Overview
| CODE | REASON | EFFECT |
| Fault Code: 6688 PID: SPN: 5835 FMI: 9/9 LAMP: Amber SRT: |
No communication or an invalid data transfer rate detected on the J1939 data link between the ECM and the aftertreatment particulate matter sensor.
|
Possible reduced engine performance. |
Circuit Description
The aftertreatment particulate matter sensor is a smart device and communicates with the engine control module (ECM) via the J1939 data link. The aftertreatment particulate matter sensor performs internal diagnostics and reports malfunctions back to the primary ECM using the J1939 data link. The particulate matter sensor is permanently attached to the particulate matter control module. They are serviced as a single component and can not be replaced individually. The aftertreatment particulate matter sensor is used to measure the soot emissions at the outlet of the aftertreatment system.
Component Location
The aftertreatment particulate matter 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 runs continuously when the engine is running.
Conditions for Setting the Fault Codes
The Engine Control Module (ECM) lost communication with the aftertreatment particulate matter sensor via the J1939 data link.
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 the engine and let it idle for 1 minute.
- The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
- 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.
- 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 weak or damaged battery.
- Battery connections are loose or dirty.
- Malfunctioning or damaged fuse.
- Malfunctioning or damaged aftertreatment power relay.
- Malfunctioning or damaged OEM wiring harness.
- Malfunctioning or damaged engine wiring harness
- Malfunctioning or damaged datalink terminating resistors.
- Malfunctioning or damaged J1939 data link component.
Troubleshooting Summary
- Check for primary fault codes
- Multiple Technical Service Bulletins are available
- Low battery voltage
- Battery load test
- Ground inspection
- Aftertreatment particulate matter sensor voltage check
- Aftertreatment particulate matter sensor battery SUPPLY to block ground check
- Fault Code 6688 triggered by a malfunction in the J1939 data link with multiple OEM fault code
- J1939 data link terminating resistance is incorrect
- Variable geometry turbocharger actuator has incorrect J1939 terminating resistance
- Engine wiring harness has incorrect J1939 terminating resistance
- OEM wiring harness has incorrect J1939 terminating resistance
- J1939 data link harness open circuit check
- ECM calibration revision history check
Solution: S00000031
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:
- Turbocharger: 1894, 2636
Linked Solutions
- None
Repair
- Perform a search on the appropriate fault codes.
Validation
- None
Solution: S00010947
Verification
Conditions
- Turn keyswitch OFF.
Action
Only refer to the technical service bulletins for the fault codes being diagnosed.
All of the technical service bulletins listed may not apply to your application. Refer to the list of affected products in each technical service bulletin.
- Technical Service Bulletin is available for the following fault codes: 3868, 4572, 4677
- Technical Service Bulletin is available for the following fault codes: 3868, 4572, 4677
- Technical Service Bulletin is available for the following fault codes: 1894, 2771, 3232, 3868, 3911, 4151, 4152, 4572, 4677, 5177, 6688
- Technical Service Bulletin is available for the following fault codes: 2771, 3232
If this engine is not in a Blue Bird™ application, then proceed to the next solution.
- Technical Service Bulletin is available for the following fault codes: 2771, 3232, 3868, 4151, 4572, 4677, 6688
If this engine is not in a Freightliner® application, then proceed to the next solution.
- Technical Service Bulletin is available for the following fault codes: 427, 1894, 2636, 2771, 3232, 3326, 3328, 3488, 3868, 4151, 4152, 4572, 4677, 5177, 6688
If this engine is not in a PACCAR™ application, then proceed to the next solution.
- Technical Service Bulletin is available for the following fault codes: 3868,4572, 4677
Specification
- Proceed to the Repair section if the Technical Service Bulletin is applicable.
Linked Solutions
- None
Repair
- Complete the action outlined in the Technical Service Bulletin.
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: S00011171
Verification
Conditions
- Turn keyswitch OFF.
Action
- Visually inspect the batteries and the battery cable connections for corrosion.
- Measure the voltage from the positive (+) battery terminal to the negative (-) battery terminal.
- If this vehicle has been repaired within the last 30 days for the same fault code, then proceed to the Linked Solutions section.
Specification
- If the battery voltage is at least 10.8 VDC (12 volt systems) or 21.6 VDC (24 volt systems), then proceed to the Linked Solutions section.
- If the battery voltage is below 10.8 VDC (12 volt systems) or 21.6 VDC (24 volt systems), then proceed to the Repair section.
- If the battery or battery cables show signs of corrosion or damage, then proceed to the Repair Section.
Repair
Repair or replace only the components that were found to be out of specification.
- Charge or replace the batteries.
Refer to OEM Service Manual
- Clean corrosion or tighten battery cable connections.
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: S00001379
Verification
Conditions
- Turn keyswitch OFF.
Action
- Disconnect the batteries from each other.
- Connect a load tester separately to each battery.
- Measure the voltage from the positive (+) battery terminal to the negative (-) battery terminal.
Specification
- For a 12 volt system, proceed to the Repair section if the battery voltage is below the following specification: 11 VDC
- For a 24 volt system, proceed to the Repair section if the battery voltage is below the following specification: 22 VDC
Linked Solutions
- None
Repair
- Charge or replace the batteries.
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: S00000754
Verification
Conditions
- Turn keyswitch OFF.
Action
- Visually inspect the ECM ground for damage, corrosion and loose connections.
- Visually inspect the aftertreatment interface wiring harness ground for damage, corrosion and loose connections.
- Visually inspect the OEM wiring harness ground for damage, corrosion and loose connections.
- Visually inspect the grounds for proper routing.
Specification
- If damage, corrosion or incorrect routing of grounds are found, then proceed to the Repair section
Linked Solutions
- None
Repair
- Clean or replace connections.
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: S00000717
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment particulate matter sensor from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Turn keyswitch ON.
- Measure the voltage between the aftertreatment particulate matter sensor battery voltage SUPPLY pin and the aftertreatment particulate matter sensor RETURN pin at the particulate matter sensor OEM wiring harness connector.
Check the voltage at key ON, while cranking the engine, and with the engine at idle.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- Proceed to the Linked Solutions section if the voltage is not within the following specification of battery voltage: 1 VDC
Linked Solutions
- Aftertreatment particulate matter sensor battery SUPPLY to block ground check
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: S00000718
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the aftertreatment particulate matter sensor from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Turn keyswitch ON.
- Measure the voltage from the aftertreatment particulate matter sensor battery voltage SUPPLY pin of the OEM wiring harness to engine block ground.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- An open circuit or high resistance has been detected in the aftertreatment particulate matter sensor battery voltage RETURN circuit if the voltage is within the following specification of battery voltage: 1 VDC
- An open circuit or high resistance has been detected in the aftertreatment particulate matter sensor battery voltage SUPPLY circuit if the voltage is not within the following specification of battery voltage: 1 VDC
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 fuse.
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: S00000716
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.
Specification
- Proceed to the next solution, if any fault code is active or has more than one inactive count within the last 25 engine operating hours from the following list: 1894, 2636, 2771, 3232, 3868, 3911, 4151, 4152, 4572, 4677
- A malfunctioning aftertreatment particulate matter sensor has been detected if a fault code from the following list is not active, or does not have more than one inactive count within the last 25 engine operating hours: 1894, 2636, 2771, 3232, 3868, 3911, 4151, 4152, 4572, 4677
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: S00000593
Verification
Conditions
- Turn keyswitch OFF.
- Wait for 90 seconds.
- Disconnect the INLINE™ adapter from the 3-pin service data link connector.
- Reconnect the variable geometry turbocharger actuator if it has been previously disconnected.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the SAE J1939 data link (+) pin and the SAE J1939 data link (-) pin at the 3-pin service data link connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- Follow your technical escalation process if the resistance is within the following specification: 54 – 66 Ω
- Proceed to the Linked Solutions section if the resistance is not within the following specification: 54 – 66 Ω
Linked Solutions
- Variable geometry turbocharger actuator has incorrect J1939 terminating resistance
- Engine wiring harness has incorrect J1939 terminating resistance
- OEM wiring harness has incorrect J1939 terminating resistance
Repair
- No additional action is required for this solution.
Validation
- None
Solution: S00001242
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the variable geometry turbocharger actuator from the engine wiring harness.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the variable geometry turbocharger actuator SAE J1939 data link (+) pin and the variable geometry turbocharger actuator SAE J1939 data link (-) pin at the variable geometry turbocharger actuator.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- A malfunctioning variable geometry turbocharger actuator has been detected if the resistance is not within the following specification: 108 Ω – 132 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.
Solution: S00000972
Verification
Conditions
- Turn keyswitch OFF.
- Reconnect previously disconnected components.
- Disconnect the INLINE™ adapter from the 3-pin service data link connector.
- Disconnect the aftertreatment intake NOx sensor from the engine wiring harness.
- 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 SAE J1939 data link (+) pin and the SAE J1939 data link (-) pin at the 3-pin service data link connector.
- 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 not within the following specification: 108-132 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.
Solution: S00000971
Verification
Conditions
- Turn keyswitch OFF.
- 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 SAE J1939 data link (+) pin and the SAE J1939 data link (-) pin at the crossover of the OEM wiring harness connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- Proceed to the next solution if the resistance is not within the following specification: 108 – 132 Ω
- Follow your technical escalation process if the resistance is within the following specification: 108 – 132 Ω
Linked Solutions
- None
Repair
- No additional action is required for this solution.
Validation
- None
Solution: S00004534
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the appropriate data link component from the data link wiring harness.
- Disconnect the engine wiring harness connector from the ECM.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the J1939 (+) pin at the appropriate component data link wiring harness connector and the appropriate data link component J1939 (+) pin at the data link wiring harness ECM connector.
- Measure the resistance between the J1939 (-) pin at the appropriate component data link wiring harness connector and the appropriate data link component J1939 (-) pin at the data link wiring harness ECM connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- A malfunctioning J1939 data link wiring harness has been detected if the resistance is greater 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.
- 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.
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.
If all steps have been completed and no root cause has been identified, then follow the technical escalation process.