2015 RAM 1500 5.7 intermittent passive entry issue

[ebirotedu]

Hi guys,

I've owned a 2015 RAM 1500 Sport (Crew cab, 4WD, 5.7L Hemi) since purchasing it new nearly 6 year ago.

Lately, I've been having a lot of problems with the keyless ignition and have spent a good bit of money at the dealership trying to resolve these issues.

To be fair, the cab had 2 water leaks, both of which took a while to find (rear sliding window seal & drain holes (clogged during initial assembly most likely - so RAM's fault, apparently), and rear exhaust vent port cracked seals).

Today the truck's passive entry didn't work, and when I did unlock the cab with the key fob button (worked fine 1st time), keyless ignition didn't work and I had to hold the key up to the starter button. I've had the truck back from the dealer for about 3 weeks now, and have been using it maybe 2-3 times a week (I work from home). Today is the first time the keyless entry on the driver's side & keyless ignition didn't work. The battery in the fob is 2-3 weeks old, so I don't think this is the problem (I've replaced the battery countless times in the past 6 months, and it's never made any difference).

Two questions for forum denizens:

1 - Does anyone know why the keyless entry & ignition (keyless entry means not having to touch or hold the key fob to unlock, and keyless ignition is the same as it applies to starting the truck) would fail when the fob still works? My understanding is that the wireless key module (and mine is brand new as of visit #2 to the dealer last spring) is responsible for detecting the key. But if it works for the active key transmissions, which it did today when I unlocked the cab with a single press of the unlock button, why didn't it work for passive detection? I'm pretty sure if I were to bring it to the dealer and the put the code reader on it, they'd tell me that they could see that the wireless module showed disconnects from some of the antennae - but the diagnostic tool wouldn't tell me why, and that's where we'd be absent someone with some automotive electrical skills (which seem to be in short supply) doing some troubleshooting.

Kinda' concerned that passive key detection is going to lead to complete failure to detect the key under any circumstance (another wireless radio module failure), which is what had me leaving the truck at the dealer back in February in the first place. If the only thing wrong with my RAM is that keyless entry & ignition stop working, I could probably live with that, or at least troubleshoot it at my leisure. But this is too much like what happened 6 months ago for me to think so, where it was unusable on account two failed modules (WIN and wireless radio module).

2 - Any recommendations on where I might find wiring diagrams for the truck's electrical system so I could try to troubleshoot this issue myself? As I've noted, the truck has been to the dealer 5 times going back 6 months now, and my problem still isn't resolved in spite of having spent a good bit of money to fix it.

3 - If anyone happens to know of a good automotive electrical mechanic or shop in the Atlanta area, let me know. This problem seems to beyond the ability of my dealer to resolve.

Thanks in advance!

-Ted

 

[KDT1970]

Have you tried a new FOB?

 

[ebirotedu]

Yes. I've replaced the batteries numerous times. I've tried both fobs. I've replaced the WIN module which required replacing both key fobs.

It's not the key fobs.

 

[crash68]

When you state wireless key module, are you referring to the button in the dash?
I'm wondering if there a problem with the RF Hub module that's mounted on the back wall of the cab(behind the seats(driver's side).

 

[ebirotedu]

Both modules (WIN - starter button & RF Hub - Wireless Radio module) have already been replaced once since this problem first occurred.

What I don't understand is how the active key fob transmitter worked today when the passive entry and keyless ignition did not. When the RF hub/wireless radio failed (per the dealer's diagnosis) and was replaced, the truck wouldn't unlock or start reliably (even though the WIN module had been replaced and the keys fobs were new).

Maybe the dealer was mistaken regarding the problem when the RF hub was replaced the first time. Does anyone know if the active key fob transmitter and touching the key to the start button would work if the RF hub were broken? Put another way, is the RF hub only for passive entry & keyless ignition?

 

[ebirotedu]

Update on this. With no obvious course of action to pursue on my own, and given time & money already spent at the dealer to diagnose & fix the issue, I ended up dropping the truck off at the dealer again.

Long story short, the dealership did (I think) a good job in tracking down the culprit. They believe it was the engine junction connector (normally mounted on the driver's side firewall under some cladding), which was found to be full of water. This likely due to some cowl drainage issues (since fixed) and that I park nose down on a hilly driveway. The connector has been relocated away from the firewall and tethered to a location a few inches behind the battery, also well away from the inner fender.

Shorts in this connector would explain the all of the various bus error codes that would appear intermittently, including the most egregious: transmission gear position sensor failure, which caused the engine to shut off 4 times total on 3 separate trips. (didn't mention this in my original post, but these failures made the vehicle unsafe and undriveable - 3 failures happened on 2 trips back to the dealer - spooky to say the least when you're sticking to the right lane and identifying safe places to roll off the road onto the shoulder so you can stop, put it in park, and attempt a restart...)

I won't know for sure until I've had the truck back for a few weeks, but hopefully, this is my last post, and maybe this information will be of use to someone else in the future.

The moral? Don't park on a hilly driveway if you can avoid it. And if you do, make sure your cowl drainage isn't getting clogged up with disintegrating bits of leaf and other tree detritus. It's a little disappointing that the drainage design didn't account for parking on an incline - it's not like there's any secondary covering on the junction connector to keep water from running onto it. But my experience of parking on an incline (let's call it a 15% or 20% slope) is probably not what 99% of other owners are doing, so extra cost for secondary protection against water getting into the connector was likely deemed unnecessary)

 

[Mister Luck]

I have a one inch strip of adhesive backed weather stripping on the driver-side ( left ) that looks like an after thought to prevent some type of water intrusion across a gap between the cowl and the back of the hood ( engine bonnet ) cover .

Thank you for posting the fix to your issue.

I have noticed the opportunity for moisture to be either trapped both either in and around this side of the engine compartment and adjacent electrical components. battery / fuse box

It is a common theme with manufacturers and their design issues that were abandoned for the sake of production costs through labor and or parts availability.

Either earlier models or later ones with parts revisions can you find the solutions but for an interim those same models with excluded covers, seals ect can be fixed by a dealer or shorten their useful life as a vehicle.

 

[BossHogg]

Both modules (WIN - starter button & RF Hub - Wireless Radio module) have already been replaced once since this problem first occurred.

What I don't understand is how the active key fob transmitter worked today when the passive entry and keyless ignition did not.

New doesn't mean working.

The FOB is two different radio frequency units in one device, the typical FOB functions like lock, unlock, and panic are on a transmitter in the 330 MHz or 433 MHz range.

The passive entry and keyless start operate on a lower frequency. When you grab the door handle or press the engine start button, the RF Hub sends out a signal at around, if memory serves me, 120 MHz with coded information the passive system in the FOB will recognize. In turn, the FOB's passive circuit will send out a coded response that the truck expects and then will execute the function.

The passive entry uses antennas in the doors of the truck, the keyless start uses interior antennas.

When the keyless start fails, does using the FOB to push the start button work? Your issue could be antenna related.

 

[ebirotedu]

New doesn't mean working.

The FOB is two different radio frequency units in one device, the typical FOB functions like lock, unlock, and panic are on a transmitter in the 330 MHz or 433 MHz range.

The passive entry and keyless start operate on a lower frequency. When you grab the door handle or press the engine start button, the RF Hub sends out a signal at around, if memory serves me, 120 MHz with coded information the passive system in the FOB will recognize. In turn, the FOB's passive circuit will send out a coded response that the truck expects and then will execute the function.

The passive entry uses antennas in the doors of the truck, the keyless start uses interior antennas.

When the keyless start fails, does using the FOB to push the start button work? Your issue could be antenna related.

Thanks for explaining the RF Hub's role in passive entry. The dealership said the antennae are all working but that components would sometimes disconnect from the electrical bus (codes would be evident from an OBD2 diagnostic), which is why passive entry would sometimes fail on the passenger side door, but work on the driver side, indicating that the passenger antenna had dropped off the bus; and other times passive entry would fail entirely along with keyless ignition, meaning the RF hub had dropped off the bus.

 

[BossHogg]

I would have to assume the water leaks are the root cause of your issues. Maybe the water got into the connectors and cause corrosion on the circuit boards of the modules.

From what you have provided, my best guess is your dealer is not diagnosing the root cause of the issue but just draining your wallet.

 

[ebirotedu]

I would have to assume the water leaks are the root cause of your issues. Maybe the water got into the connectors and cause corrosion on the circuit boards of the modules.

From what you have provided, my best guess is your dealer is not diagnosing the root cause of the issue but just draining your wallet.

That was my concern when I asked the dealer why my WIN and then RF Hub modules had failed (replaced on two consecutive visits a month apart), thinking that the failures were symptomatic of another problem that had not yet been diagnosed. At the time, I was assured that my problem was fixed.

However, per my post above from last Thursday, I think they did finally identify the root cause:

"Long story short, the dealership did (I think) a good job in tracking down the culprit. They believe it was the engine junction connector (normally mounted on the driver's side firewall under some cladding), which was found to be full of water. This likely due to some cowl drainage issues (since fixed) and that I park nose down on a hilly driveway. The connector has been relocated away from the firewall and tethered to a location a few inches behind the battery, also well away from the inner fender.

Shorts in this connector would explain the all of the various bus error codes that would appear intermittently, including the most egregious: transmission gear position sensor failure, which caused the engine to shut off 4 times total on 3 separate trips. (didn't mention this in my original post, but these failures made the vehicle unsafe and undriveable - 3 failures happened on 2 trips back to the dealer - spooky to say the least when you're sticking to the right lane and identifying safe places to roll off the road onto the shoulder so you can stop, put it in park, and attempt a restart...)"

I wasn't charged for the last visit, and I estimate that they must have spent a minimum of 4 hours shop labor - I think it was likely more time given that they pulled apart the cab interior to get at the wiring harnesses to check for moisture. The shop foreman was also driving my truck to and from work as part of his daily commute (at my request) for the better part of a week, to see if they could reproduce the transmission gear position sensor failure. Ultimately, I think the money I paid up front to replace those two modules, and charges for a water leak test & replacement of the rear cab vents back in June, bought me some goodwill when problems persisted.

Anyway, it's been raining off and on here since Thursday or Friday, and I've been driving it pretty much every day, running errands, and parking it nose down as per usual. The junction connector doesn't seem to be getting wet in its relocated position, though I will need to keep an eye on that (i.e., what happens if I park nose up, or on a level surface?). Still feel like I'd be happier if I can fit a water proof cover/container/shield with some vent holes on the bottom, just in case some stray water splashes into the engine compartment. Probably won't feel confident that the issue has been fixed for certain until I wake up one day and realized I haven't thought about it for a few weeks.

 

[ebirotedu]

Alas! Truck went back to the dealer yesterday. I had used it for roughly a week and a half with no problems/issues - passive entry and keyless ignition worked fine. I used the truck almost daily, and put 150 miles on it.

On Sunday it sat idle all day.

Then on Monday, passive entry failed to work on either door, and keyless ignition also did not work. But the fob unlocked it fine, and it started when I held the key to the starter button. I ran a short errand, parked it for 10-15 minutes, at which point I returned to the truck and passive entry and keyless ignition worked. Parked it for a few hours, and passive entry / keyless ignition ceased working but the fob would unlock & start when held to starter button. Same behavior on Tuesday.

On Wednesday behavior was the same, but after I started it and while it was idling in park the engine simply shut off. Did not get an engine light. Electrics all stayed on (fan blowing, UConnect screen showing, music playing, dash lit). It restarted with the key against the starter button no issue, but that spooked me enough to drive it straight to the dealer.

It did rain a bit over the weekend off and on. No evidence of water anyplace I can detect in the cab or in the engine compartment and the junction connector is dry.

Was really hoping it was fixed this time.

 

[ebirotedu]

Latest update:

The dealer spent some time checking power from the TIPM to various systems and eventually determined that a power lead between two connectors in the cab wiring harness was the cause for the RF hub to intermittently disconnect and finally fail completely. They theorize that water may have gotten into that section of the harness and spliced in a new power lead between connectors. The keyless issues (door access & ignition) appear to be fixed now - that the connector finally failed completely made it possible to track down. Admittedly, I’m still a little hazy about how the RF hub failing would cause an already running truck to simply shut off without throwing a code, but that only ever happened once as mentioned in my last post. Anyway, they put 80 miles on it and didn’t have notice any further issues.

For now, I’m hoping that this is the end of the issue. Only time will tell!

 

[ebirotedu]

Posting a final close-out on this issue:

Keyless entry & ignition have worked flawlessly since my last post in September. Even took a 2500 mile out of area round trip a few months ago and had no issues. That was a big test and a huge leap of faith after months of back and forth with the dealer last year.

However, even a few weeks after the fix, water was still finding it's way into the cab at least some of the time when it rained, and the leak test tech at the dealer was unable to find it when I brought it back again in September. There's no doubt in my mind that moisture getting into the cab was the cause of my keyless entry/ignition issues so I didn't want a repeat.

Watching the tech do the leak test on an incline ramp (simulating my driveway) at the dealership, I noted that he was only using a garden hose worth of water volume to simulate rainfall.

In retrospect, I concluded that during especially heavy rainfall (like a thunderstorm), parked nose down at a 15-20 degree angle, and because I have a tonneau cover on the bed, that there was likely a rather large volume of water sheeting into the cab-bed gap and right onto those cab exhauster vent ports. As those port fixtures have a small lip on the outside to anchor them onto the cab wall, I think that if there's enough water hammering them some of that water will find a way past the one-way vent ports and into the cab.

So, in October, I started parking the truck nose up unless loading or unloading into the garage, and I have not noticed any moisture in the cab since. This includes checking the carpet, looking for condensation on the inside windshield or windows, and checking for any damp/musty smells.

Relieved that this is resolved. I guess my 'use case,' that of parking outside, nose down at an incline, and with a tonneau cover, isn't particularly common. Glad to have my truck back!