Cummins ISX: CM871 vs CM2250 vs CM2350 — Buyer’s Guide
Choose the right ISX/ISX15 replacement by matching ECM generation, emissions hardware, and harnessing to your chassis.
CM871 (EGR/DPF era)
- Simpler ATS (no SCR). Different sensor/doser approach vs later models.
- Confirm harness pinouts and cluster comms before install.
CM2250 (EGR/DPF/SCR first wave)
- Introduces SCR with additional NOx sensors and dosing hardware.
- Match ATS footprint and temperature probe layouts to your chassis.
CM2350 (Refined ATS, newer logic)
- Updated ECM strategy and sensor mapping; stricter plausibility checks.
- Keep ECM/ATS hardware families consistent to avoid nuisance faults.
Buyer Notes (All Generations)
- Verify calibration (governed speed, torque) against your transmission/axle ratios.
- Pressure-test CAC; log rail pressure, VGT position, and EGR delta-P on first run.
- Document DPF ash load and regen count before install.
