Buy 04-30774-005 / 04-30774-001 - Genuine Freightliner DEF Header 6 Gallon - wisentpartscenter.com

Description

04-30774-005 / 04-30774-001 is a Genuine Freightliner DEF header for select 6-gallon Diesel Exhaust Fluid tank applications. This header sits inside the DEF tank and is used to read DEF level, temperature, and quality/concentration data for the SCR system. It may also include the DEF pickup and heater-related functions depending on the tank setup.

Purpose of the Part

The DEF header sends tank information to the truck’s aftertreatment system so the ECM can monitor DEF level, temperature, and fluid quality. If the header stops communicating or sends incorrect data, the truck may show false DEF level/quality readings, set SCR faults, or enter an emissions derate even when the tank has good DEF.

Issue Symptoms / When to Replace

Common signs that 04-30774-005 / 04-30774-001 may need inspection or replacement include:

  • DEF gauge flashing, incorrect, or stuck
  • “Poor DEF Quality” warning with clean DEF in the tank
  • DEF level, temperature, or quality sensor faults
  • Check engine light, aftertreatment warning, or SCR inducement
  • 25% derate or progressive emissions derate
  • Communication loss from the DEF header/sensor assembly
  • Corrosion, crystallization, damaged pins, or harness damage at the DEF header connector

Possible related Cummins/DEF-header fault examples include 3868, 4572, and 4677. Depending on engine calibration and diagnostic system, related SPNs may involve DEF level, temperature, or quality circuits such as SPN 1761, SPN 3031, or SPN 3364. These codes do not prove the header is bad by themselves. Check DEF quality, tank contamination, power/ground, harness condition, connector pins, and OEM troubleshooting before replacing the header.

Brand Information

Freightliner is part of Daimler Truck North America and supplies OEM service parts for Freightliner commercial trucks. Genuine Freightliner DEF headers are preferred when the truck needs the correct tank depth, sensor communication, connector fit, and tank sealing. A cheaper header can cost more if it causes repeat DEF derates, false poor-quality readings, or another removal from the DEF tank.

Installation Notes

Before replacing the DEF header, confirm the VIN, original part number, tank size, connector, and supersession list shown on this page. Drain or lower the DEF level as needed, disconnect the harness, and remove the header without bending the pickup tube or damaging the tank opening. Clean DEF crystallization from the sealing area and inspect the connector for corrosion or fluid intrusion. Install the new header with the correct seal, route the harness like the original, refill with clean DEF, then verify DEF level, temperature, and quality readings with the proper diagnostic tool.

How to Identify an OEM Part

A Genuine Freightliner DEF header should be verified by the Freightliner part-number label, original packaging, connector style, tank depth, pickup tube layout, and sensor head configuration. Match the removed unit to 04-30774-005 / 04-30774-001 and to the supersession list shown on this product page. Do not rely on visual match only; similar 6-gallon DEF headers can differ by harness, sensor output, tank application, or engine/emissions configuration.

Technical Documents

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Warranty & Return Information
Warranty Information

Wisent Parts offers a 1-year warranty on all parts from the date of delivery. This warranty covers orders placed directly through our website. If a part fails during this period, we’re here to help - whether it’s a replacement, repair, or refund. For full details, refer to the Warranty page.

Return Information

Wisent Parts accepts returns within 30 days of delivery. All returns are subject to a restocking fee. To qualify, parts must be unused and in their original condition. For full return instructions and restocking fee details, please refer to the Returns page.