SPN 3361 FMI 13 – DEF Dosing Correction Factor Not Available via CAN Fault Code (Symptoms, Causes & Fix)
The SPN 3361 FMI 13 fault code indicates that the DEF Dosing Correction Factor is not available via the CAN bus. This diesel engine fault code suggests a communication issue between the DEF dosing control unit and the ECM, which can affect the aftertreatment system's performance.
What SPN 3361 FMI 13 Means
SPN 3361 FMI 13 represents a failure in the communication of the DEF dosing correction factor over the CAN network. The ECM relies on this data to adjust the DEF dosing accurately. When this information is unavailable, it can lead to improper DEF dosing, affecting emissions control.
Common Causes of This Fault Code
- Faulty DEF dosing control unit
- CAN communication issue
- DEF dosing valve malfunction
- Wiring harness damage or corrosion
- Faulty NOx sensors
Symptoms Drivers May Notice
When the SPN 3361 FMI 13 fault code is active, drivers may notice a check engine light or a DEF system warning on the dashboard. In some cases, there might be a reduction in engine performance or increased emissions.
How Technicians Diagnose This Fault
Technicians begin by checking the battery voltage and overall system voltage to ensure proper power supply. Next, they verify the power supply and ground circuits for the DEF dosing control unit. Using a diagnostic tool, they check the integrity of the CAN bus communication. A visual inspection of the wiring harness for damage or corrosion is crucial. Technicians also perform continuity and resistance tests on the wiring related to the DEF system. Finally, they verify the operation and readings of the NOx sensors using a scan tool or multimeter.
Common Misdiagnosis
A common misdiagnosis is replacing the DEF dosing valve without verifying CAN communication issues. Technicians may also assume a DEF quality issue without checking electrical connections or overlook wiring harness damage due to environmental exposure.
Can You Keep Driving?
While it may be possible to continue driving with the SPN 3361 FMI 13 fault code active, it is not advisable. The fault can lead to engine derate or protection mode, affecting vehicle performance and emissions compliance. Addressing the issue promptly is recommended.
Mechanic's Diagnostic Tip
Always verify the CAN bus communication integrity before replacing any components. This step can prevent unnecessary part replacements and ensure accurate diagnosis.
Frequently Asked Questions
What does SPN 3361 FMI 13 indicate? It indicates a communication issue with the DEF dosing correction factor over the CAN network.
Can this fault code affect engine performance? Yes, it can lead to engine derate or increased emissions if not addressed.
What should be checked first when diagnosing this code? Start with checking the battery voltage and overall system voltage, followed by CAN bus communication integrity.
