Make: Cummins
Engine: X15 CM2450 X124B (2018 & Newer)
Fauld Code: 1921
PID: SID 324
SPN: 3251
FMI: 16
Description: Aftertreatment Diesel Particulate Filter Differential Pressure- Data Valid But Above
Normal Operating Range- Moderately Severe Level
Troubleshooting:
Circuit Description
The engine aftertreatment system monitors the soot load in the aftertreatment diesel particulate
filter. Under normal operating conditions, the aftertreatment diesel particulate filter is selfcleaning,
where soot is converted to carbon dioxide, nitrogen, and water. Under light load
operating conditions, it can be necessary to perform a stationary regeneration of the
aftertreatment diesel particulate filter. The soot load in the aftertreatment diesel particulate filter
is estimated, using the aftertreatment differential pressure sensor and the calculated soot
output of the engine.
Component Location
The aftertreatment diesel particulate filter is located in the exhaust system and is installed by
the original equipment manufacturer (OEM). Refer to the OEM service manual.
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) detected the soot load of the aftertreatment diesel
particulate filter was moderately severe. The aftertreatment system needs to be regenerated to
remove the soot.
Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs
and fails.
The ECM will flash the aftertreatment lamp immediately after the diagnostic fails.
Torque output of the engine will be reduced as the soot load in the aftertreatment diesel
particulate filter increases.
Mobile regeneration of the diesel particulate filter will be disabled.
Exhaust Gas Recirculation (EGR) valve operation will be disabled.
Conditions for Clearing the Fault Code
After completing a stationary regeneration (as instructed in this fault code troubleshooting tree)
and no additional faults become active, the repair has been validated.
The fault code status displayed by INSITE™ electronic service tool 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.
The Reset All Faults command in INSITE™ electronic service tool can be used to clear active
and inactive faults, as well as extinguish the MIL for OBD applications.
Shop Talk
Note: This fault code indicates that the aftertreatment diesel particulate filter requires
maintenance by performing a stationary regeneration procedure. This is a maintenance
procedure only and is not covered by Cummins® warranty.
Note: Repeated occurrences of this fault code may indicate the engine requires frequent
regeneration. Refer to symptom tree t147 (Aftertreatment Diesel Particulate Filter-Excessive
Automatic and/or Stationary Regeneration) to identify the cause of frequent regeneration.
Possible causes of this fault code include:
The engine has been operating in a light load condition that prevents exhaust temperatures
from being high enough to actively regenerate the aftertreatment diesel particulate filter.
Possible engine damage that causes excessive black soot to be generated.
If Fault Code 2777 is active along with Fault Code 1921, this indicates that a regeneration
inhibit message has been received by the engine ECM and that active regeneration of the
aftertreatment diesel particulate filter was not permitted. Confirm that OEM settings for the
aftertreatment permit switch are configured correctly. A stationary regeneration of the
aftertreatment diesel particulate filter can be performed. Use INSITE™ electronic service tool.
Possible Cause:
1) Damaged DPF
2) ECM calibration
Make: Cummins
Engine: X15 CM2450 X124B (2018 & Newer)
Fauld Code: 1922
PID: SID 324
SPN: 3251
FMI: 0
Description: Aftertreatment Diesel Particulate Filter Differential Pressure- Data Valid But Above
Normal Operating Range- Most Severe Level
Troubleshooting:
Circuit Description
The engine aftertreatment system monitors the soot load in the aftertreatment diesel particulate
filter. Under normal operating conditions, the aftertreatment diesel particulate filter is selfcleaning,
where soot is converted to carbon dioxide, nitrogen, and water. Under light load
operating conditions, it can be necessary to perform a stationary regeneration of the
aftertreatment diesel particulate filter. The soot load in the aftertreatment diesel particulate filter
is estimated, using the aftertreatment differential pressure sensor and the calculated soot
output of the engine.
Component Location
The aftertreatment diesel particulate filter is located in the exhaust system and is installed by
the original equipment manufacturer (OEM). Refer to the OEM service manual.
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) detected the soot load of the aftertreatment diesel
particulate filter had exceeded the maximum operating limits.
Action Taken When the Fault Code is Active
The ECM illuminates the red STOP ENGINE lamp immediately after the diagnostic runs and
fails.
Torque output of the engine will be reduced as the soot load in the aftertreatment diesel
particulate filter increases.
Active and stationary regeneration of the diesel particulate filter will be disabled.
Exhaust Gas Recirculation (EGR) valve operation will be disabled.
Conditions for Clearing the Fault Code
Use INSITE™ electronic service tool to perform the Diesel Particulate Filter Reset procedure
found under the Aftertreatment Maintenance section of Advanced ECM Data.
After completing a stationary regeneration (as instructed in this fault code troubleshooting tree)
and no additional faults become active, the repair has been validated.
The ECM will turn off the red STOP ENGINE lamp immediately after the diagnostic runs and
passes.
Shop Talk
Note: Repeated occurrences of this fault code may indicate the engine requires frequent
regeneration. Refer to symptom tree t147 (Aftertreatment Diesel Particulate Filter-Excessive
Automatic and/or Stationary Regeneration) to identify the cause of frequent regeneration.
Possible causes of this fault code include:
The aftertreatment wiring harness or the aftertreatment temperature sensor connector pin
installation may be incorrect.
The engine has been operating in a light load condition that prevents exhaust temperatures
from being high enough to actively regenerate the aftertreatment diesel particulate filter.
A possible base engine malfunction that causes excessive black soot to be generated.
If both Fault Code 1921 and 2777 are inactive with an active Fault Code 1922, this indicates
that a regeneration inhibit message has been received by the engine ECM and that active
regeneration of the aftertreatment diesel particulate filter was not allowed. Use the OEM
manuals to confirm that the OEM settings for the aftertreatment permit switch are configured
correctly.
Possible Cause:
1) Aftertreatment DPF differential pressure sensor failure
2) DPF failure
3) ECM calibration
Make: Cummins
Engine: ISX CM871 (2007-09)
Fauld Code: 1981 (CPL 3774 y 3775)
PID: SID 324
SPN: 3251
FMI: 0
Description: Aftertreatment Particulate Filter Differential Pressure – Data Valid But Above
Normal Operating Range – Least Severe Level. The aftertreatment differential pressure has
exceeded the maximum operating limits or the diesel particulate filter is plugged.
Troubleshooting:
Verify the electronic control module (ECM) calibration is correct. Check the calibration revision
history found on QuickServe™ Online for applicable changes to the calibration stored in the
ECM. If necessary, calibrate the ECM.
An engine torque derate for extended EGR valve closed operation exists for this fault code.
The engine torque derate for extended EGR valve closed operation operates on a time based
system. The time based system will count up anytime a fault code that closes the EGR valve is
active. Once the timer reaches 20 hours, an engine torque derate of approximately 15 percent
will be applied.
The engine torque derate will be removed as soon as the fault code goes inactive, and the
timer will begin to count down. If the fault code reoccurs within the next 20 hours of engine
operation, the engine torque derate will immediately be applied, and the timer will then reset to
20 hours. The engine must operate for 20 hours with no active faults that close the EGR valve
for the timer to clear. After the timer has cleared, the engine must then operate for another 20
hours with an active fault code that closes the EGR valve to apply the derate.
This fault code indicates that the soot load inside the aftertreatment diesel particulate filter has
reached the maximum level. Regeneration of the aftertreatment diesel particulate filter at this
stage is not possible. The aftertreatment diesel particulate filter must be inspected. If it meets
the inspection criteria, it can be cleaned using an SPX air pulse cleaning machine (or
equivalent machine). If it does not meet the inspection criteria, it must be replaced.
Possible causes:
1)The aftertreatment diesel particulate filter can be plugged with soot.
2)The engine has been operating in light load conditions that prevent exhaust temperatures
from being high enough to actively regenerate the aftertreatment particulate filter.
3)The aftertreatment wiring harness connectors could be connected to the wrong
aftertreatment exhaust gas temperature sensor.
4)The aftertreatment wiring harness or aftertreatment exhaust gas temperature sensor
connector pin installation could be incorrect.
5)The aftertreatment diesel particulate filter differential pressure sensor has malfunctioned.
6)An engine malfunction that is elevating the engine smoke output.
7)The aftertreatment diesel particulate filter can accumulate an excessive amount of ash in a
short time period. This can be due to excessive oil consumption or due to non-combustible
elements such as, but not limited to, iron, potassium, or calcium contained in fuel additives.
Possible repairs:
1)Replace the aftertreatment diesel particulate filter differential pressure sensor.
2)Install the aftertreatment wiring harness connectors in the correct locations.
3)Install the pins in the correct connector locations.
4)Install the turbocharger actuator.
5)Replace the DPF.
6)Replace the ECM.
Page
Make: Cummins
Engine: ISX CM871 (2007-09)
Fauld Code: 1981 (NON CPL 3774 y 3775)
PID: SID 324
SPN: 3251
FMI: 0
Description: Aftertreatment Particulate Filter Differential Pressure – Data Valid But Above
Normal Operating Range – Least Severe Level. The aftertreatment differential pressure has
exceeded the maximum operating limits or the diesel particulate filter is plugged.
Troubleshooting:
Verify the ECM calibration is correct. Check the calibration revision history found on
QuickServe™ Online for applicable changes to the calibration stored in the ECM. If necessary,
calibrate the ECM.
An engine torque derate for extended EGR valve closed operation exists for this fault code.
The engine torque derate for extended EGR valve closed operation operates on a time based
system. The time based system will count up anytime a fault code that closes the EGR valve is
active. Once the timer reaches 20 hours, an engine torque derate of approximately 15 percent
will be applied.
The engine torque derate will be removed as soon as the fault code goes inactive, and the
timer will begin to count down. If the fault code reoccurs within the next 20 hours of engine
operation, the engine torque derate will immediately be applied, and the timer will then reset to
20 hours. The engine must operate for 20 hours with no active faults that close the EGR valve
for the timer to clear. After the timer has cleared, the engine must then operate for another 20
hours with an active fault code that closes the EGR valve to apply the derate.
This fault code indicates that the soot load inside the aftertreatment diesel particulate filter has
reached the maximum level. Regeneration of the aftertreatment diesel particulate filter at this
stage is not possible. The aftertreatment diesel particulate filter must be inspected. If it meets
the inspection criteria, it can be cleaned using an SPX air pulse cleaning machine, or
equivalent machine. If it does not meet the inspection criteria, it must be replaced.
Possible causes:
1)The aftertreatment diesel particulate filter can be plugged with soot.
2)The engine has been operating in light load conditions that prevent exhaust temperatures
from being high enough to actively regenerate the aftertreatment particulate filter.
3)The aftertreatment wiring harness connectors could be connected to the wrong
aftertreatment exhaust gas temperature sensor.
4)The aftertreatment wiring harness or aftertreatment exhaust gas temperature sensor
connector pin installation could be incorrect.
5)The aftertreatment diesel particulate filter differential pressure sensor has malfunctioned.
6)An engine malfunction that is elevating the engine smoke output.
7)The aftertreatment diesel particulate filter can accumulate an excessive amount of ash in a
short time period. This can be due to excessive oil consumption or due to non-combustible
elements such as, but not limited to, iron, potassium, or calcium contained in fuel additives.
Possible repairs:
1)Replace the aftertreatment diesel particulate filter differential pressure sensor.
2)Install the aftertreatment wiring harness connectors in the correct locations.
3)Install the pins in the correct connector locations.
4)Install the turbocharger actuator.
5)Replace the DPF.
6)Replace the ECM.