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

Illustration 1	g00433604
Engine Speed Sensor Schematic

CID 0190 FMI 02 service code is recorded when the power train electronic control module (ECM) reads the signal of the engine speed sensor as erratic, intermittent or incorrect. To determine the existence of this condition, the power train ECM compares the engine speed sensor signal to the torque converter output speed sensor signal. A failure is recorded when the power train ECM detects the engine speed sensor signal as below the dropout signal level and the torque converter output speed sensor senses the engine speed as above low idle. Because of this fault, the power train ECM is unable to calculate torque converter ratio.

Note: The engine must be running in order for the power train ECM to show this fault.

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 the two contacts of the speed sensor connector.

      Expected Result: The resistance should be between 90 and 250 Ohms.

      Results:

      • OK - The speed sensor is not faulty. Proceed to Step 2.

      • NOT OK - The speed sensor has failed. Replace the sensor. Adjust the speed sensor properly when you install the sensor. Refer to Testing and Adjusting, "Speed Sensor - Adjust". STOP.

2. Check the return circuit.

   The machine harness remains disconnected from the sensor.

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

   2. At the machine harness connector for the sensor, measure the resistance between contact 1 (wire G939-PK) and the frame ground.

      Expected Result: The resistance should be 20 ohms or less.

      Results:

      • OK - The return circuit is correct. Proceed to Step 3.

      • NOT OK - The return circuit (wire G939-PK) in the machine harness has excessive resistance (open). Repair the machine harness or replace the machine harness. STOP.

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

   1. At the machine harness connector for the speed sensor, place a jumper between the two contacts.

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

   3. At the machine harness connectors, measure the resistance from J2-38 (sensor signal) to J1-15 (return).

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

      Results:

      • OK - The signal circuit in the machine harness is correct. Proceed to Step 4.

      • NOT OK - The signal circuit (wire 450-YL) is open in the machine harness. Repair the machine harness or replace the machine harness. STOP.

4. Check the signal for a short.

   1. Remove the jumper from the previous test.

   2. At the harness connectors, measure the resistance between J2-38 (wire 450-YL) and all 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.

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

      Results:

      • OK - The machine harness is correct. Proceed to Step 5.

      • NOT OK - There is a short in the machine harness. The short is between the signal circuit (wire 450-YL) and the circuit with low resistance. Repair the machine harness or replace the machine harness. STOP.

5. Check whether the fault is still present.

   1. Clean the contacts of the harness connectors.

   2. Reconnect all harness connectors.

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

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

   5. Enter the service mode of the Caterpillar Monitoring System. Put the CID 0190 FMI 02 service code on hold.

   6. 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. Proceed to Step 6.

      • 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.

6. Check the adjustment of the sensor.

   1. To check the speed sensor adjustment, refer to Testing and Adjusting, "Speed Sensor - Adjust".

   2. Repeat the steps from the above test ("Check whether the fault is still present").

      Expected Result: The fault remains present.

      Results:

      • YES - The fault remains present. Replace the speed sensor. If conditions are not resolved, proceed to Step 7.

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

7. 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. Turn the disconnect switch and the key start switch to 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 0190 FMI 02 service code is present.

      Expected Result: The CID 190 FMI 02 service code is present. ("SERV CODE" is showing.)

      Results:

      • YES - The fault has not been corrected. It is unlikely that the power train ECM is faulty. Perform the test for CID 0190 FMI 02 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 information on replacing the power train ECM. STOP.

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