Safety recall for automatic transmission module re-programming

Go directly to:     PCM Reprogramming



A total of 14,370 AT (automatic transmission) Miatas from the 2016-2019 model years, along with 8,933 AT 124 Spiders from MY 2017-2019 [U.S. market, through mid-December 2018] are being recalled, because the  transmissions could suddenly downshift into 1st gear without warning, resulting in “an unexpected and abrupt deceleration”, which both automakers fear could result in a crash.  The problem has been traced to missing conditional programming for potential EMI (electromagnetic interference) conditions in the transmission control module (TCM) firmware, although I’m not sure if a CAN message was perhaps garbled and misinterpreted, or just EMI in general.

Fortunately, no related crashes or injuries are known and the automakers very much want to avoid this ever happening.   Assuming that the beta testing of the firmware has been successful, and the distribution to the network of Fiat dealerships is in the works, we should soon receive a notification in the mail asking us to bring our cars into a dealership in late March / early April 2019 (at no cost to the vehicle owner), so that a technician can connect their Mopar diagnostic equipment into the OBDII port, to flash (overwrite) the existing firmware within our TCM (part # 05150944) to firmware level AF.


recall2 ↑ Part 573 Safety Recall Report 19E-008 [edited]

Manufacturer Information :

Manufacturer Name : Aisin World Corp. of America (AW)
Address : 15300 Centennial Drive
Northville, MI 48168

Number of potentially involved : 24,265
Estimated percentage with defect : 1 %

Description of the Defect : Vehicles with automatic transmissions using this TCM with a changed shift range detection system on vehicles manufactured since 2016MY  may experience electrical noise in the range signal (such as “Neutral” and “Parking”), which may be detected by the TCM unit while driving in “D” range (including in “Manual” mode). In the Mazda vehicles, this electrical noise’s interaction with the control logic of the clutch control software may result in the vehicle downshifting unexpectedly and an abrupt deceleration of the drive wheels. This report is filed in accordance with 49 CFR 573.3(f) because AW supplies a similar TCM to FCA, but to date, AW is not aware of any reports of this condition manifesting itself in the FCA vehicles.

Description of the Safety Risk : Each affected OEM should evaluate the potential safety risk in its vehicles. An unexpected and abrupt deceleration could potentially increase the risk of an accident under certain conditions.

Description of the Cause : The control logic in the TCM’s internal software does not  appropriately account for the electrical noise.

Identification of Any Warning that can Occur : None.

Chronology :
September 2016: AW received a Field Quality Information Report (FQIR) from Mazda reporting a downshifting issue.
November 2016: AW investigated the inhibitor switch and found no failure.
August 1, 2018: AW received a second FQIR from Mazda and commenced an investigation into the issue.
August – December 2018: AW investigated the inhibitor switch, automatic transmission, and Onboard Data Recorder (ODR) data. Analysis of the ODR indicated that a driveline shock occurred along with deceleration of the vehicle, when noise of the range signal was detected while driving in “D” range. Mazda requested to perform a re-creation test by simulator for the TCM. AW replicated the same phenomenon reflected in the ODR data by utilizing a TCM simulator. No failure was found in the inhibitor switch and automatic transmission. AW continued data analysis of the automatic transmission control program. AW reviewed the automatic transmission control program and the internal logic of the TCM and began developing changes to its internal logic.
December 15, 2018: AW began production of TCMs with software modification into the mass production line for Mazda.
January 31, 2019: Mazda informed AW that it had determined this issue presented a safety-related defect in its vehicles.
January 31, 2019: AW’s Regulatory Safety Committee reviewed the information from Mazda and determined that, because AW supplies this TCM to more than one OEM (Mazda and FCA), it would report the issue to NHTSA in accordance with 49 CFR 573.3(f).

AW is aware of two complaints from Mazda and zero complaints from FCA relating to the affected equipment.  AW is not aware of any accidents or injuries related to this issue.



[UPDATE 4/3/2019, 5/3/2019]
I just learned that the dealers have now received the updates, and are now installing them to all applicable unsold vehicles on their lots, as well as sold vehicles (by appointment), as they are brought in.   Be aware that concurrently, the dealers have apparently also been instructed to flash the PCM (power control module, aka ECU; part # 68231492) to firmware level AK, so that the “customer experience will be improved”…

  • AD ~ some of us with MY 2017 Spiders may still be at this “original” firmware version, which already had the T19 recall fix incorporated, that sometimes limited engine speed (to idle) when fully depressing the gas pedal
  • AE ~ is the U76 emissions recall, mandatory for California vehicles (may have been “ignored” in other states) to address  software calibration that may inadvertently suspend some required OBD monitors, when the P1D7F fault code is set
  • AF, AG, and AH  ~ unknown change(s)*
  • AI ~ consequently, most of the earlier Spiders probably never got this PCM update to alter the engine operating temperature vs. time algorithm, so that the CEL (and the P0128 trouble code) isn’t illuminated for marginal thermostat behavior, especially for North American market thermostats, which are spec’d differently
  • AJ ~ unknown change(s)*
  • AK ~ improved ambient temperature algorithm, so that the displayed “outside” temperature will more quickly reflect the actual temperature

NOTE:  If you have installed a modified aftermarket PCM tune, because the firmware version will have been modified to include the changes listed, you may need to obtain a tune update, prior to attempting to re-flash that tune.  Consider asking the dealer to skip this optional update, if you are in this situation (or at least returning your PCM back to stock configuration prior to your dealer visit).

*    Other reported differences, that are presumed to have been intentional, include:

  1.  briang reports (and other Miata drivers too) that the annoying difference between the metric Cruise setting (KM/H) and the actual speed, seems to have been corrected in one of these versions.

I have installed digital speedometer tweak, and [now the] Cruise [speed setting] value, digital [GPS] value and standard speedometer [value] all match when cruise is set to 100 km/h now, whereas prior to recall, I needed to set to 105 km/h to get 100 km/h.

19 thoughts on “Safety recall for automatic transmission module re-programming

    • No, I don’t expect it to. In fact, I suspect the ignition is off during this re-programming operation. I know I will give specific instructions for them to skip their complementary wash, and whatever else they might normally have in mind 😉 .

      SInce I have id7 installed, if they wish to upgrade my CMU firmware to 70.00.1xx, that would be OK, but I am unaware of any dealers receiving any firmware updates recently.


      • I will give specific instructions not to touch or update my infotainment program but I know how well service depts. listen. So, if they do update my infotainment to new firmware will it wipe out the AIO tweaks I’ve done. I have also installed id7 but if I understand correctly I would have to reload the tweaks thru the USB port? Is this correct.


      • I think so, but I’ve never taken my car to the dealer either, so the original software remains. I recall that Fiat reported that no cars had ever experienced the suspect glitch, so personally, I wouldn’t worry about it.


      • Thank you. I just got reply from 124Scottish Abarth on the forum telling me this;

        “My car threw red malfunction hissy fit and went into limp mode, but I had experienced her jumping a gear a couple of times just prior to that. Went over a bump and I had to pull over on the motorway as this is when she went into limp.”


  1. As of 03/16/2019 my Fiat service dept. told me that they STILL do not have the software to apply the fix. They said they’ve been waiting for over three weeks and still do not have an ETA. I’m supposedly on a list to be notified when they get the software. It’s a two hour drive in lousy traffic to my dealer and I’ve got a couple of other things I need done so I’m trying to wait and get it all done in one trip. I’ll post when (if) the software shows up.


  2. Update from my call to FCA today, 27 March 2019: The customer service rep said that the software will be rolling out in “April”. No definite date other than “sometime in April”.


  3. UPDATE 29 March 2019: Update software has been released. I’ve confirmed with my dealer and will get the update done this Monday. Will report if any perceived changes to transmission.


  4. I just learned that the dealers have apparently been instructed to also flash the PCM (aka ECU) to firmware level AK, during the same visit, so that an improved ambient temperature algorithm that’s been in the works for awhile, can also be installed.  Also, most of the earlier Spiders probably never got the PCM update to firmware level AI, to alter the engine operating temperature vs. time algorithm somewhat, so that the CEL (and the P0128 trouble code) isn’t illuminated for marginal thermostat behavior, and that is included, as well.

    If you have installed a modified PCM tune, because the firmware version will have been modified, you may need to obtain a tune update, prior to attempting to re-flash that tune.


  5. In theory, you can determine the revision level of your ECU with a OBDII scanner. I’m not aware of how safety issues are announced in UK, but I’m guessing that your Fiat dealer quietly updates TCM and PCM firmware when you bring your vehicle in for scheduled maintenance.


    • But they “should” have to put the update in your paperwork as they did for mine, and advise you that updates are going to be done to what modules. The dealer did not inform me of the PCM update prior to doing it. Because of that I will now ask any time I need to bring the car in to the dealer for anything if they are planning to flash the TCM or PCM and if so, what the changes entail.

      As a customer, I should still have the right to approve or refuse any proposed updates…unless it’s a Federally mandated safety recall. So this time, theoretically, I could have refused the PCM update, not that I had any reason to, but then I’m not running a flash tune either. If it’s only the ambient temperature algorithm being updated, that’s a quality of life update, not a safety-related one like the TCM.


  6. Just contacted my dealer regarding the updates here in the UK which are now available.
    After all my problems with the poor running of the auto gearbox to find after several visits saying there was no problem, then to find that the auto box was nearly 2 ltrs short saying it holds 7.5 ltrs, this made a massive difference, it was nice to be told that they’ve also had another auto abarth with the same issue!!
    So [if] poor changing [gears,] get it [fluid level] checked.

    Thanks ian


  7. my attempt to refuse the PCM update and get only the TCM update has met with somewhat mixed results. Dealer did perform the TCM update, but is telling me that the PCM update is also mandatory as part of the V20 recall, and that i should take off my tune (EC), and bring the vehicle back for the PCM update….. I don’t intend to do that…..


    • Dave,

      As you stated, just never get around to that follow-up visit 😉

      No where in the official documents, is the PCM mentioned, so I don’t think that dealer is being honest.


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