Fault Code 965: Rail Road Mode Switch
J1939: SA 3 SPN 7941 FMI 9, 13, 19
Overview
The Transmission Control Module (TCM) receives the vehicle’s Rail Road Mode Switch message from a vehicle Electronic Control Unit (ECU) over the Primary Data Link (J1939A). This information is used to determine transmission operation.
Detection
The TCM monitors Rail Road Mode Switch messages. If messages are not received or are invalid, the fault is set Active.
Conditions to Set Fault Code Active
FMI 9 – Abnormal Update Rate: Rail Road Mode Switch messages not received for 5 seconds.
FMI 13 – Out of Calibration: Rail Road Mode Switch message not available for 5 seconds.
FMI 19 – Received Network Data in Error: Rail Road Mode Switch messages invalid for 5 seconds.
Fallback
FMI 9, 13, 19:
- Amber warning lamp on
- No degraded modes
- Rail Road Mode will not function
Conditions to Set Fault Code Inactive
FMI 9, 13, 19: Rail Road Mode Switch messages received and valid for 10 seconds.
Possible Causes
FMI 9, 13, 19:
- Vehicle Components - Vehicle ECU(s)
- Rail Road Mode Switch message not enabled
- Other vehicle ECU(s) faulted
- Vehicle Harness - Primary Data Link (J1939A)
- Shorted to power, shorted to ground or open circuit
- Terminals bent, spread, corroded, or loose
Fault Code 965 Troubleshooting
Set vehicle parking brake and chock wheels.
Record transmission fault codes, FMIs, occurrences, and timestamps from Service Activity Report created during the Diagnostic Procedure.
If Fault Code 965 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V
If Fault Code 965 FMI 9 or 19 is Active or Inactive, refer to OEM guidelines for repair of the vehicle Rail Road Mode Switch message (SPN 7941). Go to Step V
If Fault Code 965 FMI 13 is Active, refer to OEM and enable Rail Road Mode Switch message (SPN 7941). Go to Step V
If Fault Code 965 FMI 13 is Inactive, Rail Road Mode is properly configured. Go to Step V.
Key off.
Reconnect all connectors and verify all components are properly installed.
Key on with engine off.
Connect ServiceRanger.
Go To “Fault Codes”.
Select “Clear All Faults”.
Operate vehicle and attempt to reset the fault code or duplicate the previous complaint.
Check for fault codes using ServiceRanger.
If no fault codes set and vehicle operates properly, test complete.
If Fault Code 965 sets Active, Go to Step A
If a fault code other than 965 sets Active, troubleshoot per the Fault Code Isolation Procedure Index.