What is SPN 101 FMI 16 & How to Solve It?

What is SPN 101 FMI 16:

SPN 101 is the Mass Air Flow (MAF) Sensor, and FMI 16 indicates a signal or performance degradation over time.

This typically results in incorrect airflow data reaching the ECM, causing poor fuel/air balance.

‍

Why This Happens

• Sensor is dirty or degraded.
• Air filter restriction or oil contamination.
• Loose or cracked intake piping.
• ECM software not processing values correctly.

‍

How to Fix It

1. Inspect and clean the MAF sensor.
2. Replace the air filter if overdue.
3. Repair any intake leaks.
4. Replace the sensor if values remain unstable.
5. Clear the code and test fuel trims.

‍

How to Avoid It Before It Happens

1. Clean MAF sensors regularly.
2. Use dry air filters instead of oiled filters.
3. Log airflow vs boost pressure weekly.