Total Solutions Flyer Canada - Flipbook - Page 4
DEF HEADER
REPLACEMENT
TIPS
KEY THINGS TO LOOK FOR WHEN
REPLACING A DEF HEADER
4
TANK CONDITION
Inspect inside the DEF tank for:
Crystallization buildup
Dirt or contamination
• Clean if necessary
•
1
The Alliant Power DEF
Header serves as the
central component of the
DEF system. Designed
for efficiency and ease of
integration, it combines
fluid level, concentration,
and temperature sensing
functions into a single unit.
Utilizing advanced ultrasonic sensing
technology, the solid-state sensor avoids
many of the reliability issues commonly
found in mechanical sensor systems. The
signals generated by these sensors are fully
compatible with most major DEF dosing
systems currently used in the industry.
The DEF Header also incorporates a
heater powered by engine coolant,
enabling DEF to thaw and operate
effectively in temperatures as low as
-40°F (-40°C). This heating system is
engineered to deliver reliable performance
while complying with OEM requirements
and applicable regulatory standards.
Available optional accessories include
remote fill ports and vent assemblies,
lockable caps, coolant control valves,
electrically heated suction, return, and
pressure lines, as well as mounting
hardware and brackets.
4
ROOT CAUSE OF FAILURE
Before swapping parts, confirm why the
original header failed:
Electrical failure (open circuit, bad sensor)
• Heater failure (common in cold climates)
• Contamination or crystallized DEF
• Wiring harness damage
•
TIP: Don’t just replace—diagnose
first using scan tool data and fault codes.
2
WIRING HARNESS &
CONNECTOR CONDITION
•
TIP: Dirty tanks can quickly ruin
a new header.
5
O-RING SEAL &
MOUNTING SURFACE
Always replace O-ring seals (never reuse)
• Lightly lubricate seal with clean DEF
• Inspect tank flange for cracks or warping
•
TIP: Improper sealing = leaks and
sensor issues.
This is one of the most common issues:
Check for corrosion, DEF contamination,
or moisture intrusion
• Look for bent pins, loose terminals,
or damaged seals
• Inspect harness routing for chafing
or rubbing
6
•
TIP: If you see DEF crystals, clean or
replace the connector —DEF is corrosive
when dried.
3
•
•
CORRECT PART & CALIBRATION
Verify the OEM vs aftermarket compatibility
Ensure part matches:
• Tank size
• Sensor type
• Software requirements
TIP: Many trucks (e.g., Cummins,
Detroit, Paccar) require VIN-specific or
calibrated headers.
DEF QUALITY
Check DEF fluid:
•
•
Should be clear (not cloudy)
No debris or discoloration
TIP: Contaminated DEF can damage
sensors and SCR system
7
HEATER CIRCUIT &
POWER SUPPLY
Verify voltage supply and ground to
the heater
• Check fuse and relay operation
• Cold-weather failures often stem from
power supply issues, not the header itself
•
