The DEF header failed on this truck and it causes the vehicle to be disabled. The DEF header is an emissions part. PART NUMBER 04-31354-004 HEADER-SSI,CONC,6 BOLT,CMNS
2020 Custom Fire Freightliner M2
Owner reports · Recalls · Investigations
Limited comparison data
There is not enough comparable history to draw a useful model-year comparison.
About this comparison →How this year compares
Owner complaints by model year
Compare all Freightliner M2 years →Counts vary with age, sales and reporting. They are not failure rates.
What owners reported most
Tap a category to read its complaints. One report may name several components.
When problems were reported
Mileage at the reported incident
Limited mileage data: 0 of 1 reports include usable mileage. There isn’t enough coverage to show a useful chart.
NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.
NHTSA owner reports · September 18, 2026 snapshot.
What owners actually said
1 reportsOfficial recalls
121V620000 · Fuel System, Diesel:fuel Injection System:fuel Rail
Aug 6, 2021
Custom Fire Apparatus, Inc. (Custom Fire) is recalling certain 2017-2021 Peterbilt 348, Freightliner M2, Kenworth T370, and T880 emergency vehicles equipped with Cummins L9 diesel engines. The sealing washer may not seat correctly in the pilot boreholes, allowing the high-pressure fuel rail assembly to leak.
Consequence & remedy
Consequence: A fuel leak in the presence of an ignition source increases the risk of a fire.
Remedy: Cummins will inspect the rail threads and fuel lines, and replace the rail as necessary, free of charge. Owner notification letters were mailed on August 9, 2021. Owners may contact Custom Fire's customer service at 1-715-294-2555.
Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗
NHTSA investigations
0No exact-year investigations in this snapshot.
Illustration