SPN 524285 FMI 2 identifies the Detroit DD Series fault “NAND checksum error” for engines on all model years. This fault-code sheet documents SPN 524285 / FMI 2 together with the diagnostic steps a technician follows with a diesel diagnostic tool.
Official document details
| Brand | Detroit (Detroit Diesel) |
| Model coverage | DD Series diesel engines (EPA 2007-Current) |
| System / Group | DTCs — fault code reference |
| Publication no. | TruckFaultCodes.com reference, 2017 |
| Year / Revision | all model years |
| Pages | 1 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification
- Fault description
- Contact the Customer Support Center (CSC)
- Replace the ECU
- Module and OEM references
Applicable truck models covered
This fault-code sheet applies to Detroit DD Series diesel engines on all model years. It describes the nand checksum error condition reported under SPN 524285 / FMI 2. Detroit documentation notes that some CPC4 digital outputs share an SPN with Motor Control Module (MCM2.1) faults, so the diesel diagnostic tool makes the distinction. For official service resources, see Detroit’s official website.
Understanding SPN 524285 FMI 2
This sheet identifies the fault as “NAND checksum error”. Using a diesel diagnostic tool, the procedure first checks for related Common Powertrain Controller (CPC) battery-voltage codes and other active faults, then works through the documented steps. The sheet gives two short actions: contact the Customer Support Center (CSC) and replace the ECU, indicating an internal controller memory fault rather than a wiring problem. A NAND checksum error usually points to corrupted internal flash memory inside the controller, which is why the procedure moves straight to controller replacement instead of harness, sensor or connector checks.
Who needs the SPN 524285 FMI 2 sheet
Detroit diesel technicians, DD Series fleet workshops and mobile repair units use this fault-code sheet to read the condition correctly, follow the right diagnostic path with a diesel diagnostic tool, and reference Original Equipment Manufacturer literature for the matching wiring schematics before making a repair.
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