DPF Forced Regen Tools - What works and What does not

[stang37]

In 43,033 mile I have seen the regen emblem once. Our group was traveling on a two lane road for a long time averaging between 40 and 55 mph. We were stopping at a rest area and it came on as I pulled into a parking spot. I didn't realize what it was until after turning off the engine. It came back on when we were leaving. That was 3 yrs ago.

 

[stang37]

What gets my attention is the time it took for your regen, that to me means your soot level was higher than "normal" and it's good you did the regen. Maybe try another regen? Mine took two. We really need to get better numbers on soot level, maybe @Rich W. can work with Diesel Laptops to get that in an update???

I was getting concerned also thinking something might be wrong or I was suppose to stop the regen after an hour. I called tech support. The senior diesel mechanic that the tech talked to said there was no set time to complete the regen. He stated it should take between 1 to 1 1/2 hours. He also said the truck they do their testing on takes a little over 1 hour. He also said the 1050 degree temperature was normal.

 

[Neal]

Wherever I read about regens it said 20 minutes min is normal, up to 1.5 hours is normal too. My first one with the tech about 1.5 hours, then when I saw the light and pulled over the 2nd regen lasted 20 minutes. So yeah, it's normal, I just think that long means more soot but I have no idea, it's just a guess.

 

[Rich W.]

DPF regen completed 1 hr 20 minutes. After cool down I now have the amber engine emblem light. None prior to regen. SPN 5862 Aftertreatment 1 SCR intermediate temperature. Status Active FMI=3 . I think this will clear after several engine starts, but not sure.

I would use the code reader to clear the code and see if it returns. Chances are it wont. Also An hour and 20 minutes is about normal for my regens. Also 1050° is a good regen temp.

 

[Rich W.]

What gets my attention is the time it took for your regen, that to me means your soot level was higher than "normal" and it's good you did the regen. Maybe try another regen? Mine took two. We really need to get better numbers on soot level, maybe @Rich W. can work with Diesel Laptops to get that in an update???

Its on my list of things to do, calls to make. I’d like to know what “normal” is (the range), what levels constitute low and high, and how these would be represented on the device.

 

[stang37]

I would use the code reader to clear the code and see if it returns. Chances are it wont. Also An hour and 20 minutes is about normal for my regens. Also 1050° is a good regen temp.

The code was still showing this morning. I cleared the code and started the engine and let it run unit air tanks filled the code didn't return. I cleared the code with the Diesel handheld unit.

 

[Neal]

The code was still showing this morning. I cleared the code and started the engine and let it run unit air tanks filled the code didn't return. I cleared the code with the Diesel handheld unit.

Did you ever decipher what the code meant? Did I miss that?

 

[Rich W.]

Did you ever decipher what the code meant? Did I miss that?

I did but didnt want to post it until it cleared:

Fault Code: SPN 5862 FMI 3 (4518)
PRINT
PID:—
SID:—
SPN: 5862
PSID:—
FMI: 3
PPID:—
Aftertreatment SCR Intermediate Gas Temperature Sensor Circuit - Voltage Above Normal or Shorted to High Source
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Reason:
High signal voltage detected at the aftertreatment SCR intermediate temperature sensor circuit.

Circuit Description:
The aftertreatment SCR (selective catalytic reduction) temperature sensor module is a smart device that communicates with the engine control module via the J1939 data link. The aftertreatment SCR temperature sensor module performs its own internal diagnostics and reports malfunctions back to the engine control module using the J1939 data link.

The aftertreatment SCR temperature sensor module is used to measure the aftertreatment SCR intermediate temperature and aftertreatment SCR outlet temperature. The temperature probes are permanently attached to the aftertreatment SCR temperature sensor module and can NOT be replaced individually.

The aftertreatment SCR temperature sensor module reported the aftertreatment SCR intermediate temperature signal was out of range high.

1. The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
2. Diesel exhaust fluid injection into the aftertreatment system is disabled.
3. Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
4. Possible reduced engine performance.

The aftertreatment SCR temperature sensor module is mounted on the aftertreatment SCR catalyst.

1. To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2. The fault code status displayed by the diagnostic tool will change to INACTIVE immediately after the diagnostic runs and passes.
3. The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4. 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.
5. The Reset All Faults command in the diagnostic tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

This diagnostic runs continuously when the key switch is in the ON position or when the engine is running.

Possible Cause of this Fault Code:
Malfunctioning aftertreatment SCR intermediate temperature sensor

 

[Rich W.]

The last line was a but alarming but so often the numerous sensors in the system send erroneous data that it is always best to clear the codes and see what happens before becoming concerned about an actual problem.

In this case it would seem the SCR temp sensor read high because of the regen and reported it as such, but I’ve done a lot of regens and I’ve never seen this before and the system should “know“ when a regen has occurred. Hopefully the code stays cleared but its worth mentioning next time he’s talking to a Freightliner tech.

4518 is the Cummins equivalent of 5862/3. Its also a nice Mountain Aire floor plan….

 

[Rich W.]

Recommended Reading

This will help as you decipher codes. I never paid much attention to the SA number before but will from now on.

What are SA SPN FMI - Beginners guide to fault codes

Trouble codes are populated following a protocol, which is just a form of communication for computer networks. One of the most common protocols used in trucking is J1939.

otrperformance.com

In Stang37’s case, given an FMI of 3, I would lean toward a data communication error before going further.

Enjoy!