FILM 3C8492 - Caterpillar

Illustration 1 g01192908
Schematic of the Speed Sensor (Torque Converter Output)
This diagnostic code is recorded when the ECM reads the signal of the torque converter output speed sensor as being out of range or erratic.Note: This diagnostic code is usually an intermittent condition. The diagnostic code can be active or the diagnostic code can be not active.The possible causes of this condition are listed:
The signal circuit is intermittently shorted to the +battery circuit or shorted to ground.
The sensor has failed.Note: The following diagnostic code procedure can create other related diagnostic codes. Perform the following procedure. Reconnect all harnesses. Then clear all the related diagnostic codes.Note: The machine must be in gear 2F and the machine drops out of gear more than 6 times within a ten second period.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 Expected Result:The diagnostic code is NO longer active.Results:
YES - The diagnostic code is NO longer active. The sensor has failed.Repair: Replace the sensor. Verify that the new sensor corrected this diagnostic code. The diagnostic code should NOT be active.STOP
NO - 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 ECM.
At the J1 machine harness connector for the ECM, measure the resistance between the signal contact J1-4 (wire L910-PK(Pink)) to all other J1 and J2 contacts. Expected Result:Each resistance measurement should be greater than 5 ohms.Results:
YES - Each resistance measurement is greater than 5 ohms. The harness is correct. The ECM has failed.Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this diagnostic code procedure again. If the cause of the diagnostic code is not found, replace the transmission/chassis ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOP
NO - Each resistance measurement is NOT greater than 5 ohms. The machine harness has failed. Repair: There is a short in the machine harness. The short is between the signal circuit (wire L910-PK(Pink)) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOP