2866643 | Genuine Cummins® Outlet Module

1. Compatible Engines & Emissions Platforms

Part number is specifically engineered for Cummins® heavy-duty engines operating with EPA 2010 to EPA 2017 aftertreatment systems:

• Cummins® Engine Platforms: ISX15, X15, ISL9, L9, and ISM series diesel engines.

2. Vehicle Fitment

This outlet module fits a wide range of Class 7 and Class 8 commercial trucks and buses:

• Freightliner: Cascadia, Columbia, Coronado, and M2 106/112 models.

• International / Navistar: ProStar, LT Series, LoneStar, and 8600/9900 models.

• Peterbilt: 389, 579, 386, and 567 models.

• Kenworth: T680, T880, W900, and T800 models.

• Volvo / Western Star: Select heavy-duty models equipped with factory Cummins engines.

1. What is it?

Part is a heavy-duty stainless steel canister that houses the final exhaust components downstream of the Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR) catalysts. It manages the final purification and discharge of exhaust gases into the vehicle's tailpipe.

2. Core Functions & Components

• Ammonia Slip Catalyst (ASC): Contains an internal catalyst substrate that oxidizes any unreacted ammonia ($\text{NH}_3$) left over from DEF dosing, preventing chemical smells or toxic gas release.

• Sensor Mounting Points: Features precision-welded ports for the downstream outlet NOx sensor and Exhaust Gas Temperature (EGT) sensors to provide closed-loop feedback to the Engine Control Module (ECM).

• Exhaust Flow Distribution: Directs clean, treated exhaust gases smoothly out of the aftertreatment system into the main exhaust pipe with minimal backpressure.

1. Active Check Engine Light (CEL) & Emissions Diagnostic DTCs

When internal substrate degradation or port blockage affects sensor readings, the Engine Control Module (ECM) registers relevant fault codes:

• Common Diagnostic Trouble Codes (DTCs):

  • SPN 3226 / FMI 13, 20 (Aftertreatment Outlet $\text{NO}_x$ Sensor - Drift High / Low)

  • SPN 4364 / FMI 18 (Selective Catalytic Reduction (SCR) Conversion Efficiency - Low)

  • SPN 3251 / FMI 0 (Aftertreatment DPF Differential Pressure - Extremely High)

2. Ammonia Smell from Exhaust (Ammonia Slip)

• Symptom: A sharp, pungent chemical/ammonia odor coming directly from the vehicle’s exhaust pipe while the engine is running under normal operating temperatures.

• Cause: The internal Ammonia Slip Catalyst (ASC) substrate has degraded or face-plugged, failing to neutralize unreacted DEF ($\text{NH}_3$) before gas exits the tailpipe.

3. Frequent DPF Regenerations & Reduced Engine Power

• Symptom: The vehicle triggers engine derate (power loss) and initiates constant passive or active DPF regenerations while driving.

• Cause: Heavy soot or crystallized urea accumulation inside the module creates restriction, causing abnormal exhaust backpressure readings upstream.

4. Cracked Housing, Weld Failure, or Exhaust Leaks

• Symptom: Visible soot tracking (black powder marks) around the module body, sensor mounting bungs, or clamp flanges, accompanied by elevated exhaust noise under load.

• Cause: Thermal stress and vibration cause structural cracking around weld seams or sensor ports, allowing untreated exhaust gas to leak out.