OIL 3E9714 - Caterpillar

Illustration 1 g01940794
Connections of the dropbox disconnect speed sensor 1 on a CX31-P600 with a dropbox
This diagnostic code is associated with the dropbox disconnect speed sensor 1. The FMI 08 means that the ECM has determined that the signal frequency is not within the expected range.This sensor is a frequency sensor. The sensor sends a frequency to the ECM as the gear teeth pass the magnet. The voltage is proportional to the speed of the output shaft from the transmission. The frequency that is sent to the ECM increases when the speed of the teeth increases.The possible causes of this diagnostic code are listed below:
Intermittent connections or poor connections
The sensor is loose.
The sensor has failed.
The ECM 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 2998 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. INSPECT THE HARNESS CONNECTIONS.
Turn the disconnect switch and the key start switch to the OFF position.
Inspect all harness connections that are related to the sensor. Make sure that the connectors are clean and tight.
Check the connectors for proper mating. Ensure that all the seals are present and in place.
Check the harness for signs of damage or abrasion.
Check the wires at the connector. Ensure that the wires are secured tightly into the connector.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit. Take care not to pull the wire out of the connector.
Check the exposed wires at the connectors for nicks or signs of abrasion.
Check for moisture inside the connector.
Check the connectors for dirty contacts or corroded contacts.
Check each pin and each socket of the machine harness connectors. Ensure that the contacts are properly installed. The contacts should mate correctly when the two pieces of the connector are placed together. Expected Result:The machine harness connectors are tight and free of corrosion.Results:
OK - The machine harness connectors are tight and free of corrosion. Proceed to test step 2.
NOT OK - The machine harness connectors are in need of repair.Repair: Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK THE CIRCUIT FOR AN OPEN.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness from the sensor.
At the machine harness connector for the sensor, install a jumper wire between contact 1 and contact 2 of the harness.
Disconnect the machine harness connector J1 from the ECM.
At the J1 machine harness connectors for the ECM, measure the resistance from contact J1-6 for the sensor to J1-7. Expected Result:There should be less than 5.0 ohms resistance.Results:
YES - The machine harness is correct. Proceed to Test Step 3.
NO - There is an open circuit in the machine