621K OEM Wheel Tractor-Scraper Sensor Signal (PWM)

Table 1
Implement ECM (MID 82)
DTC	Code Description	System Response
3836-3	Cushion Hitch Cylinder Position Sensor : Voltage Above Normal	The diagnostic code will cause the solenoids for the cushion hitch control to be set to the minimum command. Control of the cushion hitch will not return until the diagnostic code is inactive. The signal from the position sensor must be in the neutral position for at least 2 seconds.
3836-4	Cushion Hitch Cylinder Position Sensor : Voltage Below Normal	The diagnostic code will cause the solenoids for the cushion hitch control to be set to the minimum command. Control of the cushion hitch will not return until the diagnostic code is inactive. The signal from the position sensor must be in the neutral position for at least 2 seconds.
3836-8	Cushion Hitch Cylinder Position Sensor : Abnormal Frequency, Pulse Width, or Period	The diagnostic code will cause the solenoids for the cushion hitch control to be set to the minimum command. Control of the cushion hitch will not return until the diagnostic code is inactive. The signal from the position sensor must be in the neutral position for at least 2 seconds.

Transmission/Chassis ECM

The following is a list of diagnostic codes that are associated with the PWM Sensors of the machine.

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Table 2
Transmission/Chassis ECM (MID 27)
DTC	Code Description	System Response
668-3	Transmission Shift Lever : Voltage Above Normal	Operator will be unable to shift transmission.
668-4	Transmission Shift Lever : Voltage Below Normal	Operator will be unable to shift transmission.
668-8	Transmission Shift Lever : Abnormal Frequency, Pulse Width, or Period	Operator will be unable to shift transmission.
833-3	Rear Brake Temperature Sensor : Voltage Above Normal	The reading for this sensor will be less than the actual temperature at the brake.
833-4	Rear Brake Temperature Sensor : Voltage Below Normal	The reading for this sensor will be greater than the actual temperature at the brake.
833-8	Rear Brake Temperature Sensor : Abnormal Frequency, Pulse Width, Or Period	The reading for this sensor will drift or appear erratic.
2976-3	Parking Brake Oil Pressure Sensor : Voltage Above Normal	The sensor has failed, gauge pressure display (if any) is incorrect.
2976-4	Parking Brake Oil Pressure Sensor : Voltage Below Normal	The sensor has failed, gauge pressure display (if any) is incorrect.
2976-8	Parking Brake Oil Pressure Sensor : Abnormal Frequency, Pulse Width, or Period	The sensor has failed, gauge pressure display (if any) is incorrect.
2988-3	Brake Charge Pressure Sensor #2 : Voltage Above Normal	The sensor has failed, gauge pressure display (if any) is incorrect.
2988-4	Brake Charge Pressure Sensor #2 : Voltage Below Normal	The sensor has failed, gauge pressure display (if any) is incorrect.
2988-8	Brake Charge Pressure Sensor #2 : Abnormal Frequency, Pulse Width, or Period	The sensor has failed, gauge pressure display (if any) is incorrect.
3534-8	Left Front Axle Speed Sensor : Abnormal Frequency, Pulse Width, Or Period	The output from the sensor will be erratic and incorrect.
3535-8	Right Front Axle Speed Sensor : Abnormal Frequency, Pulse Width, Or Period	The output from the sensor will be erratic and incorrect.
3652-3	Steering Pump Oil Pressure #1 Sensor : Voltage Above Normal	The sensor signal wire is shorted to a power supply circuit. The signal output will be consistently high.
3652-4	Steering Pump Oil Pressure #1 Sensor : Voltage Below Normal	The sensor signal wire is shorted to a ground circuit. The signal output will be consistently low.
3652-8	Steering Pump Oil Pressure #1 Sensor : Abnormal Frequency, Pulse Width, Or Period	The signal circuit is erratic which is an indication of a loose connection or corrosion at a connector location.
3652-14	Steering Pump Oil Pressure #1 Sensor : Special Instruction	This diagnostic trouble code (DTC) is active with DTC 3653-14. The steering sensors are mismatched but in the proper operating range. Inspect both sensors for out of specification issues and replace the faulted sensor or both sensors.
3653-3	Steering Pump Oil Pressure #2 Sensor : Voltage Above Normal	The sensor signal wire is shorted to a power supply circuit. The signal output will be consistently high.
3653-4	Steering Pump Oil Pressure #2 Sensor : Voltage Below Normal	The sensor signal wire is shorted to a ground circuit. The signal output will be consistently low.
3653-8	Steering Pump Oil Pressure #2 Sensor : Abnormal Frequency, Pulse Width, Or Period	The signal circuit is erratic which is an indication of a loose connection or corrosion at a connector location.
3653-14	Steering Pump Oil Pressure #2 Sensor : Special Instruction	This diagnostic trouble code (DTC) is active with DTC 3652-14. The steering sensors are mismatched but in the proper operating range. Inspect both sensors for out of specification issues and replace the faulted sensor or both sensors.

Seat ECM

The following is a list of diagnostic codes that are associated with the PWM Sensors of the machine.

Note: Review all active diagnostic codes before troubleshooting begins. If a Primary Code (See) is active, troubleshoot this code first. After correcting the active Primary Code, use Cat ET or the operator monitor to review a list of the remaining diagnostic codes.

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Table 3
Primary Code ⁽¹⁾	Secondary Code ⁽²⁾
J520707-5	J520713-5
J520707-6	J520707-2
J520708-6	J520709-2 J521217-21 J521761-31
J520709-2	J520713-5

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⁽¹⁾	Troubleshooting first when secondary code(s) are active.
⁽²⁾	Ignore until primary code has been corrected.

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Table 4
Seat ECM (MID 314)
DTC	Code Description	System Response
521217-12	Seat Oil Pressure Sensor : Bad Component	The operator will notice a change in the motion of the seat.
521217-20	Seat Oil Pressure Sensor : Data Drifted High	The operator will notice a change in the motion of the seat.
521217-21	Seat Oil Pressure Sensor : Data Drifted Low	The operator will notice a change in the motion of the seat.

Suspension System ECM

The following is a list of diagnostic codes that are associated with the PWM Sensors of the machine.

Note: Review all active diagnostic codes before troubleshooting begins. If a Primary Code (See 5) is active, troubleshoot this code first. After correcting the active Primary Code, use Cat ET or the operator monitor to review a list of the remaining diagnostic codes.

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Table 5
Primary Code ⁽¹⁾	Secondary Code ⁽²⁾
J520707-6	J520707-2 J521760-15
J520708-6	J520705-2 J521249-21
J520741-12	J520741-2

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⁽¹⁾	Troubleshooting first when secondary code(s) are active.
⁽²⁾	Ignore until primary code has been corrected.

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Table 6
Suspension System ECM
DTC	Code Description	System Response
520705-2	Valve Position Sensor : Data Erratic, Intermittent, or Incorrect	Cause: Occurs when output is less than 2.5 VDC or greater than 4.75 VDC. Effect : Cushion Hitch will not operate smoothly.
520705-7	Valve Position Sensor : Not Responding	Cause: Occurs when output is less than 2.5 VDC or greater than 4.75 VDC. Effect : Cushion Hitch will not operate smoothly.
520741-2	Cylinder Position Sensor : Data Erratic, Intermediate, or Incorrect	Cause: The most likely cause for this issue is an intermittent short causing the voltage to the sensor to go unexpectedly high or low. Effect: Cylinder position may not report to ECM correctly.
520741-12	Cylinder Position Sensor : Bad Component	Cause: Sensor has likely been damaged physically. Effect: Movement of cylinder is restricted by ECM.
521249-12	Cushion Hitch Oil Pressure Sensor : Bad Component	Cause: Sensor is displaying no pressure or is associated with an erratic output. Effect: Machine operator is alerted to the fault.
521249-20	Cushion Hitch Oil Pressure Sensor : Data Drifted High	Cause: Occurs when the air pressure exceeds 2300 psi. Effect: Machine operator is alerted to the fault.
521249-21	Cushion Hitch Oil Pressure Sensor : Data Drifted Low	Cause: Occurs when the air pressure falls below 150 psi. Effect: Machine operator is alerted to the fault.

Possible Causes and Conversion Charts

Possible Causes for an FMI 2 Diagnostic code are:

A shorted wiring harness or an open wiring harness.
The transmission gear sensor has failed.
The ECM has failed. A failure of the ECM is unlikely.

Possible Causes for an FMI 3 Diagnostic code are:

The sensor supply or the ground circuit in the machine harness is open.
The signal circuit in the machine harness is shorted to another circuit.
The signal circuit in the machine harness is open or the sensor is disconnected.
The sensor has failed.
The ECM has failed. A failure of the ECM is unlikely.

Possible Causes for an FMI 4 Diagnostic code are:

The signal circuit in the machine harness is shorted to ground.
The sensor has failed.
The ECM has failed. A failure of the ECM is unlikely.

Possible Causes for an FMI 7 Diagnostic code are:

The component responds improperly.
Physical damage to the transducer (failure).
The component is stuck in a position.

Possible Causes for an FMI 8 Diagnostic code are:

The signal circuit is shorted to the battery or shorted to the ground connection intermittently.
The signal circuit is open intermittently or the sensor is disconnected.
The sensor has failed.
The ECM has failed. A failure of the ECM is unlikely.

Possible Causes for an FMI 12 Diagnostic code are:

There is a failure of the electronic control.
There is a failure on the data link.

Possible Causes for an FMI 14 Diagnostic code are:

A hydraulic problem is causing above normal hydraulic pump pressure.
Both pressure sensors are installed and do not agree with each other.
The sensor has failed.
The signal circuit for the sensor is shorted to a voltage source.
The ECM has failed. This condition is unlikely.

Note: The output of the Steering Flow Pressure Sensors does not match. The output of the sensors is within the valid operating range. The Transmission/Chassis ECM will activate an FMI 14 for this sensor when the reading of the standby pressure transducer at the discharge side of the hydraulic pump is above 7500 kPa (1089 psi). This pressure is confirmed at engine low idle after the speed has stabilized. The pressure is also confirmed immediately after the Secondary Steer Test switch has been moved to the TEST position.

For the "Transmission Shift Lever Sensor", the following duty cycles apply based on shift lever position.

Transmission Shift Lever Sensor Conversion Chart

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Table 7
Conversion Chart for Transmission Shift Lever Sensor
Switch Position	Electrical Circuit Angle 15 ° ± 2 ° Between	Switch Pin Number
Switch Position	Electrical Circuit Angle 15 ° ± 2 ° Between	1	2	4	5	6
R	320.5 ° to 339.5 °	1.15	1.15	5.25	5.25	5.25
N	350.5 ° to 9.5 °	1.15	5.25	1.15	5.25	5.25
1	20.5 ° to 39.5 °	1.15	5.25	5.25	1.15	5.25
2	50.5 ° to 69.5 °	1.15	5.25	5.25	5.25	1.15
3	80.5 ° to 99.5 °	5.25	1.15	1.15	5.25	5.25
4	110.5 ° to 129.5 °	5.25	1.15	5.25	1.15	5.25

Front/Rear Brake Temperature vs. Duty Cycle

For the "Front Brake Oil Temperature Sensor", the following duty cycles apply based on temperature.

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Table 8
Temperature Conversion Chart for Front Brake and Rear Brake Oil Temperature Sensor
Celsius Temperature	Fahrenheit Temperature	Duty Cycle At Temperature
−40° C	−40° F	10.01%
−30° C	−22° F	10.48%
−20° C	−4° F	11.32%
−10° C	14° F	12.72%
0° C	32° F	14.97%
10° C	50° F	18.36%
20° C	68° F	23.17%
30° C	86° F	29.51%
40° C	104° F	37.22%
50° C	122° F	45.84%
60° C	140° F	54.70%
70° C	158° F	63.12%
80° C	176° F	70.61%
90° C	194° F	76.94%
100° C	212° F	82.07%
110° C	230° F	86.12%
120° C	248° F	89.26%

Steering Pump Oil Pressure vs. Signal Voltage Chart

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Table 9
Steering Pump Oil Pressure Sensor 1 Signal Voltage versus Pressure
Pressure	Signal Voltage	Pressure	Signal Voltage
6895 kpa (1000 psi)	0.9 VDC	24.1 mpa (3500 psi)	2.9 VDC
13.8 mpa (2000 psi)	1.7 VDC	25.6 mpa (4000 psi)	3.3 VDC
17.2 mpa (2500 psi)	2.1 VDC	31.0 mpa (4500 psi)	3.7 VDC
20.7 mpa (3000 psi)	2.5 VDC	34.5 mpa (5000 psi)	4.0 VDC

Schematic Information

Note: Before beginning procedure, use Cat^® ET or the machine monitor to check active DTC codes indicating failure of a power supply on the ECM. If the code is present, refer to the Sensor Supply - Test story to correct this problem before continuing.

Note: Some test procedures may create additional diagnostic codes. Ignore these created diagnostic codes and clear the codes when the original diagnostic code has been corrected.

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Illustration 1	g03350269
The diagram above is simplified schematic of the Implement ECM connections for the PWM sensors.

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Illustration 2	g03317621
The diagram above is simplified schematic of the Transmission/Chassis ECM connections for the PWM sensors.

Note: The schematics shown above are electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the electrical schematic. The electrical schematics for specific machine models are listed below:

The electrical schematic for model 621K is Electrical Schematic , KENR9577.

Note: Prior to beginning procedure, use Cat^® ET to check for active DTC that indicates failure of a power supply on the ECM. If the code is present, refer to the Sensor Supply - Test story to correct this problem before continuing.

Note: Some test procedures may create additional diagnostic codes. Ignore these created diagnostic codes and clear the codes when the original diagnostic code has been corrected.

Diagnostic Trouble Code Procedure

Note: Poor harness connections are often the cause of a problem in electrical circuits. Before performing any troubleshooting procedure, inspect all of the connectors involved in the circuit. Verify that all of the connections in the circuit are dry, clean, secure, and in good condition. Each pin and socket in the connectors should mate correctly when the connectors are fastened together. Check for exposed wires at the connectors for nicks or abrasion. If a problem is found with any of the connections: correct the problem and verify that diagnostic code is still active, before performing the following procedures. For more information, refer to Troubleshooting, "Electrical Connector - Inspect".

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Table 10
Troubleshooting Test Steps	Values	Results
1. Identify Active FMI Code Associated With Sensor Circuit.	Code present.	FMI 2 diagnostic code, proceed to Test Step 2. FMI 3 diagnostic code, proceed to Test Step 6. FMI 4 diagnostic code, proceed to Test Step 12. FMI 7 diagnostic code, proceed to Test Step 15. FMI 8 diagnostic code, proceed to Test Step 17. FMI 12 diagnostic code, proceed to Test Step 19. FMI 14 diagnostic code, proceed to Test Step 22.
Begin Process For FMI 2 Troubleshooting HERE
2. Check The Supply Voltage For The Sensor. A. Turn the disconnect switch and key start switch to the ON position. B. At the voltage connector for the sensor, measure the voltage from the voltage connection to frame ground.	The voltage should equate to the battery voltage.	OK - The voltage reading is equal to the battery voltage. Proceed to Test Step 3. NOT OK - The voltage is not approximately battery voltage. Repair - Repair or replace the wiring harness. Verify that the repair corrects the problem.
3. Check The Ground Circuit. A. Turn the disconnect switch and key start switch to the OFF position. B. At the connector measure the resistance from ground connection to frame ground.	The resistance measures less than 5 Ω.	OK - The resistance is less than 5 Ω. Proceed to Test Step 4. NOT OK - The resistance is greater than 5 Ω.. Repair - There is an open in the ground circuit. Repair the harness or replace the harness. Verify that the repair corrects the problem.
4. Check The Signal Circuit For A Short. A. The disconnect switch and key start switch remain in the OFF position. B. Disconnect the connector from the control lever module or the sensor. C. Disconnect the J1 and J2 harness connectors from the ECM. D. Measure resistance between a signal contact for the Gear Switch (or sensor) and each of the contacts for the J1 and J2 ECM harness connectors. E. Repeat the process above until all of the signal contacts have been checked.	Each resistance reading is greater than 5K Ω.	OK - Each of the resistance measurements is greater than 5K Ω. The resistance measurements are correct. Proceed to Test Step 5. NOT OK - One or more of the resistance measurements is less than 5 Ω. Repair - There is a short in the machine harness. The short is between the signal wire and pin location where the low resistance was observed. Examine all locations in the circuit for loose connections or signs of corrosion. Repair or replace the harness as needed.
5. Check The Switch. Note: The following procedure is only used for checking the output of the gear handle. A. The disconnect switch and key start switch remain in the OFF position. B. At the harness connector for the control lever, use a wire removal tool to remove signal contact from the harness. C. Reconnect the harness connector to the control lever. D. At the harness connector for the control lever (or sensor), insert the negative multi-meter probe at contact G. E. Turn the disconnect switch and key start switch to the ON position. Do not start the engine. F. Measure the voltage output of the switch while the gear handle is moved through each position. G. Refer to Table 7 for the expected output. H. Return to Step B and repeat the process for each of the signal contacts.	The voltage output is in the acceptable range for each output.	OK - The voltage is within the acceptable range for each output. Proceed to Test Step 19. NOT OK - The voltage output is not within the acceptable range that is listed for each position. Repair - The switch has failed. Replace the switch. Verify that the replacement of the switch has corrected the problem.
Begin Process For FMI 3 Troubleshooting HERE
6. Check The Supply Voltage At The Sensor. NOTE- Use a calibrated digital multimeter for the measurements in this procedure. A. Turn key start switch and disconnect switch ON. B. Do not disconnect the sensor from the machine harness. C. Refer to the schematic to determine the voltage source for the suspected faulty sensor. D. At the back of the contacts for the sensor, insert multimeter probes at the supply contact to frame ground. Measure the voltage.	The voltage measures either 8.0 VDC or 24 VDC, depending on the source. (See schematic for specific sensor.)	OK - The voltage reading is correct for the suspected faulty sensor. Proceed to Test Step 7. NOT OK- The voltage is NOT correct for the circuit. Repair - There may be an open or short in the machine harness. The open or short will be on the power or ground circuit wires. Repair or replace the machine harness. STOP
7. Check For Proper Ground At The Sensor. A. The machine harness remains connected to the sensor. B. Turn the key start switch and the disconnect switch OFF. C. At the back of the harness connector for the sensor, insert a Multimeter Probe along the ground wire contact. D. Measure the resistance from the ground contact to frame ground.	The resistance is less than 5 Ω..	OK - The resistance is less than 5 Ω.. The ground circuit is correct. Proceed to Test Step 8. NOT OK - The resistance is greater than 5 Ω.. The ground circuit in the machine harness has failed. Repair: Replace or repair the machine harness. STOP
8. Check The Signal Of The Sensor. A. Turn the disconnect switch and the key start switch OFF. B. At the back of the harness connector for the sensor, insert a Multimeter Probe along the signal and ground wires. C. Turn the disconnect switch and the key start switch to the ON position. D. Monitor the signal of the sensor using the multimeter. E. If possible, without disconnecting the sensor or the hardware associated with the sensor from the machine, take the sensor through the full operating range. (Start the engine if necessary. Apply and hold the brake until the engine is shut off.)	The signal from the sensor responds in the manner expected.	OK- The sensor is operating correctly. Proceed to Test Step 9. NOT OK- The signal from the sensor indicates the sensor does not operate correctly. Repair- Replace the faulty sensor. After replacing the sensor, operate the machine to confirm that the diagnostic code is not active.
9. Check The Signal At The ECM. A. Turn the key start switch and the disconnect switch to the OFF position. B. Insert the multimeter probes into the back of the ECM connector along the signal and ground wires. C. Turn the disconnect switch and the key start switch to the ON position. D. Monitor the signal of the sensor with a Digital Multimeter. E. If possible, without disconnecting the sensor or the hardware associated with the sensor from the machine, take the sensor through the full operating range. (Start the engine if necessary. Apply and hold the brake until the engine is shut off.)	The signal from the sensor responds in the manner expected.	OK- The sensor is operating correctly. Proceed to Test Step 10. NOT OK- The signal from the sensor indicates the sensor does not operate correctly. Repair- Repair the machine harness or replace the machine harness. STOP
10. Check For An Open In The Sensor Circuit. A. The sensor remains disconnected from the machine harness. B. Turn the key start switch and the disconnect switch OFF position. C. At the harness connector for the sensor, place a jumper wire between the ground contact and the signal contact. D. Disconnect J1 and J2 harness connectors from the ECM. E. At machine harness connector for ECM, measure the resistance from the signal contact to return contact. F. Gently pull on the wires and move the wires in a circular motion at ECM connector and observe the resistance readings. Repeat the process for the sensor connector.	The resistance is less than 5 Ω. at all times during the check of the harness.	OK- The resistance is less than 5 Ω.. The signal circuit and the ground circuits of the sensor are not open in the machine harness. Proceed to Test Step 11. NOT OK- Resistance reading for the signal circuit or the return circuit is greater than 5 Ω. Repair: Check the signal circuit or the ground circuit for opens or bad connections. Note: A resistance greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit. STOP
11. Check Signal Circuit For A Short To Another Circuit. A. The Sensor and the ECM are disconnected from the harness. B. Turn the disconnect switch and the key start switch OFF. C. At machine harness connector J1 and J2 measure the resistance from signal contact to all contacts in the harness connectors.	Resistance greater than 5K Ω for all readings.	OK- The resistance is greater than 5K Ω. The harness circuit is correct. Proceed to Test Step 19. NOT OK- The resistance less than 5 Ω. Repair: A short exists in the harness between the +battery and signal circuit. Repair or replace the machine harness. Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit. STOP
Begin Process For FMI 4 Troubleshooting HERE
12. Check The Sensor. A. With FMI 4 active, disconnect the sensor from the machine harness. B. Observe Cat ET or the operator monitor for code change as the sensor is disconnected and connected to harness.	Code changes from FMI 4 to FMI 3.	OK - The diagnostic changed to FMI 3 when the sensor was disconnected. Repair: Replace the sensor. STOP NOT OK - The FMI 4 diagnostic code remains active when sensor is disconnected. The sensor is not the cause of the problem. Proceed to Test Step 13.
13. Check The Signal Circuit For A Short To Ground. A. Turn the key start switch and the disconnect switch OFF. B. The sensor remains disconnected from the harness. C. Disconnect the J1 harness connector from the ECM. D. Measure the resistance between the signal contact for sensor and frame ground.	The resistance is greater than 5K Ω.	OK - The resistance is greater than 5K Ω. The harness circuit is correct. Proceed to Test Step 14. NOT OK - The resistance is less than 5 Ω. A short circuit exists between frame ground and the signal circuit. Repair: Repair or replace the machine harness. Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit. STOP
14. Check The Supply Voltage at the Sensor. A. Turn key start switch and disconnect switch ON. B. Disconnect the machine harness from sensor. C. Refer to the schematic to determine the voltage source for the suspected faulty sensor. D. Measure voltage between signal and ground contacts at the machine harness connector for the sensor.	The voltage measures 8.0 VDC.	OK - The voltage reading is correct for the suspected faulty sensor. Proceed to Test Step 19. NOT OK- The voltage is NOT correct for the circuit. Repair - There may be an open or short in the machine harness. The open or short will be on the power or ground circuit wires. Repair or replace the machine harness. STOP
Begin Process For FMI 7 Troubleshooting HERE
15. Check The Status Of The Diagnostic Code. A. Start the engine. B. Active the Valve Position Sensor for the suspension system. C. Check the status of the diagnostic code.	The diagnostic code remains active.	OK: The diagnostic code is no longer active. Repeat the test to the left to verify the result. STOP NOT OK: The diagnostic code indicator is active. The machine harness or the position switch may have failed. Proceed to Test Step 16.
16. Check for Other Recorded Diagnostic Codes. Note: The presence of other diagnostic codes may indicate a reason for the suspect diagnostic code. A. Check for other recorded diagnostic codes.	There are no other active diagnostic codes.	OK: No other diagnostic codes are active or logged recorded. Proceed to Test Step 17. NOT OK: There are other recorded diagnostic codes. Repair: Exit the current procedure. Correct the other active or logged diagnostic codes. After troubleshooting the active or logged codes, return to Test Step 15. STOP
Begin Process For FMI 8 Troubleshooting HERE
17. Check The Duty Cycle And The Signal Frequency At The Sensor. A. Turn the key start switch and the disconnect switch to the OFF position. B. At the machine harness connector for the sensor, use a 151-6320 Removal Tool to remove the signal wire and socket at the signal contact connector. The machine harness connector remains connected to the sensor. C. At the back of the sensor connector, insert multimeter probes along the ground contact (2) and the signal contact (3). D. Turn the disconnect switch and the key start switch to the ON position. E. Measure the frequency of the signal from the sensor. F. Observe the measurement and wiggle the sensor connector. Gently pull on the wires and wiggle the wires.	The frequency of the signal is correct based on observation. The frequency is stable during the manipulation of the harness connector and the wiring.	OK - The signal frequency of the sensor is correct. The sensor is not the cause of the problem. Proceed to Test Step 18. NOT OK- The signal frequency of the sensor is not correct according to the description at the beginning of this procedure. The sensor has failed. Repair - Perform this test step again to verify that the sensor signal is not correct. The operation of the sensor is not correct. Replace the sensor. After replacement, verify that the operation is correct before operating the machine. STOP
18. Check For An Open In The Sensor Circuit A. Turn the disconnect switch and the key start switch OFF B. Reconnect the wire and the socket, removed in the previous test step, into the original locations in the sensor connector. Verify that all wires of the sensor circuit are secure in the connector. C. Disconnect the machine harness connector from the sensor. At machine harness connectors, place a jumper wire between the signal contact 3 and frame ground. Note: Ensure that the frame ground contact point is clean and free of paint, oil, dirt, and any other debris. D. Turn the key start switch and the disconnect switch to the ON position. E. Observe the status of the active DTC.	The active FMI 8 is no longer active. An FMI 4 is active when the signal wire is grounded.	OK - The active FMI 8 is no longer active. An FMI 4 has been activated after the signal wire is grounded. Proceed to Test Step 26. NOT OK -The FMI 8 diagnostic code remains active. The status of the active code does not change when the signal wire is grounded. There is an open or a poor connection in the signal wire. Repair: Check the signal circuit for an open or for a poor connection. Repair or replace the machine harness. STOP
Begin Process For FMI 12 Troubleshooting HERE
19. Check the PWM Duty Cycle. A. Check the PWM duty cycle at each switch position, between the PWM signal wire and sensor excitation wire. B. Extend the suspected cylinder and monitor the output of the sensor. C. Monitor the connections of the position sensor while the cylinder is lowered.	All duty cycles are within 5% of one another.	OK: All duty cycles are within 5% of one another. Proceed to Test Step 20. NOT OK: The most likely cause is a failed switch. Check the condition of the switch. STOP
20. Check The Signal Circuit For A Short To Ground A. Turn the key start switch and the disconnect switch OFF. B. Disconnect the J1 harness and J2 connectors from the ECM. C. Measure the resistance between the signal contact for sensor and all other contacts used in the J1 and J2 harness connectors.	All resistance measures are greater than 5K Ω.	OK: The resistance is greater than 5K Ω. The harness circuit is correct. Proceed to Test Step 21. NOT OK: One or more measurements are less than 5 Ω. A short circuit exists between frame ground and the signal circuit. Repair: Repair or replace the machine harness. Note: A resistance that is greater than 5 Ω. but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit. STOP
21. Check If The Diagnostic Code Remains A. Inspect the harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing. B. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit. C. Reconnect all of the harness connectors to make sure that the connectors are fully seated. Observe that the clips for each connector are fastened securely. D. Turn the key start switch and the disconnect switch ON. E. Clear all diagnostic codes. F. Operate the machine. G. Stop the machine and engage safety lock lever. H. Check if diagnostic code for the sensor is active.	Diagnostic trouble code is no longer active.	OK - Diagnostic code does not exist at this time. Repair: The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors. Resume normal machine operation. NOT OK - Diagnostic trouble code has not been corrected. Repair: If the diagnostic code has not been corrected after performing the procedure a second time, follow the procedure below for replacing the ECM. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare^®. This consultation may greatly reduce repair time. If the ECM requires replacement, see Troubleshooting, "ECM - Replace". STOP
Begin Process For FMI 14 Troubleshooting HERE
22. Check The Hydraulic Pump Discharge Pressure. Note: Check that a diagnostic code CID 262 for the 5V sensor supply is not active before performing this procedure. If an active CID 262 diagnostic code is present, correct the problem and clear the diagnostic code before performing this procedure. Note: This test step requires the installation of a pressure gauge at the tap for the outlet pressure for the main hydraulic pump. A. After a pressure gauge is installed at the main hydraulic pump pressure tap, start the engine and run the engine at low idle. Note: Ensure that all the following conditions are in place before proceeding to the next step: 1. Disable the steering system by not having the operator in the operator seat. 2. Move the implement lockout switch to the LOCK position. B. Use the Cat^® Electronic Technician (Cat ET) to check the status of the main hydraulic pump pressure. C. Compare the status screen pressure reading in Cat ET to the pressure gauge from the pump outlet.	The pressure is observed on the Cat ET status screen and the pressure that is observed on the pressure gauge are approximately the same. However, the pressure reading is above the 7500 kPa (1089 psi) standby pressure limit.	OK - The pressure observed on the status screen and the value displayed on the pressure gauge are approximately the same. However, the pressure is above the 7500 kPa (1089 psi) standby pressure limit. There is a problem with the operation of the main hydraulic pump. Repair: The standby pressure of the main hydraulic pump is above normal. Repeat this test step to ensure that all of the listed conditions for testing are correct. If the main hydraulic pump standby pressure is still above normal, refer to the Testing and Adjusting service manual, for the specific machine under test, for more information on troubleshooting the hydraulic pump. STOP NOT OK- The pressure value displayed on the Cat ET status screen and the value displayed on the pressure gauge are not approximately the same. The Cat ET status screen is indicating a higher value than the pressure indicated on the gauge. There is a problem with the pressure sensor or in the circuit of the pressure sensor. Proceed to Test Step 23.
23. Check the Sensor. A. Disconnect the press gauge installed for the earlier troubleshooting. B. Turn the key start switch to the OFF position. C. Disconnect the machine harness connector from the pressure sensor. D. Turn the key start switch to the ON position. Do not start the engine. E. Observe the status of the active diagnostic code for the sensor.	The active FMI 14 diagnostic code changed to an active FMI 3 diagnostic code after disconnecting the sensor.	OK- The active FMI 14 diagnostic code changed to an active FMI 3 diagnostic code after disconnecting the sensor. The sensor is the cause of the problem. Repair: Replace the pressure sensor. After the sensor is replaced, verify that the problem has been corrected before operating the machine. STOP NOT OK- The status of the active FMI 14 diagnostic code did not change when the sensor was disconnected from the machine harness. The sensor is not the cause of the problem. Proceed to Test Step 24.
24. Check The Sensor Circuit At The ECM. A. The key start switch remains in the ON position. The engine is not running. B. Reconnect the machine harness connector to the pressure sensor. Verify that the FMI 14 diagnostic code is active. C. At the machine harness connector for the ECM, use a 151-6320 Removal Tool to remove the signal wire and socket of the suspect sensor from the harness connector. The machine harness connector remains connected to the ECM. D. Observe the status of the FMI 14 diagnostic code after the signal wire is removed from the connector.	The active FMI 14 diagnostic code changed to an active FMI 3 diagnostic code after removing the signal wire.	OK- The active FMI 14 diagnostic code changed to an active FMI 3 diagnostic code after removing the signal wire. The ECM is not the cause of the problem. Note: Reconnect the signal wire and the socket in the machine harness connector for the ECM before proceeding to the next test step. Proceed to the Test Step 25. NOT OK- The active FMI 14 diagnostic code did not change when the signal wire was removed from the machine harness. The ECM may have failed. Repair: Reconnect the signal wire and the socket in the machine harness connector for the ECM. If the ECM is still activating the FMI 14 diagnostic code after removing the signal wire, the Transmission/Chassis ECM has failed. Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. If the ECM requires replacement, refer to Troubleshooting, "ECM - Replace". STOP
25. Check The Signal Circuit Of The Sensor For A Short. A. Turn the disconnect switch and the key start switch to the OFF position. B. Disconnect the machine harness connector from the sensor. C. Disconnect the machine harness connector J1 and J2 from the ECM. D. At the harness connector for the Transmission/Chassis ECM, measure the resistance from signal contact to all of the other contacts that are used for the J1 and J2 connectors on the ECM.	Each resistance measurement is greater than 5000 ohms.	OK- Each resistance measurement is greater than 5000 ohms. The signal circuit is not shorted to another circuit in the machine harness. Proceed to Test Step 26. NOT OK- One or more of the resistance measurements is less than 5000 ohms. There is a short in the machine harness. Repair: The signal wire of the sensor is shorted to the circuit with the low resistance measurement in the machine harness. Refer to the complete Electrical System Schematic of the machine. Examine all of the connectors in the circuits for potential shorted locations in the machine harness. For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Short Circuit - Test". Repair the machine harness or replace the machine harness. STOP
26. Check The Status Of The Diagnostic Code. A. Inspect the harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation that can be caused by excessive heat, battery acid, or chafing. B. Perform a 45 N (10 lb) pull test at the connectors that are used in the sensor circuit. C. Reconnect all harness connectors. Make sure that the connectors are fully seated and locked. D. Turn the disconnect switch and the key start switch to the ON position. E. Operate the machine. F. Determine if the FMI 14 diagnostic code is active.	The FMI 14 diagnostic code is not active.	OK- The FMI 14 diagnostic code is not active. The problem has been corrected. Repair: The initial diagnostic code could have been caused by a poor electrical connection at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation. STOP NOT OK- The FMI 14 diagnostic code is still active. The problem has not been corrected. Repair: Perform this test step again. If the problem has not been corrected, proceed with the following process. Use a Cat Electronic Technician service tool and perform a wiggle test on the sensor circuit for the machine wiring harness of the machine. The wiggle test can be used to detect momentary short circuit connections. The wiggle test can also be used to detect open connections in the machine wiring harness. If a problem is not found in the machine harness, replace the pressure sensor. If the problem is still present after replacement of the sensor, the ECM may have failed. Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. If the cause of the diagnostic code is not found, replace the Implement ECM. Refer to Testing and Adjusting, "ECM - Replace". STOP