Cummins X12 CM2350 X119B (2018 & Newer) Fault Code: 5655 PID: SPN: 4364 FMI: 31 Aftertreatment 1 SCR Conversion Efficiency- Condition Exists - EcuForce Truck (2024)

FAQs

What is the code 4364 31 on a Cummins engine? ›

This fault code indicates that the nox emissions are not being reduced enough by the SCR catalyst. There are many possible causes for this fault code including: Degraded DEF fluid. A faulty SCR catalyst.

SPN 4364 FMI 18 is an engine error code related to the aftertreatment system of a diesel engine. It can indicate a variety of issues, ranging from a faulty NOx sensor to a malfunctioning DEF system. Symptoms include the illumination of the check engine light and potential engine derate mode.

SPN 4364/FMI 18. Description This code sets when the Aftertreatment Control Module (ACM) detects that the Selective Catalyst Reduction (SCR) NOx Conversion efficiency is low.

The 4364 fault is for scr cat efficiency. This fault is present whenever the scr can not treat the nox levels. The very first thing is to check for any charge air leaks, check for any obvious ex or egr leaks. Make sure the engine does not have extended crank.

Poor DEF Quality: Contaminated or diluted diesel exhaust fluid (DEF) can compromise SCR efficiency, leading to reduced NOx conversion rates. Low DEF Pressure: Inadequate DEF pressure impedes proper dosing, affecting NOx conversion performance.

The diagnostic trouble code (DTC) P2BAC indicates “NOx Exceedance – Deactivation of EGR.” Since the ECM can monitor NOx as a rationality check, the ECM will typically set this code if the level of NOx indicates the EGR isn't working properly. But the ECM can't determine what the issue is from NOx measurement alone.

SPN stands for Suspected Parameter Number which tells you the circuit where the fault occurred. For example, if you had a SPN 1791 code, it would point to a fault detected in the EGR Valve Control Circuit. FMI stands for Failure Mode Indicator which tells you the reason the fault code was set.

Failure Mode Indication (FMI), as part of the J1939 standard used in heavy-duty vehicles, functions by closely monitoring system components. When a fault occurs, FMI generates a precise code that identifies the specific nature of the issue, much like an advanced version of a 'check engine' light.

SPN is short for suspect parameter number. It identifies which electrical circuit, part or component of your truck isn't working properly. FMI stands for failure mode identifier—this part of the fault code tells you what type of problem your truck has.

SPN stands for Suspect Parameter Number. It's a diagnostic trouble code that provides detailed information about specific faults detected by the vehicle's ECU, making it easier to identify and address issues within the vehicle's electronic systems.

What is the code SPN 94? ›

This diagnostic is typically Fuel Compensation Pressure (FCP) Sensor Circuit Failed Low.

Description This fault indicates a missing fuel level signal at the Common Powertrain Controller (CPC). Check as follows: NOTE: Fuel level sensor is hardwired to instrument cluster. Fuel level signal is multiplexed from instrument cluster to the CPC.

The NOx sensors tells the ECU how much DEF should be injected into the exhaust before it enters the SCR. If the sensors are faulty, you'll likely see increased DEF consumption and fuel spending, alongside erratic or unstable idling.

OBD error codes ranging from P2200 to P2225 are the codes commonly associated with a NOx sensor fault. A NOx sensor error in Bank 1 is usually P2202. In Bank 2, it might be a P2213.

An oxides of nitrogen sensor is used to monitor the levels of oxides of nitrogen that a vehicle emits to ensure it is compliant with emissions regulations. Oxides of nitrogen (otherwise known as NOx) are pollutants that have both environmental and health impacts.

One of the most common NOx sensor failures is high fuel consumption. This can be caused by an oxygen sensor not reading correctly, which causes your Cummins engine to run lean. A lean mixture will burn more fuel, leading to increased emissions.

NOx Sensor for NOx aftertreatment system

The sensor located upstream of the SCR catalyst directly measures the engine-out NOx gas concentration, which helps determine the optimum amount of urea injection. The NOx sensor downstream of the SCR catalyst is used to monitor the performance of the catalyst.

How do you clean a NOx sensor? Cleaning a NOx sensor is not recommended. NOx sensors are actually self-cleaning, so if the sensor is displaying signs that it isn't working properly, it should be replaced rather than cleaned manually to solve the issue.

Diesel NOx sensors are dual-purpose, in that they are used to measure both the oxygen level in the exhaust as well as NOx (NO and NO₂) content. The measurements take place in two separate chambers in the sensor, and the exhaust gases flow sequentially through one and then into the other.