This MCM 5V sensor supply sheet describes Detroit SPN 3509 FMI 3 on an EPA07 engine, set when the Motor Control Module detects a short to power above 5.3 volts on any of its reference pins. It points the technician at the harness chart and the repair-and-verify workflow. It is a short wiring reference.
Official document details
| Brand | Detroit |
|---|---|
| Model coverage | DD Series (EPA 2007-Current); also filed under Series 60 (DDEC VI – EPA 2007) |
| System / Group | DTCs — 5V Sensor Supply Bank 1 Circuit Failed High |
| Fault code | SPN 3509 / FMI 3 |
| Source | www.TruckFaultCodes.com (© 2017) |
| Pages | 1 |
| File size | 0.2 MB |
| Format | |
| Language | English |
MCM 5V sensor supply diagnostic guide
The document states the fault is a short to power (voltage above 5.3 volts) on one of the module reference pins listed in its chart. The direction is to inspect the harness on the affected branch, repair the short as necessary and verify the repair. Because the reference is shared, a single damaged wire can raise the code for several sensors, so the chart is used to narrow the search before any part is replaced.
Document table of contents
- Fault code identification: SPN 3509, FMI 3
- Fault condition: reference shorted to power above 5.3 volts
- Module pin reference chart
- Harness inspection, repair and verification
Applicable truck models
This procedure applies to Detroit DD Series engines built for EPA 2007 and later, covering EPA07 calibrations as printed on the document cover, and the identical SPN/FMI sheet is also filed under Detroit Series 60 (DDEC VI, EPA 2007). Confirm the emissions platform on your truck and cross-check the connector and pin numbers against the official Detroit engine support site before making any repair.
Who needs this MCM 5V sensor supply manual
A technician on an EPA07 Detroit engine seeing a high reference code across grouped sensors uses this sheet to confirm a short to power in the harness before spending money on a control module.
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