PM620, PM622, PM820, PM822 and PM825 Cold Planers Electronic System Speed Signal

Table 1
Transmission ECM (MID 81)
DTC	Code Description	System Response
959-8	Rotor Speed Sensor: Abnormal Frequency, Pulse Width, or Period	A Level 2 warning will activate. The rotor drive will be allowed to continue functioning normally if the fault is active. The Low Rotor Speed event will be disabled if the fault is active.

Possible Causes for an FMI 8 diagnostic code are:

The sensor has failed
The spacing of the sensor is incorrect
Intermittent connections or poor connections
Mechanical devices are loose
Incorrect software is loaded to the ECM
The ECM has failed. ECM failure is unlikely

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Illustration 1	g06015274
Transmission ECM Speed Sensor Connections

Note: The diagram above is a simplified schematic of the Transmission ECM. The schematic is electrically correct. However, not all the possible harness connectors are shown.Refer to the appropriate media number below for the complete Electrical Schematic: (S/N: JCF; LH9; 8RF; EL6) Machines refer to Electrical Schematic, UENR6397. (S/N: JB9; JFC; LB8; FG4; TPH; XS6) Machines refer to Electrical Schematic, UENR6398. (S/N: JB7; HN8; HC8; RL3; H6S; 626) Machines refer to Electrical Schematic, UENR8363. (S/N: SL8; TLZ; ESE; AK5; AN8; EE2; E8S; 3C6; 627) Machines refer to Electrical Schematic, UENR8362.The schematic will illustrate locations for all the electrical components and harness connectors that are installed on the machine.

Troubleshooting Procedure

Note: Poor harness connections are often the cause of a problem in electrical circuits. Before performing any troubleshooting procedure, inspect all the connectors involved in the circuit. Verify that all 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 2
Troubleshooting Test Steps	Values	Results
1. Inspect The Harness Connectors A. Turn the disconnect switch and the key start switch to the OFF position. B. Inspect all harness connections that are related to the sensor. Make sure that the connectors are clean and tight. C. Check the connectors for proper mating. Ensure that all the seals are present and in place. D. Check the harness for signs of damage or abrasion. E. Check the wires at the connector. Ensure that the wires are secured tightly into the connector. F. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit. Take care not to pull the wire out of the connector. G. Check the exposed wires at the connectors for nicks or signs of abrasion. H. Check the connectors for moisture, dirt, or corrosion.	The machine harness connectors are tight and free of corrosion.	OK- The machine harness connectors are tight and free of corrosion. Proceed to Test Step 2. NOT OK- The machine harness connectors are in need of repair. Repair- Repair the machine harness or replace the machine harness. STOP
2. Check The Circuit For An Open A. Turn the disconnect switch and the key start switch to the OFF position. B. Disconnect the machine harness from the sensor. C. At the machine harness connector for the sensor, install a jumper wire between contact 1 and contact 2 of the harness. D. Disconnect the machine harness connector from the ECM. E. At the machine harness connector for the ECM, measure the resistance between the positive and negative contacts for the sensor.	There was less than 5 Ω of resistance measured.	OK- The machine harness is correct. Proceed to Test Step 3. NOT OK- There is an open circuit in the machine harness. The open is in the positive or negative wire for the sensor. Repair- Repair the machine harness or replace the machine harness.
3. Check The Sensor For An Open A. The disconnect switch and the key start switch remain in the OFF position. B. Remove the jumper wire that was used in the previous Test Step. C. The sensor remains disconnected from the machine harness. Insert a multimeter probe in contact 1 and contact 2 of the sensor. Measure the resistance of the sensor.	The resistance should be between 600 Ω and 1800 Ω from −40° C (−40° F) to 120° C (248° F).	OK- The resistance is between 600 and 1800 ohms. Proceed to Test Step 4. NOT OK- The resistance is not between 600 and 1800 ohms. The sensor has failed. Repair- Replace the sensor.
4. Check For The Active Diagnostic Code 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 harness connectors to make sure that the connectors are fully seated. Observe that the clips for each connector are fastened securely. D. Turn the disconnect switch and the key start switch to the ON position. E. Operate the machine. F. Determine if the diagnostic code is active.	The diagnostic code is no longer active.	OK- The diagnostic code is no longer active. The diagnostic code does not exist currently. 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. STOP NOT OK- The diagnostic code is active. Repair- Check the circuit again. A failure of the ECM is unlikely. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may greatly reduce repair time. See Troubleshooting, "ECM - Replace".