Use this procedure to troubleshoot the list of codes associated with the Transmission/Chassis ECM.
|Transmission/Chassis ECM (MID 27)|
|1046-3||Power train Oil Filter Bypass Switch : Voltage Above Normal||All transmission commands are still functional.|
|3916-3||Brake Charge Pump Filter Bypass Switch : Voltage Above Normal||All transmission commands are still functional.|
Use this procedure to troubleshoot the list of codes associated with the Implement ECM.
|Implement ECM (MID 82)|
|3917-3||Cushion Hitch and Implement Pilot Supply Filter Bypass Switch : Voltage Above Normal||All implement commands are still functional.|
|3918-3||Elevator Charge Pump Filter Bypass Switch : Voltage Above Normal||All implement commands are still functional.|
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. Check the wiring for pinch points or abrasions. Look for and repair areas that indicate wires are exposed. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing a troubleshooting procedure.
Possible Causes for an FMI 3 Diagnostic code are:
- The ground source is bad.
- The signal is permanently open.
- The switch has failed.
- The ECM has failed. A failure of the Transmission/Chassis ECM is unlikely.
Schematic of the J1 and J2 Condition Switch connections for the Transmission/Chassis ECM.|
Schematic of the J2 Condition Switch connections for the Implement ECM.|
Note: The diagrams above are simplified schematics of the ECM connections. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic for your specific machine. Refer to the list below to identify the correct schematic for your machine.
- Electrical Schematic, UENR2689 for the 621H Tractor/Scraper.
Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.
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".
|Troubleshooting Test Steps||Values||Results|
|1. Identify Active FMI Code Associated With Sensor Circuit||
|FMI 3 diagnostic code, proceed to Test Step 2.|
|Begin Process For FMI 3 Troubleshooting HERE|
|2. Check the Harness For an Open
A. Turn key start switch and disconnect switch OFF.
B. Disconnect the machine harness connectors from the switch and the ECM.
C. At the machine harness connector for the switch, place a jumper wire between the signal contact and the return circuit.
D. At the ECM machine harness connectors, measure the resistance between the signal contact and the return circuit.
The resistance is less than 5 ohms.
|OK - The resistance measurement is less than 5 ohms. The circuit is not open.
Proceed to Test Step 3.
NOT OK - The resistance is greater than 5K ohms. The switch circuit is open or the switch circuit has a bad connection.
Repair: Either the return circuit wire or the supply circuit wire has a bad connection or an open in the machine harness. Refer to the complete machine Electrical System Schematic. Examine all of the connectors that are in the circuit. Ensure that the connections are clean, secure and in good condition. Repair the machine harness or replace the machine harness.
Note: A resistance that is greater than 5 ohms but less than 5K ohms indicates a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K ohms indicates an open in the circuit.
|3. Check The Switch Circuit For A Short To +Battery.
Note: The harness connectors remain disconnected from the switch and the ECM.
A. At the machine harness connector, measure the resistance between the switch signal contact and all of the other J1 and J2 contacts that are used in the machine harness.
Each resistance measures greater than 5K ohms.
|OK - Each resistance measurement is greater than 5K ohms. The circuit is not shorted.
Proceed to Test Step 4.
NOT OK - One or more of the resistance measurements is less than 5K ohms. The circuit is shorted in the machine harness.
Repair: There is a short to a +battery source in the machine harness. The short is between the signal contact wire and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.
|4. Check The Status Of The Diagnostic Code
A. Inspect the harness connectors and clean the contacts of the harness connectors.
B. Perform a
C. Reconnect all harness connectors.
D. Turn key start switch and disconnect switch ON.
E. Operate the machine.
F. Check the status of the diagnostic code.
The diagnostic code is active.
|OK - The diagnostic code is still active.
Repair: Check the status of the diagnostic code. If the cause of the problem is not found, 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 greatly reduce repair time.
If the ECM requires replacement, see Troubleshooting, "ECM - Replace".
NOT OK - The continuity check is not correct.
Repair: There is an open in the signal circuits of the machine harness. Repair or replace the machine harness.