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SPN 1761 FMI 17

Aftertreatment 1 DEF Tank Volume — Value too low (least severe).
The reading is below normal, but only at the lowest warning level.

What the SPN covers: How full the diesel exhaust fluid (DEF) tank is. More on SPN 1761.

What FMI 17 usually points to: An early warning: slightly low level or pressure, or a sensor starting to drift low. More on FMI 17.

Severity

MEDIUM — fix soon

Running low on DEF leads to inducement derates and eventually a speed limit. Fill up.

Likely causes

  1. Low DEF level
  2. Frozen DEF
  3. Faulty level sensor (often combined with temperature/quality sensor)
  4. Wiring fault

Checks & fixes (easiest first)

  1. Fill the tank with fresh, certified DEF
  2. Check the tank sender for crystal buildup
  3. Compare gauge with a visual check

FAQ

What does SPN 1761 FMI 17 mean?

Aftertreatment 1 DEF Tank Volume — value too low (least severe). The reading is below normal, but only at the lowest warning level.

Is SPN 1761 FMI 17 serious?

Running low on DEF leads to inducement derates and eventually a speed limit. Fill up.

What should I check first for SPN 1761 FMI 17?

Fill the tank with fresh, certified DEF; Check the tank sender for crystal buildup; Compare gauge with a visual check.