COVER AS-OIL PUMP 3P7951 - Caterpillar

Illustration 1 g03366473
Schematic of the "Transmission Input" Speed Sensor
This diagnostic code is recorded when the ECM receives an incorrect output signal from the speed sensor. The signal is below the dropout signal level. The engine must be running to log the diagnostic code for the sensor initially. The incorrect signal that is being read by the ECM has the following characteristics: erratic, intermittent and incorrect. The following conditions must be present before the diagnostic code will be active:
The signal from the speed sensor to the ECM is incorrect.Note: The ECM will not see a signal from the speed sensor unless the engine is running. When the ECM determines that a signal exists, the diagnostic code is NOT active.Note: Each connector contact should withstand 45 N (10 lb) of pull. Each wire should remain in the connector body. This test checks whether the wire was properly crimped in the contact and whether the contact was properly inserted into the connector. Test Step 1. CHECK THE SENSOR RESISTANCE.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the speed sensor.
At the connector for the speed sensor, measure the resistance between the two contacts of the connector of the speed sensor. Expected Result:The resistance is between 600 ohms and 1800 ohms. Results:
OK - The resistance is between 600 ohms and 1800 ohms. The speed sensor has not failed. Proceed to Test Step 2.
NOT OK - The resistance is not between 600 ohms and 1800 ohms. The speed sensor has failed.Repair: Replace the sensor. STOPTest Step 2. CHECK THE SIGNAL CIRCUIT FOR AN OPEN IN THE MACHINE HARNESS.
Place a jumper between the two contacts of the machine harness connector for the speed sensor.
Machine harness connectors J1 and J2 remain disconnected from the ECM.
Measure the resistance from the sensor signal J1-2 (wire E908-BR(Brown)) to the return contact J1-3 (wire E909-WH(White)) of the machine harness. Expected Result:The resistance is less than 5.0 ohms.Results:
OK - The resistance is less than 5.0 ohms. The signal circuit in the machine harness is correct. Proceed to Test Step 3.
NOT OK - The resistance is greater than 5000 ohms. There is an open in the signal circuit of the machine harness.Repair: Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK THE SIGNAL FOR A SHORT.
Remove the jumper between the two contacts of the speed sensor of the previous test "CHECK SIGNAL CIRCUIT FOR AN OPEN IN THE MACHINE HARNESS".
Reconnect the machine harness to the speed sensor.
At the J1 and J2 harness connectors, measure the resistance between J1-2 (wire E908-BR(Brown)) and all sources of positive voltage and ground. Expected Result:Each resistance measurement is greater than 5000 ohms. Results:
OK - The resistance measurements are greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 4.
NOT OK - Each resistance measurement is not greater than 5000 ohms. There is a short in the machine harness.Repair: The short is between the signal circuit (wire E908-BR(Brown)) and the circuit with the