Product Description
CUMMINS 3947799 OEM FUEL RAIL PRESSURE RELIEF VALVE (PRV) – RAM 5.9L (2003–2007)
Restore factory fuel rail pressure control on your 2003–2007 Dodge Ram 5.9L Cummins with this genuine Cummins 3947799 fuel rail pressure relief valve (PRV). This OEM valve is the calibrated “safety fuse” in the common-rail system – it opens only when pressure exceeds the designed limit, protecting your injectors, CP3 pump, and fuel rail from damage while keeping hot-start performance and drivability on point.
Why Choose the Genuine Cummins 3947799 PRV?
- Direct-fit OEM valve for 2003–2007 Ram 5.9L ISB common-rail trucks.
- Properly calibrated pressure relief to protect injectors, CP3 pump, and fuel rail.
- Helps cure low rail pressure, hot-start complaints, and pressure-related fault codes.
- Built to Cummins/Bosch specifications for sealing, response, and durability.
Many cheap aftermarket valves are mis-calibrated or inconsistent, which can lead to over-pressure damage or chronic low-pressure issues. With this genuine Cummins 3947799 PRV, you get the correct opening pressure and OE reliability your common-rail system was designed for.
Verified Fitment
Automotive:
- 2003–2007 Dodge Ram 2500 5.9L Cummins (ISB 24V common-rail)
- 2003–2007 Dodge Ram 3500 5.9L Cummins (ISB 24V common-rail)
Industrial / Off-Highway: Also used on select ISB/QSB 5.9 common-rail engines. Always verify by engine serial number (ESN) before ordering.
Cross-Reference & Related Cummins Fuel Rail Components
For a complete, OE-correct repair of rail pressure issues on an 03–07 5.9L, pair this PRV with matching genuine Cummins components:
- CUMMINS 5297641 OEM FUEL RAIL PRESSURE SENSOR – ISB 5.9L (2003–2007)
- CUMMINS 3957079 OEM FUEL RAIL SUPPLY LINE (CP3 TO RAIL) – RAM 5.9L (2003–2007)
Common cross-reference numbers (for identification only):
Bosch 1110010029, Bosch F00R00632, Bosch 1-110-010-029, Cummins 3963808 (alternate PRV used in similar applications).
Specifications for cummins 3947799
| Brand | Cummins (Genuine OEM) |
|---|---|
| Cummins Part Number | 3947799 |
| UPC | 0725704928503 |
| GTIN | 0725704928503 |
| Application | Fuel rail pressure relief (pressure limiting) valve for 2003–2007 Ram 5.9L ISB common-rail and select ISB/QSB 5.9 industrial engines (verify by ESN). |
| Shipping Info | Typically ships via standard ground. Part weight approx. 0.35–0.40 lb with packaging. CPP Diesel offers fast shipping and free shipping eligibility per site policy. |
| Cross Reference | Bosch 1110010029, Bosch F00R00632, Bosch 1-110-010-029, Cummins 3963808 (alternate PRV; verify calibration). |
| E-Codes / Emissions | Not specified; part is used across multiple ISB/QSB 5.9 emissions families. Confirm using VIN/ESN and local emissions requirements. |
| Prop 65 | WARNING: This product can expose you to chemicals including fuel and fuel combustion by-products which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov. |
What’s In the Box
- (1) Genuine Cummins 3947799 Fuel Rail Pressure Relief Valve (PRV)
- Seals/washers as supplied by Cummins (some rail styles may require separate sealing washers)
Installation Notes
- Always depressurize the common-rail system and disconnect batteries before service.
- Clean the rail port and surrounding area to prevent debris from entering the fuel system.
- Torque the PRV to the factory spec from Cummins service information.
- After installation, prime the system, check for leaks, and verify commanded vs. actual rail pressure with a scan tool.
