This DEF pressure limiting circuit sheet documents Detroit fault code SPN 4336 / FMI 3 on EPA10 engines, a circuit-failed-high condition with a 25% derate. It confirms the fault with an Output Component Test, then hunts a short to battery in the wiring to the ACM.
Official document details
| Brand | Detroit |
| Model coverage | Detroit DD-Series (DD13, DD15, DD16) and Series 60 (DDEC VI) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | SPN 4336 / FMI 3 |
| Fault name | Pressure limiting unit circuit failed high |
| Emissions platform | EPA10 |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
| Source | TruckFaultCodes.com (© 2017); Detroit Power Service Literature |
DEF pressure limiting circuit sections covered
The two-page routine verifies the code, inspects the connector, and points to a short to battery when the pins are clean.
- Monitored parameter and 25% engine derate; MIL and CEL
- Connect the diesel diagnostic tool and run the Output Component Test
- Repeat the test three times, cycling ignition between runs
- Disconnect the pressure limiting unit harness connector
- Inspect the harness for bent, spread or corroded pins
- Repair the short to battery at pin 1 / ACM pin 26
Applicable truck models
These steps cover Detroit DD-Series (DD13, DD15 and DD16) and Series 60 DDEC VI engines on the EPA10 platform with the ACM aftertreatment control module. Removal and component detail are published in Detroit Power Service Literature at the Detroit Diesel official website.
Who needs this DEF pressure limiting circuit manual
This pressure limiting circuit manual is for technicians resolving SPN 4336 / FMI 3, giving the exact test-repeat sequence and pin locations so the short is found without replacing a good unit.
The full 2-page PDF is available in the DiagTechPro manuals library; a free account is required to download. For workshop reference, Detroit documents the matching component removal and installation steps for SPN 4336 / FMI 3 in Power Service Literature, and technicians should keep the wiring pin numbers shown in this sheet on hand while testing on the bench.
Related manuals library
