966G Wheel Loader and 972G Wheel Loader Power Train Caterpillar

Illustration 1	g00437303
Transmission Output Speed Sensor 1 Schematic

CID 0585 FMI 02 service code is recorded when the power train electronic control module (ECM) reads the speed sensor signal as being 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 power train ECM determines the existence of this fault by comparing the signals from sensor 1 and from sensor 2. This fault is recorded when one of the sensors shows a valid speed signal above the minimum and the other sensor signal is below the dropout signal level.

Because of this condition, the power train ECM is unable to calculate speed ratios.

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.

1. Check the resistance of the sensor.

   1. Turn the key start switch and the disconnect switch to the OFF position.

   2. Disconnect the machine harness from the speed sensor.

   3. Measure the resistance between contacts 1 and 2 of the speed sensor connector.

      Expected Result: The resistance should be between 800 and 1800 ohms.

      Results:

      • OK - The speed sensor has not failed. Proceed to Step 2.

      • NOT OK - The speed sensor has failed. 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. STOP.

2. Check the signal circuit for an open in the machine harness.

   1. The key start switch and the disconnect switch remain in the OFF position.

   2. At the machine harness connector for the speed sensor, place a jumper between contact 1 and contact 2.

   3. Disconnect machine harness connectors J1 and J2 from the power train ECM.

   4. At machine harness connector J2, measure the resistance between contact J2-20 (+signal) and contact J2-14 (-signal).

      Expected Result: There should be continuity (less than 5.0 Ohms resistance).

      Results:

      • OK - The machine harness is correct. Proceed to Step 3.

      • NOT OK - There is an open circuit in the machine harness (wire E900-WH or wire E901-GN). Repair the machine harness or replace the machine harness. STOP.

3. Check the signal for a short.

   1. Remove the jumper between contact 1 and contact 2 of the machine harness connector for the speed sensor.

   2. Reconnect the speed sensor to the machine harness.

   3. At the machine harness connectors J1 and J2, measure the resistance between contact J2-20 (+signal) and all possible sources of positive voltage and and all possible sources of ground.

      The following contacts are possible sources of positive voltage: J1-1, J1-4, J1-6, J1-8, J1-10, J1-11, J1-12, J1-17, J1-18, J1-40, J2-1, J2-2, J2-7, J2-8, J2-13, J2-19 and J2-37. The following contacts are possible sources of ground: J1-2, J1-5, J1-7, J1-15, J1-16, J2-3 and frame ground.

   4. Repeat Step 3.c for contact J2-14 (-signal).

      Expected Result: Each resistance should be greater than 5000 Ohms.

      Results:

      • OK - The machine harness is correct. Proceed to Step 4.

      • NOT OK - There is a short in the machine harness. The short is between the signal circuit (wire E900-WH or wire E901-GN) and the circuit with low resistance. Repair the machine harness or replace the machine harness. STOP.

4. Check whether the fault is still present.

   1. Clean the contacts of the harness connectors.

   2. Reconnect all harness connectors.

   3. Turn the key start switch and the disconnect switch to the ON position.

   4. Start the engine and run the engine at low idle.

   5. Operate the machine. The transmission must be engaged in a direction and in a speed and the machine must be moving.

   6. Enter the service mode of the Caterpillar Monitoring System. Put the CID 0585 FMI 02 service code on hold.

   7. Observe the status of the fault present indicator. (Check whether "SERV CODE" is shown.)

      Expected Result: The fault present indicator shows "SERV CODE".

      Results:

      • YES - The fault is present. Proceed to Step 5.

      • NO - The fault is not present. The fault does not exist at this time. The initial fault was probably caused by a poor electrical connection or by a short at one of the harness connectors that was reconnected. Resume normal machine operation. STOP.

5. Check the adjustment of the sensor.

   1. Check the speed sensor adjustment. Refer to Testing and Adjusting, "Speed Sensor - Adjust" for more information on adjusting the speed sensor.

   2. Perform Step 4 again. Observe the status of the fault present indicator. (Check whether "SERV CODE" is shown.)

      Expected Result: The fault present indicator shows "SERV CODE".

      Results:

      • YES - The fault remains present. Replace the speed sensor. If conditions are not resolved, proceed to Step 6.

      • NO - The fault is not present. Adjusting the speed sensor has corrected the fault. STOP.

6. Check whether the fault is still present.

   1. Remove connectors J1 and J2 from the power train ECM. Inspect the contacts and clean the contacts of the harness connectors.

   2. Reconnect all harness connectors.

   3. The key start switch and the disconnect switch remain in the ON position.

   4. Enter the service mode of the Caterpillar Monitoring System. Clear all inactive faults.

   5. Operate the machine.

   6. Check whether the CID 0585 FMI 02 service code is present.

      Expected Result: The CID 0585 FMI 02 service code is present. ("SERV CODE" is shown.)

      Results:

      • YES - The fault has not been corrected. It is unlikely that the power train ECM is faulty. Perform the test for the CID 0585 FMI 02 service code again. If the cause of the fault is not found, replace the power train ECM. Refer to Testing and Adjusting, "Electronic Control Module (Power Train) - Replace" for more information on replacing the power train ECM. STOP.

      • NO - The fault is not present. The fault does not exist at this time. Installing a new speed sensor corrected the fault. Resume normal machine operation. STOP.