2G Weird electrical problem with tps and park neutral switch

[m1nd64m3]

So my car is throwing two codes, one for the tps sensor and another for the park neutral switch. The car is a 98 gst auto, so the park neutral switch is located on the trans itself.

This is where it gets weird, from what I gather on the park neutral switch from searching here is that if it is faulty then the car won't even start, but it starts up fine.

For the tps sensor, it checks out fine on the s-afc, goes 0-100% like it should. Only cause for concern is that the tps will sometimes read between 1-2% after startup (without pressing the throttle), not sure if this is normal or not.

Now the car itself is acting kind of funky lately. First off the car will downshift into first hard enough to chirp the tires, but it only does this after first starting the car and putting it into drive. It seems like it's holding onto 2nd or 3rd and when it finally shifts it may downshift hard if I'm accelerating, or it will shift into the next gear if I'm babying it and go real easy on the gas. This all started after I pulled the engine/transmission to fix some other unrelated things. And it will do this every time after starting it, even if it's shut off and turned back on. I thought the problem was related to my mounts being shot, but I just filled them and it did it again once out of the 4 times I've started it since, so I believe the problem is still there but the mounts were making it worse.

The car is also idling high this past day since I have filled my mounts. It is idling between 1500 and 2000 so I believe it could be related to the tps and park neutral switch some how. I also disconnected the isc to see if that would cause anything but it did nothing so I suspect the isc may be bad as well.

I already see how to test the tps sensor, and what I'm looking for looks to be the continuity between the 3 and 4 terminals to test for the idle switch.

I am totally unsure as to how to test the park neutral switch, I can't find anything on it regarding automatics.

I also wonder if my ecu could be causing this, I've had problems with previous alternators having bad voltage regulators so the car would regularly see 14.5-15.1 volts, i wonder if that could cause the caps to leak? And another ecu related thing is that I am able to pass emissions with none of the emissions solenoid's vacuum lines hooked up (although they are still connected to the wire harness), no egr installed, and no cat, but it never throws a code and it's been this way for many years. I do have another ecu with ecmlink v3 on it ready to go in but I wanted to pass emissions first before I start messing with ecmlink.

Can anyone shed some light on this? Looking for some pointers or some advice.

 

[avefenix]

whenever i have dealt with codes i always start by resetting the computer...if it kicks the code again then look at each sensor a little closer, i personally dont trust code readers to remove codes and them stay off so i would always do a manual reset then drive it a couple days....by doing a full reset which im sure there will be several opinions on this, you allow the car to reprogram itself along with programming to your driving ability, the computer will store this...to reset mine i had to put the key in the ignition, turn to the on position and pull the positive terminal while on, then turn off remove keys and let sit with no power for 5 minutes, re attach the terminal and start the vehicle , complete reset...

now that its reset drive it a few days, and see what it stores and go from there...i learned this from a master technician for lexus toyota in richmond bc, it is similar for many vehicle apps other then these as well...

 

[m1nd64m3]

I'll try that. I have disconnected the battery a couple times and it cleared it but after a short while the light pops back up.

 

[bo0st]

whenever i have dealt with codes i always start by resetting the computer...if it kicks the code again then look at each sensor a little closer, i personally dont trust code readers to remove codes and them stay off so i would always do a manual reset then drive it a couple days....by doing a full reset which im sure there will be several opinions on this, you allow the car to reprogram itself along with programming to your driving ability, the computer will store this...to reset mine i had to put the key in the ignition, turn to the on position and pull the positive terminal while on, then turn off remove keys and let sit with no power for 5 minutes, re attach the terminal and start the vehicle , complete reset...

now that its reset drive it a few days, and see what it stores and go from there...i learned this from a master technician for lexus toyota in richmond bc, it is similar for many vehicle apps other then these as well...

this seems helpful, would this work on N/A eclipses as well? such as a 1998 RS?

 

[m1nd64m3]

An update on my problems:

I have fixed the idle issue. Turns out the throttle cable was too tight and would not allow the throttle to close all the way and close the idle switch. Loosened it up and now there is no more high idle problems, and it idles great.

My hard downshift problem is still there. I did ditch my old inserts and filled the mounts with the forsche liquid urethane and it cured a squeaky sound I was having and it also caused the hard downshift to happen a lot less often, but it still does it sometimes.

When it does it is still only after turning it on, putting it into drive and going, and if it does it then it will shift down hard enough to chirp the tires or it will shift up as normal, but won't do it again till the car is turned off and back on, seems to do it more on hot starts. So i suspect the park/nuetral switch is at fault still because that was one of the codes it was throwing. Does anyone know how to test the park/neutral switch? I think its working because it only starts in park or neutral but its tripping a code and i need to get rid of it for emissions. I do have dsmlink v3 but its not installed, would i be able to use dsmlink to bypass the problem so I can get the cel off? Again this is an auto.

The cel came back on, not sure why yet, going to stop and have it scanned tomorrow. But I have the battery disconnected right now because I'm going to try and get the emissions done tomorrow, and it only trips the light after the second start up after resetting the light. So hopefully I can start it and get it to the emissions station before it trips the light again.

Looking for any insight people may have on problems with the park/neutral switch.

 

[m1nd64m3]

I have resolved all the issues I had. Turns out it was a bad park neutral switch, the sensor got bent when I was putting my engine and trans in last time. I tested it using a diagram I found while searching p0705.

 

[992gst]

I have resolved all the issues I had. Turns out it was a bad park neutral switch, the sensor got bent when I was putting my engine and trans in last time. I tested it using a diagram I found while searching p0705.

Did it ever nt want to go in a gear while in frove ? Im haveing the same issues but inbettween the gears would nt catch a gear but it was doing the down shift not letting the gears change like u stated. Can u show where the where the park natural switch is?

 

[1990TSIAWDTALON]

Very old thread, but lets give him a "call"
@m1nd64m3, thanks for putting a resolution into the end of your old thread (9 years ago)!!!
We have a new member hear, can you be of any help in his issue?
@992gst, the "Inhibitor Switch" or neutral safety switch, is mounted on the shift shaft of the transmission. It will have 10-12 wires coming out of it and should be obvious. It is held on with two 10mm bolts. I am putting my AWD auto back in my car and had to rob one off of a spare trans, as mine didn't have one on it when I got it.
BTW, Welcome to the forum, there is a wealth of knowledge held in these threads!
I will post up a picture of it as soon as I can.
Marty

 

[1990TSIAWDTALON]

A picture is worth 1000 words. This is an AWD unit but the FWD's are in the same place.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[992gst]

A picture is worth 1000 words. This is an AWD unit but the FWD's are in the same place.

You must be logged in to view this image or video.

Thanks you good sir

 

[1990TSIAWDTALON]

Here to help out, anytime!

 

[992gst]

could you point me in the direction of ordering a new switch? ever where i look seem to be out of stock or its for the gs auto not the gst or a part number

 

[m1nd64m3]

I think I had to have the dealer order it, but I’m not 100% sure since it was so long ago.

 

[luv2rallye]

could you point me in the direction of ordering a new switch? ever where i look seem to be out of stock or its for the gs auto not the gst or a part number

According to ASA I think the Mitsu part number you're looking for is MD753985 (Park/neutral position switch for 2gst auto).

 

[992gst]

I think I had to have the dealer order it, but I’m not 100% sure since it was so long ago.

Im try that first before I even think about shaping trans hopefully it is jst the switcb

 

[992gst]

According to ASA I think the Mitsu part number you're looking for is MD753985 (Park/neutral position switch for 2gst auto).

Yeah im try the dealer first thanks