815 Soil Compactor and 816 Landfill Compactor Systems Sensor Signal (PWM)

Table 1
Transmission ECM (MID 081)
J1939	CDL	Code Description	System Response
	1693-3	Decelerator Pedal Sensor : Voltage Above Normal	The pedal position is not known. The decelerator feature will not function when the pedal is pressed.
	1693-4	Decelerator Pedal Sensor : Voltage Below Normal	The pedal position is not known. The decelerator feature will not function when the pedal is pressed.
	1693-8	Decelerator Pedal Sensor : Abnormal Frequency, Pulse Width, or Period	The pedal position is not known. The decelerator feature will not function when the pedal is pressed.
	1693-13	Decelerator Pedal Sensor : Out of Calibration	The pedal has not been calibrated. Use ET to calibrate the pedal.
	2976-3	Parking Brake Oil Pressure Sensor : Voltage Above Normal	The parking brake state is not known. Lower the bucket to the ground and chock all wheels before the operator leaves the cab.
	2976-4	Parking Brake Oil Pressure Sensor : Voltage Below Normal	The parking brake state is not known. Lower the bucket to the ground and chock all wheels before the operator leaves the cab.
	2976-8	Parking Brake Oil Pressure Sensor : Abnormal Frequency, Pulse Width, or Period	The parking brake state is not known. Lower the bucket to the ground and chock all wheels before the operator leaves the cab.
	2987-3	Brake Charge Pressure Sensor #1 : Voltage Above Normal	Move the machine to a safe location and cease operation. The signal from the sensor is disabled. When the diagnostic code is active, the parking brake indicator will not illuminate when the switch is pressed.
	2987-4	Brake Charge Pressure Sensor #1 : Voltage Below Normal	Move the machine to a safe location and cease operation. The signal from the sensor is disabled. When the diagnostic code is active, the parking brake indicator will not illuminate when the switch is pressed.
	2987-8	Brake Charge Pressure Sensor #1 : Abnormal Frequency, Pulse Width, or Period	Move the machine to a safe location and cease operation. The signal from the sensor is disabled. When the diagnostic code is active, the parking brake indicator will not illuminate when the switch is pressed.

Pulse Width Modulation (PWM) is a technique for controlling analog circuits with digital outputs. The duty cycle of a square wave is modulated to encode a specific analog signal level. The duty cycle is the ratio of the on-time to the period. The modulating frequency is the inverse of the period. The duty cycle is programmed into the software of the ECM.

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Illustration 1	g06602618
Transmission ECM PWM Sensors

The preceding diagram is a simplified schematic of the Transmission ECM connections. The schematic is electrically correct. However, not all the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, M0115149 or Electrical Schematic, M0115151 for the complete schematic.

Implement ECM

The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the PWM sensors of the machine.

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Table 2
Implement ECM (MID 082)
J1939	CDL	Code Description	System Response
	1078-3	Blade Control Handle Lift Position Sensor : Voltage Above Normal	All lift functions are disabled.
	1078-4	Blade Control Handle Lift Position Sensor : Voltage Below Normal	All lift functions are disabled.
	1078-8	Blade Control Handle Lift Position Sensor : Abnormal Frequency, Pulse Width, or Period	All lift functions are disabled.
	1078-13	Blade Control Handle Lift Position Sensor : Out of Calibration	All lift functions are disabled.
	1079-3	Blade Control Handle Tilt Position Sensor : Voltage Above Normal	All tilt functions are disabled.
	1079-4	Blade Control Handle Tilt Position Sensor : Voltage Below Normal	All tilt functions are disabled.
	1079-8	Blade Control Handle Tilt Position Sensor : Abnormal Frequency, Pulse Width, or Period	All tilt functions are disabled.
	1079-13	Blade Control Handle Tilt Position Sensor : Out of Calibration	All tilt functions are disabled.
	1870-3	Blade Control Handle Thumb Rocker Position Sensor : Voltage Above Normal	All pitch functions are disabled.
	1870-4	Blade Control Handle Thumb Rocker Position Sensor : Voltage Below Normal	All pitch functions are disabled.
	1870-8	Blade Control Handle Thumb Rocker Position Sensor : Abnormal Frequency, Pulse Width, or Period	All pitch functions are disabled.
	1870-13	Blade Control Handle Thumb Rocker Position Sensor : Out of Calibration	All pitch functions are disabled.
	3654-3	Implement Pump Pressure Sensor : Voltage Above Normal	All implement functions are disabled.
	3654-4	Implement Pump Pressure Sensor : Voltage Below Normal	All implement functions are disabled.
	3654-8	Implement Pump Pressure Sensor : Abnormal Frequency, Pulse Width, or Period	All implement functions are disabled.

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Illustration 2	g06602621
Implement ECM PWM Sensors

The preceding diagram is a simplified schematic of the Implement ECM connections. The schematic is electrically correct. However, not all the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, M0115149 or Electrical Schematic, M0115151 for the complete schematic.

Diagnostic Trouble Code Procedure

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Table 3
Required Tools
Tool	Part Number	Description	Qty
T1	146-4080⁽¹⁾	Digital Multimeter Group	1
	8T-3224	Needle Tip Group	1
	7X-1710	Multimeter Probe Group	1
	8T-8726	Cable Assembly (Three Pin) (3-Pin Breakout)	1
T2	JERD2129	Cat^® Electronic Technician (Cat ET)	1
		Windows-based PC	1
	538-5051	Communication Adapter Gp	1
T3	6V-4148	Connector Repair Kit (Sure Seal)	1
T4	190-8900	Connector Field Repair Kit (Deutsch)	1
T5	175-3700	Connector Repair Kit Deutsch DT	1

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⁽¹⁾	This multimeter can use an RS232C cable to connect to a Laptop computer or Dataview tool gp for troubleshooting.

Prior to beginning this procedure, use Cat^® Electronic Technician (Cat^® ET) Service Tool or the machine monitors to check for an active DTC 41 code. The DTC 41 indicates a failure of the 8 VDC power supply on the ECM. If the code is present, refer to the Sensor Supply - Test story to correct this problem before continuing. For transducers powered via the fuse panel, check the condition of the appropriate fuse before beginning the troubleshooting procedure.

Inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. If a problem with a connection is found, correct the problem and verify that the diagnostic code is active before performing a troubleshooting procedure. For sensors powered via the fuse panel, check the condition of the appropriate fuse before beginning the troubleshooting procedure.

Identify the active FMI code associated with the components.
Determine which code is present and use the list below to determine which procedure to follow.

FMI 3 diagnostic code, proceed to "FMI 3".
FMI 4 diagnostic code, proceed to "FMI 4".
FMI 8 diagnostic code, proceed to "FMI 8".
FMI 13 diagnostic code, proceed to "FMI 13".

FMI 3

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Table 4
Check The Voltage At The Sensor
Troubleshooting Test Steps	Values	Results
1. Turn key start switch and disconnect switch ON. 2. Refer to the schematic to determine the voltage source for the sensor. 3. At the machine harness connector for the sensor, insert 7X-1710 multimeter probes along the contact of the sensor supply and along frame ground. 4. At the sensor harness connector, measure voltage between the sensor supply and frame ground.	Voltage reading is correct for the sensor.	Result: The voltage reading is correct for the sensor. Proceed to "Check The Harness For An Open" Table 5. Result: The voltage is NOT correct for the sensor. Repair: Examine all the connectors that are in the circuit. Ensure that the connections are clean, secure, and are in good condition. Repair or replace the machine harness. Proceed to "Check If The Diagnostic Code Remains" Table 7.

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Table 5
Check The Harness For An Open
Troubleshooting Test Steps	Values	Results
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 the sensor return contact and signal contact. 4. Turn the key switch and disconnect switch ON. 5. Observe the status of the diagnostic code.	The diagnostic code changes from an FMI 3 to an FMI 4.	Result: The diagnostic code changes from an FMI 3 to an FMI 4. The sensor has failed. Repair: Replace the sensor. Proceed to "Check If The Diagnostic Code Remains" Table 7. Result: The diagnostic code does not change from an FMI 3 to an FMI 4. Proceed to "Check Signal Circuit For A Short to +Battery" Table 6.

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Table 6
Check Signal Circuit For A Short to +Battery
Troubleshooting Test Steps	Values	Results
1. Turn the key start switch and the disconnect switch to the OFF position. 2. Disconnect the ECM harness connectors. The sensor harness connector remains disconnected. 3. Remove the jumper wire that was installed in the previous test step. 4. At the ECM harness connector, measure the resistance between the signal contact and all other +battery circuits used in the ECM harness connectors.	Each resistance is greater than 5K Ω.	Result: Each resistance is greater than 5K Ω. The harness circuit is correct. Proceed to "Check If The Diagnostic Code Remains" Table 7. Result: The resistance is less than 5 Ω. Repair: A short exists in the harness between the signal circuit and the circuit with the low-resistance measurement. Repair or replace the machine harness. Note: A resistance greater than 5 Ω but less than 5K Ω indicates a loose or corroded connection in the circuit. A resistance measurement greater than 5K Ω indicates an open in the circuit. Proceed to "Check If The Diagnostic Code Remains" Table 7.

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Table 7
Check If The Diagnostic Code Remains
Troubleshooting Test Steps	Values	Results
1. Reconnect all harness connectors. Return machine to normal operating condition. 2. Turn the key start switch and the disconnect switch ON. 3. Clear all diagnostic codes. 4. Operate the machine. 5. Stop the machine and engage the safety lock. 6. Check if the diagnostic code is active.	The diagnostic code is no longer present.	Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. STOP. Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. Follow the steps in Troubleshooting, "ECM - Replace" if the ECM needs to be replaced. STOP.

FMI 4

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Table 8
Check The Sensor
Troubleshooting Test Steps	Values	Results
1. Turn the disconnect switch and the key start switch to the ON position. 2. Disconnect the sensor from the machine harness. 3. Observe the status of the diagnostic code as the sensor is disconnected from the harness.	The code changes from an FMI 4 to an FMI 3 when the sensor is disconnected.	Result: The code changes from an FMI 4 to an FMI 3 when the sensor is disconnected. The sensor has failed. Repair: Replace the sensor. Proceed to "Check If The Diagnostic Code Remains" Table 10. Result: The FMI 4 diagnostic code remains active when sensor is disconnected. The sensor is not the cause of the problem. Proceed to "Check The Signal Circuit For A Short To Ground" Table 9.

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Table 9
Check The Signal Circuit For A Short To Ground
Troubleshooting Test Steps	Values	Results
1. Turn the key start switch and the disconnect switch to the OFF position. 2. Disconnect the harness connectors from the ECM. The sensor remains disconnected from the machine harness. 3. At the ECM harness connector, measure the resistance between the sensor signal contact and all possible sources of ground.	All resistance values are greater than 5K Ω.	Result: All resistance values are greater than 5K Ω. The harness circuit is correct. Proceed to "Check If The Diagnostic Code Remains" Table 10. Result: One or more readings are less than 5 Ω. A short circuit exists between the signal circuit . Repair: Repair or replace the machine harness. Note: A resistance greater than 5 Ω but less than 5K Ω indicates a loose or corroded connection in the circuit. A resistance measurement greater than 5K Ω indicates an open in the circuit. Proceed to "Check If The Diagnostic Code Remains" Table 10.

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Table 10
Check If The Diagnostic Code Remains
Troubleshooting Test Steps	Values	Results
1. Reconnect all harness connectors. Return machine to normal operating condition. 2. Turn the key start switch and the disconnect switch to the ON position. 3. Clear all diagnostic codes. 4. Operate the machine. 5. Stop the machine and engage the safety lock . 6. Check if the diagnostic code is active.	The diagnostic code is no longer present.	Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. STOP. Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. Follow the steps in Troubleshooting, "ECM - Replace" if the ECM needs to be replaced. STOP.

FMI 8

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Table 11
Check The Signal Of The Sensor
Troubleshooting Test Steps	Values	Results
1. Turn the key start switch and disconnect switch to the OFF position. 2. At the back of the harness connector for the sensor, insert multimeter probes along the signal contact and return contact. Note: Use Cat^® Electronic Technician (Cat^® ET) Service Tool if access to the sensor while operating the machine, is not safe. 3. Turn the disconnect switch and the key start switch to the ON position. 4. Monitor the signal of the sensor with a digital multimeter. 5. Without disconnecting the sensor or the hardware that is associated with the sensor from the machine, take the sensor through the full operating range. Note: Refer to the table above for the proper signal.	The signal from the sensor responds in the manner that is described in the table above.	Result: The signal from the sensor responds correctly. The sensor is operating correctly. Proceed to "Check For An Open In The Signal Circuit" Table 12. Result: The signal from the sensor does not respond correctly. The sensor is not operating correctly. Repair: Replace the sensor. Proceed to "Check If The Diagnostic Code Remains" Table 13.

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Table 12
Check For An Open In The Signal Circuit
Troubleshooting Test Steps	Values	Results
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 the return contact and signal contact . 4. Disconnect the machine harness connectors J1 and J2 from the ECM. 5. At the ECM harness connector, measure the resistance between the signal contact and return contact.	The reading is less than 5 Ω.	Result: The measurement is less than 5 Ω. The signal and return circuit are correct. Proceed to "Check If The Diagnostic Code Remains" Table 13. Result: The measurement is greater than 5K Ω. The signal circuit in the harness is open. Repair: Repair or replace the machine harness. Proceed to "Check If The Diagnostic Code Remains" Table 13.

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Table 13
Check If The Diagnostic Code Remains
Troubleshooting Test Steps	Values	Results
1. Reconnect all harness connectors. Return machine to normal operating condition. 2. Turn the key start switch and the disconnect switch to the ON position. 3. Clear all diagnostic codes. 4. Operate the machine. 5. Stop the machine and engage the safety lock lever. 6. Check if the diagnostic code is active.	The diagnostic code is no longer present.	Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. STOP. Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. Follow the steps in Troubleshooting, "ECM - Replace" if the ECM needs to be replaced. STOP.

FMI 13

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Table 14
Check the Calibration
Troubleshooting Test Steps	Values	Results
1. Perform the calibration procedure for the sensor. Refer to the "Calibration" procedure in this manual. 2. Observe the status of the diagnostic code.	The code is no longer active.	Result: The FMI 13 is no longer active. The calibration corrected the condition that caused the diagnostic code. Proceed to "Check If The Diagnostic Code Remains" Table 15. Result:The FMI 13 Code is active. The diagnostic code has not been corrected. Verify that the correct software has been flashed into the ECM, or that the correct ECM is installed on the machine. Then repeat the calibration. Proceed to "Check If The Diagnostic Code Remains" Table 15.

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Table 15
Check If The Diagnostic Code Remains
Troubleshooting Test Steps	Values	Results
1. Turn the key start switch and the disconnect switch ON. 2. Clear all diagnostic codes. 3. Operate the machine. 4. Stop the machine and engage the safety lock lever. 5. Check if the diagnostic code is active.	The diagnostic code is no longer present.	Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. STOP. Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. Follow the steps in Troubleshooting, "ECM - Replace" if the ECM needs to be replaced. STOP.