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| Illustration 1 | g01377703 |
Right front drive motor speed sensor circuit | |
This diagnostic code is recorded when the all wheel drive (AWD) ECM detects an abnormal number two right motor speed sensor signal frequency. The FMI 02 diagnostic code is activated when the ECM detects an abnormal output frequency of the sensor.
The following conditions could cause this diagnostic code:
- Sensor power wire (T800-OR) open.
- Sensor return wire (J767-GY) open
- Sensor return wire (J767-GY) shorted to + battery circuit
- Signal wire (J719-PU) open
- Signal wire (J719-PU) shorted to + battery circuit
- Signal wire (J719-PU) shorted to ground
- Faulty sensor
- Faulty ECM
Test Step 1. CHECK THE RETURN CIRCUIT
- Turn off the keyswitch.
- Disconnect the harness from the sensor.
- At the harness connector for the sensor, measure the resistance from contact 2 (wire J767-GY) to frame ground.
Expected Result:
The resistance is 5 ohms or less.
Results:
- OK - The resistance is 5 ohms or less. Proceed to Test Step 2.
- NOT OK - The resistance is greater than 5000 ohms. The return circuit is open.
Repair: Repair or replace the harness.
STOP
Test Step 2. CHECK THE VOLTAGE AT THE SENSOR
The harness connector remains disconnected from the sensor.
- Turn on the keyswitch.
- At the harness connector for the sensor, measure the voltage between contact 1 (wire T800-OR) and contact 2 (wire J767-GY).
Expected Result:
The voltage is approximately 8 DCV.
Results:
- OK - The voltage is approximately 8 DCV. Proceed to Test Step 3.
- NOT OK - The voltage is not approximately 8 DCV. Wire T800-OR is open.
Repair: Repair or replace the harness.
STOP
Test Step 3. CHECK THE SIGNAL CIRCUIT FOR AN OPEN
The harness connector remains disconnected from the sensor.
- Turn off the keyswitch.
- Remove the harness connectors from the all wheel drive ECM.
- At the harness connector for the sensor, place a jumper from contact 2 (wire J767-GY) to contact 3 (wire J719-PU).
- At the harness connector for the ECM, measure the resistance from contact J1-5 to contact J1-45.
Expected Result:
The resistance is 5 ohms or less.
Results:
- OK - The resistance is 5 ohms or less. Proceed to Test Step 4.
- NOT OK - The resistance is greater than 5000 ohms. The signal circuit is open.
Repair: Repair or replace the harness.
STOP
Test Step 4. CHECK THE SIGNAL CIRCUIT FOR A SHORT
The harness connectors remain disconnected from the sensor and the ECM. The keyswitch remains off.
- Remove the jumper at the harness connector for the sensor.
- At the harness connector for the ECM, measure the resistance between J1-5 (wire J719-PU) to all harness contacts the Number Two Right Motor Speed Sensor circuit.
Expected Result:
Each resistance is greater than 5000 ohms.
Results:
- OK - Each resistance is greater than 5000 ohms. Proceed to Test Step 5.
- NOT OK - Each resistance is not greater than 5000 ohms. There is a short between the signal circuit (wire J719-PU) and the circuit with the low resistance.
Repair: Repair or replace the harness.
STOP
Test Step 5. CHECK IF THE DIAGNOSTIC CODE REMAINS
- Visually inspect and clean the harness connectors.
- Reconnect all harness connectors.
- Turn on the disconnect switch and the keyswitch.
- Operate the machine in fourth gear of manual mode.
- Check the status of the CID 2322 FMI 02.
Expected Result:
CID 2322 FMI 02 is not active.
Results:
- OK - CID 2322 FMI 02 is not active.
Repair: The initial diagnostic code was probably caused by a poor connection or short at one of the connectors that was disconnected and reconnected. Resume normal operation.
STOP
- NOT OK - CID 2322 FMI 02 is active. Proceed to Test Step 6.
Test Step 6. CHECK THE SIGNAL FROM THE SENSOR
- Turn off the keyswitch.
- At the harness connector for the all wheel drive ECM, insert a 7X-1710 Multimeter Probe along the contact J1-5 (wire J719-PU).
- Insert the other 7X-1710 Multimeter Probe along the contact J1-45 (wire J767-GY).
- Set up a calibrated 146-4080 Digital Multimeter or similar meter to measure frequency.
- Start and operate the machine in a low gear, with AWD in manual mode and the aggression dial at the center detent position.
- Monitor the sensor frequency.
Expected Result:
The frequency is approximately 38 Hz for every km/h (61 Hz for every mph).
Results:
- OK - The frequency is approximately 38 Hz for every km/h (61 Hz for every mph). The ECM may have failed, however, ECM failure is unlikely.
Repair: Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact the Technical Communicator at your Cat® dealer. If ECM replacement is required, see Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NOT OK - The frequency is not correct. The speed sensor has failed.
Repair: Replace the sensor.
STOP