ESS Generic Priority Function

[JTL21]

Let me start by saying I did perform a search with little to no results. Also, I’m not interested in deleting aux battery or disabling the ESS functionality. What I’m after is a deeper understanding of what influences the system.

Having said that here’s my situation. Every now and then the ESS shows “Not Ready” with no further details. The truck is warmed up, sometimes HVAC is on other times it’s not, battery SOC is >91% and SOH is usually around 64Ah. I’m using OBDLink MX+ and there are somewhere around 75 parameters available to monitor related to the ESS Deactivation status in the ECM alone. One of them is “Stop & Start Function Reversible Deactivation- S&S Deactivation for Generic Priority Function…”. In the occasional situation when I expect ESS to be available but it’s not this flag is set to 1. When ESS is available this flag is 0. Trouble is I don’t know what that parameter actually means. Does anyone know what the possible scenarios are that can cause that parameter to go high and prevent ESS from being enabled?

For the record I have new batteries installed (not Mopar either) and this is a ‘21 JTOD with no mods.

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[Mr._Bill]

ESS monitors all the systems in the truck. There is no clear listing, that I'm aware of, that details what will affect activation.

Common items are Low Voltage, Seatbelt not buckled, CEL, Misfire, Wheel turned, and Cabin Temperature.

 

[JTL21]

What I find interesting is that the list of parameters in OBDLink is quite extensive and discretely lists the things you mention plus a ton more but it has this one “Generic” parameter that seems to be the outlier. The SCR system has a parameter that is the reason it’s deactivated occasionally as well but I’m curious what the generic parameter represents.
Could be only stellantis knows and they won’t tell me?

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