PACCAR (Kenworth & Peterbilt)
PACCAR fault code
SPN 5024 / FMI 11
PACCAR Fault Code P3868: Heater Element NOx Sensor Before Catalyst – Warm-up Failed
P3868 on PACCAR (Kenworth & Peterbilt) engines means: Heater Element NOx Sensor Before Catalyst – Warm-up Failed. The failure mode (FMI 11) is “root cause not known”.
Code details
- Manufacturer
- PACCAR (Kenworth & Peterbilt)
- Applies to
- PACCAR MX-13 (2013–2016)
- Fault code
- P3868
- J1939 SPN
- 5024
- FMI
- 11 — Root cause not known
- 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 11 tells the shop the type of failure to test for: root cause not known.
- 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.
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Related fault codes
- PACCAR Fault Code P3868 — PM Sensor – Voltage Too High or Short Circuit to Supply
- PACCAR Fault Code P3867 — PM Sensor – Power Supply Intermittent
- PACCAR Fault Code P3867 — Heater Element NOx Sensor Before Catalyst Performance – Malfunction
- International Fault Code SPN 5024 FMI 10 — Aftertreatment 1 Intake NOx Sensor Heater Ratio: Abnormal Rate of Change
Source: PACCAR MX-13 2013–2016 fault code list (Diesel Laptops). See also OBD-II codes.