Overview
| CODE | REASON | EFFECT |
| Fault Code: 3143 PID: SPN: 4360 FMI: 4/4 LAMP: Amber SRT: |
Low signal voltage detected at the selective catalytic reduction (SCR) intake temperature sensor circuit.
|
Engine power derate. |
Circuit Description
The selective catalytic reduction (SCR) intake temperature sensor is used by the engine control module (ECM) to monitor the engine exhaust temperature entering the SCR catalyst. The ECM monitors the voltage on the signal pin and converts this to a temperature value.
Component Location
The SCR intake temperature sensor is located in the aftertreatment system. It is located between the diesel particulate filter and the SCR catalyst in the exhaust system.
Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position.
Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the SCR intake temperature sensor signal voltage was less than 0.13-VDC for more than 2 seconds.
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.
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
Possible causes of this fault code include:
- Malfunctioning or damaged aftertreatment SCR temperature sensor module.
- Malfunctioning or damaged aftertreatment SCR intake temperature sensor.
- Malfunctioning or damaged OEM wiring harness.
- Malfunctioning or damaged SCR aftertreatment interface harness
Troubleshooting Summary
- Aftertreatment SCR temperature sensor module circuit resistance check
- Aftertreatment SCR temperature sensor circuit response
- Aftertreatment SCR intake temperature sensor circuit pin to ground short
- Aftertreatment SCR intake temperature sensor circuit pin to pin short
- Aftertreatment SCR temperature sensor module pin to pin short circuit check
Solution: S00002924
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
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: S00004037
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment SCR intake temperature sensor from the aftertreatment SCR temperature sensor module.
Action
- Inspect the pins and connectors for damage.
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
- Wait 30 seconds before checking the circuit response.
- Use the recommended Cummins® electronic service tool or equivalent to read the fault codes.
Specification
- A malfunctioning aftertreatment SCR intake temperature sensor has been detected if the following fault code became active with the sensor disconnected: 3142
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: S00003396
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the OEM wiring harness connector from the ECM.
- Disconnect the aftertreatment SCR temperature sensor module from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the aftertreatment SCR intake temperature sensor SIGNAL pin at the OEM wiring harness 14-pin crossover connector and ground.
- 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.
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: S00003325
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment SCR intake temperature sensor from the aftertreatment SCR temperature sensor module.
- Disconnect the engine wiring harness from the OEM wiring harness crossover connector.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the aftertreatment SCR intake temperature sensor SIGNAL pin at the OEM wiring harness 14-pin crossover connector and all other pins in the connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- Proceed to the Repair section if the resistance is less than the following specification:
Linked Solutions
- None
Repair
- Replace SCR aftertreatment interface harness.
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: S00003032
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
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.