EXTENSION 4936916 - Caterpillar

Illustration 1 g00450788
Schematic for Speed Sensor (No. 2) (Transmission Output)
This diagnostic code is recorded when the transmission electronic control module (ECM) reads a transmission output speed sensor 2 that is erratic, intermittent, or incorrect.There are two speed sensors for transmission output speed: the transmission output speed sensor 1 and the transmission output speed sensor 2. The transmission ECM determines the existence of this diagnostic code by comparing the signals from sensor 1 and from sensor 2. The diagnostic code is recorded when one of the sensors shows a valid speed signal that is above the minimum. The diagnostic code is also recorded when one of the sensors shows a valid speed signal that is below the signal level.The transmission ECM is unable to calculate any ratios for speed in this condition.Note: Failures of the transmission output speed sensor will be shown only while the machine is moving.Note: The support bracket of the left rear platform may require removal in order to access to the sensor. Replacement of the sensor may require removal of the cab.Possible causes of this diagnostic code are listed:
There is a malfunction or misalignment of the sensor.System Response:The machine response is listed:
Transmission shifting may be harsh.
Shift hesitation during directional shifts.
Calibration for the transmission clutch cannot be performed.Test Step 1. CHECK THE SENSOR
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the speed sensor.
Measure the resistance between contact 1 and contact 2. Expected Result:The resistance should be between 800 and 1800 ohms.Results:
YES - The speed sensor has not failed. Proceed to Test Step 2.
NO - The speed sensor has failed.Repair: Replace the speed sensor. Adjust the speed sensor properly when you install the sensor. Refer to Testing and Adjusting, "Speed Sensor - Adjust" for more information on adjusting the speed sensor.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT FOR AN OPEN IN THE MACHINE HARNESS
The key start switch and the disconnect switch remain in the OFF position.
At the machine harness connector for the speed sensor, place a jumper between contact 1 and contact 2.
Disconnect machine harness connectors J1 and J2 from the transmission ECM.
Measure the resistance from the sensor signal J2-31 (wire E907-GY(Grey)) to the return contact J2-25 (wire E906-OR(Orange)) of the machine harness connector. Expected Result:There should be continuity (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 harness (wire E906-OR(Orange) or wire E907-GY(Grey)).Repair: Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK THE SIGNAL FOR A SHORT
Remove the jumper between contacts 1 and 2.
Reconnect the speed sensor to the machine harness.
The machine harness connector measures the resistance between contact J2-25 and all possible sources of positive voltage.
Repeat Test Step 3.C. Expected Result:Each resistance should be greater than 5000 Ohms.Results:
YES - The machine harness is correct. Proceed to Test Step 4.
NO - There is a short in the machine harness. The short is between the signal circuit (wire E906-OR(Orange) or