4375 FMI 4 DTCs is the Detroit Diesel diagnostic trouble code set when a DEF Pump Circuit Failed Low condition is detected on DD Series (EPA 2007-current) engines. This 1-page troubleshooting sheet lists the fault definition, the relevant monitor or note data, and a numbered diagnostic routine that ends in the correct wiring or component repair. It is drawn from TruckFaultCodes.com (© 2017) and applies to the EPA10 / GHG14 emissions calibration.
Official document details
| Brand | Detroit Diesel |
|---|---|
| Model coverage | DD Series engines (EPA 2007-current) |
| System / group | DTCs — DEF pump circuit |
| Suspect parameter (SPN) | SPN 4375 |
| Failure mode (FMI) | DEF pump circuit failed low |
| Emissions calibration | EPA10 / GHG14 |
| Dash lamps | MIL, CEL |
| Engine reaction | 25% derate |
| Verification | SCR air pressure test |
| Source / copyright | TruckFaultCodes.com, © 2017 |
| Pages | 1 |
| File size | 0.2 MB |
| Format / language | PDF / English |
4375 FMI 4 DTCs table of contents
With the ignition off, the DEF pump harness connector is disconnected and inspected for bent, spread or corroded pins. The ACM 120-pin connector is then unplugged and the resistance measured between pin 2 on the harness side of the DEF pump connector and ground. A reading under 1K ohms points to a wiring repair between pin 2 and ACM pin 20; a higher reading calls for replacing the DEF pump module per the Detroit Power Service Literature.
- Fault code header and copyright
- Description: monitored parameter, lamps and derate
- Troubleshooting steps 1 to 5
- Resistance-to-ground check and wiring/component decision
- DEF pump module replacement reference
Applicable truck models
This sheet is part of the DD Series diagnostic trouble code library and addresses the DEF pump low-side circuit in the SCR dosing system. The 4375 FMI 4 DTCs procedure applies to Detroit DD Series (EPA 2007-current) engines running the EPA10 / GHG14 calibration, and the same code index is cross-referenced under the Detroit Series 60 (DDEC VI, EPA 2007) fault-code set. For engine identification and warranty details, see the Detroit Diesel official site.
Who needs this FMI 4 DTCs manual
It is aimed at technicians resolving a low-side DEF pump circuit fault and a 25% derate on Detroit DD Series trucks. The single-page flow shows the go/no-go resistance value and the exact pin-2-to-ACM-pin-20 wire to repair before condemning the pump module.
The full 1-page PDF is available in the DiagTechPro manuals library; a free account is required to download.
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