Aftertreatment 1 SCR Outlet Temperature Sensor Circuit – Voltage Above Normal or Shorted to High Source
Overview
| CODE | REASON | EFFECT |
| Fault Code: 3146 PID: SPN: 4363 FMI: 3/3 LAMP: Amber SRT: |
High signal voltage detected at the SCR outlet temperature sensor circuit.
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Possible reduced engine performance.
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Aftertreatment SCR Catalyst Temperature Sensor Module
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Circuit Description
The aftertreatment SCR (selective catalytic reduction) temperature sensor module is a smart device that communicates with the engine control module via the J1939 data link. The aftertreatment SCR temperature sensor module performs its own internal diagnostics and reports malfunctions back to the engine control module using the J1939 data link. The aftertreatment SCR temperature sensor module is used to measure the aftertreatment SCR intermediate temperature and aftertreatment SCR outlet temperature. The temperature probes are permanently attached to the aftertreatment SCR temperature sensor module and can not be replaced individually.
Component Location
The aftertreatment SCR temperature sensor module is mounted on the aftertreatment SCR catalyst.
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 SCR temperature sensor module reported the aftertreatment SCR outlet temperature signal was out of range high.
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.
Possible causes of this fault code include:
- Open return circuit in the harness, connectors, or sensor
A malfunctioning aftertreatment SCR outlet temperature sensor
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.
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
- Aftertreatment SCR temperature sensor module circuit resistance check
- Aftertreatment SCR temperature sensor circuit response
- Aftertreatment SCR temperature sensor open circuit check
- Aftertreatment SCR outlet temperature sensor circuit pin to pin short
- Aftertreatment SCR temperature sensor module pin to pin short circuit check
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment SCR temperature sensor module from the OEM wiring harness.
- Disconnect the aftertreatment SCR outlet temperature sensor from the aftertreatment SCR temperature sensor module.
- Disconnect the aftertreatment SCR intake temperature sensor from the aftertreatment SCR temperature sensor module.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance of each circuit contained within the aftertreatment SCR temperature sensor module.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- If the resistance is not within specification, then a malfunctioning aftertreatment SCR temperature sensor module has been detected.
Linked Solutions
- None
Repair
- Replace the aftertreatment SCR temperature sensor module.
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.
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment SCR outlet temperature sensor from the aftertreatment SCR temperature sensor module.
Action
- Inspect the pins and connectors for damage.
- Wait 30 seconds before checking the circuit response.
- Place a jumper wire between the aftertreatment SCR outlet temperature sensor SIGNAL pin and the aftertreatment SCR outlet temperature sensor RETURN pin at the aftertreatment SCR outlet temperature sensor connector of the OEM wiring harness.
- Turn keyswitch ON.
- Use the recommended Cummins electronic service tool or equivalent to read the fault codes.
Specification
- A malfunctioning aftertreatment SCR outlet temperature sensor has been detected if the following fault code became active with the jumper wire in place: 3147
Linked Solutions
- None
Repair
- Replace aftertreatment SCR outlet temperature sensor.
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.
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment SCR temperature sensor module from the OEM wiring harness.
- Disconnect the engine wiring harness connector from the ECM.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the engine wiring harness ECM connector SCR outlet temperature sensor SIGNAL pin and the engine wiring harness 14-pin crossover connector aftertreatment SCR outlet temperature sensor SIGNAL pin.
- Measure the resistance between the engine wiring harness ECM connector SCR outlet temperature sensor RETURN pin and the engine wiring harness 14-pin crossover connector aftertreatment SCR outlet temperature sensor RETURN pin.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- A malfunctioning engine wiring harness has been detected if the resistance is greater than the following specification: 10 Ω
Linked Solutions
- None
Repair
- Repair or replace the engine wiring harness.
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.
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment SCR temperature sensor module from the OEM wiring harness.
- Disconnect the aftertreatment SCR outlet temperature sensor from the aftertreatment SCR temperature sensor module.
- Disconnect the aftertreatment SCR intake temperature sensor from the aftertreatment SCR temperature sensor module.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between aftertreatment SCR outlet temperature sensor SIGNAL pin in the aftertreatment SCR temperature sensor module connector to all other pins in the aftertreatment SCR temperature sensor module connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- A malfunctioning OEM wiring harness has been detected if the resistance is less than the following specification:
Linked Solutions
- None
Repair
- Repair or replace the OEM wiring harness.
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.
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment SCR temperature sensor module from the OEM wiring harness.
- Disconnect the aftertreatment SCR outlet temperature sensor from the aftertreatment SCR temperature sensor module.
- Disconnect the aftertreatment SCR intake temperature sensor from the aftertreatment SCR temperature sensor module.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between aftertreatment SCR intake temperature sensor SIGNAL pin in the aftertreatment SCR temperature sensor module connector to all other pins in the aftertreatment SCR temperature sensor module connector.
- Measure the resistance between aftertreatment SCR outlet temperature sensor SIGNAL pin in the aftertreatment SCR temperature sensor module connector to all other pins in the aftertreatment SCR temperature sensor module connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- A malfunctioning aftertreatment SCR temperature sensor module has been detected if the resistance is less than the following specification: 100k Ω
Linked Solutions
- None
Repair
- Replace the aftertreatment SCR temperature sensor module.
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.