SPN(Suspect Parameter Number) FMI(Failure Mode Identifier)

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The suspect parameter number (SPN) is diagnostic fault code terminology found on some of our equipment using a J1939 CAN data link.

Represents the SPN with error. Every defined SPN can be used in a DTC.

The FMI is used along with the SPN to provide specific information that relates to a diagnostic trouble code (DTC). The FMI may indicate that a problem with an electronic circuit or an electronic component has been detected. The FMI may also indicate that an abnormal operating condition has been detected.

FMI represents the nature and type of error that occurred, e.g., value range violation (high or low), sensor short-circuits, incorrect update rate, calibration error.

The FMI may also indicate that an abnormal operating condition has been detected. The codes are displayed in the form 'SPN - FMI'. The ECM / ECU also attaches a text description to the message that is transmitted over the J1939 data link. This text description is used to describe the SPNFMI.

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The failure mode of the DTC is determined by evaluating the electronic signal from the suspect circuit. The failure mode identifiers can be divided into two categories:

  • Codes that indicate that a problem with an electronic circuit or an electronic component has been detected
  • Codes that indicate that a system event has been detected

Typically, the first category of code is generated when the signal for the circuit is outside the range of the sensor. The second category of code indicates that the sensor signal is OK, but the signal is outside the normal operating range of the parameter. Refer to the troubleshooting guide for the specific product. The troubleshooting guide procedure will help determine the root cause of a DTC.

DTC codes includes SPN and FMI also ;

  • A SPN (a PID from J1587)
  • A SID (same as J1587)
  • An FMI (expanded from J1587)
  • Occurence count (same as J1587)

SPN FMI Codes

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This solution is intended as supplemental reference information to be used in a general context to assist in troubleshooting. Where Used When Fault Code Descriptions do not provide the level of detail needed to diagnose an issue i.e. "too vague". This may also be useful in cases where multiple codes have identical fault descriptions.

SPN Codes

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Suspect parameter numbers (SPN) can vary on trucks, it begins from 1 to 5 digit numbers and located different part of the vehicle such as ECM, GWM, HVAC-C, CMS, ICU, CHM, TCU, PLC, ABS/ATC and TM units. We listed all the SPN codes below.

Check all spnfmi code list above.

Engine Brands :

Freightliner SPN Codes

freightliner code

List of Freightliner Trucks is an American truck manufacturer SPN FMI error codes.

SPNFMI Faults and Engine error code check tool. SPN code listing with names and descriptions.

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