Vehicles

SPN 3058 FMI[10,16,18] Engine Faults Explained

SPN 3058 means that the EGR system monitor has a problem. Each FMI is different as shown below.

FMI 10 – Abnormal rate of change

FMI 16 – Data valid but above normal – moderately severe

FMI 18 – Data valid but below normal – moderately severe

FMI 0 – Data Valid But Above Normal Operational Range (Most Severe Level)
This FMI indicates that the EGR mass flow rate is higher than the acceptable range. Check for issues with the EGR valve, such as sticking or not closing completely, and inspect the EGR cooler for clogging or damage. Additionally, look for any vacuum leaks, damaged wiring, or faulty sensors.

FMI 1 – Data Valid But Below Normal Operational Range (Least Severe Level)
This FMI suggests that the EGR mass flow rate is lower than the acceptable range. Inspect the EGR valve for sticking or not opening completely, and check for clogging or damage in the EGR cooler. Also, check for vacuum leaks, damaged wiring, or faulty sensors.

FMI 2 – Data Erratic, Intermittent, or Incorrect
This FMI indicates that the EGR mass flow rate data is inconsistent or incorrect. Inspect the EGR valve and EGR cooler for proper operation, and check the wiring and connections to the EGR sensors. Look for loose connections, corrosion, or damaged wires.

 

 

Things to check:
motor control module software version
EGR sensor
Clean exhaust gas recirc system

 

The Exhaust Gas Recirculation (EGR) system monitor is a component of a vehicle’s onboard diagnostic system (OBD-II) that checks the functionality and efficiency of the EGR system. The EGR system helps reduce nitrogen oxide (NOx) emissions by recirculating a portion of exhaust gases back into the engine’s combustion chamber. This reduces peak combustion temperatures, which in turn reduces the formation of NOx.

The EGR system monitor performs several tasks, including:

  1. Monitoring the position of the EGR valve: The ECU or ECM checks whether the EGR valve is functioning properly by comparing its expected position with its actual position. If there is a significant discrepancy, a diagnostic trouble code (DTC) may be triggered.
  2. Checking EGR flow: The EGR system monitor evaluates the flow of exhaust gases through the EGR system. If the flow is insufficient or excessive, a DTC may be triggered.
  3. Evaluating EGR system components: The EGR system monitor checks the functionality of various components, such as the EGR valve, EGR control solenoid, and EGR temperature sensor. If any of these components are not functioning properly, a DTC may be triggered.
  4. Monitoring EGR system efficiency: The EGR system monitor evaluates the overall efficiency of the EGR system by comparing the NOx levels before and after the EGR process. If the system is not reducing NOx emissions effectively, a DTC may be triggered.

 

 

 

Other SPN codes: