I was told by two dealers that the P1451 is a code that is set by excessive idling, one mech asked me If I had a Catalyst message and about two weeks ago I did.
I have a partial TSB to show you I could give you the whole thing but i't starscan info.

Ram Truck 2500 & 3500 - Excessive Soot Accumulation In Exhaust, PCM May Not
Reprogram, OBD Readiness Status And Other Engine System Enhancements
OVERVIEW:
This bulletin involves selectively erasing and reprogramming the Powertrain Control
Module (PCM) with “bootloader” software and application software.
CAUTION: A special “bootloader” software with special reprogramming (flash)
procedures must be installed in the PCM before the application software.
Once the “bootloader” software has been successfully installed (flashed)
in the PCM, then the application software can be reprogrammed (flashed)
into the PCM.
MODELS:
2007 (DH/D1) Ram Truck (2500 & 3500)
NOTE: This bulletin applies to Ram Truck 2500 & 3500 vehicles equipped with 6.7L
Cummins turbo-diesel engine (sales code ETJ) built on or before June 11,
2007 (MDH 0611XX).
SYMPTOM/CONDITION:
The vehicle operator and/or technician may experience one or more of the following
conditions and/or enhancements:
1. The technician may not be able to reprogram (flash) the PCM with new
application software.
NUMBER: 18-033-07 REV. B
GROUP: Vehicle Performance
DATE: June 28, 2007
2. The vehicle may fail an Emission Inspection Maintenance (I/M) Test because two or
more On-Board Diagnostic (OBD) monitors report that they are not ready for testing.
This condition may cause the customer vehicle to not pass an Emissions I/M test. The
following is a list of OBD Monitors that may report as not ready for testing:
a. Non-Methane Hydrocarbon (NMHC) Catalyst Monitor.
b. Nitrogen Oxide (NOx) Absorber Monitor.
c. Exhaust Gas Temperature Sensor Monitor.
d. Electrical Charging System Monitor.
e. EGR System Monitor.
f. Oxygen Sensor Monitor.
3. After extensive idling of the vehicle engine or if an intake air leak is present, the
vehicle operator may experience a MIL illumination and/or an Electronic Vehicle
Information Center (EVIC) message alert due to one or more of the following DTC's:
a. P1451 - Diesel Particulate Filter System Performance.
b. P2463 - Diesel Particulate Filter - Soot Accumulation.
c. P242F - Diesel Particulate Filter Restriction - Ash Accumulation.4.[/COLOR] The vehicle operator may experience a MIL illumination due to one of the following
DTC's:
a. P0106 - Manifold Absolute Pressure Sensor Performance.
b. P242B - Exhaust Gas Temperature Sensor Circuit Performance - Bank 1 Sensor 3.
c. P245A - EGR Cooler Bypass Control Circuit - Open.
5. An intermittent rough engine idle and/or white smoke following initial engine start.
6. A throttle tip-in stumble at engine speeds of 1,300 to 2,100 rpm.
7. An engine hesitation at altitude of 5,000 feet between engine speeds of 1,200 to 1,600
rpm.
8. A turbocharger “chuff-like” sound during rapid deceleration.
DIAGNOSIS:
1. Connect the StarSCAN® to the vehicle Diagnostic Link Connector (DLC).
2. From the “Home” menu, select:
a. “ECU View”.
b. “PCM Powertrain Control Module”.
c. “View DTC's”.
3. Record DTC's that are present in the PCM.
4. Is DTC P242F present?
a. If YES >>> then STOP. Contact STAR for additional technical assistance.
b. If NO >>> then proceed to the next step.
5. Are either (or both) DTC P1451 or P2463 present?

 

A fellow on another forum gave me this info about the 1451 code, I didn't think the dealer really knew for sure on the code, the 1451 code is set by the colder exhaust temps.

P1451-DIESEL PARTICULATE FILTER SYSTEM PERFORMANCE


Theory of Operation
The engine Exhaust system monitors the soot load in the After treatment diesel particulate filter. Under normal operating conditions the After treatment diesel particulate filter is self-cleaning, where accumulated soot is converted to ash. Under light load operating conditions, the driver may be notified via the vehicle's EVIC message center ("CATALYST FULL: SEE OWNERS MAN" message will be displayed) that it is necessary to modify the vehicles driving routine/duty-cycle (see Owner's Manual for details) in order to allow the After treatment diesel particulate filter system to self clean. If the vehicle's EVIC message center notification is ignored, the vehicle will eventually derate the engine and set a fault, requiring service. The soot load in the After treatment diesel particulate filter is estimated by the ECM using the Exhaust Pressure Sensor values and the calculated soot output of the engine. This fault code will be triggered if the application is not operating at a duty cycle high enough to allow active regeneration of the After treatment diesel particulate filter. This fault code is an indication that the exhaust temperatures exiting the turbocharger are not high enough to allow active regeneration of the soot that is trapped in the After treatment diesel particulate filter. It may be necessary to increase the duty cycle of the application in order to prevent excessive soot accumulation and plugging of the After treatment diesel particulate filter. The ECM will set this fault if it detects that the soot level has exceeded the normal desoot trigger threshold by a sufficient amount to indicate that the driver intervention is required. There is not a MIL lamp associated with this fault code, though the driver will be notified via the EVIC message.

When Monitored:
Engine Running

Set Condition:
The ECM will set this fault if it detects that the soot level has exceeded the normal desoot trigger threshold by a sufficient amount to indicate that the driver intervention is required.

Possible Causes

ENGINE HAS BEEN OPERATING IN LIGHT LOAD CONDITIONS THAT PREVENT EXHAUST TEMPERATURES FROM BEING HIGH ENOUGH TO ACTIVELY REGENERATE THE AFTER TREATMENT PARTICULATE FILTER

PROGRESSIVE DAMAGE TO THE AFTER TREATMENT SYSTEM FROM AN ENGINE FAILURE, INCLUDING BUT NOT LIMITED TO EXCESSIVE FUEL, OIL OR COOLANT IN THE AFTER TREATMENT SYSTEM

EXHAUST LEAK PREVENTING DIESEL PARTICULATE FILTER REGENERATION TEMPERATURES FROM BEING ACHIEVED

 

Don't idle your engines. Start it and drive it. Extended idling is just wasting fuel.

 

That's one of the reasons I buy diesels, they idle for long periods and use very little fuel. Why are they ruining a good thing!!

 

I'm getting tired of people (especially the dealer) telling me not to idle these engines, yah get in it and go, do some people not realise what happens when two dissimilar metals expand at different rates, I doubt it that the dealer will warrent a engine because the customer scuffed his pistions and liners just because he didn't want to plug up the DPF. let say this to the engineers at DC there is only difference between driving your truck around town at 1100 to 1500 rpm and letting you truck idle in the winter at the same rpm, that is the truck will regen while your driving it, but alas it seems alot of the systems in these trucks work in conjunction with the ambiant temp on the overhead, if the truck is sitting in the driveway and the overhead is reading a cold temp, and i'm pretty sure you cannot light snow on fire why can't the truck regen
during a idle like the over the road "big trucks" do and some of there trucks have exhaust close to the ground.
Sorry guys and gals for the rant but this emmisions crap is really starting on my last nerve.

 

I believe that the latest flash addresses the issue you're speaking of Caper11. It allows the 6.7 to regenerate while idling, assuming of course that the engine is up to operating temperature. Once it's been warmed up, it can idle all day without the DPF being plugged up. Diesel is added to the exhaust stream to bring the EGT's up to the proper temperature for regeneration to occur. Excessive idling however will lead to more events than working the truck will, leading to a quicker accumulation of ash (burnt off soot from regen) in the DPF, meaning it will have to be cleaned out before the estimated 120,000 mile mark. So while it's still not the best thing to idle these rigs excessively, it won't lead to the DPF clogging up because it can't perform a regen. I'm with you on letting them warm up though. DPF or not, regen or not, the physics of dissimilar metals remains the same. I let mine warm at least 10 minutes in the morning, after having been plugged in at night, exhaust brake on before driving away. A person could probably go a few minutes less and keep the revs below 1500 as well. Driver preference I suppose.

 

any others with it in this cold weather? just mine?

 

T-Stat Performance Error...thermostat issue. They are on backorder forever!!

 

Got mine in last week (took 2 weeks on back order),
I don't believe its a weather issue, my code went on when it was 50 out

After spending so much _____ money we shouldn't have to worry about this crap, at least not yet.

 

Sorry guys, but this is not true. I have a juice w/ attitude and it tells you when you go into regen. As soon as you put it in park the regen goes off. I confirmed this at my High Performance friendly dealer. No REGEN IN PARK. I have the latest flash on my truck too. So this is not a cure.

 

Pretty much try I started the regen at idle thing because I have a manual, I can park and sit there and it will regen but as soon as I set the park brake it will stop regen. So you can regen in a manual but not an auto.

 

Oops! Didn't think of the manuel trans thing. So what do you do,,,, chalk your wheels?