ROD AS-CONTROL 7M0829 - Caterpillar

MID 027 CID 2999 FMI 08Conditions Which Generate This Code:
Illustration 1 g01959395
Connections of the dropbox disconnect speed sensor 2 on a CX31-P600 with a dropbox
This diagnostic code is associated with the dropbox disconnect speed sensor 2. 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 2999 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 to the ON position.
Ensure that the diagnostic code is active.
Disconnect the sensor from the machine harness. Expected Result:The diagnostic code is not active.Results:
OK - The diagnostic code is not active. The sensor has failed.Repair: Replace the sensor. Verify that the new sensor corrected this diagnostic code. The diagnostic code is NOT active.STOP
NOT OK - The diagnostic code remains active. The sensor is not the cause of the diagnostic code. Proceed to Test Step 2.Test Step 2. CHECK FOR A SHORT IN THE HARNESS.
The sensor remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the J1 and J2 machine harness connectors from the Transmission ECU.
At the J1 machine harness connector for the ECU, measure the resistance between contact J1-17 (wire X966-BR(Brown)) to all other J1 and J2 contacts.
At the J1 machine harness connector for the ECU, measure the resistance between contact J1-18 (wire X967-OR(Orange)) to all other J1 and J2 contacts. Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - The resistance that is measured is greater than 5000 ohms for each measurement. The harness is correct. The ECU may have failed. Proceed to Test Step 3.
NOT OK - The resistance that is measured is NOT greater than 5000 ohms for each measurement. The machine harness has failed.Repair: There is a short in the machine harness. The short is in the circuit for wire X966-BR(Brown) or wire X967-OR(Orange) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
Reconnect all harness connectors in order to make sure that the connectors are fully seated. Also, make sure that the clips for each connector are