SIL 21-TR-20
November 30, 2020
Page 1 of 4
SUBJECT:

Emissions Certified Vehicle Calibration Change Restrictions

MODELS AFFECTED:

1000/2000/3000/4000 Series Transmissions

Introduction
Effective September 3, 2020 with the release of BC 194 software, functionality has been added to identify
calibrations that are used in emissions certified vehicles. In order to maintain regulatory compliance, a setting of
"YES" for any of the following parameters will prevent modification of the parameter(s) and any affected features or
parameters (refer to the Affected Features and Parameters section later in this publication for a list of affected
features and parameters).
• EMISSION CREDIT VEHICLE: Neutral at Stop - Premium
• EMISSION CREDIT VEHICLE: Transmission File Used in GEM Simulation
• EMISSION CREDIT VEHICLE: Powertrain Certified Calibration

Neutral at Stop - Premium
Neutral at Stop (NAS) - Premium can enhance fuel economy and reduce CO2 emissions. When compared to a
vehicle without NAS, drivers may notice a delay when accelerating from a stop as the transmission is shifting from
neutral back to drive. Depending on the OEM’s NAS integration, drivers may feel the shift from neutral to drive
when the service brake is released and if quickly applying the throttle pedal.

Customer Requests to Disable/Change Features
If any of the above mentioned Emission Credit Vehicle parameters are set to "YES", then the OEM has indicated
that the vehicle is emissions certified. Changes to affected features or parameters in the vehicle’s calibration can
only be made if the OEM has granted approval and may be limited to within a certain time window after the
vehicle’s OEM build date. Using the TCM or TCM calibration from another vehicle is prohibited.
Requests to change affected features or parameters require written approval from the OEM before any such
changes will be supported. The OEM approval letter must meet the following requirements:
• From the OEM factory (not a Dealer)
• On the OEM’s letterhead or clearly identifying the OEM as the email source
• Stating approval of changes to the calibration settings for all affected parameters, including original and
new settings
• Identifying the name, position, and contact information of the OEM representative approving the change
AR / SL8784EN

5304211

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SIL 21-TR-20
November 30, 2020
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• Listing the VIN and transmission serial number
• Identifying the original calibration information (TCM Assembly Number or TCM Serial Number), if available.
NOTE: 1000/2000 Series transmissions have specific hardware requirements for use with Neutral at Stop.
Refer to SIL 18-1K2K-16: NAS Disabler Separator Plate and SIL 13-1K2K-17: NAS Retrack Valve Body to
determine if transmission hardware changes are required in conjunction with calibration modifications.

How to Determine the Calibration Setting in the TCM
The settings for Emissions Credit Vehicle parameters can be found using Allison DOC® Premium version 2020.1 or
later by choosing “Additional Calibration Information” on the Calibration Information screen.

The settings for emissions certified vehicle parameters can be also found in the EPA Emission Credit section of
Allison Calibration Configuration Tool (ACCT), which can be found in the Engineering section of the Allison HUB.
The ACCT Calibration Summary Report will display these new parameter and calibration settings only if the
answer is set to “YES” in the calibration for one or more of the emissions certified vehicle parameters. Refer to
the following example.

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SIL 21-TR-20
November 30, 2020
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When viewing or editing service calibration requests in ACCT, users will be unable to disable emissions certified
vehicle parameters or change any affected features. These parameters can only be modified by Allison service
personnel upon receipt of OEM authorization.

Calibration Request Submittal
The following documentation should be submitted to Allison Transmission Calibration Support at
[email protected].
• Recalibration Email Request Form, which can be found in the Service section of the Allison HUB. Go to
Allison TCM ReflashTM, Forms and Guides
• OEM authorization letter

Affected Features and Parameters
The following table lists the features and parameters that are affected when one or more of the above mentioned
Emission Credit Vehicles parameters is set to “YES.”
Table 1.
Emission Credit
Vehicle Parameter

Affected Feature/Parameter
Neutral at Stop

EMISSION CREDIT
VEHICLE: Neutral at
Stop - Premium

FS2.0 Coasting Neutral at Stop
Neutral at Stop: Brake Application Pressure Activation
Neutral at Stop: Brake Application Pressure Deactivation
Number of Engine Cylinders

EMISSION CREDIT
VEHICLE: Transmission
File Used in GEM
Simulation

Primary Mode Gears
Secondary Mode Gears
Custom Shift Schedule
First Lockup

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SIL 21-TR-20
November 30, 2020
Page 4 of 4

Table 1. (cont'd)
Emission Credit
Vehicle Parameter

Affected Feature/Parameter
Number of Engine Cylinders
Engine Governed Speed
Acceleration Rate Management and related parameters
Low Speed Grade Assist
Dynamic Shift Sensing and related parameters
Primary Mode Gears
Primary Mode: Shift Schedule
Primary Mode: Shift Speed

EMISSION CREDIT
VEHICLE: Powertrain
Certified Calibration

Secondary Mode Gears
Secondary Mode: Shift Schedule
Secondary Mode: Shift Speed
Custom Hold Override and Preselects
Custom Hold Override and Preselects: Hold Override - Offset to Governed Speed
Custom Hold Override and Preselects: Preselects - Offset to Governed Speed
Custom Shift Schedule
DynActive Shifting and related parameters
First Lockup
Kickdown Input
Kickdown Input: Time Out Duration

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