Aftertreatment 1 Diesel Oxidation Catalyst Missing
The CUMMINS-1663 (Cummins) diesel fault code means: Aftertreatment 1 Diesel Oxidation Catalyst Missing. This is a critical severity code.
- Keep driving?
- No — stop driving
- DIY difficulty
- advanced
- Estimated cost
- $1,500-$4,500
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View pilot availability →What Are the Symptoms of CUMMINS-1663?
- Engine protect mode or forced shutdown
- DPF lamp illuminated on dash
- Active regeneration messages on dash
- Increased backpressure and reduced power
- Higher than normal fuel consumption
- Black smoke out of stack when accelerating
What Causes CUMMINS-1663? (Most Likely First)
- DPF severely loaded with soot requiring forced regen Very Likely
- Excessive ash accumulation (cleaning required) Likely
- Failed differential pressure sensor or hoses plugged Likely
- Short-trip duty cycle prevented passive regen Possible
- Faulty DOC (upstream oxidation catalyst) Possible
- Aftertreatment fuel injector stuck or clogged Less Likely
Can I Still Drive with CUMMINS-1663?
No — stop driving. CUMMINS-1663 is rated critical severity. Continuing to drive in this state risks further damage — get it looked at before your next trip.
Frequently Asked Questions
What is Cummins fault code 1663?
Cummins fault code 1663 indicates: Aftertreatment 1 Diesel Oxidation Catalyst Missing. It is a critical-severity fault in the aftertreatment or emissions system.
Can I drive with Cummins fault code 1663?
No. Fault code 1663 triggers protective engine shutdown or severe derate. Continued operation risks engine damage or stranding. Tow to a Cummins dealer or qualified diesel shop.
How much does it cost to fix Cummins fault 1663?
Repair cost is approximately $1,500-$4,500 including parts, labor, and any dealer programming required. DIY repairs (sensor replacement) fall at the low end; pump, aftertreatment, or ECM work falls at the high end and usually requires INSITE diagnostic software.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose CUMMINS-1663?
Connect INSITE and read soot load estimate, differential pressure, and last regen status for fault 1663.
Park truck safely in non-combustible area with parking brake and initiate a parked/forced regeneration via INSITE.
If forced regen fails or DPF is above 100% soot load, remove DPF for professional cleaning (ash + soot bake).
Inspect differential pressure sensor hoses at DPF for soot clogging or kinks -- replace if obstructed.
Verify DOC inlet temperature rises above 570 degrees F during regen command (DOC functional check).
Inspect aftertreatment fuel doser or dosing injector for clogging; clean or replace as needed.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J1939-73Application Layer: Diagnostics (defines the SPN/FMI fault-identifier framework)
Which Vehicles Commonly Get CUMMINS-1663?
- Peterbilt 579, 567 with Cummins ISX/X15
- Kenworth T680, T880 with Cummins X15
- Freightliner Cascadia with Cummins ISX15
- Ram 2500/3500 with 6.7L Cummins
- Freightliner M2 106 with Cummins ISL9/L9
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