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| Illustration 1 | g02837236 |
Schematic of the torque converter output speed sensor | |
A CID 0672 is associated with the torque converter output speed sensor. FMI 08 indicates the Power Train Electronic Control Module (ECM) is receiving erratic, intermittent, or incorrect signals from the speed sensor.
Possible causes for this diagnostic code are:
- Incorrectly installed speed sensor
- Speed sensor failure
- Speed sensor circuit open
- Speed sensor circuit shorted
- The ECM has failed. The ECM is unlikely to have failed
Note: Poor connections often cause problems in electrical circuits. Before performing this procedure, inspect all of the harness connectors involved in the circuit. Verify that all circuit connections are clean, secure, and in good condition. If a problem is found with any of the connections: correct the problem, and verify that diagnostic code CID 0672 FMI 08 is still active, before performing the following procedures.
Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes now, but clear those codes after the original diagnostic code has been corrected.
Test Step 1. CHECK THE SENSOR MOUNT
- Move the disconnect switch and the key start switch to the OFF position.
- At the torque converter output speed sensor, perform the following procedure:
- Loosen the locking nut on the speed sensor.
- Move the speed sensor in a clockwise direction until the tip of the sensor contacts the top of a gear tooth.
- Move the sensor in a counterclockwise direction between one half and three quarters of a full turn.
- Tighten the locking nut securely.
- After adjusting the sensor, move the disconnect switch to the ON position and start the engine. Operate the machine and observe the status of the CID 0672 FMI 08 diagnostic code.
Expected Result:
CID 0672 FMI 08 is not active.
Results:
- YES - CID 0672 FMI 08 is not active. The adjustment procedure corrected the problem.
Repair: Return machine to normal operation.
STOP
- NO - CID 0672 FMI 08 is still active. The adjustment procedure did not correct the problem. Go to Test Step 2.
Test Step 2. CHECK SENSOR TO CASE RESISTANCE
- Move the key start switch and the disconnect switch to the OFF position.
- Disconnect the machine harness connector from the sensor.
- At the sensor, measure resistance from contact 1 (wire L910-PK), and then from contact 2 (wire L911-YL) to the sensor case.
Expected Result:
Resistance is more than 10,000 ohms.
Results:
- YES - The resistance is more than 10,000 ohms. Go to Test Step 3.
- NO - The resistance is less than 10,000 ohms. The speed sensor has failed.
Repair: Replace the sensor.
Go to Test Step 6.
Test Step 3. CHECK THE SENSOR RESISTANCE
- The key start switch and the disconnect switch remain in the OFF position.
- The harness connector remains disconnected from the sensor.
- At the sensor connector, measure resistance between contact 1 (wire L910-PK) and contact 2 (wire L911-YL).
Note: The sensor resistance is between 1000 ohms and 1200 ohms at 25° C (77° F).
Expected Result:
The resistance is approximately 1100 ohms.
Results:
- YES - The resistance is 1100 ± 100 ohms. The sensor has not failed. Go to Test Step 4.
- NO - The resistance is not 1100 ± 100 ohms. The sensor has failed.
Repair: Replace the sensor.
Go to Test Step 6.
Test Step 4. CHECK THE SENSOR CIRCUIT FOR AN OPEN
- The key start switch, and the disconnect switch, stay in the OFF position.
- The harness connector remains disconnected from the sensor.
- Disconnect J1 harness connector from the Power Train ECM.
- At the sensor harness connector, place a jumper wire from contact 1 (wire L910-PK) to contact 2 (wire L911-YL.
- At the ECM J1 harness connector, measure the resistance from contact J1-6 (wire L910-PK) to J1-7 (wire L911-YL).
Expected Result:
The resistance is less than 5 ohms.
Results:
- YES - The resistance is less than 5 ohms. There are no open circuits in the harness. Go to Test Step 5.
- NO - The resistance is more than 5 ohms. There is an open circuit in the harness.
Repair: The open is in wire L910-PK, or in wire L911-YL. Repair or replace the harness.
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Test Step 5. CHECK THE SENSOR CIRCUIT FOR A SHORT
- The key start switch, and the disconnect switch, remain in the OFF position.
- The harness connector remains disconnected from the sensor, but the jumper wire is removed.
- At the J1 harness connector, measure resistance from contact J1-6 (wire L910-PK) to all other contacts used in the ECM J1 harness connector. Measure resistance from contact J1-7 (wire L911-YL) to all other contacts used in the J1 harness connector.
Expected Result:
Each resistance is greater than 5 ohms.
Results:
- YES - Each resistance is greater than 5 ohms. Go to Test Step 6.
- NO - A resistance measured less than 5 ohms. There is a short in the harness.
Repair: The short is in wire L910-PK, or from wire L911-YL, to the wire with the low resistance. Repair or replace the harness.
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Test Step 6. CHECK THE STATUS OF THE DIAGNOSTIC CODE
- Reconnect all disconnected machine harness connectors. Make sure that all the connectors are clean, and fully seated. Observe that the clips for each connector are securely fastened.
- Move the key start switch and the disconnect switch to the ON position.
- Clear all inactive diagnostic codes.
- Operate the machine.
- Check the status of the CID 0672 FMI 08 diagnostic code.
Expected Result:
CID 0672 FMI 08 is not active.
Results:
- YES - CID 0672 FMI 08 is no longer active and does not exist at this time.
Repair: Return machine to normal operation.
STOP
- NO - CID 0672 FMI 08 is still active. The problem has not been corrected. The ECM may have failed.
Repair: Check the harness connectors.Clean the contacts of the harness connectors. Check the wires for damage to the insulation caused by excessive heat, battery acid, or chafing.Perform a 45 N (10 lb.) pull test on each of the wires that are associated with the sensor circuit.Perform a "wiggle test" on the sensor circuit of the machine wiring harness, using the Caterpillar Electronic Technician (ET) service tool. The "wiggle test" can be used to detect open or shorted connections in the machine wiring harness.Reconnect all harness connectors. Make sure that the connectors are fully seated. Observe that the clips for each connector are fastened.Perform Test Step 5 again.If the problem is not found, and the original code is still active, the Power Train ECM may have failed.Prior to replacing an ECM, always contact your Dealership Technical Communicator for possible consultation with Caterpillar, or with the Dealer Solutions Network.This consultation may greatly reduce repair time.If the ECM needs to be replaced, see Troubleshooting, Testing, and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP