What This FMI Means
FMI 19 indicates the receiving module has received J1939 network data that contains an error status in the message payload. The transmitting module is sending a message, but that message includes an error indicator — a J1939-defined value that means 'the data I am sending is not valid.' The receiving module detects this error status and logs FMI 19.
This distinguishes FMI 19 from FMI 9 (missing update rate): FMI 9 means the data has stopped arriving; FMI 19 means the data is arriving but contains an explicit error flag from the transmitting module. The transmitting module is actively reporting that its data should not be trusted.
How It Appears With SPN Codes
FMI 19 appears on network-received SPNs — parameters whose values come from another module over J1939. The source address in the fault code identifies the receiving module (the one logging FMI 19). The transmitting module is the source to investigate — it is the one whose data contains the error status.
Common scenarios include a transmitting module with its own sensor fault (a voltage or threshold fault on its input) that causes it to flag its output as invalid. The receiving module detects this invalid flag and logs FMI 19 on the SPN it expected to receive. Checking the transmitting module's fault code log typically reveals the underlying sensor or circuit fault that caused the invalid data flag.
How to Approach Diagnosis
FMI 19 is essentially a secondary fault — it reflects the receiving module's response to the transmitting module's problem. Identify the transmitting module for the SPN showing FMI 19 using the source address. Read that module's fault code log. The underlying fault is almost always visible there.
Resolving the transmitting module's primary fault — the sensor or circuit issue causing it to flag its data as invalid — will typically cause the FMI 19 in the receiving module to clear as well. Clearing FMI 19 without addressing the transmitting module's underlying fault will result in its return.
What Drivers Should Record
Record all active fault codes from all modules, not just the module displaying FMI 19. A complete multi-module fault code report provides the full picture needed for diagnosis. The transmitting module's codes are the primary fault; FMI 19 is the downstream effect.
Note whether the FMI 19 appeared simultaneously with other codes or appeared after other codes were cleared. Clearing a primary sensor fault in the transmitting module often clears related FMI 19 codes in receiving modules at the same time, confirming the causal relationship.
Related Pages
Sources
- SAE J1939 Standards Collection SAE International · official · accessed 2026-05-05 · confidence medium
Source: SAE International, SAE J1939 Standards Collection. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - NHTSA Manufacturer Communications Search National Highway Traffic Safety Administration · government · accessed 2026-05-05 · confidence high
Source: National Highway Traffic Safety Administration, NHTSA Manufacturer Communications Search. This page paraphrases factual fields only and is not a substitute for the original document.
Open source
FAQ
What causes FMI 19 (received network data in error)?
FMI 19 means a module received a J1939 message from another module, but the data in that message appears to be in error — the value is out of range, invalid, or implausible based on what the receiving module expects. This is different from FMI 9 (message not arriving at all). The source module is transmitting, but the content of what it transmits is not valid.
Is FMI 19 typically caused by a failed sending module, or can it come from network errors?
Both. A module broadcasting corrupted data due to an internal failure will produce FMI 19 on every module that receives and validates its messages. Network bit errors from damaged wiring, EMI, or CAN bus faults can also corrupt messages in transit, causing the received values to fail the receiving module's plausibility check. Network health (bus resistance, noise level) is worth verifying alongside the sending module.
If FMI 19 appears alongside FMI 9 on the same SPN, what does that combination suggest?
FMI 9 (abnormal update rate) and FMI 19 (data in error) on the same SPN suggest a module that is both sending messages inconsistently and sending invalid data when it does transmit. This is consistent with a module experiencing power supply issues, an internal fault, or a degraded CAN transceiver. Address network and power supply conditions before concluding the module itself has failed.