Cummins ISX11.9 CM2250 – Service Manual 011-063   Aftertreatment Diesel Exhaust Fluid Dosing Unit Override Test

Perform a dosing cycle to check the:

• Aftertreatment diesel exhaust fluid (DEF) dosing valve spray characteristics
• Amount of DEF to be delivered in a specified time (6 minutes).

The test can be accessed through INSITE™ electronic service tool, under ECM Diagnostic Tests. Follow the on-screen instructions to perform the test.

Check for any leaks, blockages, or restrictions in the DEF line, between the aftertreatment DEF dosing unit and the aftertreatment DEF dosing valve.

Repair as necessary. Refer to the OEM service manual.

Check for an adequate amount of DEF in the DEF tank prior to starting this test.

Check the concentration and quality of the DEF. Refer to Procedure 011-056 in Section 11.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injeury, 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.

NOTE: Low battery voltage can cause the dosing volume to be low. Check the batteries. Refer to the OEM service manual.

• Remove the aftertreatment DEF dosing valve. Refer to Procedure 011-059 in Section 11.
• Make sure the batteries are connected correctly. Refer to the OEM service manual.

CAUTION  Care should be taken when handling and/or disconnecting the DEF line from the aftertreatment DEF dosing valve. The intake connection of the aftertreatment DEF dosing valve is plastic and can be easily damaged.

CAUTION  Do not connect a 12-VDC or 24-VDC supply to the aftertreatment DEF dosing valve. This will cause permanent damage.

Connect the electrical and DEF lines. Refer to Procedure 011-059 in Section 11.

NOTE: The coolant plumbing does not need to be connected for this test.

NOTE: There may not be enough length for the existing electrical and/or DEF line to allow the aftertreatment DEF dosing valve to be placed in the container. Use service tool kit, Part Number 4919573, which contains:

1. Wiring harness extension, Part Number 4919575
2. DEF extension line, Part Number 4919574
3. Coolant line plug, Part Number 4919576.

NOTE: It is usually easier to capture the DEF in a clean container and transfer the DEF to the measuring device for the final measurement.

Obtain a clear plastic container (large enough to hold the aftertreatment DEF dosing valve) and a graduated beaker, Part Number 4919139, or equivalent. A measurement cup that is marked in milliliters (ml) or ounces (oz) can also be used.

The measuring device must be capable of measuring between 0 ml [0.0 oz] and 500 ml [17.0 oz] in 5 ml [0.34 oz] increments.

Place the aftertreatment DEF dosing valve into the container.

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 DEF is ingested, contact a physician immediately. Reference the materials safety data sheet (MSDS) for additional information.

NOTE: When the test is started, the dosing system will first prime. During this process the aftertreatment DEF dosing valve will open intermittently to purge air from the system. In doing so, some DEF will be sprayed from the tip. This is a normal operating characteristic.

When the test is being performed, the aftertreatment DEF dosing valve will spray a very fine mist of diesel exhaust fluid. To prevent fine mist from escaping into the air, and to make sure of an accurate measurement, place a clean shop towel or cover over the valve and container.

When the test begins, briefly monitor the spray pattern of the DEF exiting the aftertreatment DEF dosing valve. Look for:

• Signs of larger drops and/or dripping DEF from the tip
• A spray pattern that is not symmetrical (sprays more to one side).

If any of these symptoms are noted, stop the test and inspect the aftertreatment DEF dosing valve tip. Use the Clean and Inspect section of the following procedure. Refer to Procedure 011-059 in Section 11.

If necessary, perform the test again and monitor the spray pattern. If the problem persists, replace the aftertreatment DEF dosing valve. Refer to Procedure 011-059 in Section 11.

NOTE: Prior to performing this test, if not already directed by a fault code troubleshooting tree, view and troubleshoot any fault codes with INSITE™ electronic service tool and the ISB6.7 CM2250, ISC8.3 and ISL9 CM2250, and ISX15 CM2250 Fault Code Troubleshooting Manual, Bulletin 4022225.

• Turn the keyswitch ON.
• Connect INSITE™ electronic service tool.
• Locate the DEF Doser Pump Override Test under ECM Diagnostic Tests.
• Follow the on-screen instructions to perform the test.

INSITE™ electronic service tool will start the test and will inject the DEF for 6 minutes. INSITE™ electronic service tool will automatically disable the injector at the end of the test.  If the test needs to be stopped before finishing, click the Stop button.

After the test is complete (the test runs 6 minutes), measure the amount of DEF sprayed into the container. Pour the DEF into the graduated beaker, Part Number 4919139, or equivalent.

Perform the test three times and average the results of the three tests.

Aftertreatment DEF Dosing Valve Volume Specifications

NOTE: Do not pour the DEF back into the DEF tank. Dispose of the DEF in accordance with local environmental regulations.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injeury, 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.

NOTE: Low battery voltage can cause the dosing volume to be low. Check the batteries. Refer to the OEM service manual. View and troubleshoot any fault codes with INSITE™ electronic service tool and the ISB6.7 CM2250, ISC8.3 and ISL9 CM2250, and ISX15 CM2250 Fault Code Troubleshooting Manual, Bulletin 4022225.

If the amount of DEF is not within specification, verify the DEF filter is not plugged and check for leaks, blockages, or restrictions in the DEF line between the aftertreatment DEF dosing unit and the aftertreatment DEF dosing valve. 

If the amount of DEF collected is not within specification, and none of the above are found to be causing an issue, replace the aftertreatment DEF dosing valve.

NOTE: The aftertreatment DEF dosing valve may have been plugged by debris. Also inspect the aftertreatment DEF dosing unit filter for signs of contamination and debris prior to installing the new aftertreatment DEF dosing valve. Refer to Procedure 011-060 in Section 11.

CAUTION  Do not submerge the aftertreatment DEF dosing valve in solvent or water. Damage to the aftertreatment DEF dosing valve will result.

After the test is complete, a light coating of DEF will cover the aftertreatment DEF dosing valve, DEF line, and electrical line. 

Use a clean shop towel soaked in warm water to wipe the coating of DEF from the components prior to disconnecting anything.

NOTE: Make sure to clean any service tools used for this test with warm distilled water prior to storage.

Disconnect the electrical and DEF lines.  Refer to Procedure 011-059 in Section 11.

If used, remove the service tool extensions.

• Connect the batteries. Refer to the OEM service manual.
• Install the aftertreatment DEF dosing valve. Refer to Procedure 011-059 in Section 11.
• Operate the engine and check for leaks.