Revisions to this document are noted
by a stripe in the left-hand margin

SUBJECT:

SIL 09-TR-24, Rev. A
June 28, 2024
Page 1 of 8

Updates for Neutral at Stop Low-Speed Coasting Feature

MODELS AFFECTED:

1000 SeriesTM, 2000 SeriesTM, 3000 SeriesTM, 4000 SeriesTM

Introduction:
On May 7, 2024, Allison released BCN 243 software which addresses the item below. If the vehicle is exhibiting
any of the complaints or issues mentioned below, please follow the outlined service procedure.

Description of Complaint:
BCN 243 PC addresses a shift quality complaint for low speed Neutral at Stop Coast to 1 (First Range) shifts
related to the 6th Generation Controls feature Neutral at Stop with low-speed coasting. Some of the shift quality
complaints are accompanied with a P0722, P0731 or P27B6 Diagnostic Trouble Code (DTC). Please contact your
local Allison Dealer or Distributor for additional information.
• P0722 – Output Shaft Speed Sensor Circuit – No Signal
• P0731 – Incorrect 1st Gear Ratio
• P27B6 – Internal Control Module Transmission Speed Sensor Performance
If the vehicle exhibits these low-speed abrupt Neutral at Stop Coast to 1 (First Range) shifts or any of these DTCs
are triggered along with low-speed Neutral at Stop Coast to 1 (First Range) shifts and the vehicle is equipped with
the Neutral at Stop low-speed coasting feature, it is advised to update the transmission software to BCN 243 or
above. If you are unable to update the transmission software, then it is recommended to disable the Neutral at
Stop low-speed coasting feature.
To verify the software level and whether the vehicle is equipped with the Neutral at Stop low-speed coasting
feature, follow these steps in Allison DOC®. You may also be able to view a vehicle summary report in ACCT or
TCM ReflashTM as well.

Updating TCM Software:
Confirming TCM Software:
Before updating the TCM software, you must confirm that the TCM software level is at B242, C242, N242 or prior.
Additionally, verify Neutral at Stop low-speed coasting feature is enabled. To check these items, please follow
the steps outlined below.

KB / SL9189EN

6747107

Copyright © 2024 Allison Transmission, Inc. All Rights Reserved.

SIL 09-TR-24, Rev. A
June 28, 2024
Page 2 of 8
• Confirm that the current TCM software level is at B242, C242, N242 or prior. If the TCM software level is
B243, C243, N243 or above, the information in this Service Information Letter is not applicable to your
vehicle. The software level can be found by connecting the TCM with Allison DOC. The DTC and General
Info will show in the TCM Information section. The first four digits of the Cal ID indicate the current software
level. If the software level is B242, C242, N242 or prior and the vehicle is exhibiting the symptoms described
above, the software level should be updated to either B243, C243, N243 or above.

Figure 1. Current Software Level Example in Allison DOC

Copyright © 2024 Allison Transmission, Inc. All Rights Reserved.

SIL 09-TR-24, Rev. A
June 28, 2024
Page 3 of 8
Confirming Neutral at Stop Low-Speed Coasting Feature:
• Confirm that the Neutral at Stop low-speed coasting feature is enabled in the transmission calibration. If the
Neutral at Stop low-speed coasting feature is not active, then the information in this Service Information
Letter is not applicable to your vehicle. The calibration setting can be found by connecting the TCM with
Allison DOC. The Neutral at Stop low-speed coasting feature can either be enabled or disabled in the
reprogramming menu under the FuelSense® section, as shown below in Figure 2.

Figure 2. Confirming Neutral at Stop Coasting
Updating TCM Software:
• If the current software is older than B243, C243 or N243, update software to B243, C243 or N243 or above
by programming based on the TCM serial number in TCM Reflash. To receive the latest software level, it is
necessary to check the box labeled “Download Latest Calibration” on the Add screen in TCM Reflash (refer
Copyright © 2024 Allison Transmission, Inc. All Rights Reserved.

SIL 09-TR-24, Rev. A
June 28, 2024
Page 4 of 8
to Figure 3). After programming is complete, use Allison DOC to verify that the second through fourth digits
of the Cal ID are 243 or above (refer to Figure 4).

Figure 3. Updating to Latest Software Level in TCM Reflash
NOTE: The “Download Latest Calibration” option in TCM Reflash should only be used when there is a
specific need to update the software.

Copyright © 2024 Allison Transmission, Inc. All Rights Reserved.

SIL 09-TR-24, Rev. A
June 28, 2024
Page 5 of 8

Figure 4. Updated Software Level Example in Allison DOC

Disabling Neutral at Stop Low-Speed Coasting
Confirming Neutral at Stop Low-Speed Coasting Feature:
Before disabling the Neutral at Stop low-speed coasting feature, confirm that the feature is enabled. To check,
please follow the steps outlined below.
• Confirm that the Neutral at Stop low-speed coasting feature is enabled in the vehicle’s calibration. If the
Neutral at Stop low-speed coasting feature is not active, then the information in this Service Information
Letter is not applicable to your vehicle. The calibration setting can be found by connecting the TCM with
Allison DOC. The Neutral at Stop low-speed coasting feature can either be enabled or disabled in the
reprogramming menu under the FuelSense section, as shown below in Figure 5.

Copyright © 2024 Allison Transmission, Inc. All Rights Reserved.

SIL 09-TR-24, Rev. A
June 28, 2024
Page 6 of 8

Figure 5. Confirming Neutral at Stop Coasting Enabled
Disabling Neutral at Stop Low-Speed Coasting Feature:
• To disable the feature without updating vehicle software level, click the arrow drop down by Enabled,
and select Disabled. Then select the button marked Reprogram TCM. This will reprogram the TCM and
disable the feature. To verify, open the reprogramming menu and check the calibration setting status as
shown in Figure 6.
NOTE: If the vehicle must be serviced later and the TCM is reprogrammed with the original TCM Assembly
Number, the feature will be re-enabled. Reprogramming with the TCM Serial Number will not re-enable
the feature. To permanently disable the feature, please contact Allison for a new calibration.

Copyright © 2024 Allison Transmission, Inc. All Rights Reserved.

SIL 09-TR-24, Rev. A
June 28, 2024
Page 7 of 8

Figure 6. Neutral at Stop Coasting Disabled

Claim Submittal Information:
Warranty:
The actions described in this document will be covered by the standard warranty, supplemental or ETC coverage,
whichever is relevant on your Repair Order Open Date. If the transmission no longer has an active coverage,
this action will not be covered by warranty.
Include an attached Allison DOC screen capture of the “DTC and General Information” page showing the TCM
serial number and Cal ID fields prior to updating the calibration as shown in Figure 1.

Copyright © 2024 Allison Transmission, Inc. All Rights Reserved.

SIL 09-TR-24, Rev. A
June 28, 2024
Page 8 of 8
Table 1. Claim Information
CLAIM TYPE

Machine

PRIMARY FAILED PART

400

PRIMARY FAILED PART SERIAL NUMBER

TCM Serial Number shown in Allison DOC Snapshot

Include reference to this SIL in the 4WARDTM Work Performed Comments field with your normal complaint, cause
and correction narrative as per example shown below:

Table 2. Labor Codes/Hours
LABOR OPERATION CODE

LABOR HOURS

LABOR OPERATIONS

00096501

1.0

RECALIBRATE TCM

00096400

0.5

TEST DRIVE

Any additional parts, labor or net items required to complete this action must be justified in the Work Performed
Comments field of the claim.

Copyright © 2024 Allison Transmission, Inc. All Rights Reserved.