Raider 4WD V6-3.7L SOHC (2007)
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For shifts out of NEUTRAL, any time a shift is commanded out of NEUTRAL, the system needs to get out. The FCM should never go to
NEUTRAL unless the driver is commanding it and all required conditions are being met.
ENCODER DRIFT CORRECTION
Whenever a shift is completed, the FCM stores the position in memory as the transfer case's intended position. The FCM continuously monitors the
mode sensor and if the mode sensor drifts toward into a NEUTRAL region sensor position for 2.0 seconds, the FCM will perform a motor drive to
correct the drift. The transfer case will be driven toward the intended position for 1.0 seconds ±100 msec. The FCM will wait for 2.0 seconds ±50 msec.
and repeat the attempt to shift to the desired position. This will continue until the intended position is reached.
SHIFT MOTOR CONTROL
The FCM will have the ability to vary the speed of the transfer case motor through pulse width modulation (PWM). It is PWM from 0 to 100% at
100Hz. The PWM will function as follows:
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Apply an initial duty cycle (APPROXIMATELY 94%) to shift motor control wires.
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Control the acceleration of the shift motor by increasing the applied duty cycle at a specified rate.
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Control the deceleration of the shift motor by updating the applied duty cycle to the shift motor control wires at a specified rate based upon the
difference between the desired position and the current position.
SHIFT ATTEMPT LIMIT
To protect the transfer case system, the FCM will impose a limit on the number of shifts that can occur over a calibrated time period. The system will
monitor the number of mode sensor position changes that occur in any 25 second time period. If the number of changes is 10 or greater, the system will
go into a default mode. The default mode of operation for shifting is that the number of allowed changes 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:
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The attempt limit will not prevent shifts coming out of NEUTRAL, they will be allowed regardless of the counter/timer.
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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.
Position changes 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 position changes towards the 10 position changes to go
into default mode as defined above. Current attempt limit values are 10 transitions in 25 seconds and default mode values are 1 transitions every
10 seconds for 5 minutes.
