CX28, CX31 and CX35 On-Highway Transmissions Power Train Electronic Control System Caterpillar

Transmission, SPN 639 - FMI 14

Usage:

CX31 B3X

Conditions Which Generate This Code:

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Illustration 1	g01257797
Schematic of the J1939 Data Link

The diagnostic trouble code is associated with the Transmission ECU. The FMI 14 means that the ECU is not receiving the proper information from the data link.

Note: Ensure that all of the electronic control units are powered and that the wiring for the J1939 data link is properly connected. This diagnostic trouble code will become active when the Transmission ECU is powered and the Engine ECM is not powered.

Probable Causes:

Incompatible software or missing parameters from a message
Requests of complete parameter are missing.
Expecting parameters from features that are not enabled
Problems with the data link during ECU flash programming.
The incorrect flash program was performed.
Problems with the data link during downloads of data
Errors in the data link from other controls on the data link

System Response:

Transmission, SPN 639 FMI 14 is logged by the ECU. The diagnostic trouble code remains active until a power cycle has occurred and the requested parameters have been received.

Test Step 1. TROUBLESHOOTING PROCEDURE

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Table 1
Troubleshooting Test Steps	Values	Results
1. Verify Latest Software Version Is Used A. Verify that the Transmission ECU and other ECU / ECM on the data link has the correct, most current software.	All software is current	OK - All of the software is current. Proceed to Test Step 2. NOT OK - The software is not current. Flash with the latest software release. ⁽¹⁾ Refer to Testing and Adjusting, "Electronic Control Unit - Flash Program". STOP Proceed to Test Step 2, if the diagnostic code is still active after the ECM is updated with the latest software.
2. Inspect The Harness Connections A. Key switch and disconnect switch are OFF B. Inspect all of the harness connections. Make sure that the connections of the connectors are clean, dry, and tight. Also check the harness for damage. Follow the steps in Testing and Adjusting, "Electrical Connector - Inspect".	Machine harness and connections are good	OK - The harness connections are good. Proceed to Test Step 3. NOT OK - The harness connections are faulty. Repair: Repair or replace the machine harness. STOP Proceed to Test Step 3, if the diagnostic code is still active.
3. Check the Enabled Parameters for the Machine A. Key switch and disconnect switch are ON B. Use Cat ET to view all of the enabled parameters. ⁽²⁾	Parameters are Not enabled for transmission functions that are unavailable	OK - The parameters enabled for the transmission are correct. Proceed to Test Step 4.. NOT OK - Parameters are enabled for functions that are not available on the transmission. Repair: Disable the parameters that are not available. Turn the key start switch OFF and then back ON. ⁽³⁾ Proceed to Test Step 4, if the diagnostic code is still active after the unavailable parameters are disabled.
4. Check if the Diagnostic Code Remains A. Operate the vehicle. B. Check the status of the SPN 639 FMI 14 trouble code.	SPN 639 FMI 14 is Not active	OK - SPN 639 FMI 14 is not active. The diagnostic trouble code does not exist at this time. The initial diagnostic trouble code was probably caused by a poor electrical connection at one of the harness connectors that was disconnected and reconnected. Resume normal vehicle operation. STOP NOT OK - SPN 639 FMI 14 is active. The diagnostic trouble code has not been corrected. Recheck the circuit and perform this procedure again. If the diagnostic trouble code has not been corrected after performing this procedure a second time, follow the below ECU replacement advice. STOP

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^( 1 )	There can be problems during attempts to download data. The problems can come from an ECU that requests a parameter when a flash program is being attempted. The ECU may only service one of the requests. Problems can occur when an ECU is expecting a parameter from another ECU that does not support the message.
^( 2 )	The diagnostic trouble code will remain active until a power cycle has occurred and the requested parameters have been received.
^( 3 )	Changing parameters or configurations might require a power cycle. The power cycle clears diagnostic trouble codes that are caused by missing parameters or incompatible software. When the parameters are changed, the ECU will request the parameters again. The ECU then clears the diagnostic trouble codes.

Expected Result:

The procedure corrected the issue.

Results:

Yes - SPN 639 FMI 14 is not active. Resume operation. STOP
No - SPN 639 FMI 14 is active. The diagnostic trouble code has not been corrected.
Repair: If the cause of the diagnostic code is not found, replacement of the ECU may be necessary. Prior to replacing an ECU, always contact the Technical Communicator (TC) at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. Refer to Testing and Adjusting, "Electronic Control Unit - Replace" if the ECM needs to be replaced.
STOP