Overview
| CODE | REASON | EFFECT |
| Fault Code: 1681 PID: SPN: 3361 FMI: 12/12 LAMP: Amber SRT: |
An internal error has been detected in the aftertreatment diesel exhaust fluid dosing unit.
|
Possible reduced engine performance. |
Circuit Description
The aftertreatment diesel exhaust fluid dosing unit precisely measures the amount of aftertreatment diesel exhaust fluid to be injected into the aftertreatment system. The aftertreatment diesel exhaust fluid dosing unit has three primary cycles. A priming cycle makes sure that aftertreatment diesel exhaust fluid is available at the aftertreatment diesel exhaust fluid dosing unit. During the dosing cycle, aftertreatment diesel exhaust fluid is being delivered to the aftertreatment dosing valve. A purge cycle occurs when the engine is turned OFF. The purge cycle makes sure that all the aftertreatment diesel exhaust fluid is removed from the diesel exhaust fluid lines and dosing valve.
Component Location
The aftertreatment diesel exhaust fluid dosing unit location is original equipment manufacturer (OEM) dependent. Refer to the OEM service manual.
Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.
Conditions for Setting the Fault Codes
The aftertreatment diesel exhaust fluid dosing unit detected an internal error.
Action Taken When the Fault Code is Active
- The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
- Diesel exhaust fluid injection into the aftertreatment system is disabled.
Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
Conditions for Clearing the Fault Code
- To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
- The fault code status displayed by the recommended Cummins® electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
- The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
- For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
- The “Reset All Faults” command in the recommended Cummins® electronic service tool or equivalent can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.
Shop Talk
Fault code 1681 is triggered when the aftertreatment diesel exhaust fluid dosing unit has detected an internal error.
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.
Troubleshooting Summary
- Check for primary fault codes
- Technical Service Bulletin is available
- Aftertreatment diesel exhaust fluid dosing unit connector is malfunctioning
- Aftertreatment diesel exhaust fluid dosing unit line or fittings are cracked, plugged or restricted
- Leaks in the aftertreatment diesel exhaust fluid dosing system
- OEM ambient air temperature sensor stuck in-range
- Aftertreatment diesel exhaust fluid controller software phase check
- Aftertreatment diesel exhaust fluid dosing unit is malfunctioning
Solution: S00002314
Verification
Conditions
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Use the recommended Cummins® electronic service tool or equivalent to read the fault codes.
Specification
Before troubleshooting this fault code, troubleshoot any fault code that is active or has more than one inactive count within the last 25 engine operating hours from the following list:
- Intake manifold temperature: 436
- Ambient air temperature: 2398
- Aftertreatment diesel exhaust fluid system: 1679, 3426, 3429, 3557, 3571, 3572, 3577, 3578, 3679, 4157
- Aftertreatment diesel exhaust fluid dosing unit: 2976, 3558, 3559, 3679
Linked Solutions
- None
Repair
- Perform a search on the appropriate fault codes.
Validation
- None
Solution: S00009675
Verification
Conditions
- Turn keyswitch OFF.
Specification
- Proceed to the Repair section if the Technical Service Bulletin is applicable.
Linked Solutions
- None
Repair
- Complete the action outlined in the Technical Service Bulletin.
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the «Conditions for Clearing the Fault Code» found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00002928
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment diesel exhaust fluid dosing unit from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Inspect all connections for corrosion or loose connections.
Specification
- If the aftertreatment diesel exhaust fluid dosing unit connector or the aftertreatment diesel exhaust fluid dosing unit wiring harness connector show signs of diesel exhaust fluid, then a malfunctioning aftertreatment diesel exhaust fluid dosing unit connector has been detected.
Linked Solutions
- None
Repair
Repair or replace only the components that were found to be out of specification.
- Replace aftertreatment diesel exhaust fluid dosing unit.
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the «Conditions for Clearing the Fault Code» found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00000664
Verification
Conditions
- Turn keyswitch OFF.
Action
- Verify the lines are not swapped at the dosing unit, dosing valve or diesel exhaust fluid tank connections.
- Visually inspect the aftertreatment diesel exhaust fluid tank connections for cracks or pitting.
- Visually inspect the aftertreatment diesel exhaust fluid tank vent line for restrictions.
- Visually inspect the aftertreatment diesel exhaust fluid line for damage.
- Visually inspect both dosing unit connections and fittings for loose, leaking, or damaged connections.
- Disconnect the suction line and pressure line dosing unit connectors and look for signs of build-up or blockage.
- Inspect the aftertreatment diesel exhaust fluid dosing unit inlet connector screen.
- Visually inspect the suction line for signs of leakage or openings which will allow the dosing unit to suck in air with the diesel exhaust fluid.
- Visually inspect the pressure line for signs of leakage or rupture.
- Verify proper sealing at all connection points, including diesel exhaust fluid tank, dosing unit, and dosing valve.
Specification
- If there are aftertreament diesel exhaust fluid lines reversed, damaged, leaking or restricted connections found, then proceed to the Repair section.
Linked Solutions
- None
Repair
- Repair or replace damaged components.
Refer to OEM Service Manual
- Replace the aftertreatment diesel exhaust fluid dosing unit inlet connector screen.
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the «Conditions for Clearing the Fault Code» found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00002840
Verification
Conditions
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Perform the Aftertreatment Diesel Exhaust Fluid System Leak Test found under ECM Diagnostic Tests.
- While the test is running, inspect the diesel exhaust fluid tank connectors, diesel exhaust fluid dosing unit and dosing unit connectors, diesel exhaust fluid lines, and diesel exhaust fluid dosing valve for signs of external leaks.
Specification
- If a line, fitting, connection, or dosing unit is leaking, then a malfunction has been detected in the aftertreatment diesel exhaust fluid system or dosing unit.
Linked Solutions
- None
Repair
Repair or replace only the components that were found to be out of specification.
- Replace aftertreatment diesel exhaust fluid dosing unit.
- Replace the aftertreatment diesel exhaust fluid dosing valve.
- Repair or replace the leaking diesel exhaust fluid line, connector or fitting.
Refer to OEM Service Manual
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the «Conditions for Clearing the Fault Code» found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00000339
Verification
Conditions
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Use the recommended Cummins® electronic service tool or equivalent.
- Monitor the OEM ambient air temperature sensor.
Specification
- A malfunctioning temperature sensor has been detected if the temperature sensor is not within the following specification of local ambient air temperature: 5°F [2.8°C]
Linked Solutions
- None
Repair
- Replace the ambient air temperature sensor.
Refer to OEM Service Manual
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the «Conditions for Clearing the Fault Code» found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00003120
Verification
Conditions
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Use the recommended Cummins® electronic service tool or equivalent.
- Verify the present aftertreatment diesel exhaust fluid controller software phase.
Specification
- If the aftertreatment diesel exhaust fluid controller software phase revision is not the latest, then proceed to the Repair section.
Linked Solutions
- None
Repair
- Download the updated diesel exhaust fluid controller calibration code.
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the «Conditions for Clearing the Fault Code» found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00000677
Verification
Conditions
- Connect the aftertreatment diesel exhaust fluid dosing unit to the OEM wiring harness.
Action
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
- Use the recommended Cummins® electronic service tool or equivalent.
- Perform the Aftertreatment Diesel Exhaust Fluid System Leak Test found under ECM Diagnostic Tests.
Specification
- If the fault code is still active after the Aftertreatment Diesel Exhaust Fluid System Leak Test is completed, then a malfunctioning aftertreatment diesel exhaust fluid dosing unit has been detected.
Linked Solutions
- None
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the «Conditions for Clearing the Fault Code» found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
If all steps have been completed and no root cause has been identified, then follow the technical escalation process.