Technical New Owner 2016 P1634 error code

[fpjeepy05]

Hello. Just joined the site. Bought my gf a 500x from a less-than-trustworthy guy on FB marketplace. Needless to say, I'm now having issues.

2016 500X Lounge ZFBCFXDT9GP392179

She remote started the vehicle the other day and when she got in the check engine light was on and drive mode unavailable. I'm 1000 miles away most of the time. Yesterday I was visiting and had a few minutes I ran my OBD scanner and got the code P1634. Looking up online wasn't easy. Some sites say "ignition 1 switch" others "TCM module failure" and one Italian site I translated to "alternator not charging"

The vehicle has been shifting hard when it's cold and we were planning on bringing it to the shop to be serviced. But the previous owner did replace the alternator so I figured I would spend a couple mins see if any wires were blatantly not connected. I did find the negative battery terminals was pretty loose. I've never seen a battery connection like that - no adjustment. I finally got it to work by jamming it down before clamping.

I started the car up and the check engine light was out. Ran out of time, and had to leave for a wedding. Didn't get to drive it before I flew back.

So my question is - will disconnecting the battery reset the ECU and clear out the error codes? Or is it possible that the loose battery terminal was actually the problem? What is a good source for looking up error codes on these vehicles?

 

[s130]

I don't have a 500X with an auto box so no experience there.

Attached is the official 500x P1634 diagnostic information. This is from 2015 / 2018.

Not very informative I'm afraid. If you can get a more advanced EOBD scanner connection reading then besides the P1634 error there may be/should be some extra information that may prove useful.

 

[fpjeepy05]

I don't have a 500X with an auto box so no experience there.

Attached is the official 500x P1634 diagnostic information. This is from 2015 / 2018.

Not very informative I'm afraid. If you can get a more advanced EOBD scanner connection reading then besides the P1634 error there may be/should be some extra information that may prove useful.

Codice Errore Fiat | Biemmepi Autoattrezzature

Codici Errore Eobd Alfa Romeo

biemmepiautoattrezzature.it

That's where I saw the code being for an alternator.

 

[s130]

Codice Errore Fiat | Biemmepi Autoattrezzature

Codici Errore Eobd Alfa Romeo

biemmepiautoattrezzature.it

That's where I saw the code being for an alternator.

I would be inclined to think that the KeyLEARN/eLEARN info I posted is correct for the 500X. P-Codes and manufacturer specific and I've seen P and other manufacturer specific same codes actually meaning different things for different vehicles.

Also in your listing is says Mazda.

Here are some other Fiat/Other codes (sorry about formatting etc as pasted from other docs/sources

P1634 Mercedes: Ignition 1 Switch Circuit​

BMW P1634: Throttle Valve Adaptation Spring Test Failed (Bank 1)​

P1634

Data Output Link Circuit Failure (Fiat)

P1634=Circuito collegamento uscita dati o sistema di comando alternatore - assenza di carica (Mazda)

P1634

Ignition 1 Power Circuit Low Voltage (other)

 

[fpjeepy05]

She drove it a bit today, and the check engine light hasn't come back on yet. However, it's still shifting a bit rough, especially before it warms up.

I called a shop that I trust to schedule an appointment. I asked if they would recommend a transmission fluid flush, but they said no. They did mention they could drain and replace the transmission fluid, though they didn’t think it would help much. I find that odd since the car has 107k miles, and I have no proof the transmission fluid has ever been changed. From what I’ve read, it should be changed every 30k miles.

I also looked into the TCM (Transmission Control Module), which doesn’t seem too expensive, but I haven’t figured out how much labor is involved in replacing it.

If the check engine light stays off, I’m okay with her continuing to drive it as-is, but only if it won’t cause any further damage to the transmission. Any advice or thoughts on what to do next?

 

[fpjeepy05]

Trying to cost out a new TCM. The shop we brought it to is suggesting checking the wiring harness first. $400 labor and then replacing the TCM if that doesn't fix it. They said they can replace the TCM, but the Fiat dealership will have to program. I'm trying to figure out if that is standard operation procedure or if another shop might be able to install and program.

Thanks