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Subaru Ascent Recall Support and ATP Updates

Subaru_Ascent_2019+_Chris Daley_(105)

In November of 2019, Subaru of America announced an ECU Recall/Update for select 2019-2020 Subaru Ascents.  The recall consists of an ECU update to address potential disabling of the vehicle’s VDC function which can lead to EyeSight, Reverse Automatic Braking (RAB), and the Electronic Park Brake (EPB) functions to fail.  If you are unsure if your Ascent is a part of this recall, you can check by inputting  your vehicle’s VIN here:


What does this mean for Accessport users?

Until today, this unfortunately meant that you were unable to install an Accessport to tune your Ascent if you had received the ECU update by your Subaru Dealer.  Some vehicles were also being delivered with the ECU updates already being applied, and owners of those Ascents have not been able to tune their ECU at all.  Subaru’s update strategy meant that our COBB engineers had to re-do a large chunk of the development work previously done for the initial release of 2019-2020 Ascent tuning support.  We’re excited to announce that as of today we fully support Subarus latest ECU strategy for the 2019-2020 Ascent.  Those of you with Accessports can now simply update firmware (firmware update instructions here) on your Accessport and install as usual.

Updated Off The Shelf Maps

A part of adding support for the post-recall ECU update is offering updated OTS maps.  All maps listed below have been up-revved to v1.10 to indicate compatibility with the post-recall ECU update.  A small note, during installation you will now notice a (PR1) at the end of the vehicle identification string, this is to indicate Post Recall 1 ECU support.  No calibration changes have been made, these maps are simply updated to add compatibility with new ECU programming.

  • 2019 USDM Ascent CVT (PR1)
    • Stage0 v110.ptm
    • Stage1 87+ Economy Mode v110.ptm
    • Stage1 87+ v110.ptm
    • Stage1 87+ Valet Mode v110.ptm
    • Stage1 93 v110.ptm
    • Vehicle Anti-Theft Mode v110.ptm
  • 2020 USDM Ascent CVT (PR1)
    • Stage0 v110.ptm
    • Stage1 87+ Economy Mode v110.ptm
    • Stage1 87+ v110.ptm
    • Stage1 87+ Valet Mode v110.ptm
    • Stage1 93 v110.ptm
    • Vehicle Anti-Theft Mode v110.ptm

Subaru Accesstuner Pro Updates

The following updates are rolled into this Accesstuner Pro update.  Adding vehicle support for the post-recall Ascent ECU is the headline, but a handful of additions were made to other vehicle applications as well.

Deprecated 2019-2020 USDM Ascent CVT definition files



  • 2019 and 2020 USDM Ascent CVT maps will no longer directly open through the File → Load Accessport Map tools.
  • Please leverage the File → Import Tables from Map OR Compare → Compare to Accessport → Comparison Summary → Import tools to migrate existing Ascent calibration data to new definition files.

2015-2020 USDM STI: Added new MAP/MAF correlation limit table to allow accurate triggering of failsafe with aftermarket MAP sensors


  • New table: “MAP Sensor Throttle Position Correlation DTC Limits (High/Low)(P0068) in the “Sensor Calibrations table group.
  • P-codes added to existing MAP Sensor Voltage Delay/Limit table names for better clarity.

2015-2020 USDM STI: Added new MAP sensor voltage monitor

  • Manifold Abs. Pressure Sensor Voltage

All Vehicles: New labels added to select 1D table axes to make it easier to reference switching states and/or conditions


  • Labels have been added to most multi-cell 1D tables.

Improved P0244 DTC description for Ascent

ECUs in 2.4L DIT Subarus use P0244 DTC in a different fashion than all other supported Subaru ECUs.  When working in an Ascent ECU file, the Advanced Engine Parameters dialog box will display the correct DTC description for the ECU type.  Below is an example of what you will see for 2019-2020 Subaru Ascent.


Monitor name changes to improve log graphing compatibility

  • All special characters were removed from monitor names to prevent issues with math expression parsers in 3rd party graphing software.
  • Monitor names use capitalization where emphasis is needed.
  • Examples:
    • OLD = Ethanol Concentration {Final}
    • NEW = Ethanol Concentration FINAL
    • OLD = Cranking Fuel IPW Base {Table}
    • NEW = Cranking Fuel IPW Base TABLE