FMI 9 — Abnormal update rate
A module stopped sending its message often enough. Usually a network or a module-power problem, not the sensor.
Common causes
- Failing datalink wiring or terminating resistor
- Module losing power or ground intermittently
- Overloaded or noisy J1939 bus
- Failing source module
What to test, in order
- Measure J1939 resistance at the diagnostic connector — about 60 ohms with the key off
- Check power and ground at the module that stopped reporting
- Look for other modules missing at the same time — that points at the bus, not one module
- Inspect the backbone and stub connectors for corrosion
Codes we document with FMI 9
SPN 639 FMI 9J1939 network abnormal update rate · CATSPN 639 FMI 9J1939 network abnormal update rate · DetroitSPN 639 FMI 9J1939 network abnormal update rate · InternationalSPN 639 FMI 9J1939 network abnormal update rate · PACCARSPN 639 FMI 9J1939 network abnormal update rate · MERCEDESSPN 639 FMI 9J1939 network abnormal update rate · VolvoSPN 639 FMI 9J1939 network abnormal update rate · MackSPN 639 FMI 9J1939 network abnormal update rate · CumminsSPN 1231 FMI 9Missing message from the transmission · All makes
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