824H Wheel Dozer, 825H Soil Compactor and 826H Landfill Compactor Power Train Caterpillar

Illustration 1	g00450721
Schematic of the Torque Converter Output Speed Sensor

CID 0672 FMI 01 diagnostic code is recorded when the ECM reads the speed sensor signal as being below the expected limit.

The possible causes of this diagnostic code becoming active are:

• The sensor has failed.

• The signal circuit of the sensor is shorted to the ground.

• The sensor needs to be calibrated.

• The ECM has failed. This is unlikely.

Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected.

Test Step 1. INSPECT THE SENSOR

1. Perform a visual inspection of the sensor, the wiring for the sensor and the hardware that is associated with the sensor.

Expected Result:

There is no apparent damage to the sensor, the wiring for the sensor or the hardware that is associated with the sensor.

Results:

• OK - There is no apparent damage to the sensor, the wiring for the sensor or the hardware that is associated with the sensor. Proceed to Test Step 2.

• NOT OK - There is apparent damage to the sensor, the wiring for the sensor or the hardware that is associated with the sensor.

  Repair: Replace the damaged part.

  Proceed to Test Step 6.

Test Step 2. 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 is between 800 and 1800 ohms.

Results:

• YES - The resistance is between 800 and 1800 ohms. Proceed to Test Step 3.

• NO - The resistance is not between 800 and 1800 ohms.

  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.

  STOP

Test Step 3. 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. Measure the resistance between contact J2-23 and contact J2-29.

Expected Result:

There is continuity (less than 5.0 ohms resistance).

Results:

• YES - There is less than 5.0 ohms resistance. The machine harness is correct. Proceed to Test Step 4.

• NO - There is more than 5 ohms resistance.

  Repair: There is an open circuit in the machine harness (wire E909-WH or wire E908-BR). Repair the machine harness or replace the machine harness.

  STOP

Test Step 4. CHECK THE SIGNAL CIRCUIT 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 J2-23 and all possible sources of positive voltage and at all possible sources of ground.

4. At the machine harness connectors J1 and J2, measure the resistance between contact J2-29 and all possible sources of positive voltage and at all possible sources of ground.

Expected Result:

The resistance is greater than 5000 ohms.

Results:

• YES - The resistance is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 5.

• NO - The resistance is less than 5000 ohms. There is a short in the machine harness. The short is between the signal circuit (wire E909-WH or wire E908-BR) and the circuit with low resistance.

  Repair: Repair the machine harness or replace the machine harness.

  STOP

Test Step 5. CHECK WHETHER THE DIAGNOSTIC CODE 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 0672 FMI 01 diagnostic 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 present indicator shows "SERV CODE". The diagnostic code is present. Proceed to Test Step 6.

• NO - The fault present indicator does not show "SERV CODE".

  Repair: The diagnostic code is not present. The diagnostic code does not exist at this time. The initial diagnostic code 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

Test Step 6. CHECK THE ADJUSTMENT OF THE SENSOR

1. Check the speed sensor adjustment. Refer to Testing and Adjusting, "Speed Sensor - Adjust".

2. Perform the previous test step 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 present indicator shows "SERV CODE". Proceed to Test Step 7.

• NO -

  Repair: The fault present indicator does not show "SERV CODE".

  STOP

Test Step 7. CHECK WHETHER THE DIAGNOSTIC CODE 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 diagnostic codes.

5. Operate the machine.

6. Check whether the CID 0672 FMI 01 diagnostic code is present.

Expected Result:

The CID 0672 FMI 01 diagnostic code is present. ("SERV CODE" is shown.)

Results:

• YES - The CID 0672 FMI 01 diagnostic code is present.

  Repair: Perform the test for the CID 0672 FMI 01 diagnostic code again. If the cause of the diagnostic code is not found, replace the power train ECM. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace" for more information on replacing the power train ECM.

  STOP

• NO - The CID 0672 FMI 01 diagnostic code is not present.

  Repair: The diagnostic code does not exist at this time. Installing a new speed sensor corrected the diagnostic code. Resume normal machine operation.

  STOP