SPN 520329 FMI 31 is a Detroit DD Series diagnostic fault-code sheet that documents the DEF Pump Speed Low condition and its factory troubleshooting sequence. The sheet lists the SPN and FMI identifiers, a short description of the condition, and the repair steps in the order Detroit recommends. It is a concise reference sheet, 1 page long, aimed at technicians who read the code with a scan tool and need to know the correct next step.
SPN 520329 FMI 31 troubleshooting overview
This sheet covers the DEF Pump Speed Low condition, monitored on DEF pump speed and typically lasting about two seconds with the CEL illuminated and no engine reaction. Detroit verifies the fault by a parked regeneration and routes the repair to the troubleshooting for code SPN 5435/FMI 7.
Official document details
| Brand | Detroit (Detroit Diesel) |
| Model coverage | DD Series (EPA 2007-Current) |
| System / group | Diagnostic Trouble Codes (DTCs) |
| SPN | 520329 |
| FMI | 31 — DEF Pump Speed Low |
| Source | TruckFaultCodes.com fault-code reference (Copyright 2017) |
| Pages | 1 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification: SPN and FMI header
- Description: monitored parameter, enabling conditions, dash lamps (CEL) and verification by parked regeneration
- Note: retain a log file if Detroit Customer Assistance is required
- Troubleshooting Step 1: follow the procedure for code SPN 5435/FMI 7
Applicable truck models
This code sheet applies to Detroit DD Series engines (DD13, DD15 and DD16) built to GHG14 emissions specifications under the EPA 2007-Current platform, and Detroit cross-lists it under both the DD Series and Series 60 (DDEC VI, EPA 2007) diagnostic trees. For factory service literature and warranty details, refer to the official Detroit Diesel website.
Who needs this SPN 520329 FMI 31 manual
This reference is written for technicians working the Detroit aftertreatment DEF system who need the monitor description and the SPN 5435/FMI 7 cross-reference. Keep the 520329 FMI 31 sheet on hand so the code can be diagnosed and verified before it is cleared.
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