IT38G Series II Integrated Toolcarrier and 938G Series II Wheel Loader MID 081 - CID 0673 - FMI 02 Caterpillar

Conditions Which Generate This Code:

Illustration 1	g00450788
Speed Sensor (No. 2) for Transmission Output

CID 0673 FMI 02 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 diagnostic code by comparing the signals from sensor 1 and the signals from sensor 2. This diagnostic code 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.

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.

Test Step 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 is between 800 and 1800 ohms.

Results:

• YES - The resistance is between 800 and 1800 ohms. Proceed to test step 2.

• 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 Troubleshooting, "Speed Sensor - Adjust" for more information on adjusting the speed sensor.

  Stop.

Test Step 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. Measure the resistance between contact J2-25 and contact J2-31.

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 3.

• NO - There is more than 5000 ohms resistance.

  Repair: There is an open circuit in the machine harness (wire E906-OR or wire E907-GY). Repair the machine harness or replace the machine harness.

  Stop.

Test Step 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 J2-25 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 J2-31 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 4.

• NO - The resistance is less than 5 ohms. There is a short in the machine harness. The short is between the signal circuit (wire E906-OR or wire E907-GY) and the circuit with low resistance.

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

  Stop.

Test Step 4. CHECK IF THE DIAGNOSTIC CODE REMAINS

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. Use the AVSpare Electronic Technician in order to determine if the diagnostic code is present.

Expected Result:

The diagnostic code is present.

Results:

• YES - The diagnostic code is present. Proceed to Test Step 5.

• NO - The diagnostic code is NOT present.

  Repair: 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 5. CHECK THE ADJUSTMENT OF THE SENSOR

1. Check the speed sensor adjustment. Refer to Troubleshooting, "Speed Sensor - Adjust".

2. Perform the previous test step again. Observe the status of the diagnostic code.

Expected Result:

The diagnostic code is present with the AVSpare Electronic Technician.

Results:

• YES - The diagnostic code is present. Proceed to Test Step 6.

• NO - The diagnostic code is NOT present.

  Repair: The diagnostic code is not present. Adjusting the speed sensor has corrected the diagnostic code.

  Stop.

Test Step 6. CHECK IF THE DIAGNOSTIC CODE REMAINS

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. Clear all inactive diagnostic codes.

5. Operate the machine.

6. Check whether the CID 0673 FMI 02 is present.

Expected Result:

The CID 0673 FMI 02 is present.

Results:

• YES - The CID 0673 FMI 02 is present.

  Repair: Repeat the diagnostic code procedure for CID 0673 FMI 02. If the cause of the diagnostic code is not found, replace the power train ECM. Refer to Troubleshooting, "Electronic Control Module (ECM) - Replace" for more information on replacing the power train ECM.

  Stop.

• NO - The 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.