Shift Attempt Limit

To protect the transfer case system, the TCCM will impose a limit on the number of shifts that can occur over a calibrated time period. The system will monitor the number of 'D' channel segment transitions that occur in any 30 second time period. If the number of segment transitions is 30 or greater, the system will go into a default mode. The default mode of operation for shifting is that the number of allowed 'D' channel transitions permitted to occur will be 3 over each 15 second +/-100 msec calibrated window of time. After 5 minutes +/-100 msec, the motor can be assumed to have cooled down and the system will revert to normal operation. The following rules also apply to the shift limit:

• The attempt limit will not prevent shifts coming out of NEUTRAL, they will be allowed regardless of the counter/timer.
• Any shift that is in progress when the counter reaches a maximum count in time will be allowed to complete before the default mode is entered. D-channel transitions during this period will not be counted towards the default mode limit.
• A block, regardless of the direction, whether towards destination or back towards reversal target (shift timer expiring), will count as a value of 2 transitions towards the 30 segment transitions to go into default mode as defined above. Current attempt limit values are 30 transitions in 30 seconds and default mode values are 3 transitions every 15 seconds for 5 minutes.