Range And Mode Shifts

The process for performing all the range and mode shifts are the same. The following steps describe the process. 

• Allow time for Selector Switch debounce; 250 msec ±50 msec. 
• Activate/deactivate the 4WD system message icons in the instrument cluster as necessary. 
• Engage the shift motor for a maximum of 1 second ±100 msec per mode sensor target segment in the destination gear's direction while monitoring the mode sensor. 
• Disengage the shift motor when the correct mode sensor position is recognized. 
• Solidly illuminate the achieved position's instrument panel icon, unless the target is 2WD or AWD. 
• Transmit a bus message that the transfer case shift is complete. 
• If the desired mode sensor position is not reached after the shift timer expires (i.e.: a blocked shift motor or other condition exists), the FCM will stop driving the motor and wait for 200 msec ±50 msec. The shift motor is then reversed in the direction back toward the source gear for up to 1.0 seconds ±100 msec. per mode sensor target segment. The FCM waits for 2.0 seconds ±50 msec. and repeats the attempt to shift to the desired position. 

The exception to the preceding sequence is when a shift from 4LO to 2WD or AWD is requested. If 2WD or AWD is requested from the 4LO position, the transfer case is first driven to the 4LOCK position. If the 4LOCK position is reached, the transfer case is then driven back to the 2WD or AWD position and the shift is considered complete.