I hope I can find some help because I have been suffering with my 2016 Accord. I bought it with just below 15k miles on it. After a few days and when I was on the highway, it started downshifting and then up shifting with a jerk at speeds higher than 70 km/h. It does this more so when the speed remained stable, and most times I would hear a screech like the sound the fan belt makes when it gets wet.

I took it in, and it read code p1890 – which after looking into with the shop (several actually) all confirmed I had to replace the transmission and then try to update the software. I replaced the transmission (second hand) and took the car to the dealer as the problem persisted! The software did not update, i.e. it did not need to be ( I was told it should automatically update if it needs it) and that the transmission that was put in also needs to be replaced again.

I feel like I am going in circles and fear the problem is elsewhere.

 

They are correct. The PGM-FI software needs to be updated and if it doesn't work the transmission needs to be replaced. Sadly a second hand transmission may already be effected from the issues they are having with the 15-16 CVT transmissions. TSB 16-053 is out there for you to read more on the issue you are having.

I would suggest a new or reman transmission. If the shop you took it to chose or suggested the used transmission and fitted have them make a warranty claim on the transmission and put a new one in at no cost. If you picked the transmission out you're at least stuck with the labor cost again.

 

My Accord has a trasnmission control modules that affect the transmission in those ways when it's going bad. I'm surprised you haven't dropped into Limp Mode. Do you have a S mode indicator light? If you disconnect the negative battery cable for a few minutes then replace it, does the issue go away for a while. My Accord transmission doesn't work at all if I put some other type of tranny fluid besides the specific Honda Transmission fluid in it. Most service centers will often tell you to get a new transmission when all you need to do is fix some surrounding issues.

 

Thank you so much for your reply. A follow up question. Has the same problem been reported with other Accord models, i.e. would installing a 2017 transmission help/work?

 

Yes I tried replacing transmission fluid and software update. Any other issues to check for?

 

Well if you're still having issues there is something to consider. A lot of us have difficulties diagnosing random car ailments. When I read this again I think I realized something. Let's say your driving along and suddenly your transmision starts acting up. I take it this occurs, say after it heats up. Does it come and go. Transmissions work with hydrolics and I haven't seen a filter so it wouldn't be a clogged one. It's the noise thing. Have you ever heard the sound of a tourque converter that's low on fluid? It's kind of like a belt squeal but a mechanical sounding one. However this sounds oddly like an elecrtical issue. A relay, control unit or brain. I'd bet money on that.

 

Hi all,
Hope I'm in the right section.

To make a long story short (see my presentation for details), I had tranny issues that made me lose all the gears but first... Tranny was reman completely, gears came back but not smooth enough according to the dealer...
After another reman tranny and a TCU change, gears are still very chaotic (switches when it shouldn't and doesn't when it should which results in a roller coaster-like ride...).

I'm getting my car back from the dealer in this state (unrepaired...) and I'm looking for help to fix this.

Any help and ideas appreciated

Thanks in advance.

 

I believe from the sounds of it you are in what's been described as limp mode.
https://www.transmissionrepaircostguide.com/limp-mode/#:~:text=Fail%20Code%20conditions%20or%20%E2%80%9C Limp,logic%20of%20a%20vehicle's%20computer.&text=A s%20long%20as%20the%20computer,the%20transmission% 20will%20operate%20normally.