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Discussion Starter · #1 ·
I have a 2021 4x4 with 14K miles on it. Got the code late last week. Cleared it and it ran fine in limited use over the weekend. Came back on Monday morning. Shoot. Dropped it off at the dealership for repair.

They called me soon after and told me the malfunction was with the active shutters in front of the intercooler. Apparently the diesels have two shutters. Upper one in front of the radiator (same as a gas 1500) and lower one in front of the intercooler. That was all news to me as I don't usually read the owner's manual very much and this one was no exception.

Anyway, it took a day to get the part and pretty much a full day to change it. Service dude said they had to remove the entire front clip to get access. The top shutter system system is an easier deal, but as per usual, I don't usually break the easier to fix stuff.

I did look up the code on line and one of the MANY things that could set this code was an intercooler that wasn't doing its job. Restricting its airflow would damn sure make it tough to do its thing.

I do absolutely love this truck. Rides better than any truck I've ever owned. That and consistent 25-26 mpg in mixed use has me very pleased. Thought I would report on what I found. This happening does have me considering the extended warranty. I've never bought one in 45 years of truck ownership. Also, never owned a truck with this much going on that could fail either.
 

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When it happened to me last week, I looked up this thread and it had nothing to do with the grille shutters. Seems to be related to NOX sensor low condition.
 

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Discussion Starter · #3 ·
Here's what I found:

RAM DTC P225D
Make:RAMCode:p225DDefinition:NOx Sensor 1/1 Performance - Signal Stuck LowDescription:The aftertreatment system is equipped with two Nox Sensors and modules. The upstream NOx Sensor 1/1 is located on the Turbocharger elbow downpipe and is permanently connected to a corresponding Nox Sensor Module mounted to the hot side of the engine block. The downstream NOx Sensor 1/2 is located at the outlet of the SCR Catalyst and is permanently connected to a corresponding Nox Sensor Module which is mounted on the right frame rail. The NOx Sensors and NOx Sensor Modules are calibrated to each other and must be replaced as an assembly. The two NOx Sensor and Module asemblies are not interchangeable. The NOx Sensor Modules are smart devices and communicate with the Powertrain Control Module (PCM) over the J1939 Data Link. The NOx Sensor Modules perform their own internal diagnostics and report malfunctions back to the PCM. The NOx Sensors are used to monitor the efficiency of the SCR Catalyst and dosing system. The PCM will illuminate the Malfunction Indicator Lamp (MIL) after the diagnostic runs and fails in two consecutive drive cycles. The PCM will turn off the MIL immediately after the monitor runs and passes.Cause:
  • CHARGE AIR COOLER RESTRICTED
  • EXHAUST SYSTEM LEAK
  • INTAKE SYSTEM LEAK
  • EGR VALVE LEAK
  • NOX 1/1 SENSOR
  • POWERTRAIN CONTROL MODULE

The first possible cause mentioned is "CHARGE AIR COOLER RESTRICTED". I'm relatively certain that the shutters not opening would restrict the charge air cooler. Plus, that's what they fixed and I've driven quite a ways now with no code popping up.
 
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