SCR Inducement Change
SCR Inducement Change
The EPA has released a revision to its guidelines related to selective catalytic reduction (SCR) inducement.
Cummins will implement these updated guidelines across impacted on highway applications. The update will be available to take advantage of additional flexibility introduced by EPA with our engineers minimizing inconveniences associated with inducements to the extent our engines are able to maintain compliance with the relevant requirements.
See Table 1 for the final inducement speed limits.
| Application | Final Inducement Speed Limit |
|---|---|
| Truck | 25 mph after safe harbor is met |
| Motorcoach | 50 mph after same harbor is met |
The change is managed through updated design options (DO) [Motorcoach only] and engine control module (ECM) calibration code revisions, covering model years 2017 to present, beginning January 2026, with rollout continuing thereafter. This change is not covered under warranty.
As part of this update a newly added motorcoach classification requires new ECM codes. A motorcoach is defined as a heavy-duty vehicle designed for carrying 30 or more passengers over long distances. Such vehicles are characterized by row seating, restrooms, large luggage compartments, and facilities for stowing carry-on luggage. A technical service bulletin (TSB) will outline the current and new ECM codes for motorcoach applications.
What this means in practice: if a unit goes into inducement, the vehicle speed limits applied will follow updated guidelines. Operators should not rely on inducement behavior; units must be maintained to avoid entering that state.
Notice: It is unlawful to tamper with or remove any component of the emissions control or aftertreatment system. It is also unlawful to use Diesel Exhaust Fluid (DEF) that does not meet the required specifications or to operate the vehicle/equipment without Diesel Exhaust Fluid (DEF).
Check Table 2 frequently for the updated implementation schedule, dates subject to change.
| SMN | Model Year | Motorcoach | Planned Release Date |
|---|---|---|---|
| X12 CM2450 X137B |
MY25 |
No | 1/15/2026 |
| X12 CM2450 X137B | MY21 MY22 MY23 MY24 |
No | 2/15/2026 |
| X12 CM2450 X137B | MY25 MY26 |
Yes | 5/8/2026 |
| X12 CM2450 X137B | MY24 | Yes | 5/22/2026 |
| X12 CM2450 X137B | MY21 MY22 MY23 |
Yes | 6/5/2026 |
| X12 CM2350 X119B | MY18/19 | No | 6/5/2026 |
| X12 CM2350 X119B | MY20 | No | 6/5/2026 |
| X12 CM2350 X119B | MY20 | Yes | 6/19/2026 |
|
X15 CM2450 X142B |
MY26 | No | 7/3/2026 |
| X12 CM2350 X119B | MY18/19 | Yes | 7/3/2026 |
| X15 CM2450 X142B | MY25 | No | 7/17/2026 |
| X15 CM2450 X134B X15 CM2450 X142B |
MY24 | No | 7/31/2026 |
| X15 CM2450 X124B X15 CM2450 X134B |
MY23 | No | 8/14/2026 |
| L9 CM2450 L126B | MY24 MY25 MY26 |
No | 8/15/2026 |
|
L9 CM2450 L126B |
MY24 MY25 MY26 |
Yes | 8/15/2026 |
| B6.7 CM2450 B155B | MY24 MY25 MY26 |
No | 8/15/2026 |
| L9 CM2450 L126B | MY24 MY25 MY26 |
No | 8/15/2026 |
| B6.7 CM2450 B155B | MY24 MY25 MY26 |
No | 8/15/2026 |
|
X15 CM2450 X124B |
MY22 | No | 8/28/2026 |
|
X15 CM2450 X124B |
MY21 | No | 9/11/2026 |
| L9 CM2450 L126B | MY21 MY22 MY23 |
No | 9/15/2026 |
| L9 CM2450 L126B | MY21 MY22 MY23 |
Yes | 9/15/2026 |
| B6.7 CM2450 B155B | MY21 MY22 MY23 |
No | 9/15/2026 |
| L9 CM2450 L126B | MY21 MY22 MY23 |
No | 9/15/2026 |
| L9 CM2450 L126B | MY21 MY22 MY23 |
No | 9/15/2026 |
| B6.7 CM2450 B155B | MY21 MY22 MY23 |
No | 9/15/2026 |
| X15 CM2350 X116B X15 CM2450 X124B |
MY20 | No | 9/25/2026 |
| X15 CM2350 X114B X15 CM2350 X116B |
MY19 | No | 10/9/2026 |
| X15 CM2350 X114B X15 CM2350 X116B |
MY18 | No | 10/23/2026 |
| X15 CM2350 X114B X15 CM2350 X116B |
MY17 | No | 11/6/2026 |
| L9 CM2350 L116B | MY17 MY18 MY19 MY20 |
No | 12/4/2026 |
| L9 CM2350 L116B | MY17 MY18 MY19 MY20 |
Yes | 12/4/2026 |
| B6.7 CM2350 B121B | MY17 MY18 MY19 MY20 |
No | 12/4/2026 |
| B6.7 CM2350 B121B | MY17 MY18 MY19 MY20 |
No | 12/4/2026 |