PISTON & ROD GP 3710838 - Caterpillar

Failure Mode Identifier
The codes for the Failure Mode Identifier (FMI) are defined by the Society Of Automotive Engineers Inc. (SAE). The Table 4 contains the CAT definitions for the FMI. Diagram 1 illustrates FMI codes that can be generated from a sensor that has failed.
Illustration 1 g00493694
Range of possible FMI codes generated from a failed sensor
Table 4
Failure Mode Identifier Definitions
FMI Failure Description
0 Data valid but above normal operating range
1 Data valid but below normal operating range
2 Data erratic, intermittent, or incorrect
3 Voltage above normal or shorted high
4 Voltage below normal or shorted low
5 Current below normal or open circuit
6 Current above normal or grounded circuit
7 Mechanical system not responding properly
8 Abnormal frequency, pulse, or period
9 Abnormal update
10 Abnormal rate of change
11 Failure mode not identifiable
12 Bad device or component
13 Out of calibration
14 Special Instruction Detailed FMI Explanation
FMI 0 "Data Valid But Above Normal Operating Range" - Every electronic control system has a high limit setting for the expected operating range of the signal. The high limit includes over range signals. A sensor that is still operating but sending a signal above the expected limit will cause an FMI 00 to be recorded.Some possible causes of an FMI 00 are:
The signal is above normal
The signal is shorted to the +battery circuit
The sensor is out of calibrationThe following is an example of a sensor that needs calibration. A PWM signal with an 80% duty cycle is a valid signal. If the PWM signal exceeds 80%, the sensor is still working, but the signal from the sensor is above range.FMI 1 "Data Valid But Below Normal Operating Range" - Every electronic control system sets a low limit for the expected operating range of the signal. A sensor may still be working but is sending a signal below the minimum range.Some possible causes of an FMI 01 are:
The signal is below the normal range
The timing is incorrectThe following is an example of a PWM sensor. This sensor is not expected to generate a PWM signal below a duty cycle of 5% with 0 psi air pressure. A sensor that generates a signal with a duty cycle of 4% at 0 psi will work, but the signal is below range. FMI 01 will be recorded for this condition.FMI 2 "Data Erratic, Intermittent or Incorrect" - The signal from a component is present. The control that reads the diagnostic information cannot read the signal properly. The signal appears to be unstable, or invalid. The data can be intermittent. This condition can relate to communication between controls. The following conditions may cause this code to be recorded:
Failed connection
Intermittent or erratic signal
Changed software
Noisy signal
Out of range signalFMI 3 "Voltage Above Normal or Shorted High" - The component or system voltage is higher than the limit. FMI 03 most often relates to a signal circuit.Some components that could cause an FMI 03 are:
Failed sensor or switch
Damaged harness is
Failed ECMSome possible causes of an FMI 03 are:
A sensor that has failed and the voltage output is high.
Any wiring harness