Freightliner Cascadia - DD15 SPN 2791 FMI 14 EGR Valve Calibration Issue

Question

I am having an issue with my 2018 Cascadia where the check engine light keeps popping up and I'm losing power on grades. My scanner is showing SPN 2791 FMI 14 which points to a learning error with the EGR valve. The truck feels like it is lagging and the turbo geometry seems to be hunting while cruising.

Kevin Tran · Accepted Answer

Found the issue was a failed internal return spring in the EGR actuator (Part #A0002600247). The valve itself was moving but wouldn't return to the zero position fast enough for the MCM calibration check. Replaced the actuator assembly, performed the learn procedure in Diagnostic Link 8.0, and the SPN 2791 code cleared immediately. Total cost for the part was about $650 and two hours of labor.

Sarah Thompson · Answer

FMI 14 on that code usually means the MCM doesn't like the end-stop positions it's seeing from the actuator. You should check the physical linkage between the motor and the valve to ensure it isn't binding up due to soot buildup.

Marcus Bell · Answer

Before replacing parts, try using Detroit Diagnostic Link to perform the 'EGR Service Routine'. Sometimes the adaptive values just need to be reset after a software update or if the battery was disconnected for a long time.

dieselmike88 · Answer

Verify your air pressure to the VPOD if this is an older pneumatic style, but since yours is a 2018, it’s likely the S60-style electric actuator. Check the pins in the 4-pin Deustch connector for corrosion which is common in the salt belt.

Freightliner Cascadia - DD15 SPN 2791 FMI 14 EGR Valve Calibration Issue

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