S/N: 1M2AX16C7JM039990 P208064 EGT Sensor Circuit - Range/Performance (Bank 1 Sensor 1) - Signal Not Plausible Truck will complete a regen but once it stops, it still says the soot level is 3 out of 4 and it still requests a regen. I checked temps on all 3 EGT sensors when everything was cooling down and the #1 sensor stayed around 100 degrees higher than #2 and #3. I unplugged the #1 sensor connector for maybe 30 minutes. When I plugged it back in, it went to a more accurate temp, but then the #2 sensor started reading around 100 degrees higher than #1 and #3. I unplugged the #2 sensor connector for maybe 10 minutes and plugged it back in, but it stayed at a higher temp. Wiring all looked fine. What else should I check?
What's your delta across the DPF? I've seen cracked tubes cause erroneous values causing high frequency regeneration. What about hours of operation on the DPF itself? Is it due for ash cleaning?
Like fwf said above--how many miles/hours on DPF. It's not uncommon for repeated signaling for regen when DPF is plugged beyond regen capabilities.
Roughly 3,400 hours since last DPF cleaning. The DPF differential pressure at idle was 0.09, high idle 0.13 and while regening it was 0.33. As I stopped the regen, it gave a short acceleration and spiked up to 0.42. Should I pull the DPF and get it cleaned?
The gold standard is 4500 hours on new, slightly reduced on a cleaned one. Have you the means to do a smoke test or just run her open exhaust to get an idea of how clean the base engine runs. If you got a slobbering injector nozzle or bad spray pattern, it should show as smoke. How were the tubes and boots to the delta sensor? All good? What are the units for your delta pressure? InHg psi MPa KPa ?
Pressure is measured in PSI. I will have to look at the tubes to see if there is any contaminants. If the tubes look bad, I will take off a pipe and watch the exhaust while it runs.
On/off road idling is a major factor--with DPF. Not running a high constant EGT.
Dropped the whole unit. Not a ton of soot, but some. I sent out the DPF to get cleaned, but the doc is housed inside of the whole assembly and they can’t fit it up in there cleaning system. How should I clean the DOC?
I've seen where guys have simply rinsed with water until clean. The reality is, a DOC really doesn't need any service, it's just a super thin film on a honeycomb which reacts with heat and fuel to superheat the incoming exhaust stream . That superheated exhaust reduces trapped soot to ash.Ash is the final reduction that has to be removed from the DPF. Here's the challenge as I understand it. The coating is extremely soft and fragile. Sulfur will destroy the coating. It chemically alters it, reducing it's catalytic properties. If you know the history of the truck and whether or not the EGR has ever sent coolant downstream, there really is no need for any maintenance to the DOC.
Never mentioned DPF down stream temp readings while doing regen, if not getting up to full temp regen won't take. That filter doesn't look that bad. Is that an unburned fuel stain in bottom?
I can’t remember the exact temps, but I thought they were up around 500 Fahrenheit. The stain is PB blaster from trying to get a sensor out.
Took out the dpf, got it cleaned, put everything back together, ran a regen and it has the same problem. Screen says high soot level. What sensor reads that?
That's typically a calculated value. There should be an option in your service tool to tell the ecm you have cleaned the dpf. That would give you the ability to reset soot and ash to 0. Aside from that the delta sensor dictates all.
I reset it and everything seems to be working properly now. Thank you
Outstanding,
Most decent diagnostics programs I've used allow soot reset function, or DPF reprogram after clean. Problem with soot reset if not really hot and clean is system gets confused and won't regen right anyway. 500 degrees for regen is not hot enough most systems I dealt with. 1060 or 1080 degrees F was minimum for full regen. Think full SCR cycle was longer and hotter on Volvo and maybe FLR. I'm getting old and drink a lot of Old Milwaukee so numbers may not be accurate....
Those numbers look good in my book. And yes Volvo CE run a couple hundred higher 1150-1200 range. And way more complicated than it needs to be