950M and 962M Wheel Loaders Caterpillar


Speed Sensor - Test

Usage:

962M EJB

Transmission ECM

The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the speed sensor circuits of the machine.

Table 1
Transmission ECM (MID 81) 
DTC  Code Description  System Response  
585-8  Transmission Output Speed Sensor #1: Abnormal Frequency, Pulse Width, or Period  Transmission shifting may be harsh.

The transmission control will be unable to determine the direction of travel.

The transmission control will be unable to determine the ground speed of the machine if both Transmission Output Speed Sensors have failed.

The transmission control may lock out gears. 
605-2  Wheel Speed Sensor #1: Data Erratic, Intermittent, or Incorrect  Some Transmission ECM features may not function correctly. 
608-2  Wheel Speed Sensor #4: Data Erratic, Intermittent, or Incorrect  Some Transmission ECM features may not function correctly. 
672-8  Torque Converter Output Speed Sensor: Abnormal Frequency, Pulse Width, or Period  Transmission shifting may be harsh. 
673-8  Transmission Output Speed Sensor #2: Abnormal Frequency, Pulse Width, or Period  Transmission shifting may be harsh.

The transmission control will be unable to determine the direction of travel.

The transmission control will be unable to determine the ground speed of the machine if both Transmission Output Speed Sensors have failed.

The transmission control may lock out gears. 
674-8  Transmission Intermediate Speed Sensor 1: Abnormal Frequency, Pulse Width, or Period  Transmission shifting may be harsh.

The transmission control may be unable to determine the direction of travel.

The transmission control will be unable to determine the ground speed of the machine. 

Possible causes of an FMI 2 Diagnostic code are:

  • The wire is shorted to the ground circuit while the machine is in operation.

  • The wire is shorted to the + battery.

  • An open circuit exists.

  • The ECM has failed. An ECM failure is unlikely.

Possible causes of an FMI 8 Diagnostic code are:

  • The sensor has failed.

  • Transmission system pressure loss.

  • Intermittent connections or poor connections.

  • Incorrect software is loaded to the ECM.

  • The Transmission ECM has failed. An ECM failure is unlikely.


Illustration 1g03657689
Schematic of the Speed Sensor circuits

Note: The diagram above is a simplified schematic of the connections for the speed sensor circuits. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic, UENR3117 for the complete schematic.

Table 2
Sensor Description  Resistance 
(CID 585) Transmission Output Speed Sensor #1  1500 ± 100 Ohms @ 25 °C (77 °F) 
(CID 672) Torque Converter Output Speed Sensor  1500 ± 100 Ohms @ 25 °C (77 °F) 
(CID 673) Transmission Output Speed Sensor #2  1500 ± 100 Ohms @ 25 °C (77 °F) 

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.

Table 3
Troubleshooting Test Steps  Values  Results 
1. Identify The Active FMI Code Associated With Sensor Circuit 
Code present. 
FMI 2 diagnostic code proceed to Test Step 2.

FMI 8 diagnostic code proceed to Test Step 7. 
Begin Process For FMI 2 Troubleshooting HERE 
2. Check For Power At The Sensor

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

B. At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe at contact 1.

C. Turn the key start switch and the disconnect switch to the ON position.

D. Measure the voltage from contact 1 to the frame ground. 

The voltage is 10 VDC. 
OK - The voltage is 10 VDC.

Proceed to Test Step 3.

NOT OK -The voltage is not 10 VDC. The circuit is open.

Repair:Repair or replace the machine harness.

Proceed to Test Step 12. 
3. Check The Signal Circuit Of The Sensor

A. Turn the key start switch and the disconnect switch to the OFF position.

B. At the back of the harness connector for the sensor, remove the 7X-1710 Multimeter Probe from contact 1.

C. At the back of the harness connector for the sensor, insert the 7X-1710 Multimeter Probe along the ground wire at contact 2.

D. Turn the disconnect switch and the key start switch to the ON position.

E. Monitor the signal of the sensor with the 146-4080 Digital Multimeter.

F. Without disconnecting the sensor or the hardware associated with the sensor from the machine, take the sensor through the full operating range. 

The signal of the sensor responds in the manner that is described at the beginning of this procedure. 
OK - The signal from the sensor is responding correctly.

Proceed to Test Step 4.

NOT OK -The signal from the sensor does not respond correctly. The sensor is NOT operating correctly.

Repair:Replace the sensor

Proceed to Test Step 12. 
4. Check The Signal Circuit At The ECM

A. Turn the key start switch and the disconnect switch to the OFF position.

B. Insert the 7X-1710 Multimeter Probe into the back of the ECM connector along the signal pin and pin ground of the Transmission ECM.

C. Turn the key start switch and the disconnect switch to the ON position.

D. Monitor the signal of the sensor with the 146-4080 Digital Multimeter.

E. Without disconnecting the sensor or the hardware that is associated with the sensor from the machine, take the sensor through the full operating range. 

The signal of the sensor responds in the manner that is described at the beginning of this procedure. 
OK - The signal from the sensor is responding correctly.

Proceed to Test Step 5.

NOT OK -The sensor does not respond correctly. The harness has failed.

Repair:Repair or replace the machine harness.

Proceed to Test Step 12. 
5. Check The Signal Circuit For A Short In The Harness

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

B. Disconnect the machine harness connectors from the sensor and the Brake ECM.

C. Measure the resistance between the signal contact and all contacts that are used in the machine harness connectors for the ECM. 

The resistance is greater than 5000 ohms. 
OK - The resistance is greater than 5000 ohms. The circuit is correct.

Proceed to Test Step 6.

NOT OK -The resistance is less than 5 ohms. The signal circuit is shorted to another circuit in the harness.

Repair:Repair or replace the machine harness.

Proceed to Test Step 12. 
6. Check The Adjustment Of The Sensor

A. Check the adjustment of the speed sensor. The recommended torque for the speed sensor is 30 ± 4 Nm.

B. Clean the contacts of the harness connectors.

C. Reconnect all harness connectors.

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

E. Start the engine and run the engine at low idle.

F. Observe the status of the diagnostic code. 

The diagnostic code is present. 
OK - The diagnostic code is present.

Proceed to Test Step 12.

NOT OK -The diagnostic code is NOT present.

Repair:The diagnostic code is NOT present. Adjustment of the speed sensor corrected the failure.

Proceed to Test Step 12. 
Begin Process For FMI 8 Troubleshooting HERE 
7. Check for Slip Events (s)

A. Check whether one or more Transmission Slip Detected events are active and BOTH Transmission Output Speed Sensor diagnostics are active. 

One or more of EID 2201-2204 or E2301-2304 are active, and DTC 585 and DTC 673 are both active. 
OK - Both transmission output speed sensor diagnostics and transmission clutch slip event(s) are not all active at the same time.

Proceed to Test Step 8.

NOT OK - Both transmission output speed sensor diagnostics and transmission clutch slip event(s) are all active at the same time.

Repair: Proceed to the Transmission Clutch Slips Troubleshooting Procedure.

Proceed to Test Step 12. 
8. Verify The Software Version

A. Check and record the latest software version for the machine electronic controls from SIS.

B. Verify that the latest version of software has been loaded to the ECM.
 

All of the software is current. 
OK - All of the software is current.

Proceed to Test Step 9.

NOT OK - There is a more recent software release that is available.

Repair: Flash all controls with the latest software release. Refer to Troubleshooting, "ECM Software - Install".

Proceed to Test Step 12. 
9. Check The Resistance Of The Sensor
A. Remove the sensor from the machine harness. Insert a multimeter probe in contact 1 and contact 2 of the sensor.

B. Measure the resistance of the sensor. 

The resistance is within the specifications in Table 2. 
OK - The resistance is within the resistance specifications in Table 2.

Proceed to Test Step 10.

NOT OK - The resistance is not within the resistance specifications in Table 2.

Repair: Replace the speed sensor.
Proceed to Test Step 12. 
10. Check For An Open In The Sensor Circuit

A. Turn the keyswitch and the disconnect switch to the OFF position.

B. Disconnect the sensor from the ECM.

C. Disconnect the J1 and J2 wire harness from the Transmission ECM.

D. At the harness connector for the sensor, place a jumper wire between the signal contact and the supply contact.

E. At machine harness connector for ECM, measure the resistance from the signal contact the supply 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 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 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.

Proceed to Test Step 12. 
11. Check The Signal Circuit For Shorts

A. The sensor and the ECM are disconnected from the harness.

B. The disconnect switch and the key start switch remain OFF.

C. Measure the resistance between the signal wire and all other wires used in the J1 and J2 harness connectors. 

The resistance is greater than 5K Ω for all readings. 
OK - The resistance is greater than 5K Ω. The harness circuit is correct.

Proceed to Test Step 12.

NOT OK- The resistance less than 5 Ω.

Repair: A short exists in the harness between the signal wire and the wire with the low resistance reading. 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.

Proceed to Test Step 12. 
12. Check If The Diagnostic Code Remains.

A. Clear all diagnostic codes.

B. Operate the machine.

C. Stop machine and engage the parking brake.

D. 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 Transmission ECM may require replacement.

Prior to replacing the ECM, contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time.

Refer to Troubleshooting, "ECM - Replace" to replace the ECM.

STOP 

Caterpillar Information System:

950M and 962M Wheel Loaders Solenoid Valve (Switch Controlled) - Test
2014/04/08 New Brake Software Is Now Used on Certain 793F, 795F, and 797F Off-Highway Trucks {4250, 7620}
826K Landfill Compactor DEF Manifold Filters - Replace - Emission Related Component
950M, 962M, 950M Z and 962M Z Wheel Loaders Air Pump (Variable Pitch Fan) - Remove and Install
950M and 962M Wheel Loaders Solenoid Valve - Test
950M and 962M Wheel Loaders Solenoid Return - Test
950M and 962M Wheel Loaders Sensor Supply - Test
950M and 962M Wheel Loaders Sensor Signal (PWM) - Test
950M and 962M Wheel Loaders Sensor Signal (Analog, Passive) - Test
950M and 962M Wheel Loaders Sensor Signal (Analog, Active) - Test
950M and 962M Wheel Loaders Relay - Test
950M and 962M Wheel Loaders Parameter - Test
735C, 740C EJECTOR and 745C Articulated Trucks Transmission
950M and 962M Wheel Loaders Steering Control Force - Test
950M and 962M Wheel Loaders Switch Circuits - Test
730C2 and 725C2 Articulated Truck Power Train Main Drive Shaft - Remove and Install
980M and 982M Wheel Loaders Power Train, Steering, Braking, Hydraulic, and Machine Systems Electronic Control (Power Train System)
980M and 982M Wheel Loaders Power Train, Steering, Braking, Hydraulic, and Machine Systems Transmission Hydraulic System
2014/09/09 New Air Conditioner Drains Now Available for Certain R2900G Load Haul Dump Machines {7320}
826K Landfill Compactor, 825K Soil Compactor and 824K Wheel Dozer Power Train Transmission Planetary - Assemble
735C, 740C EJECTOR and 745C Articulated Trucks Alarm - Test
735C, 740C EJECTOR and 745C Articulated Trucks CAN Data Link - Test
Release Notes for Cat® Terrain v5.2 On-board Software {7605} Release Notes for Cat® Terrain v5.2 On-board Software {7605}
793F CMD (Command for Hauling) Off-Highway Truck Display and Camera - Clean - If Equipped
Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.