4 Wheel Drive (4WD) Not Working

[evillrdnikon]

Ok so I got my truck back from the dealer after they had it for 2 days troubleshooting. The end result was they did a software update on my 4wd / TCU and ECU. I did not get a clear answer as to what a cause for the 4wd to stop working only the resolution. If you want I can post either a picture of my service document or I can just annotate what it says here in this forum.

 

[PowerJrod]

Ok so I got my truck back from the dealer after they had it for 2 days troubleshooting. The end result was they did a software update on my 4wd / TCU and ECU. I did not get a clear answer as to what a cause for the 4wd to stop working only the resolution. If you want I can post either a picture of my service document or I can just annotate what it says here in this forum.

Interesting...never heard of a software update for a TCU. Guess that's a thing nowadays. Is it working like it should now?

 

[evillrdnikon]

So far it is working as intended. I also tested it in front of a service rep and had them show me so there were no questions. I will get that information and post it here.

 

[brianb6]

I had same issue just a few days ago, brought into dealership and they spent about 2 hrs diagnosing it. They said the control module is going out, new one is on the way.

Sent from my SM-G970U using Tapatalk

 

[evillrdnikon]

As promised, but took me a while, my apologies but I have attached what the dealership did to my truck. NGL I hope this won’t me and on going issue with the 2019s. This would make me not want to keep my truck(2019 limited 1500 w/air). They updated my TCM and PCM.
-updated TCM software 68360085af to an.
-updated pcm software 68376895ai to an.

I assume the software version numbers are the same except for the last two characters. I want to saw they never did give me a reason as to why it was inoperable. It seems they were unable to figure it out and they just flashed the pcm/tcm to fix it, or “reset” with new available updates from the manufacturer.

 

[PowerJrod]

As promised, but took me a while, my apologies but I have attached what the dealership did to my truck. NGL I hope this won’t me and on going issue with the 2019s. This would make me not want to keep my truck(2019 limited 1500 w/air). They updated my TCM and PCM.
-updated TCM software 68360085af to an.
-updated pcm software 68376895ai to an.

I assume the software version numbers are the same except for the last two characters. I want to saw they never did give me a reason as to why it was inoperable. It seems they were unable to figure it out and they just flashed the pcm/tcm to fix it, or “reset” with new available updates from the manufacturer.
View attachment 77037

Interesting. Well if all it takes is a software update and it's back to functioning fine, then that's good. Thank you for sharing this!

 

[Badmonkey]

I just had this exact issue. Mine was a bit different. I was getting the 4wd service light while driving in 2wd on the highway. Not trying to select or anything. Then the Stabilitrac Light would come on. Everything would reset with no messages when I got in to drive it. Then would come back about 20 miles or so. Sometimes sooner.

I took it in to get looked into and they did a flash for a recall and another recall for the wipers. Said it fixed the issue. 25 miles into driving home it came back again.

I took it back, did't hear from them for 4 days so I called. Said they were installing a new Module (likely the TCU) but I didnt ask. When I picked it up they showed me that my issue was refered to FCs Engineering group for trouble shooting because they couldnt fogure it out. So they told them to swap the box after taking pin out readings and some where off.

The light is now gone. However, now it snowed a little so I wanted to put it into 4wd auto. Nothing just a blinking light. Tried in park, neutral, while driving on the fly nothing. Tried at a stop, 4hi, on the fly into hi nothing just blinks. Stopped tried 4lo, just blinks. This is were I am now. I will try again from 4lo first then cycle. But i seriously just got it back Tuesday, and started to search and found this post. I am glad the roads where not worse. I am going tobtry again. If it happens again, I am filming it, taking it back again for warranty work. I probably should have made a new post about this but I figured I would share in here what I got going on now too.

 

[Finn5033]

I just had this exact issue. Mine was a bit different. I was getting the 4wd service light while driving in 2wd on the highway. Not trying to select or anything. Then the Stabilitrac Light would come on. Everything would reset with no messages when I got in to drive it. Then would come back about 20 miles or so. Sometimes sooner.

I took it in to get looked into and they did a flash for a recall and another recall for the wipers. Said it fixed the issue. 25 miles into driving home it came back again.

I took it back, did't hear from them for 4 days so I called. Said they were installing a new Module (likely the TCU) but I didnt ask. When I picked it up they showed me that my issue was refered to FCs Engineering group for trouble shooting because they couldnt fogure it out. So they told them to swap the box after taking pin out readings and some where off.

The light is now gone. However, now it snowed a little so I wanted to put it into 4wd auto. Nothing just a blinking light. Tried in park, neutral, while driving on the fly nothing. Tried at a stop, 4hi, on the fly into hi nothing just blinks. Stopped tried 4lo, just blinks. This is were I am now. I will try again from 4lo first then cycle. But i seriously just got it back Tuesday, and started to search and found this post. I am glad the roads where not worse. I am going tobtry again. If it happens again, I am filming it, taking it back again for warranty work. I probably should have made a new post about this but I figured I would share in here what I got going on now too.

I am now having an issue with mine. Last night on my way home I was running errands on snow covered side streets so I put it in 4 auto. Drove home that way cause I was pulling my RV fish house out to get ready for a fishing trip I’m leaving on early tomorrow. This morning after I turned onto the highway I pushed the button to return to 2wd, it just sat and blinked at me. About 5 miles down the road I pulled into a gas station and tried all modes, If I push 4high the 2wd button blinks. I put it into neutral and tried 4lo and the 2wd button blinks. The service 4wd light never comes on. If I push the 4 auto again the blinking stops. So basically according to my truck I’m stuck in 4auto. Not happy, going to see if the Dealership can take a look right away this morning.

 

[Finn5033]

I am now having an issue with mine. Last night on my way home I was running errands on snow covered side streets so I put it in 4 auto. Drove home that way cause I was pulling my RV fish house out to get ready for a fishing trip I’m leaving on early tomorrow. This morning after I turned onto the highway I pushed the button to return to 2wd, it just sat and blinked at me. About 5 miles down the road I pulled into a gas station and tried all modes, If I push 4high the 2wd button blinks. I put it into neutral and tried 4lo and the 2wd button blinks. The service 4wd light never comes on. If I push the 4 auto again the blinking stops. So basically according to my truck I’m stuck in 4auto. Not happy, going to see if the Dealership can take a look right away this morning.

So after a 40 minute drive to work I tried everything again and it was still stuck in 4 auto. Went into work for about a 30 minutes to do some research. Went back out to my truck, started it up and was able to cycle through all modes. Not sure what happened, hopefully it was just a glitch but It worries me a little. I park my truck in a heated garage that I keep at 40 degrees. It was below 0 when I left for work this morning. I don’t know if there was maybe an issue with condensation that froze and messed with something? I’ll report back if I have more issues.

 

[Badmonkey]

So after a 40 minute drive to work I tried everything again and it was still stuck in 4 auto. Went into work for about a 30 minutes to do some research. Went back out to my truck, started it up and was able to cycle through all modes. Not sure what happened, hopefully it was just a glitch but It worries me a little. I park my truck in a heated garage that I keep at 40 degrees. It was below 0 when I left for work this morning. I don’t know if there was maybe an issue with condensation that froze and messed with something? I’ll report back if I have more issues.

You are significantly farther north than I am, but I am still having issues. I am wondering if it has to do with temps, I am not getting the temps you are but it's been around 30-40 lately here, at this point I am reaching. I am taking it back for the 3rd time Monday, supposedly they have the foreman on it this time with the lead tech with FCA's Star Engineer's as well.

Mine went into 4 Low once after the last time from trying to cycle through everything, it seem to work fine after that. For about 5 minutes. Now it says it is in 2wd, but I swear it was in 4 hi based on the way it was driving, steering and braking. Only getting the Service 4wd light now though. My MPG also dropped to around 12 MPG at one point. After a day or so it seem to drive better like it was in 2wd again, and my MPG went back to normal. There is another post in the Warranty TSB section, I am jumping into another thread in there since it is similar to mine.

 

[Ram1992]

Well I just experienced this. Wife claims the truck felt it was in 4wd so she pulled over, stopped the truck and now the truck won’t engaged in 4wd. None of the 4wd or 2wd lights are lit up. Guess truck is going to the dealership.

 

[Ram1992]

You are significantly farther north than I am, but I am still having issues. I am wondering if it has to do with temps, I am not getting the temps you are but it's been around 30-40 lately here, at this point I am reaching. I am taking it back for the 3rd time Monday, supposedly they have the foreman on it this time with the lead tech with FCA's Star Engineer's as well.

Mine went into 4 Low once after the last time from trying to cycle through everything, it seem to work fine after that. For about 5 minutes. Now it says it is in 2wd, but I swear it was in 4 hi based on the way it was driving, steering and braking. Only getting the Service 4wd light now though. My MPG also dropped to around 12 MPG at one point. After a day or so it seem to drive better like it was in 2wd again, and my MPG went back to normal. There is another post in the Warranty TSB section, I am jumping into another thread in there since it is similar to mine.

Can you post the link to the other thread?

 

[hsoler]

This happened to me when I bought mine in September, while in park try cycling it starting with 4low, 4high, 4auto, then back to 2, for some reason that worked for mine, haven’t had a problem since ‍

Works on new 1500 RAM also. Drove it home from dealer two days ago and today we had snow--and no 4WD. AARGH! Thanks for the information!

 

[hsoler]

OK, so here we are with the biggest snow of the year, and the 4WD now stuck in AWD--cannot move it to 2WD or 4High, which is what I need. Switch does not cycle like it did the first time. Yes, very cold--10-25F. Even this it looks stuck in AWD, it is not in 4WD at all. I didn't buy a new 4WD truck to play slip and slide in the snow. Anybody have an answer or good experience with the service dept?

 

[saylor]

brutal. i dont know if will help any but back in the day you used to have to reverse and back up about 10 ft to get everything to line up so you could lock/engage the hubs.

and since imma boomer id never trust on the fly. id do it in N so all the transmission bits are not under any load anywhere.

i dont know if it applies to this newfangled stuff, but you could rock the truck if its kinda stuck or in between on one of the drive legs.

good luck

 

[redneck]

their have been some others with this problem try selecting 4 low first in N if that works then work your way up to 4 hi then auto then 2 wd

 

[Ajwood405]

This happened to me when I bought mine in September, while in park try cycling it starting with 4low, 4high, 4auto, then back to 2, for some reason that worked for mine, haven’t had a problem since ‍

Can you please walk me through this? I’ve tried and tried and it’s not working. Do I need to start in neutral or park? And do hold low first, then once it’s blinking change to high and so on? It won’t engage even in low

 

[saylor]

are you somewhere cold by chance ?

 

[Ajwood405]

Hey

Anyone have issues switching into 4wd? Today is the first day since buying the truck the opportunity presented itself with snow coming down here in the northeast. However, 4wd would not engage for me.

While driving I tried switching into Auto 4WD. After blinking for a few seconds it would fail to engage telling me to retry. Of course, the retry failed also. Same thing with 4WD High. Pulled into a parking lot and tried again multiple times, this time trying to engage while in Park, Neutral, and Drive. Could not get it to work any of which way. The truck eventually displayed “Service 4WD.” I shut the truck off and went into Home Depot for a bit. Came back out, service message gone, reattempted engaging Auto 4WD and 4WD High going through all the same steps above. Could not get it to work and received a service 4WD message again.

Obviously not happy. I left a message with my salesman. Slid the whole way home. *** end would kick out on start. This truck sucks in 2wd in the snow.

Can you walk me through the steps to fix?

 

[d_THRILL]

Hey

Can you walk me through the steps to fix?

First put truck neutral, press and briefly hold down the 4wd low button, then repeat for 4wd high, 4wd auto and then 2wd. Should resolve any issues.