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SPN 3242 FMI 16

Aftertreatment 1 DPF Intake Gas Temperature — Value too high (moderately severe).
The reading is above normal at a middle warning level — more serious than FMI 15, less than FMI 0.

What the SPN covers: Exhaust temperature entering the diesel particulate filter. More on SPN 3242.

What FMI 16 usually points to: A developing over-condition that often precedes a derate. More on FMI 16.

Severity

MEDIUM — fix soon

Regenerations may be blocked until fixed, leading to soot buildup.

Likely causes

  1. Failed exhaust temperature sensor
  2. Wiring damage from heat
  3. Diesel oxidation catalyst not lighting off

Checks & fixes (easiest first)

  1. Compare all exhaust temperature sensors at idle after a cold soak
  2. Inspect wiring for heat damage
  3. Check DOC performance during a regen

FAQ

What does SPN 3242 FMI 16 mean?

Aftertreatment 1 DPF Intake Gas Temperature — value too high (moderately severe). The reading is above normal at a middle warning level — more serious than FMI 15, less than FMI 0.

Is SPN 3242 FMI 16 serious?

Regenerations may be blocked until fixed, leading to soot buildup.

What should I check first for SPN 3242 FMI 16?

Compare all exhaust temperature sensors at idle after a cold soak; Inspect wiring for heat damage; Check DOC performance during a regen.