Aftertreatment 1 DPF Differential Pressure Sensor Circuit – Voltage Above Normal or Shorted to High Source
Overview
| CODE | REASON | EFFECT |
| Fault Code: 1879 PID: S324 SPN: 3251 FMI: 3/3 LAMP: Amber SRT: |
High signal voltage detected at the aftertreatment differential pressure sensor circuit.
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Possible reduced engine performance.
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Aftertreatment Diesel Particulate Filter Differential Pressure Sensor Circuit
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Circuit Description
The engine control module (ECM) provides a 5 volt supply to the aftertreatment diesel particulate filter differential pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The aftertreatment diesel particulate filter differential pressure sensor provides a signal to the ECM on the aftertreatment diesel particulate filter differential pressure sensor signal circuit. This sensor signal voltage changes, based on the differential pressure across the aftertreatment diesel particulate filter.
Component Location
The aftertreatment diesel particulate filter differential pressure sensor is mounted on the diesel particulate filter. It is a combination sensor that detects both diesel particulate filter differential pressure and outlet pressure. Refer to the original equipment manufacturer (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 particulate filter differential pressure 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.
- A default value for the aftertreatment diesel particulate filter differential pressure is used.
- Diesel exhaust fluid injection into the aftertreatment system is disabled.
- Active and stationary regeneration of the diesel particulate filter will be disabled.
- Exhaust gas recirculation (EGR) valve operation will be 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.
Troubleshooting Summary
- Check for primary fault codes
- Aftertreatment DPF differential pressure sensor voltage check
- Aftertreatment DPF differential pressure sensor circuit check
- Aftertreatment DPF differential pressure sensor circuit response
- Aftertreatment DPF differential pressure sensor open circuit check
- Aftertreatment DPF differential pressure sensor wire pin to pin short circuit check
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:
- Sensor supply 5: 1695, 1696
Linked Solutions
- None
Repair
- Perform a search on the appropriate fault codes.
Validation
- None
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment DPF differential pressure sensor from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Turn keyswitch ON.
- Measure the voltage between the aftertreatment DPF differential/outlet pressure sensor SUPPLY pin and the aftertreatment DPF differential/outlet pressure sensor RETURN pin at the sensor connector of the OEM wiring harness.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- Proceed to the Linked Solutions section and perform the open circuit check if voltage is not within the following specification: 4.75 – 5.25 VDC
Linked Solutions
- Aftertreatment DPF differential pressure sensor circuit check
Repair
- No additional action is required for this solution.
Validation
- None
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment DPF differential pressure sensor from the OEM wiring harness.
- Disconnect the OEM wiring harness connector from the ECM.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the OEM wiring harness ECM connector aftertreatment DPF differential pressure sensor SUPPLY pin and the OEM wiring harness aftertreatment DPF differential pressure sensor connector SUPPLY pin.
- Measure the resistance between the OEM wiring harness ECM connector aftertreatment DPF differential pressure sensor RETURN pin and the OEM wiring harness aftertreatment DPF differential pressure sensor connector RETURN pin.
- 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 greater than the following specification: 10 Ω
- A malfunctioning ECM has been detected if the resistance is less than the following specification: 10 Ω
Linked Solutions
- None
Repair
Repair or replace only the components that were found to be out of specification.
- Repair or replace the OEM wiring harness.
- Replace the ECM.
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 DPF differential pressure sensor from the OEM wiring harness.
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 DPF differential pressure sensor has been detected if the following fault code became active with the sensor disconnected: 1881
Linked Solutions
- None
Repair
- Replace aftertreatment DPF differential/outlet pressure 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 OEM wiring harness connector from the ECM.
- Disconnect the aftertreatment DPF differential pressure sensor from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the OEM wiring harness ECM connector aftertreatment DPF differential pressure sensor RETURN pin and the OEM wiring harness aftertreatment DPF differential pressure sensor connector RETURN pin.
- 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 greater than the following specification: 10 Ω
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 OEM wiring harness connector from the ECM.
- Disconnect the accelerator pedal or lever from the OEM wiring harness.
- Disconnect the remote accelerator pedal or lever from the OEM wiring harness.
- Disconnect the engine coolant level sensor from the OEM wiring harness.
- Disconnect the fan speed sensor from the OEM wiring harness.
- Disconnect the aftertreatment DPF differential pressure sensor from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the aftertreatment DPF differential pressure sensor SIGNAL pin in the OEM wiring harness ECM connector and all other pins in the OEM wiring harness ECM connector.
- Measure the resistance between the aftertreatment DPF differential pressure sensor SUPPLY pin in the OEM wiring harness ECM connector and all other pins in the OEM wiring harness ECM 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: 100k Ω
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.
If all steps have been completed and no root cause has been identified, then follow the technical escalation process.