What is SPN 5826 FMI 15 & How to Solve It?

What is SPN 5826 FMI 15:

SPN 5826 refers to a J1939 network error, and FMI 15 means the data being received is valid but higher than expected — often related to the rate or volume of incoming signals.

This fault typically indicates that a module is sending too much data too frequently, overwhelming the communication network and potentially affecting performance or diagnostics.

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Why This Happens

• Faulty control module flooding the network.
• Software misconfiguration or bug.
• Incorrect sensor reporting too many updates.
• Wiring issue causing network noise.
• Overlapping messages from multiple sources.

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How to Fix It

1. Use diagnostics to identify which module is creating the traffic spike.
2. Update firmware on that module to fix data rate issues.
3. Inspect wiring for grounding problems or data reflection.
4. Remove or isolate aftermarket devices causing network conflicts.
5. Clear the fault and monitor traffic behavior after reboot.

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How to Avoid It Before It Happens

1. Keep all module firmware updated with OEM specs.
2. Use only verified aftermarket devices with J1939 support.
3. Regularly log and analyze CAN traffic for unusual spikes.
4. Schedule communication diagnostics quarterly.

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