Rats. Regardless, there's one thing to do first, but this is mainly after the battery was disconnected or run dead. That is to drive it at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals. That will meet the conditions needed to relearn "minimum throttle". That is the only thing that doesn't get relearned automatically, without you noticing.
If that doesn't help, we need to look at the "idle steps" on a scanner under the "live data" menu. That pertains to the automatic idle speed motor, (idle air control valve). The Engine Computer can set that to any of 256 "steps" to adjust idle speed. For a properly running engine, expect it to be close to step 32. If it is significantly higher than that, the computer is trying to increase engine speed, but without success. A good suspect for that is an air passage around the throttle blade that's blocked with carbon. Haven't seen that much since the '90s thanks to better additives in today's gas.
If it's at a much lower step number, the computer is lowering idle speed in response to something. We have to identify that something.
If the idle steps are at "0", minimum throttle hasn't been relearned.
Chrysler made reading the diagnostic fault codes much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds, without cranking the engine. Leave it in "run", then watch the code numbers appear in the odometer display. You can go here:
https://www.2carpros.com/trouble_codes/obd2/p0400
to see the definitions, or I can interpret them for you. Let me know what you find with these things, then we'll figure out where to go next.
Wednesday, July 12th, 2023 AT 6:55 PM
