STRIP 1025849 - Caterpillar

Illustration 1 g00756427
Schematic Of The Transmission Speed SensorThis diagnostic code is recorded when the ECM reads the signal of the TOS sensor (wire 449-BU) as being not valid.The possible causes of this diagnostic code are listed:
Wire 710-GN is shorted.
The TOS sensor is not installed correctly.
The TOS sensor has failed.
The ECM has failed.Note: Ensure that the CID 0701 FMI 08 for the sensor is active.Note: The circuit for the transmission output speed sensor can also be verified by monitoring the TOS indicator on the monitor display. Note: If a diagnostic code for the sensor supply is present "CID 0269", correct this diagnostic code prior to troubleshooting CID 0701 FMI 08. The machine must be operating in second gear or higher in order for the ECM to show this diagnostic code as being present. The "SERV CODE" is ON. Ensure that the diagnostic code is on hold.As a result of this diagnostic code, the transmission will not shift above second gear and the lockup clutch will fail to engage.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Disconnect the sensor from the machine harness.Expected Result:The diagnostic code is NO longer active.Results:
YES - The diagnostic code is NO longer active.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 J2 machine harness connector for the ECM, measure the resistance between the signal contact J2-38 (wire 449-BU) to all other J1 and J2 contacts.Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
YES - Each resistance measurement is greater than 5000 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 ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Stop.
NO - The resistance is not greater than 5000 ohms for all measurements. The machine harness failed. Repair: There is a short in the machine harness. The short is between the signal circuit (wire 710-GN) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness. Stop.