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PCM/TCM Flash update possible cause...

18K views 16 replies 8 participants last post by  Beitie 
#1 ·
Apologies in advance for such a long post...

On 6/28/16 I went to dealer for oil change. After completion the service writer told me they updated my PCM & TCM. I asked him what was changed? He repeatedly told me "software update." (At the time, I was unaware of any updates & what they changed/updated) At this time, I explained I wasn't the typical "dumb blonde" (no offense to anyone) and I not only know cars, I know computer IT. To which he just looked at me confused. I explained that software updates (car/computer) are made to try and fix any issues a computer may have. And, when dealing with cars that run almost everything by computers; the updates should have either 1) updated to fix any computerized mechanics, or 2) improve performance. So I asked again, what changes were made? If none, why was it updated? He continued to stare at me confusingly and said it "just updated the software." At this time, seeing my frustration and the service writer sweating; another service writer stepped in. He explained to the first guy that "normally, customers don't know anything about these type of things and so they don't ask questions." Then looked at me and said, "we aren't sure what the update was for and we'd have to look into it if you'd like specific information." I explained to him I wasn't a "normal" customer and not to bother with it. (Thinking I could look up the info online; my mistake)

Now on to my issue. Leaving the service center I immediately noticed my initial acceleration from stop was significantly worse with its lagging (has always had a slow start). This issue, aside from annoyance, I was willing to deal with. After several days, I noticed that it shifted gears hard/late (automatic and manual). The newest issue I found, the "range to empty" has seriously dropped. Today I filled my tank and the range said 160 to empty; before the update it read anywhere between 270-320 to empty. I haven't seen a huge impact on my mpg read, while in city, says around 20; depending on conditions (traffic, weather, etc.).

Has anyone else had this issue? Can anyone explain why/what could be wrong? Did they have the right to update without informing/asking me?

Please look at the pictures; both the gas needle and range to empty.
 

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#2 ·
Typically any bcm, ecm, tcm, etc. update "resets" everything to baseline as these are adaptive systems and take some time to re-learn your driving habits and style. This would explain trans and throttle changes you are experiencing. As for the DTE, it uses a "rolling average" of your mpg to calculate the range. This may have also been cleared / reset during the process.
Had my '16 GT in at 900 miles for an alignment issue and they also performed an update with no warning...in my case the throttle response became sharper and much more like my '14 GT was...now over 3900 miles and no noticeable changes to me!
 
#3 ·
An update will not reset to baseline. That's why it's an update. It will re program to the updated file. They have to ask you if you want a TSB update. The only thing that they have to do automatically is a recall notice.
 
#5 · (Edited)
@Bianco

I fully understand how the range is calculated. My average MPG is 20'ish (in the last few weeks). So, with your answer of it being "reset" too, would suggest, that @20mpg and almost 12 gallons of gas, my DTE/range should say 240 at the very minimum. However, as shown in the pictures, my almost 12 gallons would get 159 miles. That's an 81 mile difference! And in the picture shown of 1/2 a tank (6 gallons), the range is only 66 miles. That's a whopping 11mpg. But, 6 gallons @ 20mpg should get at least 120 miles.
 
#15 · (Edited)
Not exactly...the "floating average" it uses is NOT the avg mpg number (which can be reset by the user at any time). Here is how you can test that...when you reset your avg. mpg you will notice that the average stays where it was when you reset it and then, depending on driving style, quickly begins to rise or drop. If you reset the avg. mpg and quickly switch to DTE, it will NOT quickly begin to adjust! The DTE uses a SEPARATE data channel! This is why a re-flash would cause the DTE number to drop as the data sample is now smaller / shorter and reflects your most recent MPG number and not a multi day / week average!
As for the assertion that updates do not reset stats to a baseline, I am talking about the adaptive portion of the algorithms used to set response, shift points, etc. This is best thought of as disconnecting the battery to clear a CEL which DOES reset certain data points. Perhaps my use of "baseline" was not the best choice but EVERY service manual mentions (depending on mfr) "re-learn" procedures or similar verbiage after replacement, power down, re-flash, etc.
Very good article in Motor Trend or Car & Driver a year or so ago that went into detail as to why major auto makers were currently unable to perform over the air updates (like Tesla). It went into great detail about how updates are performed (and this is NOT the same thing as a uConnect or Garmin / maps update for example) which includes actually downloading tge data from the module being updated, modifying / updating that data, and then reloading the modified data back onto the module being updated. There are many reasons it must currently be done this way including onboard memory limitations and such.
I can assure you that any re-flash or "software update" to a control module WILL initiate a re-learn process when the vehicle is returned to use!
I know most of this because I used to work for a manufacturer of the equipment used to do the updates...and yes, FCA (& Toyota) have some of the toughest code to crack! ?
 
#11 ·
Yes, as shown in the image attached. PCM flashed to latest software LOP 18-19-06-JT and TCM flashed to latest software LOP 18-19-05-C3. I wrote "possible shift improvement" after speaking with the second service writer who said "usually customers don't question this." He said shift improvement was a possible reason for he update.
 

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#13 ·
Unfortunately, those numbers don't match up to the actual TSB numbers. However, there are really only 2 TSBs that would likely be applicable to a 2015 Dart SE with an automatic transmission:

SB18-009-15REV C - Corrects a problem with overly sensitive CEL conditions and difficulties restarting the car when it is warmed up.
SB21-052-15 - Corrects shifting issues, particularly a bad 1-2 shift.

That being said, there is no TSB that should be causing the issues you're having. Your dealership might have screwed something up, which they need to fix, or possibly something went wrong with one of the flashes, in which case it may be necessary to erase and completely reflash the TCM/PCM (I'm not sure if these are separate modules with the Powertech transmission).

Also, how did you manage to get an oil change under warranty?
 
#12 · (Edited)
@Cntrollerfanboy

They had ample opportunity to come speak with me. As I was sitting in there lobby with my daughter for almost 2 hours. It wasn't mentioned until original service writer came to get me to let me know they were finished. And he was very ignorant with knowledge of what they had done. All he knew was its an update. This is the first time I'm having to deal with any of this vehicle computers, I've been "old-fashioned" up until this car (older vehicles, less computers). That's why I didn't know what it was, however, since I have extensive knowledge of computers; I knew "software update" meant something was changed, added, modified, etc. I spoke with 3 service writers that day (4 if I include the one I spoke with when I called to complain/get real answers); none of them were able to give any actual answers about the update. When I spoke with the one on the phone, super sweet but too was unaware of what the changes were and told me he'd have to look into it. Me, thinking I could find out myself online, I didn't ask him to do this "extra" work. My first and last mistake with these new computerized cars.

Yes, extremely ridiculous! Before update, I easily got @ minimum, 75 ish miles to 1/4 tank. This is why (from an earlier reply) the idea that they reset it and now it needs to relearn, doesn't make sense. Because as you can tell my average MPG while driving in city was 27 however I only had 122 miles I believe it was until empty.

1/2 tank wasn't same day as fill up. If you look @picture that shows -almost- full, I've driven (now) 30.3 miles & I have under 3/4 tank. So 30 miles used approximately 1/4 tank of gas.
 
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