What are the most likely causes of SPN 102 FMI 18?

Charge-air pipe leak or loose clamp; VGT actuator stuck with soot; Leaking or plugged charge air cooler

How do you diagnose code SPN 102 FMI 18?

1) Pressurize the charge-air system to 25 psi — Less than 5 psi drop in one minute 2) Command the VGT actuator with the scanner and watch travel — Full, smooth 0 to 100% travel 3) Compare intake pressure with barometric pressure, engine off — Both equal within 1 kPa

What part is usually replaced for SPN 102 FMI 18 and how much does it cost?

Boost pressure sensor: $60–$260 USD (aftermarket to dealer), plus 0.5–1 h of labor.

← All codes

SPN 102 FMI 18

CAUTION

Boost pressure

Intake manifold pressure is low: the truck is down on power.

SPN 102 FMI 18: Intake manifold pressure is low: the truck is down on power. Caution: you can keep driving carefully, but the engine may derate; get it addressed soon.

Mechanical · Air intake / Turbo

Can I keep driving?

Caution: you can keep driving carefully, but the engine may derate; get it addressed soon.

What it means

Boost pressure fell below the expected value for that load and rpm. It is usually a charge-air leak, a sooted-up variable geometry actuator, or a leaking charge air cooler long before it is a failed turbo.

Most likely causes

Charge-air pipe leak or loose clamp
Very likely
VGT actuator stuck with soot
Very likely
Leaking or plugged charge air cooler
Likely
Intake pressure sensor reading low
Likely

Tests, cheapest and most decisive first

1. Pressurize the charge-air system to 25 psi
Expected result: Less than 5 psi drop in one minute
Tool: Pressure test kit
2. Command the VGT actuator with the scanner and watch travel
Expected result: Full, smooth 0 to 100% travel
Tool: J1939 scanner
3. Compare intake pressure with barometric pressure, engine off
Expected result: Both equal within 1 kPa
Tool: J1939 scanner