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Discussion Starter #1
A couple of months ago, I posed this. The car was running fine after changing out the sensor.

However, About 2 weeks ago, it went bad again. Was heading to town one morning and after about 5 minutes of driving, I lost the speedometer again, and shortly after, the at/power steering lights came on. I took it back home, ran the scanner, and it gave me p0720 again.

I was annoyed, but bought another sensor anyway. I finally put the sensor on last weekend, took it for a short test drive (maybe 10 minutes) and it was perfect again. The next morning I was leaving for work, and noticed as I was pulling out of my driveway that the speedo wasn't working, and sure enough about 30 seconds later the other lights popped on.

Today I had some time to mess with it, and pulled the sensor back out for a few minutes (out of boredom more than anything), and then put the car all back together. Tried another test drive and the speedo worked for maybe 15 seconds as I was pulling out of the driveway, and then of course, goes back out.

What can be causing these sensors to go bad?
 

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Discussion Starter #3
I check them, and they appear fine. I rummaged around yesterday and found a couple of spots off issue (maybe?)

The first was the connector, where the wires enter it. A very tiny section of the rubber was cracked open and exposing the wire. (the brown/white one)
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The next spot was the wiring for the tcm. A good section of tape had been rubbed away, but the only wires that were exposed were ones that appear to be uncoated on purpose (or I assume anyway) Took the picture after removing all the old tape, the area that's circled was where it was open.
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I taped both of the areas, and took it for a test. I went maybe a tenth of a mile and the speedometer still wasn't working, so I went back home but left it idling since I needed to go to my neighbors for a minute and was just going to drive this car since they're close. However when I headed over there, the speedometer was working.

I left my neighbors and went for a longer drive and it all appeared to be working as normal. I went home, then went to the store a little while later, and it still worked.

This morning I wanted to see if it was still working, so I backed up/re-parked in my driveway and so far so good.

So I honestly have no idea. I don't know if taping those spots actually helped, or my car is just being temperamental.
I never changed out this sensor (since the one I have ordered still hasn't come), so the sensor isn't bad, but something is making the car think it is?


Also, probably unrelated, but while I was digging around, I found a spot underneath in the transmission that looks like it's missing a bolt? It goes through to the other side, and that side is threaded. Any ideas what's missing, and if it's uh, important?
105881
 

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Discussion Starter #4
Another update:

Anyone have any tips on setting a car on fire? Would be much appreciated.

But seriously, all week it has just been working and then not working, with no rhyme or reason to it. Sometimes I can start it without touching anything under the hood, and everything works fine for a bit. Then there are times where I can start the car and it's still not working/lights on.

When it does work, I can drive for a while and it will either cut out while driving, or just stop working after idling in park, or turning off/on. One day I drove most of the day to several locations running errands, and it never gave me an issue. The next day I didn't make it 20 minutes before it dropped to zero again, and refused to come back even after changing the sensor to a new one.

I don't know what to look for next. Everything online points to this being either the sensor or the wiring, but nothing I've done has fixed it (permanently)


Really sad considering I bought this car to replace my 02 accord with a messed up transmission and bad head gasket, and yet that car is still running.
 

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Have you checked that the terminals in the speed sensor harness plug have proper tension? The plug can look perfectly fine but over time the little piece of metal in the connector that keeps pressure on the terminal tab it's connecting to can get weak causing an intermittent connection and all sorts of issues. A new plug might be worth a shot.
 

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Discussion Starter #6
Have you checked that the terminals in the speed sensor harness plug have proper tension? The plug can look perfectly fine but over time the little piece of metal in the connector that keeps pressure on the terminal tab it's connecting to can get weak causing an intermittent connection and all sorts of issues. A new plug might be worth a shot.

That sounds like a good next move actually. I'll order one and give that a shot.
 

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Discussion Starter #7
Also, does anyone know how tight the bolt is supposed to be? Like just snug, or tightened until you can't move it anymore?

Because yesterday I was messing with it, and I noticed there was transmission fluid kind of pooled around the sensor and on the connector (which I haven't noticed before), so I thought maybe this last time I didn't tighten it enough, so I tightened it as far as I could get it, but it looks like the metal bracket is sort of bent now.
 

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That's probably because you didn't push the sensor all the way into the transmission. Most likely the O-ring didn't go all the way into the hole.
 

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Discussion Starter #9
This is probably going to be a dumb question, especially this late into the game, but I need to clarify that I'm changing the right sensor, because I keep running across conflicting info.

The one I've been changing is on the top of the transmission, has a 2 prong connector, and has the bolt 180 degrees from the connector side. When I look at part sites, this one is labeled as the output sensor, which is what I need according to the code I'm getting. (Like this)

However when I look at diagrams (and a lot of youtube videos), they have them swapped: the output sensor is on the back of the trans, and is the one with a 3 pin connector, and the bolt 90 degrees from the connector (Like this), and the input is the one on top.

Have I been changing the wrong sensor?

Though that just makes me wonder if I did change the wrong one, why did it work for 3 weeks?
 

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I just checked the factory service manual, the one on the back of the trans, by where the axles go in, is referred to as the "vehicle speed sensor" and it has a 3 pins connector.
 
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