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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 4373
Experience:  Owner at DJ Wilson
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Cummins ISB fault 1921 will no go inactive.

Customer Question

Cummins ISB fault 1921 will no go inactive.
Submitted: 8 months ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 8 months ago.

Hi McCoy, My name is***** will be glad to help. Bare with me while I pull up your code information

Customer: replied 8 months ago.
Not helping anymore?
Expert:  Daniel Wilson replied 8 months ago.

Hi McCoy, I am glad you responded.Yesterday I was very sick and for some reason your question got lost in the archives... My apologies for that. I will gather this info now if you still need the help

Expert:  Daniel Wilson replied 8 months ago.

CODEREASONEFFECT

Fault Code: 1921
PID: S324
SPN: 3251
FMI: 0/16
LAMP: Amber
SRT:

Aftertreatment Diesel Particulate Filter Differential Pressure - Data Valid but Above Normal Operational Range - Moderately Severe Level. The soot load of the aftertreatment diesel particulate filter has exceeded the recommended limits.

Engine protection derate.

The engine aftertreatment system monitors the soot load in the aftertreatment diesel particulate filter. Under normal operating conditions, the aftertreatment diesel particulate filter is self-cleaning, 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.

This fault code can be triggered if the application is not operating at a duty cycle high enough to actively regenerate the aftertreatment diesel particulate filter. This fault code indicates that the exhaust temperatures exiting the turbocharger are not high enough to actively regenerate the soot that is trapped in the aftertreatment diesel particulate filter. It may be necessary to increase the duty cycle of the application in order to prevent plugging of the aftertreatment diesel particulate filter.

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.
  • 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.
Expert:  Daniel Wilson replied 8 months ago.

Try a parked regen to see if it will complete with out any other active faults

Expert:  Daniel Wilson replied 8 months ago.

If not and a reset with insite will not correct this and no actual faults exist you will need to reflash and update the ECM software. Let me know

Expert:  Daniel Wilson replied 8 months ago.

Are there any other faults?

Expert:  Daniel Wilson replied 8 months ago.

I see you have two questions open for this?

Expert:  Daniel Wilson replied 8 months ago.

3 1921 Flashing Amber Perform stationary regeneration procedure Engine protection derate

Customer: replied 8 months ago.
Regen will not go. Says "A condition exists to prevent ECM from performing this function" Can ecm software make it stuck thinking there is a problem? I have another question open because I am on highest priority and response time has been terrible.
Customer: replied 8 months ago.
Also, it is a solid check engine light. No flashing.
Customer: replied 8 months ago.
every now and then i get a 3261, 3651. but they go inactive by themselves
Expert:  Daniel Wilson replied 8 months ago.

Thanks for the update. I understand. Experts arent employees of the site. Some have full time jobs or businesses and only log in as they are able. I help on here in between jobs as I am able. But to answer your question, software can cause an ECM not to reset a code after repairs have been made. since you have the other two codes, I will dig those up in case they are why you are getting the 1921 which is very likely

Expert:  Daniel Wilson replied 8 months ago.

Possible causes of this fault include:

  • Malfunctioning line heater relay
  • Malfunctioning line heater
  • Open circuit, short circuit to ground, or a blown fuse in the aftertreatment diesel exhaust fluid controller harness
  • Malfunctioning aftertreatment diesel exhaust fluid controller.
  • Blocked or restricted coolant flow to the DEF tank heater
  • Disconnected or broken tank heater coolant supply hose
  • Malfuntioning or stuck closed DEF tank heater control valve
  • Operation in extremely cold ambient conditions

CODE REASON EFFECT

Fault Code: 3261
PID: S254
SPN: 4342
FMI: 5/5
LAMP: Amber
SRT:

Aftertreatment Diesel Exhaust Fluid Line Heater 2 Circuit - Current Below Normal or Open Circuit. Open circuit or short circuit to ground detected in the diesel exhaust fluid line heater 2.

Diesel exhaust fluid line heater 2 will be disabled

CODE REASON EFFECT

Fault Code: 3651
PID: S254
SPN: 3031
FMI: 18
LAMP: Amber
SRT:

Aftertreatment Diesel Exhaust Fluid Tank Temperature - Data Valid But Below Normal Operating Range - Moderately Severe Level. The diesel exhaust fluid tank temperature is unable to reach its set point.

Diesel exhaust fluid injection into the aftertreatment system is disabled

Expert:  Daniel Wilson replied 8 months ago.

These two faults you just posted will have to be corrected before regen is allowed. Repair these first and then try a parked regen.

Customer: replied 8 months ago.
I understand. When the codes go inactive, will still not regen. DEF pump i think has the heater built in correct? It has been replaced along with line #2. And the acm harness has been replaced.
Expert:  Daniel Wilson replied 8 months ago.

Then yes, If the repairs have been made but the ECM will not clear or allow regen, you will need to have the ECM software reflashed and updated. Then try a parked regen. As long as there are not active problems and the repairs are good, the regen should be successful.

Customer: replied 8 months ago.
Ok, so the active code for aftertreatment pressure sensor could be caused by a reflash? we know the filter is good, just was cleaned, and maintenance has been reset. I just want to make sure in your strong opinion it needs a reflash.
Expert:  Daniel Wilson replied 8 months ago.

What active code for a pressure sensor? Are there more codes? 1921, 3651, and 3261 are what I know about. What is the currently active code number? If all active code troubleshooting and repairs have been made and the ECM will not allow regen then yes, reflash the ECM but if you have an active fault that has not been repaired then reflashing will not help at all. It is only if you have confirmed all repairs on all active faults and ECM will not Regen.

Customer: replied 8 months ago.
code 1921 is aftertreatment pressure differential sensor valid but out of range.
Expert:  Daniel Wilson replied 8 months ago.

Thats right.. I was thinking of an informational code for engine derate... Sorry about the confusion. I was getting interrupted here. What are the FMI numbers for the codes?

Expert:  Daniel Wilson replied 8 months ago.

Depending on the FMI numbers it could indicate a faulty sensor or harness unless its data valid and then points to an actual plugged system and filter

Customer: replied 8 months ago.
i can go dig up those codes. History: since this truck has been down, in derate, 2 weeks total, we put a new sensor on it, acm harness, removed dpf for cleaning; passed, nox sensor, def pump, line #2. we know dpf is not plugged, its virtually brand new. reset filter and doc maintenance. no regen. ALSO: conditions for running 1921 code is engine running over 500rpm. this code comes right back after clearing, engine off.
Expert:  Daniel Wilson replied 8 months ago.

New sensor, harness, and DPF cleaned properly with the proper equipment.... Then the only thing left is ECM and ACM software. See that the FMI numbers are first....

Customer: replied 8 months ago.
SPN 3241 FMI 16
SPN 4342 FMI 5
Customer: replied 8 months ago.
those are the only active at this time.
Expert:  Daniel Wilson replied 8 months ago.

3241 or 3251?

Customer: replied 8 months ago.
MY BAD!!! ITS SPN 3251 FMI 16
Customer: replied 8 months ago.
any word?
Expert:  Daniel Wilson replied 8 months ago.

3251

16

DPF Pressure

-

Out of

Range High

Customer: replied 8 months ago.
i will schedule an appt for a reflash...
Expert:  Daniel Wilson replied 8 months ago.

SPN 3251/FMI 16 - EPA10

This diagnostic is typically Diesel Particulate Filter (DPF) Pressure Out of Range High.

This fault code sets when the DPF outlet pressure is greater than 30 kPa (4.2 psi) for more than 10 seconds.

Expert:  Daniel Wilson replied 8 months ago.

This means that the DPF Outlet sensor is reading high due to a restriction in the exhaust or faulty sensor

Expert:  Daniel Wilson replied 8 months ago.

Was it the outlet sensor you changed?

Expert:  Daniel Wilson replied 8 months ago.

check for a restricted SCR catalist

Customer: replied 8 months ago.
we changed differential pressure sensor on dpf. code comes on with out engine running..
Expert:  Daniel Wilson replied 8 months ago.

3251 16 does without engine running? If so, go with the reflash

Customer: replied 8 months ago.
sir, thank you!
Expert:  Daniel Wilson replied 8 months ago.

Pleasure to help.

Expert:  Daniel Wilson replied 8 months ago.

If the Outlet sensor on the DPF and harness are good then the fault should not exist after key on and a reflash. Keep me posted. Please remember to rate my service as that is how the site credits the experts for their time helping on here.