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I drive an 05 MDX. Was running perfect...until 2 days ago. Ran fine all day, but otw home after driving around, the speedo stopped working, and there was a whining noise. All of a sudden, all kind of lights go on, including d5 blinking and cel, and it stall and won’t start. It gave me a p0722 code, (output speed sensor). Made sense...so I changed it out. Took it for a test ride, and immediately noticed that the speedo still wasn’t working. Got 2 min down the road, and same issue. Lights all on, and car stall and won’t start. Same code, but this time a tps code as well. Has anyone had this happen? What was the fix? Thanks in advance.
 

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There are actually two sensors that must work in conjunction with each by the PCM . These are the output speed sensor and the input speed sensor. Many manufactures offer these in pairs for replacement for this reason. Even though it claims/states the output sensor it could also be the input sensor. This is where a quality OBD2 scanner comes into play that gives you data and can be bought for around $110.00 which is almost the cost the dealer charges or garage to scan and read the codes ONCE!, (something you should consider autel AL619 comes to mind).

Note: The transmission speed sensors are used to calculate the actual gear ratio of the transmission while in use. There are generally two speed sensors that work in conjunction to provide accurate transmission data to the vehicle’s power train control module. The first is known as the input shaft speed (ISS) sensor. As described, this sensor is used to monitor the speed of the transmission’s input shaft. The other sensor is the output shaft speed (OSS) sensor. If either of these two sensors falls out of alignment or experiences electrical issues, it impacts the operation of the entire transmission.
After registering data, the two transmission speed sensors, also commonly referred to as a vehicle speed sensors (VSS), send data to the power-train control module (PCM), which compares these two inputs and calculates which gear the transmission should engage for efficient driving. The actual gear ratio is then compared to the desired gear ratio. If the desired gear and the actual gear do not match, then the PCM will set a diagnostic trouble code (DTC) and illuminate the Check Engine Light.

Anyhow if you do not have one you should have the car scanned properly to see what other info it provides. It could also be your atf temp sensor and you received that code later on as you noted.
 

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I drive an 05 MDX. Was running perfect...until 2 days ago. Ran fine all day, but otw home after driving around, the speedo stopped working, and there was a whining noise. All of a sudden, all kind of lights go on, including d5 blinking and cel, and it stall and won’t start. It gave me a p0722 code, (output speed sensor). Made sense...so I changed it out. Took it for a test ride, and immediately noticed that the speedo still wasn’t working. Got 2 min down the road, and same issue. Lights all on, and car stall and won’t start. Same code, but this time a tps code as well. Has anyone had this happen? What was the fix? Thanks in advance.
Hi Panteranate & welcome to the forum! This is a great place to be.

When you removed the OSS, was it at all damaged, scraped?

If it was, check the new one - does it have the same damage?

I've attached a picture of a torn up OSS.
 

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Thanks for the responses e’one! Ok...so here’s my latest info. Yes Steve, the old sensor looked very similar to the picture you posted, and the new one looked like that after 2 min of driving, (driving in 1st gear, bc it wouldn’t shift, and no speedo). I’m going out in a limb, and saying the trans is junk. I really hope not...but it’s not looking good. To me tho, this still doesn’t explain the APP sensor code, (p2122- APP switch D), or the no-start...although I suppose it could’ve put itself in limp mode. I would still think it would start tho...just not go very good. I know cars are weird sometimes, and when something goes, it causes something else to go...but both at once? Or maybe it’s just reading the APP sensor code bc the pcm isn’t getting the right reading from the vss? Thanks so much for your time guys. Very appreciated.
 

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To add a little bit...I cleared the codes after replacing the oss. After it messed up, and stalled out on me again, I tried clearing the codes again, just to get it home. It cleared the oss code, but the app sensor code, and low voltage code associated with it, still remained. Still won’t start. Turns over, and tries to start, but dies out immediately. I unhooked the battery for a couple days, and tried again. Same result...no start, and same APP sensor and low voltage codes. OSS code still erased tho. Stumped here. Thanks again guys!
 

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Panteranate,

I'm sorry to say, I believe your transmission is shot; I had this very same thing approximately 3 years ago. I went through 3 or 4 OSS's after trying many things; Habbyguy was a great source of information, but alas, it turned out that the gear you can see if you look closely through the OSS hole, is loose, and will continue to trash every OSS you put in.

The transmission guy was intending to rebuild, and whilst I cannot recall the exact details, after just a couple of hours he said it wasn't financially viable to rebuild, and I ended up getting a recon transmission.

You are the only other '05 MDX'er I've come across with this issue. I assume it's rare in our year/model.

With that said, they're an awesome car; I chose to spend money replacing the transmission, and notwithstanding other issues I've had, I'm very happy I did not junk her!

Good luck!
 

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After clicking on your profile, I actually stumbled across your thread, and it confirmed what I already assumed. It’s a tough decision to make for me now. Although I’m fairly skilled, the research I’ve done shows that it’s a HUGE job. Is it worth it to save 2k...probably. But, it’ll require a lift, and far better work space than I have. Point is...I won’t have a car for most likely a few months, and being that I work full time, and have 3 kids that all play sports...that’s not really an option, lol. I’ve already spent $300 on rentals since this happened, so need to move quickly. Buy Honda, they told me...they last forever! Looks like it’s back to having a car payment for me...ugh!! ?
 

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After clicking on your profile, I actually stumbled across your thread, and it confirmed what I already assumed. It’s a tough decision to make for me now. Although I’m fairly skilled, the research I’ve done shows that it’s a HUGE job. Is it worth it to save 2k...probably. But, it’ll require a lift, and far better work space than I have. Point is...I won’t have a car for most likely a few months, and being that I work full time, and have 3 kids that all play sports...that’s not really an option, lol. I’ve already spent $300 on rentals since this happened, so need to move quickly. Buy Honda, they told me...they last forever! Looks like it’s back to having a car payment for me...ugh!! ?
I hear ya man. I really do.

Here's what my I did. I really love my MDX, and desperately wanted to fix it; Let me state it's possible to do yourself, and there are a few videos and how-to's on how to do that, and I could be wrong, but I seem to recall there are one, maybe two, showing how to do it without removing the subframe.

Depending on your level of skill, it could be anything from two days work upwards. I contemplated doing it myself for months, but ended up giving the shop almost $3k. Ultimately I chose not to fix myself because my driveway is gravel, and my back is already temperamental. With that said, if you or I purchase or lease a similar sized car, your payments would be, what? $350-$450 per month? 10 months of payments, and the MDX is fixed.

So I went out and bought a beater to drive around for a while (ironically a Honda CRV 4WD), whilst I saved the $3k (Due to family medical emergencies, I did not have $3k ready to give out). If you can lay your hands on $3k, and aside from the transmission, you love your car, this could be the solution.

My shop had my car for less than 30 hours total.

Finally, everything is easy when you know how, and most things seem daunting until you've tried. This would be a simple 'remove and fit new', so it's not as if you're going to strip down the old transmission and rebuild; You can pick up these transmissions for anything between $900-$1300 on ebay, and tack on a squaretrade warranty. (This information is approx 3 years old, it may have changed in either direction.)

I do not regret going down the path of repair, though I still wish I didn't have an awful driveway - I believe I would have done it myself otherwise. And I now have my MDX back on the road, and I don't have car payments.

YMMV
 

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Thanks for all the info man! It was very helpful, and helped me make a decision without paying a shop hundreds to tell me what I was already pretty sure of.
 
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