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| Illustration 1 | g02623975 |
Connections for the transmission output speed sensor | |
This diagnostic code is recorded when the ECM compares certain machine conditions with the data that is received from the sensor. The ECM will issue this diagnostic code if the sensor data is not within certain parameters.
Possible conditions that can cause this diagnostic code are listed:
- The transmission output speed sensor is not installed correctly.
- The transmission output speed sensor has failed.
- The signal circuit is shorted to ground.
- The ECM has failed. An ECM failure is unlikely.
Note: Before performing the following procedure, ensure that the CID 0585 FMI 08 code is active.
Test Step 1. CHECK THE SENSOR MOUNT
- Turn the disconnect switch and the key start switch to the OFF position.
- At the transmission output speed sensor, perform the following procedure in order to adjust the speed sensor.
- Loosen the locking nut on the speed sensor.
- Turn the speed sensor in a clockwise direction until the tip of the sensor contacts the top of a gear tooth.
- Turn 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, turn the disconnect switch to the ON position and start the engine. Operate the machine and observe the status of the active CID 0585 FMI 08 code.
Expected Result:
The CID 0585 FMI 08 code is not active.
Results:
- OK - The CID 0585 FMI 08 code is no longer active. The adjustment procedure corrected the problem.STOP
- NOT OK - The CID 0585 FMI 08 code is still active. The adjustment procedure did not correct the problem. Proceed to Test Step 2.
Test Step 2. CHECK THE RESISTANCE OF THE CASE OF THE SENSOR
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the machine harness connector from the sensor.
- Measure the resistance from contact 2 (wire E900-WH) to the case of the sensor. Measure the resistance from contact 1 (wire E901-GN) to the case of the sensor.
Expected Result:
Each resistance measurement is greater than 10,000 ohms.
Results:
- OK - The resistance measurements are greater than 10,000 ohms. Proceed to Test Step 3.
- NOT OK - Either one or both of the resistance measurements is NOT greater than 10,000 ohms. The speed sensor has failed.
Repair: Replace the sensor.
STOP
Test Step 3. CHECK FOR A SHORT IN THE RETURN CIRCUIT OF THE MACHINE HARNESS
- The key start switch and the disconnect switch remain in the OFF position.
- Disconnect the machine harness from the sensor.
- At the machine harness connector, measure the resistance between contact J1-2 (wire E900-WH) and all possible sources of ground.
- At the machine harness connector, measure the resistance between contact J1-3 (wire E901-GN) and all possible sources of ground.
Expected Result:
Each resistance measurement is greater than 5000 ohms.
Results:
- OK - Each resistance measurement is greater than 5000 ohms. Proceed to Test Step 4.
- NOT OK - One or more of the resistance measurements is less than 5000 ohms. There is a short to a ground source in the machine harness.
Repair: Refer to the complete Electrical System Schematic for your machine. Examine all connections that are in the sensor circuit. Examine the machine harness at all locations of contact with the machine frame. Repair the machine harness or replace the machine harness.
STOP
Test Step 4. CHECK THE STATUS OF THE DIAGNOSTIC CODE
- Inspect the contacts of the harness connectors and clean the contacts.
- Reconnect all harness connectors.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Check for an active diagnostic code of CID 0585 FMI 08.
Expected Result:
The diagnostic code of CID 0585 FMI 08 is not active.
Results:
- OK - The diagnostic code of CID 0585 FMI 08 is not active. The failure is no longer present.
Repair: The diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connections that was disconnected and reconnected. Resume normal machine operation.
STOP
- NOT OK - The diagnostic code of CID 0585 FMI 08 is still active. The problem has not been corrected.
Repair: Check the sensor circuit again. Use the Caterpillar Electronic Technician (ET) in order to perform a "Wiggle Test" on the machine wiring harness. The "wiggle test" can detect intermittent shorts or opens in the machine wiring harness.If the cause of this problem cannot be found and the speed sensor has not been replaced, replace the speed sensor.If replacement of the speed sensor does not correct the problem, the ECM may need replaced. Prior to replacing an ECM, always contact your dealerships Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found, replace the Machine ECM. Refer to Troubleshooting, "Electronic Control Module (ECM) - Replace".
STOP