4087159C91 | Genuine International® DEF Sensor Head Assembly

Electrical Connector: Deutsch DT4 (STD)

Sensor Type: Digital (canbus)

DEF Header Height (IN): 11

DEF Suction Fitting Dia. (IN): 3/8 SAE J2044
DEF Return Fitting Dia. (IN): 5/16 SAE J2044

Coolant Inlet Fitting Dia. (IN): 5/8 Hose Bead

Coolant Outlet Fitting Dia. (IN): 5/8 Hose Bead

In-Tank Filter: 40µ

Tank Interface: 6 Bolt

1. Compatible Vehicle Models & Chassis

• Heavy-Duty & Medium-Duty Trucks: Fits major commercial truck brands equipped with Cummins engines and Shaw/SSI style DEF tank assemblies, including:

  • Freightliner (Cascadia, M2 106, SD series)

  • Kenworth (T680, T880, W990)

  • Peterbilt (579, 567, 389)

  • International (LT, RH, HV Series)

  • Western Star (49X, 57X)

• Buses & Specialty Vehicles: Lion Bus, Spartan Motors, Eldorado, E-ONE, and custom fire/rescue chassis.

• Off-Highway & Construction Equipment: Doosan Bobcat, SANY, Wausau Equipment, CMI, MI-JACK, and GREMO AB.

2. Engine Architecture Compatibility

Compatible with Cummins® diesel engines equipped with Selective Catalytic Reduction (SCR) systems:

• ISX15 / X15

• ISL9 / L9

• ISB6.7 / B6.7

1. What is it?

The assembly combines mechanical fluid suction/return lines with electronic monitoring sensors into a single drop-in tank header module. It communicates real-time tank data to the Engine Control Module (ECM) via the SAE J1939 CAN bus network, ensuring full compliance with Selective Catalytic Reduction (SCR) emission regulations.

2. Core Functions

• Fluid Level Measurement: Uses ultrasonic sensors to track DEF level and warn the driver when a refill is needed.

• Fluid Quality & Concentration Sensing: Measures urea concentration (ensuring standard ~32.5% purity) to prevent SCR system damage from contaminated or diluted fluid.

• Temperature Monitoring & Thawing: Measures DEF temperature and utilizes an engine coolant loop to melt frozen DEF in cold climates.

• Fluid Draw & Return: Houses internal stainless steel tubes that feed fluid to the dosing pump and return excess fluid to the tank.

1. Engine Power Derate & Forced Speed Limits

The most critical symptom is an active emissions inducement protocol triggered by the ECM:

• Early Inducement: Check Engine and Stop Engine / Emissions lights illuminate on the dashboard accompanied by audible warning chimes.

• Power Reduction: Engine horsepower and torque are reduced by 25% to 40%, severely limiting towing capacity and hill-climbing performance.

• 5 MPH / Low-Idle Lockout: If the fault is ignored past the countdown timer, the ECM restricts the vehicle to a 5 mph (8 km/h) forced crawl speed.

2. Diagnostic Trouble Codes (DTCs)

Connecting Cummins INSITE™ or a J1939 diagnostic scan tool will return specific fault codes associated with the tank header:

• SPN 1761 / FMI 9 or 19: DEF Tank Level - Abnormal Update Rate or Error.

• SPN 3031 / FMI 2 or 9: DEF Tank Temperature - Data Erratic, Intermittent, or Incorrect.

• SPN 3516 / FMI 2, 9, or 12: DEF Concentration (Quality) - Bad Device, Component, or Data Erratic.

• SPN 3364 / FMI 9: Improper DEF Quality Detected.

3. Inaccurate, Frozen, or Erratic Level Gauge

A failed ultrasonic level sensing circuit inside the GA111564 causes false tank level readings:

• The DEF level gauge on the cluster stays stuck at 100% (Full) or drops instantly to 0% (Empty) despite the tank being filled.

• Repeated "Refill DEF Tank" warnings occur unexpectedly during operation.

1. Engine Power Derate & Forced Speed Limits

The most critical symptom is an active emissions inducement protocol triggered by the ECM:

• Early Inducement: Check Engine and Stop Engine / Emissions lights illuminate on the dashboard accompanied by audible warning chimes.

• Power Reduction: Engine horsepower and torque are reduced by 25% to 40%, severely limiting towing capacity and hill-climbing performance.

• 5 MPH / Low-Idle Lockout: If the fault is ignored past the countdown timer, the ECM restricts the vehicle to a 5 mph (8 km/h) forced crawl speed.

2. Diagnostic Trouble Codes (DTCs)

Connecting Cummins INSITE™ or a J1939 diagnostic scan tool will return specific fault codes associated with the tank header:

• SPN 1761 / FMI 9 or 19: DEF Tank Level - Abnormal Update Rate or Error.

• SPN 3031 / FMI 2 or 9: DEF Tank Temperature - Data Erratic, Intermittent, or Incorrect.

• SPN 3516 / FMI 2, 9, or 12: DEF Concentration (Quality) - Bad Device, Component, or Data Erratic.

• SPN 3364 / FMI 9: Improper DEF Quality Detected.

3. Inaccurate, Frozen, or Erratic Level Gauge

A failed ultrasonic level sensing circuit inside the GA111564 causes false tank level readings:

• The DEF level gauge on the cluster stays stuck at 100% (Full) or drops instantly to 0% (Empty) despite the tank being filled.

• Repeated "Refill DEF Tank" warnings occur unexpectedly during operation.

4. False "Poor DEF Quality" Warnings

If the integrated quality/concentration sensor fails internally, it reports incorrect urea purity values to the ECM:

• The driver display shows alerts such as "Incorrect DEF Quality Detected" or "Service DEF System" even when filled with clean, fresh DEF (~32.5% urea).

5. DEF Heating & Thawing Failures in Cold Weather

If the built-in thermistor or heating loop fails:

• In freezing conditions, frozen DEF will not melt properly, preventing liquid flow to the dosing pump.

• The ECM registers a lack of DEF dosing pressure and generates active SCR system codes

If the integrated quality/concentration sensor fails internally, it reports incorrect urea purity values to the ECM:

• The driver display shows alerts such as "Incorrect DEF Quality Detected" or "Service DEF System" even when filled with clean, fresh DEF (~32.5% urea).

5. DEF Heating & Thawing Failures in Cold Weather

If the built-in thermistor or heating loop fails:

• In freezing conditions, frozen DEF will not melt properly, preventing liquid flow to the dosing pump.

• The ECM registers a lack of DEF dosing pressure and generates active SCR system codes