OIL 3E9712 - Caterpillar

Illustration 1 g01959375
Connections of the dropbox disconnect speed sensor 3 on a CX31-P600 with a dropbox
This diagnostic code is associated with the dropbox disconnect speed sensor 3. The "FMI 08" means that the ECU has determined that the signal frequency is not within the expected range. The possible causes of this diagnostic code are listed below:
The sensor has failed.
The circuit has intermittent connections or poor connections.
Mechanical devices are loose.
The ECU has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 3000 FMI 08 is active before performing this procedure. The engine must be running in order for the diagnostic code to be active.Note: Use a digital multimeter for the measurements in this procedure. Test Step 1. CHECK THE SENSOR.
Turn the disconnect switch and the key start switch