Where is the Automatic Transmission Output Speed Sensor

[2009-Red-P-O-S]

Hey 2009 - Did you replace the output speed sensor? and did that fix your problem? I have the same - no speedo and no 4th gear. Thanks.

No not yet having trouble finding the part I do not know what to call it and the people I have talked to at the parts places do not seem to know what to call it either so I am going to call the dealer ship and see what they say tomorrow

[2009-Red-P-O-S]

I AM SOOOO PISSED OFF I finally went to the dealership, confirmed that the sensor in question is on the vehicle rear side of the bell housing under the master cylinder and has the rotating gear on it, confirmed the diagnostic code and bought the part. Changed the sensor out and it made no freaking difference. brought the car and had the code read again and I am still getting the P0722 output shaft sensor system no output AND the PO700 Transmission Control System Malfunction Indicator Lamp Request I am so angry I hate this frigging car it is a nightmare and it has been since I got it. If anyone has any insight or advice it is more than welcomed.

[petrified.rabbit]

did you happen to check if there is a signal being sent to the sensor?

in order for there to be an output there needs to be a signal.

[2009-Red-P-O-S]

No I did not check for a signal How would I check that or am I at the point where I need a complete diagnostic run at the dealership instead of just a code reader at Advance Auto Parts P0700 comes up (Transmission Control System Malfunction Indicator Light Request) and the P0722 (Out Put Shaft Sensor System No Signal) I am so over this car I am supposed to go out of town for Labor day with my Wife and Kids a 2 hour drive out of town and then back on Sunday night I am going to do it and just hope the car completely dies so we can dip into the emergency fund and replace the car It has been one issue after another with this thing

[Chevy Customer Svc]

We're sorry to hear that replacing the sensor didn't resolve the issues you're having with your Aveo, 2009-Red-P-O-S . If you would like for us to check into this with your dealership as well, please contact us via private message with more information (include your name, contact information, the last 8 digits of your VIN, and the name of your involved dealership).

Sarah (Assisting Jackie)
Chevrolet Customer Care

[ka1qyx]

had the same issue, drove me nuts
first the trand fl looked OK-

OUTPUT SPEED sensor is on the top of trans towards back under brake master cyl- 3 pin connector, one bolt holding it in
its a pain to twist/ get it out

pull out, put 3pin connector in, turn key to IGN ON (where everything lights up), spin the gear. does ODO work?
if yes then you know thats OK

youll feel the mating gear in the trans where you just pulled the output speed sens

can you spin it? is it loose?

if yes chances are that gear is loose and its not able to spin the output speed sens.

can it be fixed without pulling trans apart?
probably not easily. GM dealer isnt of much help. since i cant even really see it dont know if its a plastic or metal gear

from what can gather from their lousy diagrams its mounted on a shaft
mine was working just great then it stopped working after i parked it 3 hours

GM has a service bulletin on it, saying trans fl & coolant mixing so that causes this issue.....

[avguy]

....
GM has a service bulletin on it, saying trans fl & coolant mixing so that causes this issue.....

What year is your Aveo? The GM TSBs for coolant mixing with tranny fluid are generic and cover a number of different vehicles. But up to now, the only cases I've seen reported of this problem happening to Aveos were with the 2009. Not surprising, but that's the model year they changed the radiator/cooler for Aveos equiped with A/T. Probably a bad batch of that new part got out before they identified the problem with it. Not saying coolant can't mix in Aveos other than '09, just haven't seen any reports of that yet.

[chevyman]

Something I have seen at my shop is there is a gear inside the transmission that can get damaged and cause the speed sensor to not read very well... The transmission can become contaminated with antifreeze from a failed transmission cooler.... Check to see if you have trans fluid in your coolant reservoir, if you do you may have this problem... Also I found this guy put a video on it.
https://www.youtube.com/watch?v=ej_pORD7EIY

[avguy]

Something I have seen at my shop is there is a gear inside the transmission that can get damaged and cause the speed sensor to not read very well... The transmission can become contaminated with antifreeze from a failed transmission cooler.... Check to see if you have trans fluid in your coolant reservoir, if you do you may have this problem... Also I found this guy put a video on it.

The guy in the vid you posted was working on a 2007 and says this same issue is across all Aveo, both gen 1 and gen 2. That's the first time I've seen that posted - up until now it's only been reported for the gen 2, and in particular the 2009. The radiator is a different part for gen1 and gen 2, and everything I've read to date indicates that the systemic problem with the radiator was with the newer part only. Not saying it can't happen on the gen 1, only that it hasn't shown up on this forum, or any other online sites either (that I'm aware of).

However, very few pros post about their repair history on these forums, and I'm very interested in what you have to say. So at your shop, have you seen multiple gen 1 Aveos with the coolant/tranny fluid mixing in the radiator? Or has it been almost all gen 2 Aveos where you've seen this issue?

[crfiala]

Did anyone happen to have a solution for this. Same deal, no spedo/no 4th gear. I heard the ECU would have to be flashed after any repair was done. (Still paying off financing on this one) Trans light is on as well as check engine.