Overview
| CODE | REASON | EFFECT |
| Fault Code: 1678 PID: SPN: 3031 FMI: 3/3 LAMP: Amber SRT: |
Aftertreatment Diesel Exhaust Fluid Tank Temperature Sensor – Voltage Above Normal or Shorted to High Source. High signal voltage or open circuit detected at the diesel exhaust fluid tank temperature sensor circuit
|
Possible reduced engine performance. |
Circuit Description
The aftertreatment diesel exhaust fluid tank temperature sensor is used to monitor the temperature of the aftertreatment diesel exhaust fluid inside the aftertreatment diesel exhaust fluid tank.
Component Location
The aftertreatment diesel exhaust fluid tank temperature sensor is located in the diesel exhaust fluid tank. Location of the tank and temperature sensor is 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 Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid tank temperature signal voltage 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.
Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
Engine torque will be severely reduced.
Vehicle speed will be limited to 8 km [5 mi] per hour after extended engine operation with the fault code 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
Possible causes of this fault code include:
A malfunctioning aftertreatment diesel exhaust fluid tank temperature sensor
- Open return circuit in the harness, connectors, or sensor
Open signal circuit or shorted to a voltage source.
The type of diesel exhaust fluid tank temperature and level sensor used can vary depending on the vehicle OEM. As a result, the physical and/or electrical sensor configuration may vary slightly from what is shown in the troubleshooting and wiring diagram information.
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
Solution: S00000397
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment diesel exhaust fluid tank temperature sensor from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Place a jumper wire between the aftertreatment diesel exhaust fluid tank temperature sensor SIGNAL pin and the aftertreatment diesel exhaust fluid tank temperature sensor RETURN pin at the sensor connector of the OEM wiring harness.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
- 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 diesel exhaust fluid tank temperature sensor has been detected if the following fault code became active with the jumper wire in place: 1677
Linked Solutions
- None
Repair
- Replace aftertreatment diesel exhaust fluid tank 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: S00000443
Verification
Conditions
- Connect all components.
- 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.
- 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 revision listed in the ECM calibration revision history for applicable changes.
Specification
- If a calibration update for this fault code is available, the ECM calibration revision must be that revision or higher.
Linked Solutions
- None
Repair
- Prior to downloading the ECM calibration, check to see that all job images and all other troubleshooting has been documented as downloading an ECM calibration will remove the fault codes on the ECM.
- Download the updated ECM 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: S00004854
Verification
Conditions
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Verify all preceding solution verifications for this fault code have been performed.
- Use the recommended Cummins® electronic service tool or equivalent to read the fault codes.
Specification
- If the fault code is still active after all the preceding solution verifications have been performed, then a malfunctioning aftertreatment diesel exhaust fluid tank temperature sensor has been detected.
Linked Solutions
- None
Repair
If an aftertreatment diesel exhaust fluid tank level, temperature, quality sensor unit has been replaced within the last 90 days, follow your technical escalation process PRIOR to performing any of the repair actions listed below:
The aftertreatment diesel exhaust fluid tank level sensor is a integrated part of the aftertreatment diesel exhaust fluid tank level, temperature, quality sensor unit and is not a servicable part.
- Replace the aftertreatment diesel exhaust fluid tank 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.
If all steps have been completed and no root cause has been identified, then follow the technical escalation process.