Launch control help

[Slorango]

I’ve already uploaded complete BCM backups from 2023 392 Premium Durangos with no luck unfortunately.

[dodgeboy]

Is there a Chassis type? and is it the same as your Chassis type? if you change it, you might have to reinitialize the ABS module like in my car. Whatever you do, do small changes so you can revert back.

[dodgeboy]

I only used launch control 1 time in my Challenger R/T and on the street it did nothing except send my tires up in smoke running a 12.9 spinning all the way with my car's timers.

[Slorango]

The 392 and TnG have the same chassis type. I’ve also tried the Hellcat chassis type with no luck. I’ve tried every combination possible. Right now I’m running a full 392 BCM backup from an exact Durango as mine, so even if something was not mapped out in Alfa it should still be in my BCM.

[Stoopalini]

Yep, the Durango SRT 392 and the Durango R/T with Tow N Go package both share the same chassis type ID. I've also tried the Hellcat chassis type ID, followed by an ABS reinit, and it didn't work.

When I snooped the IHS canbus, I can see the "Launch" enablement message coming across, so I know the uConnect and ICS are sending the right messages. Either the BCM isn't forwarding it to the C Bus (doubtful) or there is a dependent module which needs to respond, and is not.

Could be the ABS unit, the TCM unit, or the suspension controller. My money is on the ABS since it is a different part number than the SRT 392, which the TCM and suspension controllers are shared.

[Slorango]

I’ve been contemplating switching out the ABS module, just not sure if it’s worth it, I have a few saved on EBay.

[Stoopalini]

Considering the shift light doesn't trigger the cluster illumination either though, maybe it is in fact something else? The shift light shouldn't be dependent on the ABS ... hmm ...

[Slorango]

I’m still wondering where the UConnect gets the information from to populate the shift light settings, because it’s not the same as a 392 or Hellcat. The default shift points are really low, the max is 5,500, and the reset to default button doesn’t work. I’ve read about BMW guys with ZF transmissions having shift light problems and it was in the TCM, but I don’t know if our Durango’s use the TCM, or if the UConnect populates from the VIN.

[Stoopalini]

So the Hellcat TCM OS has some extra things our OS doesn't have, like a Stall Speed section, a "Burnout Detection" section, and a few other things.

I haven't found anything in the Hellcat's TCM related to launch, but it doesn't mean it's not in there somewhere. When I started tuning the PCM, I found all sorts of mis-mapped things. HP Tuners would fix them when I submitted tickets, and after several of these tickets ... they eventually did a holistic review of my OS and found over 300 missing and/or mismapped items. I asked them to do the same holistic review on the TCM OS, and they said it was fine though.

[james1595]

I want a way to active the line lock like the 1320 and demon have. But as far as I know, it's connected to the radio, so you'd need one from that model challmeger

[dodgeboy]

I want a way to active the line lock like the 1320 and demon have. But as far as I know, it's connected to the radio, so you'd need one from that model challmeger

I used a TaZer at the tack for line lock. These changes are in the BCM and HP Tuners can not modify that.

[james1595]

Sorry, I didn't mean line lock. I meant the trans brake.

[Stoopalini]

I was thinking about this a bit more today, and I wonder if the same root cause which prevents the additional Hellcat gauges from showing up in performance pages is also preventing Launch Control activation.

I initially tried to find the PID and canbus message info for the Hellcat's wideband data on the canbus (which populates the perf pages gauge). I was then going to try and configure my AEM X-Series wideband to communicate using the same ID and structure, or if that wasn't possible, I'd use my custom microcontroller to generate the messages myself; but I never could get the AFR gauge to show up in the uConnect performance pages even with everything in the BCM set to values mirroring a Hellcat.

I'd bet whatever is preventing these additional gauges from appearing is also preventing launch control from activating.

[LilSick]

i dont have a wide band gauge but my launch control works

huge wheelies

: )

[Slorango]

I think its either something in the ECM OS or the Unconnect is configuring itself off of the 2 digits in the VIN that tell the engine size. Since they all use the same Unconnect software it’s in there, it’s just not populating. Id like to get the boost/vac gauge to populate but idk if its possible. I tried changing the engine size in the ECM to 6.4 to see if it would change anything in the Unconnect, including the HP and TQ max on the virtual engine dyno, but it didnt change anything.

[Stoopalini]

Have you tried flipping ECM [199] (Supercharger Equipped flag) to "Yes"?

This might trigger the Hellcat gauges to appear, but will result in the PCM expecting MAP signals on the PCM pins for the 3 other missing TMAPs. It might also trigger errors due to the missing wideband signals and the missing H-Bridge controller the HC PCM has to control the electronic bypass.

A previous tuner I worked with (who has inside knowledge of the GPEC OSes) put together a modified OS for me some time back to try and get some of the fields on that Supercharger page to function without flipping ECM [199] to "Yes". It did work, but it didn't solve the issue we were trying to address at the time so I reverted back.

So if flipping ECM [199] to "Yes" does in fact allow the gauges to appear, I could reach out to him and see about a modified OS to enable whatever it is triggering off of.

[Slorango]

I haven’t tried that but I thought about it, I didn’t want to fry the ECM somehow by it reconfiguring pins or something, even though I doubt it would. Maybe I’ll try it.

[Stoopalini]

I don't think it is going to reconfigure any pins. The pins for the extra sensors are unpopulated on our R/T harness. Some guys have populated the pins for various functions, but I haven't seen anyone try to populate all of the ones missing to use the Hellcat TMAP and Wideband sensors. You wouldn't be able to use the bypass controller, as the physical H-Bridge circuit needed for the PWM control is missing from our PCM; but the software is there.

PCM Wiring for Hellcat Supercharger wiring: HC_Supercharger_PCM-Wiring.jpg


PCM Wiring for R/T MAP Sensor wiring: RT_MAP_PCM-Wiring.jpg


PCM Wiring for Hellcat MAP Sensors Wiring: HC_MAP_PCM-Wiring.jpg

[Stoopalini]

Here's an XLS doing a quick compare of the pin-outs. It's not all the PCM pins, but the ones I think where there would be differences.

I didn't find the PCM pin locations for the wide bands though, as I ran out of time to continue looking.

PCM_Wiring_Compare.xlsx

[Slorango]

I’ll consider flipping the supercharger switch and see if anything changes in the Uconnect. The more I think of it, the only physical electronic part that’s different between ours and the 392 Durango is the ABS module, and I’m assuming it’s different for a reason. I might just have to order a used one off EBay and see what it does. It was also used on other vehicles other than the 392 and HC Durango, I wonder if the programming on them is all the same?