Hey all,
My 02 Q premium has 187k miles.
Transmission is going into "safe mode" because it's giving me a coast brake solinoid fault. I believe it's code p1225? I also got code p720 which is a vehicle speed sensor. I had the codes read at autozone and had them erased.
Car drove fine for a til I got it home a few miles away. I parked the car for a few days and the next time I drove it the Check engine light came back on and tranny went back into safe mode and basically does not shift.
I took the car to my local aamco and they tested the system.
They only got the coast brake solinoid "code" though. Not the vehicle speed sensor code.
They tested the solinoid and it worked fine.
They told me the tranny fluid is old and somewhat burnt.

Aamco says I need to rebuild the tranny.
I have driven the car for almost 30k miles with no shifting issues.
Should I rebuild the tranny or should I just cut my losses?

Anyone had these problems with their Q's ?
Why does it work fine after I erase the codes?
Why did the speed sensor code not show up again?
Could a bad vehicle speed sensor cause this problem?

Thanks for any advise.

A bad vehicle speed sensor and 1 bad solenoid aren't necessarily good enough reasons to completely rebuild the transmission.

Suggestion #1: Take your car to a good, independent transmission shop, and get a second opinion.

Suggestion #2: Stay away from AAMCO.

They said the solinoid is working. But it's getting "blocked"up every now and then sending the tranny into safe mode.
After their diagnostics they said the tranny needs a rebuild.
I have not seen the color of the fluid yet cause it's still at the shop.
They told me the fluid looked bad.
I wonder what would happen if I replaced the vehicle speed sensor?
They are also suggesting not putting in new fluid to try to fix the problem.
Not sure what to think. Never had to deal with a bad tranny.

A solenoid getting "blocked up" is no good reason to tear the entire transmission apart.

The solution might be as simple as a good ATF flush.

Once again - Find someone you trust who really knows transmissions, have them look at it, and take it from there.

Don't let AAMCO touch it!

Ya in grabbing it in a few hours. They have told me a few contradicting things
First time around they said fluid looked good but they had to order a "gasket" for the pan so they needed it a few more days. They told me it was probably not mechanical and they were searching for an electrical problem. Then yesterday they said the tranny had a drain plug and that the fluid looks bad.
My other question at this point is: if my Q has a tranny fluid drain plug then why did they have to drop the pan to drain fluid?

The only reason you should drop the pan is to change the filter out. I would do a drain and drop technique where you drain the fluid, fill it, drive it and then drain it again three times. (you could actually do this yourself) This will get the majority of fluid out and possibly some contamination too. Find a good shop and replace the vehicle speed sensor. If you still have issues, I would then replace the solenoid.

Ya that's my plan. My after did the same thing with his Nissan Quest's transmission. Although his tranny was not shifting correctly it helped a lot and he is still driving that van.
Guys at aamco said putting new fluid in would only make my tranny fail sooner....
Not sure where I stand on that issue.
Based on what aamco said my fluid was burnt and contaminated.
If that's the case then isn't new fluid better than leaving the old stuff in there?

Any you guys know what it's going to take to change the speed sensor and solidiod?
Will I have to drop the tranny to get to them?

Having AAMCO putting new fluid in the tranny will make it fail sooner! I have had several vehicles with over 100K miles and changing the fluid never made it worse! If the fluid is burnt and contaminated, then you need to get new fluid in ASAP!. Now a fluid flush could definitely cause the tranny to fail with the contamination, a a drop and drain is much more safe. The only way putting new fluid in can cause it to fail sooner is if the fluid had created varnish and this varnish comes loose. Get your car out of there ASAP, do not let them touch anything!

Speed sensor should be on the outside of the tranny, not sure about the solenoid. (Most likely you can get access to it when you drop the tranny oil pan)

^^ +1


A few years ago, I purchased an Infiniti I30 that had transmission fluid that looked liked burnt motor oil. It was the worst I've seen in years. It was shifting crazy also. I figured it would surely fail if I changed the fluid. So one day I decided to remove the plug and just drain the pan. Since I was unsure whether the transmission would fail and the old fluid was so bad, I used Castrol Transmax Multi Import Vehicle fluid. So I drove it and I could tell shifting was starting to improve. I drove it for roughly 200 miles and changed it again. Then another another 200 miles and repeated the process. Basically I wanted to keep from shocking the transmission with something like a quick flush. Bottom line it worked and that was roughly 30,000 miles ago.

There are electric solenoids behind the transmission pan that can be changed without having to remove the transmission.
This is a 91 transmission in the picture but somewhat similar to other RWD Infiniti transmissions with regard to solenoids.