Fault Code 985: Two Speed Axle Message
J1939: SA 3 SPN 69 FMI 13, 19
Overview
The Endurant XD Series transmission can be combined with a 2-speed axle for additional gear ratio coverage. When 2-speed axle operation is required the Transmission Control Module (TCM) receives an axle gear engagement signal (Input) then adjusts the transmission shift strategy and launch characteristics for the new axle gear ratio. Reference Endurant XD Driver Instructions TRDR0960 for Two-Speed Axle operation.
The TCM can be configured for operation with a 2-speed axle with messages over the vehicle Primary Data Link J1939A or from a switch circuit hardwired directly to the TCM. The TCM is equipped to receive 4 switch inputs and control 3 relay outputs that can be configured in an Input/Output (I/O) Package to support various vocational features.
If the TCM is configured to "2-Speed Axle - J1939", axle gear engagement messages are provided to the TCM by an OEM vehicle ECU. If the TCM is configured to "2-Speed Axle - TCM Hardwired", an axle gear engagement notification signal (Input) is provided to the TCM from a hardwired switch circuit.
The 2-speed axle circuit input is connected to the TCM in the 20-Way TCM Body Harness Connector. The 2-speed axle circuit is installed by the OEM or body builder. Reference Input / Output Calibration in the Appendix for recommended 2-speed axle circuit wiring diagrams.
Detection
The TCM monitors Two Speed Axle messages. If messages are not received or are invalid, the fault is set Active.
Conditions to Set Fault Code Active
FMI 13 – Out of Calibration: Two Speed Axle message not available for 5 seconds.
FMI 19 – Received Network Data in Error: Two Speed Axle messages invalid for 5 seconds.
Fallback
FMI 13, 19:
- Amber warning lamp on
- No degraded modes
- 2-Speed Axle operation may not function
Conditions to Set Fault Code Inactive
FMI 13, 19: Two Speed Axle messages received and valid for 10 seconds.
Possible Causes
FMI 13, 19:
- Vehicle Components - Vehicle ECU(s)
- Two Speed Axle 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 985 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 985 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V
If Fault Code 985 FMI 19 is Active or Inactive, refer to OEM guidelines for repair of the vehicle Two Speed Axle Message (SPN 69). Go to Step V
If Fault Code 985 FMI 13 is Active, refer to OEM and enable Two Speed Axle Message (SPN 69). Go to Step V
If Fault Code 985 FMI 13 is Inactive, Two Speed Axle Message 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 985 sets Active, Go to Step A
If a fault code other than 985 sets Active, troubleshoot per the Fault Code Isolation Procedure Index.