How often or when would a Jeep owner know software modules have to be updated?

jeepster789jeepster789 Member Posts: 2
edited August 2014 in Jeep

I own a 2006 Jeep Grand Cherokee Limited 4X4. Recently when the A/C runs RPM's drop upon deceleration by 800-1000RPM's or when idling too long (long red light) 500 RPM engine quits. One mechanic stated he could not replicate the problem therefore he sent me on my way. One week later, the Jeep stalls and wouldn't start. Rested on side of road for apprx 10 minutes, started with engine light on, drove directly to Jeep dealership, over $200 later, I received this receipt: Technician performed powertrain control module software flash update, Technician performed flash updated the FDCM module software. Technician who worked on the Jeep was gone for the day---NO ONE could answer-
1. what the heck do these updates mean?
2. when were they to be performed in the first place?
3. are any of these within any recalls?

Help with answers would be great.


  • jeepster789jeepster789 Member Posts: 2

    I was not the original owner, therefore when I purchased this Jeep, I reviewed the history of the Jeep I was purchased and found all necessary recalls were completed. I am unable to find a cause for the RPM deceleration and essentially engine shutting down, and now the engine light on. The PCM and FDCM modules do not give an explanation of why this is occurring while the A/C is on. My thought is the updating is only a part of the problem not the source of the deceleration and engine shutting down. What would cause these problems to occur...outside of the modules being updated?

  • eliaselias Member Posts: 2,209
    the update mentioned in previous post does not address the described symptoms. these updates are usually considered 'technical service bulletins' for which the public misnomer has sometimes been 'secret recalls'. they aren't secret. you can research/track them for any vehicle/model/year/manufacturer. to know the details of each software update beyond what is announced in the technical-service-bulleting/release-notes is unlikely without disassembling - aftermarket jeep tuner shops would know that info and some info may be online in jeep forums.
    as for the symptom of engine shutting down/off while driving, and decel to stop, it does sound like software issue could be involved with that. for the symptom of trouble idling at stop/lights with A/C running, that sounds like a possible issue with an item called something like "idle-air-control pump". if idle-air-control pump were not operating correctly, it is conceivable that the software would get confused enough to shut off the engine unintentionally if not intentionally. what are the OBD codes "thrown" after the issue occurs? btw, there can be stored codes without the light being lit. also, an issue with idle-air-control/pump/circuit could be a problem while idling down the road at low speed in top gear too, for example.
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