Active Faults 3 Freightliner

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Jennifer Kovachick

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Aug 5, 2024, 7:02:55 AM8/5/24

to halgdistternketp

Likemost filters, a DPF has a finite lifespan and requires cleaning to remain effective and, eventually, replacing. Regenerations are necessary to prevent particulate matter from quickly accumulating and rendering the DPF ineffective.

Passive regeneration happens frequently in long-haul trucking because it requires continuous driving where the DPF can hit a temperature above 1,000 degrees Fahrenheit to create the heat levels that turn soot into ash.

In these cases, an active regeneration occurs. Rather than naturally occurring when the DPF reaches the high temperature on its own, the engine undergoes a process to increase exhaust heat and create a chemical reaction that generates the temperatures needed to oxidize particulate matter.

The third type of regeneration has the aftertreatment system undergo a similar process to an active regeneration, but rather than the vehicle triggering the regen, it requires action from a third party, typically a driver or technician.

There are plenty of instances where the DPF or other component of an aftertreatment system is triggering an active fault but a forced regen is not the answer. These include cases where cleaning or replacing the DPF is required or an entirely different component of the aftertreatment system causes the fault.

A DPF system relies on many sensors working correctly. If any of these sensors has an issue that triggers a fault code, a regen will not fix the problem without first isolating and repairing the malfunctioning sensor

Available within the Aftertreatment Diagnostics feature, technicians quickly see which regen zone (0-5) the truck is in and determine the best course of action. This feature is especially helpful because technicians can tell at a glance that a forced regen is not required if the truck is in regen zone 0 or 1.

Using a diagnostic application like JPRO with troubleshooting tasks, technicians better understand what is causing the problem to decide how to fix it.Repair InstructionsAfter discovering the root cause, detailed repair manuals help guide the technician down the most efficient path to repair the problem.

Of all faults displayed on the table, none included troubleshooting steps indicating a forced regen was the recommended action. Fault 1922 included troubleshooting steps that alerted users another fault on the vehicle would likely be fixed with a forced regen, leading to a high occurrence of necessary regens. Applying this logic to all instances of a single active fault on the Cummins ISX15 EPA13, we discovered 903 necessary regens and 1,114 unnecessary regens.

Methods: We only included data when the associated fault was the only active fault code during the connection. We examined regen zone and troubleshooting steps within JPRO to determine if JPRO gave any indication that a forced regen was a necessary action.

A regen causes an engine to sustain substantial revolutions per minute (RPMs) for a considerable amount of time during the process. The heat and undue stress can weaken components and shorten their lifespan, resulting in increased trips to a service center, more parts purchasing, and unnecessary downtime.

On average, it takes between thirty and sixty minutes to complete a forced regeneration. The substantial heat required for the regen renders the engine and aftertreatment system untouchable until it has time to cool down.

For these reasons, an unnecessary regen often leads to hours of avoidable downtime before the technician can attempt the next solution. This downtime wastes labor hours and occupies a service bay, affecting downtime on trucks awaiting repairs.

Regenerations are essential functions for trucks and the environment. Often, a forced regeneration is a necessary action to either correct the issue at hand or get the vehicle out of limp mode long enough to get it to a service center. But technicians and fleet personnel must keep in mind they waste valuable time, money, and other resources when a forced regeneration occurs unnecessarily.

Friday January 02, 2009 17:35

Hi guys. i have a 2003 freightliner century, series 60. pre EGR,;888,500 miles. Last year i started to have some problems with my truck. The engine stopped from running while driving through the rain on freeway at 70 mph. i stopped on the shoulder and waited 5 min.

Then , the engine started and no problem after that. I thought: water ,maybe touch some computer wires, and a short circuit occur.

2 weeks later same thing happened. it was wet outside. i changed the TRS and SRS sensors than no problems after that. Lately I parked the truck and the 2nd day the engine won't start. I tried with starting fluid: nothing. Changed the upper sensor (SRS or TRS) and nothing happened. I got an active code on my dash board ENGINE POSITION SENSOR LOW 128s021 01.wait 15 min and than the truck started like nothing wrong happened .the active fault disappears and then I checked for other faults and what i found was:

2 HISTORY DASH FAULTS, -INSTR. OUTSIDE TEMP SHORT 140 171 06 and INSTR. FUEL LEVEL SHORT 140 096 06.

I took the truck to the shop, they got the computer on my truck and found out nothing wrong with it.

With the engine running i checked for loose connections and I grabbed all the wires from the ECM to the sensors and from the ECM to the other engine parts ,and not even a fluctuation in engine running occur.Anybody knows what that errors mean,or what could be the problem?

Thank you in advance for any suggestions regarding my problem. ReplyQuoteTopBottom

GoneFishen

Posts: 1325

Joined: Jan 2007Friday January 02, 2009 20:33

The DDEC system could care less about the fuel level. Same thing about the outside air temperature. You said you replaced the SRS and the TRS, ok good call, how about the wires to and from. HMMMMMMMMMMMM. I teach to test the system from the computer to the sensors, this way you check the wiring and the sensors. What was the ohm reading on the sensors? Has anyone checked the bull gear for play? HMMMMMMMMM excessive play on the bull gear bearing will not allow the engine to run. Did you see any lights when it quit. Does the CEL come on while cranking and NOT starting?

-------------------------

DDA tech for 30 years,all 2 cycle,series 60,50 mbe also.

1995 F250, 191k mi.

Lost Wages, Nv ReplyQuoteTopBottom

stump

Posts: 814

Joined: Aug 2007Saturday January 03, 2009 06:17

Also check all connections at battery and any in line fuses look inside the holders for corrosion all connections and grounds good and cleanand tight.start simple!! ReplyQuoteTopBottom

jason77

Posts: 24

Joined: Jan 2009Sunday January 04, 2009 14:30

When I tried to start the engine ,the CEL came on and active fault code was ENGINE POSITION SENSOR LOW 128s021 01.Nobody check for the bull gear for play.and I don't know what was the OHM reading on the sensors.The big red cable from the batteries was a little worn on the side that touch the chassis ,but after I have isolated the cable , I didn't have any problems for about 3 months.I could change the harness from and to the ECM but I'm afraid the problem would not be fixed ,and the harnesses are very expensive.I think that the other 2 faults "instr outside temp. and instr fuel level " could be recorded as faults as a malfunction of the harness ,an interrupted wire somewhere,and could shout the engine down.I don't know,it's just o supposition. If that's true which side of the ECM's harness transmits this info to the ECM or to the dash board ?I also notice a small oil leak between the air compressor and engine,and the TRS and SRS sensors have a little oil spill on the harness.The way that my truck stops and the engine dies, while driving,I thought, that it is a wire problem,or a fuse ,but I have checked the wires and the fuses and all are good. I hope it's not the ECM . Please advise. Thank you for your help. ReplyQuoteTopBottom

marc7242

Posts: 254

Joined: Sep 2008Sunday January 04, 2009 16:58

Your problem could be in the ignition switch or one of the power relays, although is not very common in Freightliners. The problem with something like this is you pretty much have to catch it while the problem is occurring. There is a key on signal to the ECM on one of the large connectors, it is a 12 volt signal and doesn't actually power anything up itsself. Check the fuse holders in the battery box and make sure the wires are tight and the terminals that grab the fuse blades aren't burned or damaged. Also grab the ground cable on the starter and see if it will move. Also try to move the ground cable at the frame rail stud near the engine and the frame rail stud near the battery box. If the cable moves you'll probably have to drill a new hole and through-bolt it. Losing the TRS or SRS alone shouldn't shut the motor down once its running. If you lost both it will die. As stump said, start simple, check the fuse holders in the battery box thoroughly. Also check the frame grounds and power relays in the fuse box. I would replace all of the power relays and ignition switch as a cheap place to start, also thoroughly inspect those connections when you have them out.

marc ReplyQuoteTopBottom

jason77

Posts: 24

Joined: Jan 2009Tuesday January 06, 2009 17:48

Today I checked the wires on the truck.The ground cable from the batteries to the frame rail got a little rust around the stud ,so I have cleaned the place good and i screwed back the cable back to the frame.I have checked for another point of contact of the ground cable with the frame and I couldn't see one .The neg. cable goes directly from the batteries to the starter,and from the batteries to the frame rail .I also check for in line fuses and I couldn't find one,except the ones in the batteries box .Those fuses are good and the cables and the fuse holders are good too.

I notice that on the solenoid starter ,one of the connectors got a little rust around it , so i tried to unscrew the connector ,but because of the rust the connector broke ,together with a small part of the solenoid .So I have changed the solenoid ($ 9.95).I hope this will solve the "not starting" problem. I still got to figure out why the engine stop while driving.Could the solenoid stop the engine too? I don't think so.I also check for past codes in the dash board,and the CEL came up with this codes:

42-Too few SRS (missing SRS)

41-Too many SRS (missing SRS)

62-Aux. output short to battery (+) or open circuit,or mech. fault

77-Fuel temperature high

43-Coolant level low

SEL- 25 (NO ACTIVE CODES).

Tomorrow I will buy the power relays and the ignition switch.

If you have any opinions about this please advice . Thank you all. ReplyQuoteTopBottom

marc7242

Posts: 254

Joined: Sep 2008Tuesday January 06, 2009 19:59

Do you have any way to know how old the SRS codes are? Were they cleared last time you replaced the sensor? A problem there is the most obvious cause of your problems. You would need to clear the codes to know for sure if this comes back or if its already been done,

marc ReplyQuoteTopBottom

GoneFishen

Posts: 1325

Joined: Jan 2007Tuesday January 06, 2009 21:40

Sounds like a bunch of old codes. However try this. When you turn on the key w/o starting then press the override switch. If you have 25 on the RED light this tells you that all is well NOW. When the codes are flashed on the YELLOW light this indicates ANY codes logged BEFORE you turning the key on. SO you indicated you had a code 25 listed. I think you did exactally what I just said. NOW when you try to start the vehicle and get a yellow light DO NOT TURN the key off. If the yellow stays on, flash the codes switch then. This will indicate what is wrong with the engine right now. When you turn off the ing. switch this turns ALL the active code back into the history file.

-------------------------

DDA tech for 30 years,all 2 cycle,series 60,50 mbe also.

1995 F250, 191k mi.

Lost Wages, Nv ReplyQuoteTopBottom

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