Remote start not working when cold

[Hrspwr88]

I believe this is a simple software issue rather than a battery issue.

My fail log shows low battery voltage is the reason for the no start. But when I start the truck manually it fires up. To me this tells me the system check for battery voltage is too conservative and needs to be adjusted. Until then this problem will happen.

As mentioned prior, I am convinced this is a remote start software issue. The battery threshold for a start vs no start needs to be updated. Until then this issue will continue. The dealer changed my battery too but even after every failed remote start my truck will manually start fine. So the battery really isn't the issue.

Let's see...

 

[Jimmy07]

Jimmy, for fuse F38 DTCM / Active CL Temp VLV, do you have any idea what valve they're referring to here?

Fuse F38 is circuit F946, and the DTCM is the only item that uses that circuit. There is no splice in that wire, and it goes directly from the exterior fuse box to the DTCM.

 

[UnloosedChewtoy]

My Rebel doesn't have 4wd Auto option I'm pretty sure it's the 44-45 transfer case.

I was looking at the diagram for the BW 44-45 transfer case and I noticed that it only has a mechanical oil pump, so I'm not sure if cooling is the reason for the parasitic loss. On my truck I'm assuming that I have the BW 44-44 transfer case as I have 4wd Auto which includes extra clutch disk in the case.

I don't think it really matters to the thread, as the same arguments can be applied, but just so you know, our trucks do not have the 44-44 and 44-45 transfer cases. These were the 4th gen units, probably still used in the 1500 Classics only.

The 5th gens use the 48-11 and 48-12 transfer cases (for Auto 4WD and non-auto 4WD units respectively). They are improved versions of the 44-44 and 44-45 units, from what I read, and I can testify to that myself. The 44-44 on my 2014 was one of my least favorite things on that truck; this 2020 with the 48-11 is sooooo much better.

I have also read, although not confirmed, that Ford uses the same transfer cases in their F-150s.

 

[jtodd5781]

As mentioned prior, I am convinced this is a remote start software issue. The battery threshold for a start vs no start needs to be updated. Until then this issue will continue. The dealer changed my battery too but even after every failed remote start my truck will manually start fine. So the battery really isn't the issue.

Let's see...

I think mine is more of a battery issue, a week ago last Friday once I got home, shut the truck off and then measured the battery, the battery measured 12.24V and the following Monday after that the dealer told me that the battery was good. After it failed to start numerous times after I went back to the deal and they installed a new battery yesterday. When I drove to work this morning and let it sit all morning at a starting temp at 7AM of 0°F till after lunch at 12PM of 10°F the battery measured 12.59V. I know that my truck will not remote start at 11.92V, which is the voltage at which I measured the battery on a morning it wouldn't start. In all aspects a battery sitting at 11.92V resting is a dead battery and therefore the BCM see's it as that. I will keep monitoring my battery and see what it does.

 

[Hrspwr88]

I think mine is more of a battery issue, a week ago last Friday once I got home, shut the truck off and then measured the battery, the battery measured 12.24V and the following Monday after that the dealer told me that the battery was good. After it failed to start numerous times after I went back to the deal and they installed a new battery yesterday. When I drove to work this morning and let it sit all morning at a starting temp at 7AM of 0°F till after lunch at 12PM of 10°F the battery measured 12.59V. I know that my truck will not remote start at 11.92V, which is the voltage at which I measured the battery on a morning it wouldn't start. In all aspects a battery sitting at 11.92V resting is a dead battery and therefore the BCM see's it as that. I will keep monitoring my battery and see what it does.

The remote start and manual start both fail? Or just the remote start?

 

[HydroRebel]

I don't think it really matters to the thread, as the same arguments can be applied, but just so you know, our trucks do not have the 44-44 and 44-45 transfer cases. These were the 4th gen units, probably still used in the 1500 Classics only.

The 5th gens use the 48-11 and 48-12 transfer cases (for Auto 4WD and non-auto 4WD units respectively). They are improved versions of the 44-44 and 44-45 units, from what I read, and I can testify to that myself. The 44-44 on my 2014 was one of my least favorite things on that truck; this 2020 with the 48-11 is sooooo much better.

I have also read, although not confirmed, that Ford uses the same transfer cases in their F-150s.

Good to know, I was unaware that they utilized different transfer cases for the 5th gens thanks for sharing. I have experience with both and while I do prefer the beefier (non-auto) transfer case, I had no issues or complaints with the 44-44 on my 4th gen. Maybe if I took that truck off-roading I would have a different opinion.

Did you let RamCares know about the issue with F38?

No I didn't. I'll be keeping my eyes on this circuit and if it does it again I will take action. Will most likely take it to the dealer.

Fuse F38 is circuit F946, and the DTCM is the only item that uses that circuit. There is no splice in that wire, and it goes directly from the exterior fuse box to the DTCM.

Ok, good to know. They could've provided a better description for that fuse IMO.

 

[jtodd5781]

The remote start and manual start both fail? Or just the remote start?

Just the remote start fails.

 

[Hrspwr88]

Just the remote start fails.

And when you go to start it manually it starts I assume? To me this means the battery actually has enough charge to still start the truck and the checklist sequence that the remote start completes for a voltage threshold check is set wrong. My $0.02 anyway...

 

[HydroRebel]

My truck failed to remote start after work today. Never had a meter on me but according to the cluster the voltage was 11.9 volts. Got home and let it sit for a bit. Battery was reading 12.46 volts when I checked it. I measured between 1.5-1.6 amp draw again. This time pulling all the fuses did nothing, the amp draw remains. I measured 12.43 volts by the time I got frustrated and left it. Unreal.

 

[UnloosedChewtoy]

Weird that pulling the fuses did not help you isolate the issue. Did you also try pulling the fuses in the little fuse box under the steering column, inside the truck?

 

[HydroRebel]

Weird that pulling the fuses did not help you isolate the issue. Did you also try pulling the fuses in the little fuse box under the steering column, inside the truck?

To be honest I never pulled every single fuse this time just a handful before my anger and frustration took over and I slammed the hood closed. When I'm off this weekend I'll pull them all one at a time including the ones under the steering wheel. I just know I'm stuck with this issue unless I figure it out myself. I have no faith in my local dealers ability to figure this out. Such a pity as I love this truck and this will be its ultimate end.

 

[UnloosedChewtoy]

To be honest I never pulled every single fuse this time just a handful before my anger and frustration took over and I slammed the hood closed. When I'm off this weekend I'll pull them all one at a time including the ones under the steering wheel. I just know I'm stuck with this issue unless I figure it out myself. I have no faith in my local dealers ability to figure this out. Such a pity as I love this truck and this will be its ultimate end.

I get it, sometimes its a love-hate relationship with our trucks. Sometimes its nice to just take a breather (at least an hour or more, sometimes a whole day depending on frustration level), and then come back to it later with a clear head and fresh eyes. You'll get it figured out, at least tracked down to the offending circuit!

 

[HydroRebel]

I get it, sometimes its a love-hate relationship with our trucks. Sometimes its nice to just take a breather (at least an hour or more, sometimes a whole day depending on frustration level), and then come back to it later with a clear head and fresh eyes. You'll get it figured out, at least tracked down to the offending circuit!

Absolutely, I couldn't agree more. After having a 4th gen for 6 years with zero issues maybe I'm spoiled.

 

[Jimmy07]

I think that this new manufacturer for the rf hubs in the 5th gens and the 2019+ HDs is using some all around buggy software. TRW Automotive built the RF Hubs for the 4th gens. Strattec Security builds the RF Hubs for the 5th gens and 2019+ HDs. For the HDs, it’s a known issue that many can not unlock the doors with the fob without multiple button presses after the truck is remote started. HD owners are also experiencing the no remote start condition in cold weather, or the command needs to be sent multiple times for the remote start to work in cold weather. Those issues, combined with the EMI sensitivity with LEDs, are probably the result of bad software in the RF Hubs across all the Ram vehicle lines. I know they have a star case for the unlock issue after remote start for the HDs, which is supposed to have a solution in the second quarter, but I’m not sure how many other issues that star case addresses, and if it’s for all Rams.

 

[RamCares]

16 degrees today. remote start did not work. Has to be a temp thing.

I'm having the same issue. Key fob doesn't work to remote start, or even unlock the truck at times. App works about 60% of the time.
Today I was locked out of my truck for 20 minutes because the fob wouldn't work, and the app kept failing.
Finally got it to unlock with the app, but took about another 10 minutes to get the truck to detect the fob for the truck to start.

Add it to the growing list of issues in the 6 months I've had it.

My truck failed to remote start after work today. Never had a meter on me but according to the cluster the voltage was 11.9 volts. Got home and let it sit for a bit. Battery was reading 12.46 volts when I checked it. I measured between 1.5-1.6 amp draw again. This time pulling all the fuses did nothing, the amp draw remains. I measured 12.43 volts by the time I got frustrated and left it. Unreal.

Hi there, we are deeply sorry for the inconvenience that this concern may be causing you. Please loop our team into a private message should you decide to address this with your dealer. We are more than willing to escalate your experiences to a specialist for additional support throughout your vehicle service - thank you!

Kathryn
Ram Cares

 

[jtodd5781]

I think that this new manufacturer for the rf hubs in the 5th gens and the 2019+ HDs is using some all around buggy software. TRW Automotive built the RF Hubs for the 4th gens. Strattec Security builds the RF Hubs for the 5th gens and 2019+ HDs. For the HDs, it’s a known issue that many can not unlock the doors with the fob without multiple button presses after the truck is remote started. HD owners are also experiencing the no remote start condition in cold weather, or the command needs to be sent multiple times for the remote start to work in cold weather. Those issues, combined with the EMI sensitivity with LEDs, are probably the result of bad software in the RF Hubs across all the Ram vehicle lines. I know they have a star case for the unlock issue after remote start for the HDs, which is supposed to have a solution in the second quarter, but I’m not sure how many other issues that star case addresses, and if it’s for all Rams.

I do know that the rf hub has nothing to do with cold weather starting on my truck as I can put a trickle charger on my truck and it starts just fine with the remote start. The truck will not start with the remote if the battery voltage is below 12V. I am going to experiment with mine a little this weekend by putting an electronic load on the battery and find at what level this occurs at.

 

[Jimmy07]

I do know that the rf hub has nothing to do with cold weather starting on my truck as I can put a trickle charger on my truck and it starts just fine with the remote start. The truck will not start with the remote if the battery voltage is below 12V. I am going to experiment with mine a little this weekend by putting an electronic load on the battery and find at what level this occurs at.

It actually does, because one of the requirements for remote start to work when the rf hub does it’s checklist once the command is received is that the battery voltage is at the acceptable level. That voltage threshold is probably higher on the new rf hubs than it was on the rf hubs used in the 4th gens, which is why they didn’t have this issue. Once you do find that threshold, there’s nothing you can do about it except try to keep the battery above that voltage in cold weather. It doesn’t necessarily mean that there’s something wrong with your truck, it’s just that’s the nature of the effects of cold weather on the battery voltage.

 

[Hrspwr88]

I do know that the rf hub has nothing to do with cold weather starting on my truck as I can put a trickle charger on my truck and it starts just fine with the remote start. The truck will not start with the remote if the battery voltage is below 12V. I am going to experiment with mine a little this weekend by putting an electronic load on the battery and find at what level this occurs at.

It actually does, because one of the requirements for remote start to work when the rf hub does it’s checklist once the command is received is that the battery voltage is at the acceptable level. That voltage threshold is probably higher on the new rf hubs than it was on the rf hubs used in the 4th gens, which is why they didn’t have this issue. Once you do find that threshold, there’s nothing you can do about it except try to keep the battery above that voltage in cold weather. It doesn’t necessarily mean that there’s something wrong with your truck, it’s just that’s the nature of the effects of cold weather on the battery voltage.

I'm not sure if it needs to be exactly 12V but whatever the value, it's too high and fails the remote start process for no reason.

 

[jtodd5781]

It actually does, because one of the requirements for remote start to work when the rf hub does it’s checklist once the command is received is that the battery voltage is at the acceptable level. That voltage threshold is probably higher on the new rf hubs than it was on the rf hubs used in the 4th gens, which is why they didn’t have this issue. Once you do find that threshold, there’s nothing you can do about it except try to keep the battery above that voltage in cold weather. It doesn’t necessarily mean that there’s something wrong with your truck, it’s just that’s the nature of the effects of cold weather on the battery voltage.

I don't think it would be the RF Hub that would make that determination as all it does is pass along information received from the Remote and other modules in the vehicle. I think that determination would be made by the BCM. I have heard people blaming the RF hub for not remote starting due to it going to sleep and needing to be woke up first before operating properly, but I don't think this is the case.

 

[jtodd5781]

I have been monitoring the battery voltage on the dash while driving to and from work the past couple of days. I noticed that the voltage would vary anywhere between 12.7 and 14.6V while driving. I wonder if the problem that we are all having stems from the fact that the battery may not be getting fully charged? I have measured voltage levels of 12.2 to 12.57V shortly after shutting my truck off. I have read that the charge voltage levels need to be higher when it's cold out, which would explain why the battery isn't getting fully charged. What are everyone's thoughts on this?