PACCAR (Kenworth & Peterbilt)
PACCAR fault code
SPN 3936 / FMI 7
PACCAR Fault Code P3802: Diesel Particulate Filter (DPF) – Filter Severely Damaged
P3802 on PACCAR (Kenworth & Peterbilt) engines means: Diesel Particulate Filter (DPF) – Filter Severely Damaged. The failure mode (FMI 7) is “mechanical system not responding or out of adjustment”.
Code details
- Manufacturer
- PACCAR (Kenworth & Peterbilt)
- Applies to
- PACCAR MX-13 (2017–2020)
- Fault code
- P3802
- J1939 SPN
- 3936
- FMI
- 7 — Mechanical system not responding or out of adjustment
- Truck models in source
- Kenworth T680, T880, W900, T800; Peterbilt 579, 389, 567, 367
What to do next
- Read active and inactive codes with the OEM service tool and note the occurrence count.
- FMI 7 tells the shop the type of failure to test for: mechanical system not responding or out of adjustment.
- Have a heavy-duty diesel technician confirm the fault against the engine or chassis service manual before replacing parts.
Get this code diagnosed
Send one request and nearby diesel shops and mobile mechanics can quote the repair.
Owner-OperatorAdd this truck & start trial
Run your own truck?
Log maintenance, track fault codes, and get roadside breakdown dispatch.
$39.99/mo
Cancel anytime
More ways Repairius keeps vehicles running
Tools for owner-operators, shops, fleets and drivers — all in one place.
Auto & Truck Shop OS
From $99.99/mo- Work orders & job management
- Digital vehicle inspections
- Parts lookup & inventory
- Estimates, invoices & payments
Fleet Maintenance
From $129/mo- Preventive maintenance schedules
- Driver DVIRs & defect reports
- Safety & compliance clearance
- Preferred shop dispatch & approvals
My Garage
100% free- Digital glovebox for your vehicles
- Maintenance history & reminders
- Recall alerts
- Book verified local shops
Owner-Operator? Track this truck for $39.99/mo
StartFix these trucks? Get your shop listed free·Find a diesel shop
Related fault codes
- PACCAR Fault Code P3991 — Exhaust Gas Temperature Sensors ECU – Software Verification Incorrect
- PACCAR Fault Code P3788 — DPF Filtration Efficiency – Data Valid But Too Low, Moderately Severe
- International Fault Code SPN 3936 FMI 0 — DPF Soot Load – Severe Derate
- International Fault Code SPN 3936 FMI 14 — DPF – Regen Duration Above Limit
- International Fault Code SPN 3936 FMI 2 — DPF System Feedback Control Fault
- International Fault Code SPN 3936 FMI 20 — DPF Feedback Adaptive Limits Reached
- International Fault Code SPN 3936 FMI 8 — DPF – Regenerations Are Occurring Too Frequently
- International Fault Code SPN 3936 FMI 15 — Aftertreatment Diesel Particulate Filter System: Data Valid But Above Normal Operating Range – Least Severe Level
Source: PACCAR MX-13 2017–2020 fault code list (Diesel Laptops). See also OBD-II codes.