24M Motor Grader Implement Electronic Control System MID 082 - CID 2252 - FMI 03 Caterpillar

Conditions Which Generate This Code:

Illustration 1	g03656425
"Machine Articulation Angle Position" Sensor location (View from the left side of the machine at the articulation hitch) (1) Articulation angle sensor (2) Mechanical linkage

Illustration 2	g03664505
Location of the position sensor for the angle of the machine articulation The view is from the left side of machine and the covers are removed. (3) Articulation angle sensor 1 (4) Articulation angle sensor 2 (2) Mechanical linkage

Illustration 3	g03656436
Connections for the single Machine Articulation Angle Position Sensor 2 with two outputs

Illustration 4	g03664506
Connections of machine articulation angle position sensor 2

Two articulation angle signals are required for correct operation of articulation on the machine. Either the two separate sensors or the dual output sensor will provide a PWM signal to the ECM.

The FMI 03 diagnostic code is activated when the ECM reads the input signal from the machine articulation angle sensor signal 2 connected to each ECM at J2-17 and the voltage of the signal is above normal. The diagnostic code can be activated by any of the following:

• Implement ECM

• Transmission/Chassis ECM

• Both the Implement ECM and Transmission/Chassis ECM

The sensor is a PWM sensor that operates at a frequency of approximately 500 hertz. The PWM sensor sends a PWM input signal to the ECM. The variations in the duty cycle of the signal follows:

• When the machine is in the neutral position, the duty cycle will be 50%.

• When the machine is articulated to the full left position, the duty cycle will be approximately 69%.

• When the machine is articulated to the full right position, the duty cycle will be approximately 32%.

The following conditions could cause this diagnostic code to be activated:

• The power supply circuit of the sensor is open.

• The return circuit is open.

• The signal circuit is open or the sensor is disconnected.

• The signal circuit is shorted to the sensor power supply.

• The sensor has failed.

• The ECM has failed. This is unlikely.

Note: Before performing this procedure, check for an active CID 0168 diagnostic code for the ECM supply voltage. Correct any problem with the 24 volt power supply before performing this procedure.

The Transmission/Chassis ECM (MID 027) and the Implement ECM (MID 082) receive an input signal from the articulation sensor signal 1. Both the electronic control modules can activate a CID 2252 FMI 03 diagnostic code when an above normal signal is detected.

If one ECM has activated a CID 2252 FMI 03 diagnostic code and the other ECM has not activated the diagnostic code, it is likely that the sensor is operating correctly. When this occurs, a poor connection in the machine harness would be suspected.

If both of the electronic control modules have activated the diagnostic code, it is unlikely that either ECM has failed.

For any of these conditions, proceed with this procedure in order to verify the cause of the problem.

Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Inspect the connections for the following:

• Connections are clean.

• Connections are secure.

• Connections are in good condition.

If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.

Note: The following test procedure may create other diagnostic codes. Clear the diagnostic codes when the original diagnostic code has been corrected.

Test Step 1. CHECK THE MECHANICAL LINKAGE

1. Turn the disconnect switch to the OFF position.

2. Turn the key start switch to the OFF position.

3. Remove any guards or shielding for the articulation sensors.

4. Check the mounting bolts of the articulation sensors. Ensure that the sensors are securely mounted.

5. Visually inspect the mechanical linkage of the articulation sensors. Verify the following:

   • All mechanical components are tight.

   • All mechanical components are in good condition.

   • The adjustment of the linkage is correct.

Expected Result:

All mechanical linkage and adjustment for the articulation sensor(s) are in good condition. No mechanical connections are loose.

Results:

• OK - All mechanical linkage and adjustment for the articulation sensor is correct. Proceed to Test Step 2.

• NOT OK - All mechanical linkage and adjustment for the articulation sensors is not correct.

  Repair: Perform the maintenance that is required in order to correct the problem with the mechanical connections for the articulation sensor(s). After the problem has been corrected, verify that this diagnostic code is still active before proceeding with this procedure.

  STOP

Test Step 2. CHECK THE SUPPLY VOLTAGE AT THE SENSOR

1. Turn the disconnect switch to the OFF position.

2. Turn the key start switch to the OFF position.

3. Do not disconnect the harness connector from the sensor.

4. At the back of the harness connector for the sensor, insert 7X-1710 Multimeter Probes along contact A (wire 147-PU(Purple)). Insert a multimeter probe along return contact B (wire 200-BK(Black)).

5. Turn the disconnect switch to the ON position.

6. Turn the key start switch to the ON position.

7. Measure the voltage from contact A to contact B.

Expected Result:

The voltage measurement is 24 VDC.

Results:

• OK - The voltage measurement is 24 VDC. The power supply circuit is correct. Proceed to Test Step 3.

• NOT OK - The voltage measurement is not 24 VDC. The power supply circuit is not correct.

  Repair: There is a problem with the power supply circuit of 24 VDC for the sensor. Refer to the Electrical Schematic of the machine. Check all of the connections that are in the power supply circuit and the return circuit. Inspect the connections for the following:

  • Connections are clean.

  • Connections are secure.

  • Connections are in good condition.
  Repair the machine harness or replace the machine harness.

  STOP

Test Step 3. CHECK FOR AN OPEN IN THE SIGNAL CIRCUIT

1. The key start switch and the disconnect switch remain in the OFF position.

2. Disconnect the machine harness connector from the sensor.

3. At the machine harness connector for the sensor, connect a jumper wire between a good ground contact and signal contact C (wire U768-BU(Blue)).

4. Disconnect the machine harness connector J2 from the Implement ECM.

5. At the machine harness connector for the Implement ECM, measure the resistance from a ground contact to contact J2-17 (wire U768-BU(Blue)).

6. While the resistance measurement is observed, wiggle the ECM connector and the sensor connector. Gently pull on the wires and move the wires for both connectors.

Expected Result:

The resistance measurement is less than 5 ohms at all times during the manipulation of the wiring harness.

Results:

• OK - The resistance measures less than 5 ohms. The signal circuit is not open. Proceed to Test Step 4.

• NOT OK - The resistance measurement is greater than 5 ohms. There is an open or a bad connection in the signal circuit.

  Repair: If both of the electronic control modules have activated the diagnostic code, there is an open or a bad connection on the sensor side of the splice of the signal wire.

  If only the Implement ECM has activated the diagnostic code, there is an open or a bad connection on the ECM side of the splice of the signal wire.

  In either case, refer to the Electrical Schematic of the machine. Check all of the connectors that are in the suspected part of the sensor signal circuit. Inspect the connections for the following:

  • Connections are clean.

  • Connections are secure.

  • Connections are in good condition.
  Repair the machine harness or replace the machine harness.

  STOP

Test Step 4. CHECK THE SIGNAL CIRCUIT FOR A SHORT

1. The key start switch and the disconnect switch remain in the OFF position.

2. The sensor connector and the Implement ECM J2 harness connector remain disconnected from the machine harness.

3. Remove the jumper wire that was installed in the last step.

4. Disconnect the J2 connector from the Transmission/Chassis ECM.

5. At the J2 machine harness connector for the Implement ECM, measure the resistance from the sensor signal contact J2-17 (wire U768-BU(Blue)) to the other J2 contact that is used for the Implement ECM.

6. At the J2 machine harness connector for the Transmission/Chassis ECM, measure the resistance from the sensor signal contact J2-17 (wire U768-BU(Blue)) to the other J2 contact that is used for the Transmission/Chassis ECM.

Expected Result:

Each resistance measurement is greater than 5000 ohms.

Results:

• OK - Each resistance measurement is greater than 5000 ohms. The signal circuit is not shorted. Proceed to Test Step 5.

• NOT OK - A resistance measurement is less than 5000 ohms.

  Repair: There is a short in the machine harness. The short is between the signal circuit and the circuit with the low resistance measurement.

  Refer to the Electrical Schematic of the machine. Check all of the connectors that are in the sensor circuit. Inspect the connections for the following:

  • Connections are clean.

  • Connections are secure.

  • Connections are in good condition.
  For information on testing for short circuits and finding short circuits, refer to the Testing and Adjusting, "Wiring Harness (Short Circuit) - Test" Story in this manual. Repair the machine harness or replace the machine harness.

  STOP

Test Step 5. CHECK THE SIGNAL OF THE SENSOR

1. The key start switch and the disconnect switch remain in the OFF position.

2. Reconnect the harness connector J2 to the connector of the Transmission/Chassis ECM and the connector of the Implement ECM.

3. Reconnect the machine harness connector to the sensor.

4. At the back of the harness connector for the sensor, insert the multimeter probe along contact B (wire 200-BK(Black)) and insert the probe along the signal contact C (wire U768-BU(Blue)).

5. Turn the disconnect switch to the ON position.

6. Turn the key start switch to the ON position.

7. Monitor the signal of the sensor with a digital multimeter.

8. Without disassembling the linkage from the sensor, detach the linkage from the frame and manually move the sensor through the full operating range of the sensor.

Expected Result:

The sensor's signal responds in the manner that is described at the beginning of this procedure.

Results:

• OK - The sensor's signal responds correctly. The sensor is operating correctly. Proceed to Test Step 6.

• NOT OK - The sensor's signal does not respond correctly. The sensor is not operating correctly.

  Repair: Replace the articulation angle 2 sensor. After replacement of the sensor, the sensor must be calibrated. Refer to the Testing and Adjusting, "Calibration" Story in this manual for the correct calibration procedure.

  STOP

Test Step 6. CHECK THE OPERATION OF THE ECM

Note: This check should be performed on the ECM that has activated the diagnostic code. If both of the electronic control modules have activated the diagnostic code, perform this check on both of the electronic control modules.

1. Turn the disconnect switch to the OFF position.

2. Turn the key start switch to the OFF position.

3. At the machine harness connector J2 for the ECM, use a 151-6320 Removal Tool to remove the sensor signal wire U768-BU(Blue) and the socket at contact J2-17 from the harness connector.

4. Turn the disconnect switch to the ON position.

5. Turn the key start switch to the ON position.

6. With a 7X-1710 Multimeter Probe that is not connected to a multimeter, connect the ECM pin at J2-17 through the empty space in the J2 connector.

7. While the status of the active CID 2252 FMI 03 diagnostic code is observed, ground the other end of the 7X-1710 Multimeter Probe to frame ground.

Expected Result:

The CID 2252 FMI 03 diagnostic code is no longer active. A CID 2252 FMI 04 diagnostic code becomes active when the ECM pin at J2-17 is grounded.

Results:

• OK - The CID 2252 FMI 03 diagnostic code is no longer active. A CID 2252 FMI 04 diagnostic code has been activated after the ECM pin is grounded. The ECM has responded correctly to the grounded circuit condition in the solenoid circuit. The ECM is not causing the problem. Reconnect the signal wire in the ECM connector before proceeding to the next test step. Proceed to Test Step 7.

• NOT OK - The CID 2252 FMI 03 diagnostic code remains active. The status of the active diagnostic code does not change when the ECM pin for the sensor signal is grounded.

  Repair: The ECM has not responded correctly to the grounded condition in the sensor circuit. The operation of the ECM is not correct.

  Prior to replacing any ECM, always contact your dealership's Technical Communicator for possible consultation with AVSpare. This consultation may greatly reduce repair time. If the ECM must be replaced, refer to the Testing and Adjusting, "Electronic Control Module (ECM) - Replace" Story in this manual.

  STOP

Test Step 7. CHECK THE STATUS OF THE DIAGNOSTIC CODE

1. Perform the following:

   • Visually inspect the harness connectors.

   • Clean the contacts of the harness connectors.

   • Visually inspect the insulation of the wires for damage that is caused by excessive heat, battery acid, or chafing.

2. Perform a 45 N (10 lb) pull test on each wire that is associated with the sensor circuit.

3. Reconnect all harness connectors. Verify the following:

   • Connectors are fully seated.

   • The clips for each connector are completely fastened.

4. Turn the disconnect switch to the ON position.

5. Turn the key start switch to the ON position.

6. Operate the machine.

7. Determine if the CID 2252 FMI 03 diagnostic code is active.

Expected Result:

The CID 2252 FMI 03 diagnostic code is not active.

Results:

• OK - The CID 2252 FMI 03 diagnostic code is not active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor connection or a short at one of the connectors that was disconnected and reconnected. Resume normal operation.

  STOP

• NOT OK - The CID 2252 FMI 03 diagnostic code is active. The diagnostic code has not been corrected.

  Repair: Check the circuit again. Perform a Wiggle Test on the machine wiring harness with the AVSpare Electronic Technician (Cat ET) service tool. The Wiggle Test can detect the following in the machine wiring harness:

  • Momentary shorts

  • Intermittent shorts

  • Opens
  If the cause of the active diagnostic code is not found, replace the sensor. After replacement of the sensor, the sensor must be calibrated. Refer to the Testing and Adjusting, "Calibration" Story in this manual for the correct calibration procedure.

  If the problem is still present after replacement of the sensor, the ECM may have failed. This is unlikely due to the following:

  • The ECM responded correctly to the change of condition in the previous test step.
  The ECM may have failed. However, it is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact your dealership's Technical Communicator for possible consultation with AVSpare. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found, and the ECM must be replaced, refer to the Testing and Adjusting, "Electronic Control Module (ECM) - Replace" Story in this manual for additional information.

  STOP