Module programmer, intermittent no-crank

Hey Randy,

Just to address the programmer on these Chrysler vehicles, it is most likely not going to work as WiTECH (OEM tool) is not just programming the VIN. These programmable modules require the VIN and build configuration to be loaded into them and that has to be downloaded from the Chrysler servers. So, you cannot just program the VIN in and have it "programmed."

There are aftermarket tools that can program these modules but not the ones that you named that I am aware of.

So, to address what may be happening, these trucks have a TRS signal that goes from the shifter (6 speed) to the right front hub and TCM. If this signal is missing, then you will get a no crank no start like you are. So, you want to monitor the TRS signal with a scan tool in the TCM. If you have an 8 speed then this is contained in the TCM/valve body.

However, there are also known wiring issues that will cause the same thing. I am attaching a number of documents from FCA that will point you to these known wiring problems.

Let me know what you find with this, and we can go from there. Thanks

Thanks a whole bunch, Kenny K. I think we have it solved. Now, the next step is to try to figure out exactly what the issue was. I know I typed a lot, but I may have forgotten to include some important observations. Most notably, this was not a starter system problem. It was a miscommunication problem. Of course that is what I'm least familiar with.

The owner's is a 2015 truck and has factory-installed remote start. My truck is exactly identical but it's a 2014, so I recognize what normal operation is. When working properly, you can hop in the truck, turn the key fob, and the engine cranks and runs. No need to close doors. No need to push the brake pedal. In fact I typically stand outside and reach in to start the engine.

Next, if you use the remote start on the key fob, press the button twice, the doors lock, the engine cranks and runs, then, you unlock the driver's door or all 4 doors with the key fob, put the fob in the ignition switch, turn it to "run", and the engine stays running. I know this sounds stupidly simple, but the process did raise questions when I was helping my friend on other car brands.

Finally, when the defect occurs, the engine will not crank from the ignition switch, but it always starts and runs when using the remote start feature. That proves at least part of the starting system is okay. With the defect occurring, and the engine running, the doors are unlocked with the key fob, stick it in the ignition switch socket, then the engine stalls when it is turned to "run". At that point it will not crank from the ignition switch. Wait 15 to 20 minutes, key fob in the ignition switch or in your pocket, and 99 percent of the time it will crank and run like normal. One point of confusion is we have to suspect the defect occurs randomly while we're driving, but once the engine does crank and start, it has never ever stalled while driving. We made a two-hour road trip yesterday to a salvage yard. Didn't stop the engine. Another two hours to home. Engine never stalled. Stopped in the shop, turned the engine off, then five seconds later it would not crank. Ten minutes later it cranked and ran fine.

Another observation was when the defect occurred, the Radio Frequency Hub and the Body Computer both showed on the scanner the output commands switching to "crank" when the ignition switch was turned to "crank", but while the starter was inoperative, it would crank if I squeezed the starter relay contacts, but the engine would not run. It was a crank / no-start. Never tried that when the defect was gone. So this was more than a starter circuit problem. This is where it appears the Body Computer sends 12 volts to the "Ignition run / start" relay in the PDC / TIPM, that relay switches on, then among other places, it sends 12 volts back to the Body Computer telling it the relay did indeed turn on, then the BCM turns 12 volts onto the second line that turns on the two starter relays. I think it's that returning 12 volts from the "ign run / start" relay that's missing. Given the tiny size of those relays, and my previous experience with relays in car radios, I'm pretty sure those are why these modules cause so many problems.

I'm going to try to figure out which is that "ign start / run" relay and focus on that, but that leads to another question. If the engine won't run when I squeezed the starter relay contacts, presumably because that return 12 volts was missing, why doesn't the engine stall while driving when that defect occurs? Could it be the relay contacts are okay, but that 12 volts leaves on multiple wires for multiple circuits, and only the one going back to the Body Computer has an intermittent break? Remember, the only fault code was "implausible data from the Radio Frequency Hub Module". That code was in the Body Computer. I'm thinking the RF Hub is telling the BCM to "crank", the BCM starts to act on that, but the returning 12 volts from the PDC is not there, therefore the two signals disagree, setting that fault code.

This was definitely a learning experience, and I didn't realize that this was a crash rebuilder seven years ago. The TIPM was in the area of damage but it wasn't replaced. Let me pause right here and ask, is "TIPM" the right term, or is that different from the "power distribution center"? The used module appears to have solved the problem. Now I'm on a mission to learn what went wrong. It did not need to be programmed, and in taking it apart, I found there are no electronics in it. Two diodes, a few resistors, tons of fuses, and a dozen small relays. Can't store fault codes. It's just a fuse / relay box. Can't read or send digital data on its own.

Three attempts at two dealers with two new RF Hub Modules right from Chrysler could not be programmed to work in this truck. Still confused about that. I forgot that software has to be loaded in along with the VIN. People are saying there's a place that sells a new RF Hub with two new key fobs for $400.00, and it's all programmed to be plug it in and go. I don't know if they ask for engine size, other optional equipment, or things like that. Other modules can be ordered already programmed. My friend says he has done that about a half dozen times per year. They don't always come from a Chrysler dealer.

As a side note, we're also working on a 2019 Cherokee, smashed pretty hard in the left front. Body Computer was broken. A used one from a salvage yard worked as soon as it was plugged in. Transmission Computer was also broken. Used one from salvage yard would not communicate with the scanner or any other modules. Here's where I learned more than I wanted to about the Can C buss, but we were chasing false clues and misinformation. Turned out to be a defective module. He popped in a new one from the dealer. Now it is up and running but we get an error message saying there's a "VIN mismatch". We finished bolting it together, then he's taking it to a dealer next week to have that computer programmed.

My last question has to do with the Snapon Solus Edge scanner. We each have one, but only my friend's has been updated regularly. For the first time, he has had to pay an extra $100.00 charge to connect to his wireless internet. That gets him into some unknown web site that allows access to a "Secure Gateway". He claims what he purchased only applies to Chrysler products; no other car brands. I'm wondering if that is getting him into the Chrysler web site and if that will allow him to install software into modules. My confusion came from the name "gateway". Snapon is headquartered in Kenosha, WI. One of our technical colleges is named "Gateway Technical College", and it is also in Kenosha. The school built a new, freestanding automotive shop and aviation shop next to the local airport, and it was partially funded by and totally stocked with Snapon equipment. Chrysler also uses a module called the Cental Gateway Module that I'm told only Chrysler dealers can access. It's a security measure, and they say that module won't even be listed on aftermarket scanners. I might have some information wrong, but regardless, the term "Gateway" is confusing.

I'm very sorry for being so long-winded, but thank you again for thinking about this. You're truly a wonderful human being. I appreciate any knowledge you can toss my way.

So, you are running into what we call the Security Gateway Module. This was Chrysler's attempt (successful attempt) at blocking hackers from getting access to the vehicle via the radio. This SGW is nothing more than a locked iron gate that will block all attempts to gain access to communicate with the vehicle's modules.

To be clear this is not on the 2015 DS truck that this post was titled but it is on the 2019 KL that you mentioned in the last response.

So, the SGW is programmed to recognize pre-determined scan tools and programmers. All others will not have access. So only the scan tool companies that applied to Chrysler to be on the approved list will be able to communicate with the vehicle.

So, your friend is correct that Chrysler is the only one that uses this so if he purchased a program that will gain access then this should work.

If it's not or you are having other issues with it, then let's get a post started on that one because we can figure something out on it.

Dandy. I think the 2019 will be handled shortly. I just added that as it referred to programming modules, (and to show how smart I are).

Friend also said he found something online about bypassing the Secure Gateway Module with a temporary jumper to connect two plugs together. That's supposed to allow scanner use for codes and data to be retrieved, then you put the module back when you're done. Don't know if that's right or not.

Nope. There are ways to connect a module, but you don’t want to bypass it.

Basically, all this is doing is putting a fence around the CAN bus networks of the vehicle. If you have physical access to the vehicle, then you just tap into the CAN via a star connector or other means. Bypassing it can cause issues on the bus and you may be chasing ghosts that you create.