906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Sensor Signal (PWM)

Sensor Signal (PWM) - Test

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System [UENR5036]

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Sensor Signal (Analog, Passive) - Test

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Speed Sensor - Test

ELECTRICAL AND STARTING SYSTEM

SENSOR GP

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Sensor Signal (Analog, Active) - Test

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Sensor Signal (Analog, Passive) - Test

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Sensor Signal (PWM) - Test

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Speed Sensor - Test

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Sensor Supply - Test

906K, 906M, 907K, 907M, 908K and 908M Compact Wheel Loaders Electrohydraulic System Calibration

1.1. Machine ECM

2.1. Diagnostic Trouble Code Procedure

Machine ECM

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

Show/hide table

Table 1
Machine ECM (MID 71)
DTC	Code Description	System Response
91-3	Throttle Position Sensor: Voltage above normal	Engine speed control is disabled. Engine is stuck at low idle.
91-4	Throttle Position Sensor: Voltage below normal	Engine speed control is disabled. Engine is stuck at low idle.
91-8	Throttle Position Sensor: Abnormal frequency, pulse width, or period	Engine speed control is disabled. Engine is stuck at low idle.
91-13	Throttle Position Sensor: Out of calibration	Engine speed control is disabled. Engine is stuck at low idle.
2305-3	Brake/Decelerator Pedal Position Sensor: Voltage above normal	Machine drive will be disabled.
2305-4	Brake/Decelerator Pedal Position Sensor: Voltage below normal	Machine drive will be disabled.
2305-8	Brake/Decelerator Pedal Position Sensor: Abnormal frequency, pulse width, or period	Machine drive will be disabled.
2305-13	Brake/Decelerator Pedal Position Sensor: Out of calibration	Machine drive will be disabled.
2716-3	Creep Control Position Sensor: Voltage above normal	Creeper feature will be disabled. The machine will otherwise perform normally.
2716-4	Creep Control Position Sensor: Voltage below normal	Creeper feature will be disabled. The machine will otherwise perform normally.
2716-8	Creep Control Position Sensor: Abnormal frequency, pulse width, or period	Creeper feature will be disabled. The machine will otherwise perform normally.
2974-3	Brake Charge Pressure Sensor: Voltage above normal	Machine will operate as normal. Brake Charge monitoring feature will be disabled.
2974-4	Brake Charge Pressure Sensor: Voltage below normal	Machine will operate as normal. Brake Charge monitoring feature will be disabled.
2974-8	Brake Charge Pressure Sensor: Abnormal frequency, pulse width, or period	Machine will operate as normal. Brake Charge monitoring feature will be disabled.

Possible causes for an FMI 3 diagnostic code are:

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

Possible causes for an FMI 4 diagnostic code are:

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

Possible causes for an FMI 8 diagnostic code are:

The sensor has failed.
Intermittent connections or poor connections.

Possible causes for an FMI 13 diagnostic code are:

New software has been flashed to the ECM.
The ECM has been replaced.

Show/hide table




Illustration 1	g03714421
Schematic of the PWM Sensors

Note: The diagram above is a simplified schematic of the Machine ECM and the PWM Sensors connections. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, UENR5407 for prefixes: L66, L77, L88, or Electrical Schematic, UENR5408 for prefixes: Z66, Z77, Z88, or Electrical Schematic, UENR5409 for prefixes: H66, H77, H88.

Diagnostic Trouble Code Procedure

Note: Prior to beginning this 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.

Show/hide table

Table 2
Troubleshooting Test Steps	Values	Results
1. Identify Active FMI Code Associated With Sensor Circuit	Code present.	FMI 3 diagnostic code, proceed to Test Step 2. FMI 4 diagnostic code, proceed to Test Step 6. FMI 8 diagnostic code, proceed to Test Step 8. FMI 13 diagnostic code, proceed to Test Step 15.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Control And The Harness 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 measurement is approximately 8 VDC.	OK - The voltage reading is correct for the suspected faulty sensor. Proceed to Test Step 3. STOP NOT OK- The voltage is NOT correct for the circuit. Repair - Refer to the diagnostic code procedure in this manual for troubleshooting of the power supply. After the power supply procedure is performed, verify the status of the sensor diagnostic code before proceeding.
3. 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. C. At the harness connector for the sensor, place a jumper wire between Pin 2 (or Pin B) and Pin 3 (or Pin C). These locations are also referred to as the ground contact and the signal contact. D. Disconnect J1 and J2 harness connectors from the ECM. E. At machine harness connector for sensor, 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 manipulation 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 4. 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 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
4. Check Signal Circuit For A Short To +Battery A. The Sensor and the ECM are disconnected from the harness. B. Turn the disconnect switch and the key start switch OFF. C. Measure the resistance between the signal and +battery contacts of the harness connector for the sensor. D. At machine harness connector J1 and J2 measure the resistance from signal contact to all possible sources of +battery.	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 5. 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
5. Check The Harness For An Open A. The disconnect switch and key start switch are OFF B. The sensor and ECM disconnected from harness. C. Connect a jumper wire from the end of the signal wire at the ECM to a known ground. D. Measure the resistance of the signal wire at ECM.	Resistance less than 5 Ω.	OK - The resistance of the signal wire is less than 5 Ω. Proceed to Test Step 14. NOT OK - The resistance is greater than 5K Ω. The signal wire is open in the machine harness. Repair: Repair or replace the 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
6. Check The Sensor A. With FMI 4 active, disconnect the sensor from the machine harness. B. Observe Cat^® Electronic Technician (Cat ET) Service Tool 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 not the cause of the problem. Proceed to Test Step 7.
7. 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 connector from the ECM. C. 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
Begin Process For FMI 8 Troubleshooting HERE
8. Check Harness For An Open A. Turn the disconnect switch and the key start switch OFF B. The sensor and ECM are disconnected from the harness. C. Connect a jumper wire from the end of signal wire at the ECM to a known ground. D. Measure the resistance of the signal wire at ECM.	The reading is less than 5 Ω.	OK - The measurement is less than 5 Ω. Proceed to Test Step 9. NOT OK - The measurement is greater than 5K Ω. The signal circuit in the harness is open. 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
9. Check The Signal Circuit For A Short To Ground A. Turn key start switch and disconnect switch OFF. B. Disconnect J1 harness connector from ECM. C. Measure resistance between signal contact for sensor and frame ground.	Reading is greater than 5K Ω.	OK - Measurement is greater than 5K Ω. Proceed to Test Step 10. NOT OK - Measurement is less than 5 Ω. The signal circuit in the harness is shorted to ground. 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
10. Check The Sensor For A Short To Case A. Turn the key start switch and the disconnect switch OFF. B. At the machine harness connector for the sensor, measure the resistance between each pin of sensor (contacts 1, 2, and 3 of the sensor). Connect the ground lead of the meter to an unpainted location on case of sensor .	The reading is greater than 5K Ω.	OK - All measurements are greater than 5K Ω. Proceed to Test Step 11. NOT OK - A measurement is less than 5 Ω. The sensor has failed.. Repair: Replace the sensor. Confirm that the new sensor corrects the problem. 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
11. Check The Sensor For A Short To +Battery A. Disconnect the machine harness at the sensor. B. Turn the key start switch and the disconnect switch ON. C. At machine harness connector for J1 connector, measure the voltage between the signal pin of sensor and frame ground.	The voltage is 0 VDC.	OK - Voltage is 0 VDC. Proceed to Test Step 12. NOT OK - Significant voltage is present in circuit. Repair: Repair or replace the machine harness. STOP
12. Check The Harness For A Short To +Battery A. Turn the key start switch and the disconnect switch ON. B. At machine harness connector for sensor, measure the voltage between each pin of sensor and frame ground (contacts 1, 2, and 3).	The voltage is 0 VDC.	OK - Voltage is 0 VDC. Proceed to Test Step 13. NOT OK - Significant voltage is present in circuit. Circuit shorted to +battery. Repair: Replace the sensor. Verify that the new sensor corrected the diagnostic code. STOP
13. Check The Sensor A. Turn the key start switch and the disconnect switch ON. B. Use Cat ET or the operator monitor to confirm the existence of the diagnostic code. C. Disconnect the sensor from machine harness.	The diagnostic code is no longer present.	OK - Diagnostic code is NO longer active. The sensor has failed. Repair: Replace the sensor. Verify new sensor corrected the diagnostic code. STOP NOT OK - The diagnostic code remains active. Proceed to Test Step 14.
14. Check If The Diagnostic Code Remains A. Turn the key start switch and the disconnect switch ON. B. Clear all diagnostic codes. C. Operate the machine. D. Stop machine and engage the safety lock lever. E. Check if the diagnostic code for the sensor is active.	The code for the sensor is NO longer present.	OK - The diagnostic code does not exist at this time. The initial diagnostic code may have been caused by a poor electrical connection or a short at one of the harness connections. Resume machine operation. STOP NOT OK - The diagnostic trouble code has not been corrected. Repair: Recheck the circuit and perform this procedure again. If the diagnostic code is still active, the Machine 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 procedure in Troubleshooting, "ECM - Replace" to replace the ECM. STOP
Begin Process For FMI 13 Troubleshooting HERE
15. Calibrate The Solenoid A. Perform the calibration procedure for the solenoid. Refer to Testing and Adjusting, "Calibration" procedure.	The calibration procedure for the solenoid was performed successfully.	OK - The calibration procedure for the solenoid was performed successfully. Resume normal machine operation. STOP NOT OK - The calibration procedure was performed successfully. Repair: Repeat the calibration procedure for the solenoid. See the Testing and Adjusting, "Calibration" procedure. STOP