PACCAR (Kenworth & Peterbilt)
PACCAR fault code
SPN 609 / FMI 9
PACCAR Fault Code P3984: CAN Communication – Timeout From Vehicle Control System
P3984 on PACCAR (Kenworth & Peterbilt) engines means: CAN Communication – Timeout From Vehicle Control System. The failure mode (FMI 9) is “abnormal update rate”.
Code details
- Manufacturer
- PACCAR (Kenworth & Peterbilt)
- Applies to
- PACCAR MX-13 (2017–2020)
- Fault code
- P3984
- J1939 SPN
- 609
- FMI
- 9 — Abnormal update rate
- 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 9 tells the shop the type of failure to test for: abnormal update rate.
- 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 P3984 — CAN Communication – Time-Out from Vehicle Control System
- PACCAR Fault Code P3862 — CAN Communication – Timeout From Engine Management System
- PACCAR Fault Code P3875 — EAS-4 ECU – Data Lost Due to Incorrect Power Down
- PACCAR Fault Code P3876 — EAS-4 ECU – Internal Error
- PACCAR Fault Code P3882 — EAS-4 ECU – Voltage Too High or Short Circuit to Supply on ECU (D442) Pin (31) or Pin (46) or Pin (47)
- PACCAR Fault Code P3883 — EAS-4 ECU – Voltage Too Low or Short Circuit to Ground on ECU (D442) Pin (31) or Pin (46) or Pin (47)
- PACCAR Fault Code U112A — CAN – Message (ACM) Time-Out From Aftertreatment System
- PACCAR Fault Code U1812 — CAN – Message (EAS_SYS_INFO) Time-Out From Aftertreatment System
Source: PACCAR MX-13 2017–2020 fault code list (Diesel Laptops). See also OBD-II codes.