Home › Codes › SPN 102 › FMI 1

SPN 102 FMI 1

Intake Manifold #1 Pressure (Boost) — Value too low (most severe).
The reading is valid but far below the normal operating range, at the most serious 'too low' level.

What the SPN covers: Boost pressure in the intake manifold after the turbocharger and charge air cooler. More on SPN 102.

What FMI 1 usually points to: A real under-condition such as very low oil pressure or low fuel pressure, or a sensor that has drifted low. More on FMI 1.

Severity

MEDIUM — fix soon

Low boost means low power and more smoke; high boost can overstress the engine. Usually drivable carefully to a shop.

Likely causes

  1. Boost leak at charge-air cooler or hoses
  2. Turbo or VGT actuator problem
  3. Clogged air filter
  4. Faulty boost sensor or plugged sensor port
  5. Exhaust restriction (DPF)

Checks & fixes (easiest first)

  1. Pressure-test the charge-air system for leaks
  2. Inspect CAC boots and clamps
  3. Check the boost sensor for oil/soot buildup
  4. Compare boost to barometric pressure with the key on, engine off
  5. Check VGT and DPF codes

FAQ

What does SPN 102 FMI 1 mean?

Intake Manifold #1 Pressure (Boost) — value too low (most severe). The reading is valid but far below the normal operating range, at the most serious 'too low' level.

Is SPN 102 FMI 1 serious?

Low boost means low power and more smoke; high boost can overstress the engine. Usually drivable carefully to a shop.

What should I check first for SPN 102 FMI 1?

Pressure-test the charge-air system for leaks; Inspect CAC boots and clamps; Check the boost sensor for oil/soot buildup.