PACCAR (Kenworth & Peterbilt)
    PACCAR fault code
    SPN 1213 / FMI 3

    PACCAR Fault Code P1751: Malfunction Indicator Lamp (MIL) – Voltage Too High or Short Circuit to Supply on ECU (D420) Pin (B23)

    P1751 on PACCAR (Kenworth & Peterbilt) engines means: Malfunction Indicator Lamp (MIL) – Voltage Too High or Short Circuit to Supply on ECU (D420) Pin (B23). The failure mode (FMI 3) is “voltage above normal, or shorted to high source”.

    Code details

    Manufacturer
    PACCAR (Kenworth & Peterbilt)
    Applies to
    PACCAR MX-13 (2017–2020)
    Fault code
    P1751
    J1939 SPN
    1213
    FMI
    3 — Voltage above normal, or shorted to high source
    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 3 tells the shop the type of failure to test for: voltage above normal, or shorted to high source.
    • 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

    Source: PACCAR MX-13 2017–2020 fault code list (Diesel Laptops). See also OBD-II codes.