Detroit SPN 4364 / FMI 18: SCR-efficiency warning context
Detroit SPN 4364/FMI 18 reports an SCR conversion-efficiency concern in the cited EPA10/GHG14 reference. It does not identify a failed catalyst, DEF component or NOx sensor by itself. Record the complete SPN/FMI pair and related faults.
Application & limits
Detroit bulletin 01 01-18, January 2018, for EPA10 and GHG14 DD-platform references. Later emissions generations and other FMI values require their own current procedure.
What the symptom or code tells you
The OEM diagnostic reference considers other faults and operating data. Its engine-generation sections are a reason to identify the exact engine before selecting tests.
A fault report and its active/inactive state help the mechanic plan an SCR assessment. Include any recent DEF, sensor or aftertreatment work without assuming the last replaced component is the cause.
Information to send
Use details already available from the normal operator position or your records. Do not run a test or approach a hazard to collect them.
- DD engine model, serial, VIN/year and emissions generation if known.
- SPN 4364 with FMI 18, plus all companion faults.
- Full warning, any derate and previous diagnostic work orders.
- Recent repair history and the service location.
What the mechanic assesses
The mechanic matches current Detroit guidance to the truck and reviews associated faults and data before selecting system tests. No threshold, forced-regen sequence or component replacement is copied from the archived procedure for an unidentified engine. Parts and repair scope follow the assessment.
Prepare a repair request
Text the machine or vehicle, exact symptom and location. We confirm scope, safe access, parts needs, pricing and availability before a visit.
Serving Langley, Port Kells and the Lower Mainland service area. Readers elsewhere can use the source references and contact a qualified local service provider.
Related service & guides
Sources & applicability
Editorial update: . Public manufacturer and authority references checked on this date. Current vehicle-specific procedures and superseding information must be matched to the actual application before diagnosis or repair.
- Detroit bulletin 01 01-18: SPN 4364/FMI 18
Detroit bulletin 01 01-18, January 2018. Historical EPA10/GHG14 guidance; later emissions generations need their own procedure.