Issues with a P1191 Code

[Railfan413]

Hello all,

I'm hoping to have some thoughts/ideas on an issue I've been having with my 2021 Ram 3500 HO. Recently when I tried remote starting my truck it started and ran for 10 seconds and shut off. I walked out to check it and it was showing "Remote Start Disabled" on the dash. I started up with the start button and it had a check engine light. My truck has a weight reduction mod so I use a Banks Idash for monitoring purposes. That was reading a P1191 code (IAT Irrational). I swapped it out for a new one which fixed it for a day or two but now I'm back where I started. I also replaced my batteries as well because they were original to the truck. The P1191 problem existed prior to the new batteries. I could use some thoughts on this rather annoying issue. With it being very cold in PA having the ability to remote start would be nice.
Greg

 

[Kubguy]

Having same issues, replaced both Batteries, only happens when weather is colder, now I keep it plugged and no issues, will need to bring it in to check it out, bad sensor I suspect. I believe I had this prob before when under warranty.

 

[Railfan413]

Having same issues, replaced both Batteries, only happens when weather is colder, now I keep it plugged and no issues, will need to bring it in to check it out, bad sensor I suspect. I believe I had this prob before when under warranty.

I noticed when plugged in it takes care of that issues. However this is definitely a new problem that is a real head scratcher. It's not impossible that the new sensor is also bad, but they currently are way to expensive and hard to get to test that without further diagnostics. Something is different but what.........?

 

[Kubguy]

one thing I notice is the draw on battery on cold start plugged in via remote, with my diagnostic tool voltage goes 13.5 11.2 like a pulse for 2 minutes.

 

[Railfan413]

I beli

one thing I notice is the draw on battery on cold start plugged in via remote, with my diagnostic tool voltage goes 13.5 11.2 like a pulse for 2 minutes.

I believe that's just the grid heater cycling on and off to warm up the intake temperature. It's duration is much longer when you don't plug in but it does do it regardless of being plugged in or not.

 

[Railfan413]

Update 1/23/25
I sent my truck into my local diesel shop for diagnostics and repair. So far nothing definitive has been found, but it's definitely looking like some sort of a wiring issue. The sensor seems to be working, but it doesn't look like it's communicating right. I will update when I have more information on the issue.

 

[Stevepat]

I have the same issue, replaced the sensor and it worked fine for a few days. I found that if I remote start it and shut it off within a couple of seconds, restart it and it works perfectly. After the second start it is fine the rest of the day.

 

[Railfan413]

I have the same issue, replaced the sensor and it worked fine for a few days. I found that if I remote start it and shut it off within a couple of seconds, restart it and it works perfectly. After the second start it is fine the rest of the day.

The shop I took my truck to determined it wasn't anything physically wrong, but made the suggestion it was tune related. I worked with my tuner, but that eventually lead to a dead end as well. I guess they got tired of trying to correct the issues as they stopped replying to my emails. Not a surprising outcome by any means. The weather warmed up and that has made the issue disappear for now. Now I'm trying to determine how cold it has to be to trigger this issue. I'll just compensate by plugging it in when it gets down to whatever that threshold happens to be. This issue is minor compared to some, but it's rather ridiculous it's even a thing to begin with.

 

[Railfan413]

I figured I'd update the situation. In the end I continued to try and get my issues resolved for the last bunch of months to no avail with my tuner. In general I wasn't happy with my tunes so I ended up going with a different group and they've been absolutely fantastic with everything! I'll be curious as to how it handles this coming winter, but I expect no issues whatsoever.

On a side note: If your not happy with your current weight loss tunes, give CA Tuning a shot. Very affordable compared to everyone else and they stand behind their product. I have Calibrated Power Aisin tunes as well and with CA Tuning plus Aisin Tuning, it runs stupidly well and smooth together.