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SPN 3251 — DPF differential pressure very high

SPN 3251 is the parameter the ECM is flagging on PACCAR, Volvo, Mack, International, CAT, Detroit, MERCEDES, Cummins engines. The FMI that comes with it tells you how it failed. Each failure mode below has its own causes and its own test order — do not treat them as the same repair.

FMI 0 · Data valid but above normal operating range — most severe level

DPF differential pressure very high

The sensor is working and the reading is real, but the value is dangerously high. This is the engine telling you it has a mechanical or system problem, not a wiring problem.

Full diagnosis for SPN 3251 FMI 0What FMI 0 means
FMI 0 · Data valid but above normal operating range — most severe level

DPF outlet pressure extremely high

The sensor is working and the reading is real, but the value is dangerously high. This is the engine telling you it has a mechanical or system problem, not a wiring problem.

Full diagnosis for SPN 3251 FMI 0What FMI 0 means
FMI 2 · Data erratic, intermittent or incorrect

DPF pressure data erratic with high restriction

The ECM is getting a signal but it jumps around or does not make sense. Nine times out of ten this is a connection, not a part.

Full diagnosis for SPN 3251 FMI 2What FMI 2 means
FMI 16 · Data valid but above normal operating range — moderately severe level

DPF differential pressure above normal - moderately severe

Real reading, clearly high. Usually the middle warning stage before a derate.

Full diagnosis for SPN 3251 FMI 16What FMI 16 means
FMI 16 · Data valid but above normal operating range — moderately severe level

DPF differential pressure above normal - moderately severe

Real reading, clearly high. Usually the middle warning stage before a derate.

Full diagnosis for SPN 3251 FMI 16What FMI 16 means
FMI 16 · Data valid but above normal operating range — moderately severe level

DPF differential pressure above normal - moderately severe

Real reading, clearly high. Usually the middle warning stage before a derate.

Full diagnosis for SPN 3251 FMI 16What FMI 16 means
FMI 16 · Data valid but above normal operating range — moderately severe level

DPF differential pressure above normal - moderately severe

Real reading, clearly high. Usually the middle warning stage before a derate.

Full diagnosis for SPN 3251 FMI 16What FMI 16 means
FMI 16 · Data valid but above normal operating range — moderately severe level

DPF differential pressure above normal - moderately severe

Real reading, clearly high. Usually the middle warning stage before a derate.

Full diagnosis for SPN 3251 FMI 16What FMI 16 means
FMI 16 · Data valid but above normal operating range — moderately severe level

DPF differential pressure above normal - moderately severe

Real reading, clearly high. Usually the middle warning stage before a derate.

Full diagnosis for SPN 3251 FMI 16What FMI 16 means
FMI 16 · Data valid but above normal operating range — moderately severe level

DPF differential pressure above normal - moderately severe

Real reading, clearly high. Usually the middle warning stage before a derate.

Full diagnosis for SPN 3251 FMI 16What FMI 16 means

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