Cummins ISX11.9 CM2250 – Service Manual 011-058   Aftertreatment Diesel Exhaust Fluid Dosing Unit

The aftertreatment diesel exhaust fluid (DEF) dosing unit draws diesel exhaust fluid from the aftertreatment diesel exhaust fluid tank, pressurizes the diesel exhaust fluid, and delivers the diesel exhaust fluid to the aftertreatment diesel exhaust fluid dosing control valve. Any unused diesel exhaust fluid is then routed back to the aftertreatment diesel exhaust fluid tank. Use the following procedure for further information on the aftertreatment diesel exhaust fluid dosing system. Refer to Procedure 011-999 in Section F.

Use the following procedure for information on handling incorrect or contaminated diesel exhaust fluid. Refer to Procedure 011-056 in Section 11.

NOTE: There are 12 and 24 volt versions of the DEF dosing unit.  The voltage rating is stamped into the housing of the aftertreatment DEF dosing unit, next to the electrical connection.  The aftertreatment DEF dosing unit can also be distinguished by its connector.  If the face of the electrical connector on the electrical harness is gray, it is a 24-VDC unit. If it is black, it is a 12-VDC unit.  The electrical connectors are keyed differently and are not interchangeable.

The aftertreatment diesel exhaust fluid dosing unit has a serviceable filter. Refer to Procedure 011-060 in Section 11.

If the aftertreatment diesel exhaust fluid dosing unit is damaged, the entire assembly must be replaced.

Check the diesel exhaust fluid lines going to and returning from the dosing unit for any signs of leak. Diesel exhaust fluid will form white deposits around leaky fittings.

If deposits are found, inspect the diesel exhaust fluid line connection fittings for damage. Refer to the OEM service manual for assistance with DEF lines.

Check around the aftertreatment DEF dosing unit filter cap for white deposits.

For visible leaks from the aftertreatment DEF dosing unit connectors or filter cap, follow the Clean and Inspect for Reuse section in this procedure.

WARNING  Diesel Exhaust Fluid (DEF) contains urea. Do not get the substance in your eyes. In case of contact, immediately flush eyes with large amounts of water for a minimum of 15 minutes. Do not swallow. In the event the diesel exhaust fluid is ingested, contact a physician immediately. Reference the Materials Safety Data Sheet (MSDS) for additional information.

WARNING  Batteries can emit explosive gases. To reduce the possibilityof personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.

WARNING  The diesel exhaust fluid line connecting the aftertreatment diesel exhaust fluid dosing unit to the aftertreatment diesel exhaust fluid dosing unit is under low pressure and should not be disconnected while the engine is running or before the system has completed the purge process after engine shutdown.  Disconnecting the diesel exhaust fluid line while under low pressure could cause diesel exhaust fluid to spray.

CAUTION  Do not pressure wash or steam clean this unit. Pressure washing or steam can damage the unit Use compressed air to remove any loose debris.

NOTE: Do not disconnect the vehicle batteries until the DEF dosing system has completed the purge cycle. Before beginning to remove and/or disconnect any components, wait at least 5 minutes after the keyswitch is turned OFF for the aftertreatment DEF dosing system to purge the DEF from the system. The purge cycle is an automatic process and does not require intervention to occur. The aftertreatment DEF dosing unit will create an audible pumping noise during the purging process.

• Disconnect the batteries. Refer to the OEM service manual.

Label and mark each diesel exhaust fluid line to its mating connector or the aftertreatment dosing control unit. If the lines are connected incorrectly, the system will not work properly and will light a fault lamp.

NOTE: The diesel exhaust fluid lines are connected to the dosing unit by quick release fittings that may vary between vehicle manufacturers. Refer to the OEM service manual for the detailed removal process.

Disconnect the diesel exhaust fluid lines and electrical connections in the following order to avoid accidental DEF contamination of the electrical connector:

1. Backflow – Diesel exhaust fluid return to the DEF tank
2. Inlet – Diesel exhaust fluid supply to the aftertreatment diesel exhaust fluid dosing unit
3. Outlet – Diesel exhaust fluid supply to the aftertreatment diesel exhaust fluid dosing valve
4. 12-pin electrical connector.

The 12-pin electrical connector can be removed by sliding the yellow portion of the connector outwards. The connector will then start to raise and disconnect itself from the DEF supply module.

Cap the connectors, DEF and electrical, of the aftertreatment diesel exhaust fluid dosing unit to prevent contamination and DEF leakage.

Remove the three mounting capscrews.

Remove the aftertreatment DEF dosing unit.

NOTE: The aftertreatment diesel exhaust fluid dosing unit must only be disassembled if a symptom has been identified that indicates further investigation is required.

Unscrew the DEF connector(s).

Once removed, make certain that the o-ring(s) is attached to the connector and not stuck inside the DEF dosing unit.

NOTE: This unit is not serviceable. Do not open the case. Return the unit to a Cummins® Authorized Repair Location.

Do not immerse the unit in any kind of solution.

Do not wash with any detergents.

Use only a clean damp cloth to wipe the unit.

Inspect the outside of the unit. If there are any cracks or other damage to the exterior of the case, electrical connectors, or the diesel exhaust fluid quick disconnect connectors, replace the dosing unit.

Use the following procedure if the aftertreatment diesel exhaust fluid dosing unit filter cap is damaged. Refer to Procedure 011-060 in Section 11.

NOTE: If damage or corrosion are found, also inspect the DEF line connection.  Refer to the OEM service manual.

If the aftertreatment DEF dosing unit connectors were removed, inspect for cracks and broken o-rings.

Replace the aftertreatment DEF dosing unit connectors or o-rings, if damaged.

The inlet connector on the aftertreatment DEF dosing unit has an incorporated, non-serviceable, filter screen.

Use a rubber tipped air gun and blow though the connector in the opposite direction of DEF flow onto a white piece of paper.

Inspect for debris on the paper, indicating a clogged connector. If the connector is clogged, replace it.

If debris is found in the inlet connector of the aftertreatment dosing valve, inspect the aftertreatment DEF tank filter. Refer to the OEM service manual.

Inspect the electrical connection of the aftertreatment DEF dosing unit for signs of corrosion and debris buildup.

If the pins are heavily corroded or damaged, replace the aftertreatment dosing unit.

If the electrical connector on the aftertreatment DEF dosing unit is damaged, also inspect the 12-pin electrical connector wiring harness. Refer to the OEM service manual.

If replacing the aftertreatment diesel exhaust fluid dosing unit, make sure to transfer the protective caps from the replacement aftertreatment diesel exhaust fluid dosing unit to the old aftertreatment diesel exhaust fluid dosing unit, prior to placing it in the core return box.

Fill out any requested information (engine serial number, mileage, VIN, etc.).

Lubricant is not required.

Install the connector.

NOTE: Make sure the aftertreatment DEF dosing unit is kept free from any contamination during installation to the vehicle. To reduce the possibility of false diesel exhaust fluid leak reports, use a clean damp cloth to wipe any spilled diesel exhaust fluid during the repair process.

Attach the aftertreatment diesel exhaust fluid dosing unit to the OEM mounting bracket and secure it with the three capscrews.

NOTE: Do not interchange 12 and 24-VDC aftertreatment diesel exhaust fluid dosing units.

Remove the caps on the electrical and DEF connectors.

Install the electrical connector first. DEF will cause the electrical connector pins to corrode. The 12-pin electrical connector can be installed by sliding the yellow portion of the connector inwards.  The connector will lower itself and lock on to the aftertreatment DEF dosing unit.

Connect the diesel exhaust fluid lines to the aftertreatment diesel exhaust fluid dosing unit in the following order, to avoid getting contamination in the electrical connector.    The DEF lines will snap when locked into place.

1. Backflow – Diesel exhaust fluid return to the DEF tank
2. Inlet – Diesel exhaust fluid supply to the aftertreatment diesel exhaust fluid dosing unit
3. Outlet – Diesel exhaust fluid supply to the aftertreatment diesel exhaust fluid dosing valve
4. 12-pin electrical connector.

Give the connectors a light tug to make sure they are secured correctly.

CAUTION  Do not use the flow test portion of INSITE™ electronic service tool Diesel Exhaust Fluid Doser Pump Override Test to check the system for leaks.  This will spray DEF into the exhaust system at too lower temperatures to evaporate, resulting in deposit formations in the exhaust system.

• Connect the batteries. Refer to the OEM service manual.
• Start and operate the engine.
• Use INSITE™ electronic service tool to check for active fault codes.

NOTE: The aftertreatment DEF dosing system will not prime until the correct selective catalytic reduction (SCR) temperatures are reached.  To verify that the system is correctly installed and does not leak, test drive the vehicle for a minimum of 15 minutes, to get the SCR system up to temperature.