4TH OR OVERDRIVE. I MADE IT HOME AND THE NEXT DAY DROVE IT TO AUTOZONE TO HOOK IT UP TO THE COMPUTER TO GET THE TROUBLE CODES. THE TROUBLE CODES WERE, p0173 WHICH IS A TROUBLE CODE FOR A VACUUM LEAK. /p0705/p0715/p0720/p0301 ANY HELP WITH THIS TRANS-NITEMARE WOULD BE APPRECIATED . THANK YOU.
 

nickb2

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#2
Ok, trans related codes are

P0705 is park/neutral switch

P0715 is input speed sensor

P0720 is output speed sensor

Most likely, all 3 did not give out at the same time, so your probably looking at a circuit problem with a related common ground, fuse, harness, connector, and lastly, hopefully not, a faulty PCM

I will provide a wiring schematic to trace the circuits in question before you start replacing sensors and switches just to find it was a bad common ground or connector issue.

Now onto the other two codes.

Po301 is a misfire of cylinder #1.

Po173 IS NOT SPECIFICALLY A VACUUM LEAK (although it is a possibility) trouble code. It is an injector fuel trim circuit issue.

Possible causes for the P0173 are maybe a bad MAF (airflow sensor), a faulty IAT sensor (intake air temperature sensor), a faulty injector, incorrect fuel pressure, AND possibly a vacuum leak, a faulty ECT sensor (engine coolant temp sensor), or a bad heater o2s sensor, also maybe an exhaust leak, and also maybe a faulty baro sensor (commonly know as a MAP sensor, and last but not least, a bad PCM.
 
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nickb2

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#3
So proper diagnostic procedure would be to diagnose the P0301 code first as it most likely is the root cause of the P0173 code.

First, check the #1 fuel injector. The injector should have 13-16ohms @ room temp (20c).

Follow the flowchart provided in ACE 1 pdf attached here.
 

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nickb2

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#4
Now onto the trans codes.

One of the trans speed sensors is the culprit possibly of your no overdive situation.

Also, you can do a continuity check on the park/neutral switch.

I also provided pdf's for those check. See ace pdf's attached here.

First check the 10 amp fuses which provides power to the prndl switch and the two trans speed sensors.

Wiring's below shows what I mean. If that is good, start tracing the wiring harness of that circuit to all three components. Screenshot (20).png
Screenshot (19).png
 

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nickb2

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#5
Now since both the trans speed sensors coded along with the PRNDL switch. Check for loose connectors a pinched wiring harness, bad ground, blown fuse etc before replacing anything. There is most likely an open circuit, short or loose connection/corrosion etc.

Let me know if ony of this helps. I think I cannot be anymore specific than that until you have done all the following checks I have asked of you.

I sure hope you have a multimeter. ;)
 

billr

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#6
Had there been any other warning lights on before the "slip & smoke" episode that turned-on the trans light?