TACHOMETER GP-ELECTRIC 9Y1132 - Caterpillar

Detailed FMI Explanation
FMI 00 "Data Valid But Above Normal Operating Range " - Every electronic control system sets a high limit for the expected operating range of the signal. The high limit includes over range signals. This could be a high temperature. A sensor that is still operating but sending a signal above the expected limit will cause a FMI 00 to be stored.Some of the possible causes of a FMI 00 diagnostic code are listed below.
The signal is above normal.
The signal is shorted to the +battery.
The sensor needs to be calibrated.This is an example of a sensor that needs calibration. A PWM signal that is at a duty cycle of 80 percent is a valid signal. If the PWM signal has a duty cycle of 81 percent the sensor is still working, but the sensor signal is above the expected signal limits.FMI 01 "Data Valid But Below Normal Operating Range" - Every electronic control system sets a low limit for the expected operating range of the signal. The limit includes signals that are under the lower limit. The low signal could be the oil pressure signal. The sensor is still working but sending a signal below the expected limit will cause a FMI 01 to be stored.Some of the possible causes of a FMI 01 diagnostic code are listed below.
The signal is below the normal range.
The timing is retarded.This is an example of a PWM sensor. This sensor is not expected to generate a PWM signal below a duty cycle of 5 percent with zero air pressure. If the sensor generates a signal with a duty cycle of 4 percent when the engine is shutdown. The sensor is still working but sending a signal below the expected limit will cause a FMI 01 to be stored.FMI 02 "Data Erratic, Intermittent or Incorrect" - The signal from a component is present. The control that reads the diagnostic information can not read the signal properly. The signal appears to be gone, unstable or invalid. The data can be correct or incorrect intermittently. Also, this condition relates to communication between controls. This is an example of communication between controls. When the monitoring system is looking for the engine speed from the engine ECM over the CAT Data Link.
There is a faulty connection.
The signal is intermittent or erratic.
The software has been changed.
The signal is noisy.
The signal is out of range.FMI 03 "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 of the components that could cause a FMI 03 diagnostic code are listed below.
The sensor or the switch is faulty.
The harness is damaged.
The electronic control has failed.Some of the possible causes of a FMI 03 diagnostic code are listed below.
A sensor that has failed and the voltage output is high.
Any wiring harness that has a sensor signal wire shorted to a high voltage. A high voltage is any voltage that is greater than the