Overview
| CODE | REASON | EFFECT |
| Fault Code: 1694 PID: SPN: 3226 FMI: 2/2 LAMP: Amber SRT: |
An incorrect NOx sensor reading has been detected by the aftertreatment outlet NOx sensor.
|
Possible reduced engine performance. |
Circuit Description
The aftertreatment outlet NOx (nitrogen oxides) sensor is a smart device and communicates with the engine control module (ECM) via the J1939 data link. The aftertreatment outlet NOx sensor performs its own internal diagnostics and reports malfunctions back to the primary ECM using the J1939 data link. The NOx sensor is permanently attached to the NOx control module. They are serviced as a single component and can not be replaced individually. The aftertreatment outlet NOx sensor is used to measure the NOx emissions at the outlet of the aftertreatment system.
Component Location
The aftertreatment outlet NOx sensor location can vary depending on engine application. It is usually located in the exhaust system at the outlet of the selective catalytic reduction (SCR) catalyst.
Conditions for Running the Diagnostics
This diagnostic has to meet specific engine and aftertreatment conditions to run and complete.
Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the aftertreatment outlet NOx sensor reading was not changing with engine conditions or is stuck.
Action Taken When the Fault Code is Active
- The ECM illuminates the amber CHECK ENGINE lamp and/or malfunction indicator lamp (MIL) after the diagnostic fails on two consecutive trips.
Conditions for Clearing the Fault Code
- To validate the repair, start and operate the engine to raise exhaust temperatures.
- To validate the repair using a Chassis Dynamometer, utilize a routine that incorporates acceleration and motoring events, steady state highway type operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.
- To validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop and go city type driving and steady state highway type driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.
- 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
Possible causes of this fault code include:
Diesel exhaust fluid crystallization or deposits
Incorrectly installed aftertreatment outlet NOx sensor
Malfunctioning aftertreatment outlet NOx sensor
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM
This diagnostic will NOT run during a regeneration.
For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.
Troubleshooting Summary
- Check for primary fault codes
- Aftertreatment exhaust system leaks
- Deposits in the SCR decomposition tube
- Leaks in the aftertreatment diesel exhaust fluid dosing system
- Aftertreatment Diesel Exhaust Fluid Doser Pump Override test
- Aftertreatment diesel exhaust fluid dosing valve is malfunctioning
- Aftertreatment outlet NOx sensor is malfunctioning
Solution: S00000146
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:
- Aftertreatment NOx: 1885, 1887, 2771, 3228, 3232, 3545, 3583, 3649, 3681, 3682, 3725, 3748, 3749
Linked Solutions
- None
Repair
- Perform a search on the appropriate fault codes.
Validation
- None
Solution: S00001008
Verification
Conditions
- Engine running.
Action
- Visually inspect for leaks in the exhaust manifold to head.
- Visually inspect for leaks from the turbocharger to exhaust manifold.
- Visually inspect for leaks in the exhaust plumbing between the turbocharger outlet and the Aftertreatment DOC intake connection.
- Visually inspect the exhaust piping for leaks, cracks, and loose connections.
- Inspect for leaks at the aftertreatment DOC housing, sensor ports and connection points.
- Visually inspect the aftertreatment and SCR components for exhaust leaks.
Specification
- If there is any damage or leaks found in the exhaust system, then proceed to the Repair section.
Linked Solutions
- None
Repair
Repair or replace only the components that were found to be out of specification.
- Replace the exhaust manifold.
- Repair or replace the exhaust plumbing.
Refer to OEM Service Manual
- Replace aftertreatment DOC.
- Replace the aftertreatment diesel particulate filter.
- Replace the aftertreatment SCR Catalyst.
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: S00000564
Verification
Conditions
- Turn keyswitch OFF.
Specification
- If any excessive aftertreatment diesel exhaust fluid deposits were found inside the decomposition tube, then a plugged or restricted aftertreatment decomposition tube has been detected.
- Proceed to Linked Solutions section for additional checks.
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: S00000735
Verification
Conditions
- Turn keyswitch OFF.
- Reconnect all aftertreatment diesel exhaust fluid lines and electrical connectors to the dosing unit and aftertreatment diesel exhaust fluid tank if they have been previously disconnected during troubleshooting.
Action
- Remove the aftertreatment diesel exhaust fluid dosing valve.
- Perform the Aftertreatment Diesel Exhaust Fluid System Leak Test found under ECM Diagnostic Tests.
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
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: S00002761
Verification
Conditions
- Reconnect all aftertreatment diesel exhaust fluid lines and electrical connectors to the dosing unit and aftertreatment diesel exhaust fluid tank if they have been previously disconnected during troubleshooting.
Action
- Remove the aftertreatment diesel exhaust fluid dosing valve from the decomposition tube.
- 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 Doser Pump Override Test.
The Aftertreatment Diesel Exhaust Fluid Doser Pump Override test can only be ran twice before a key cycle needs to be performed.
Specification
- If the Aftertreatment Diesel Exhaust Fluid Doser Pump Override Test meets the specification, then proceed to the next solution.
- If the Aftertreatment Diesel Exhaust Fluid Doser Pump Override Test does not meet the specification, then proceed to the Linked Solutions section.
Linked Solutions
Click on the link below:
- Aftertreatment diesel exhaust fluid dosing valve is malfunctioning
Repair
- No additional action is required for this solution.
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: S00002764
Verification
Conditions
- Turn keyswitch OFF.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Clean the aftertreatment diesel exhaust fluid dosing valve.
- Turn keyswitch ON.
- Use the recommended Cummins® electronic service tool or equivalent.
- Perform the Aftertreatment Diesel Exhaust Fluid Doser Pump Override Test.
Specification
- If the Aftertreatment Diesel Exhaust Fluid Doser Pump Override Test is not within specification, then proceed to the Repair section.
Linked Solutions
- None
Repair
Repair or replace only the components that were found to be out of specification.
- Replace the aftertreatment diesel exhaust fluid dosing valve.
- 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: S00000994
Verification
Conditions
- None
Action
- Verify all preceding solution verifications for this fault code have been performed.
Specification
- If the fault code is still active or inactive with more than one count within the last 25 engine hours and all the preceding solution verifications have been performed, then a malfunctioning aftertreatment outlet NOx sensor 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.