DEF pump circuit open is the Detroit DD Series (EPA 2007–Current) diagnostic trouble code SPN 4375/FMI 5 (EPA10) set when the DEF pump control circuit reads open. This 2-page EPA10 / GHG14 fault-code sheet documents the monitored parameters and the harness voltage checks, the dash-lamp indication and engine reaction, and the ordered troubleshooting steps used to confirm and clear the condition. The engine reaction is a 25% derate with the MIL and CEL on, verification is a one-minute engine idle, and the procedure works through harness pin inspection and voltage measurements back to the ACM 120-pin connector before the DEF pump module is condemned.
DEF pump circuit open document details
| Brand | Detroit (Detroit Diesel) |
|---|---|
| Model coverage | Detroit DD Series (EPA 2007-Current) engines |
| System / group | DD Series (EPA 2007-Current) / DTCs |
| Publication / source | Detroit Power Service Literature (TruckFaultCodes reference, 2017) |
| Emissions family | EPA10 / GHG14 |
| Pages | 2 |
| File size | 0.22 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code description and monitored parameters
- DEF pump harness disconnection and pin inspection
- Supply voltage measurement at pin 1
- Control voltage measurement at pin 2
- DEF pump winding resistance check
- DEF pump module replacement
Applicable truck models
This fault-code procedure applies to trucks powered by the Detroit DD Series (EPA 2007-Current) engines on the DD Series (EPA 2007–Current) platform. The technician disconnects the DEF pump harness connector, inspects the pins, measures the pin 1 voltage against battery voltage and the pin 2 voltage between 2.25 and 2.50 volts, checks the pump winding resistance against 400 ohms, and repairs the wiring to pins 1 and 20 of the ACM 120-pin connector before replacing the DEF pump module. Always confirm the engine family and EPA10 / GHG14 emissions level against the vehicle, and cross-check the latest procedure in the Detroit Power Service Literature on the official Detroit website.
Who needs this DEF pump circuit open manual
Diesel technicians, fleet maintenance teams and workshop owners diagnosing an open DEF pump control circuit, a 25% derate or an SCR dosing fault on Detroit DD Series trucks use this sheet to work the fault in order instead of guessing. The measured voltage sequence keeps the diagnosis on the wiring and connectors before the pump module itself is replaced.
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