The 4WD transfer case encoder motor position sensor or the selector switch may fail causing the service 4WD message to be displayed. Fault code(s) stored in the transfer case control module will be of assistance in determining the exact fault causing the message to be displayed.Google+
Car Problem Reports
Chevrolet Suburban 1500 4WD Transfer Case Position Sensor/Selector Switch May Fail
Chevrolet Suburban 1500 Problem
Drive Trains Affected: 2WD, 4WD
Average Mileage: 110,655 mi (55,000 mi - 180,000 mi)
4WD Service light came on intermittently. 4WD/2WD indicator lights would indicate Neutral or 4WD-L and the engine would bog down until it shifted out of Low. "System Stability Disabled" warning would also come on. Took to a mechanic that want about $570 to instal the new 4WD Transfer Case Postion Sensor. this really seams to be a manufacturing defect, but it past warranty.
Visitor, 2005 Chevrolet Suburban 1500, 4WD
My truck automatically goes from 2wd to 4wd then stays in neutral
Visitor, 2004 Chevrolet Suburban 1500, 4WD, 135,000 mi
shifts it self out of 2 wheel drive, lite blinks and will not engage and go into gear. Works later after a few minutes. When in 4 wheel , it will not in engage sometimes and message comes on to service 4 wheel drive. From research it seem that it is the transfer case sensor. It has done one or more of these things in the last 30 days and then run ok
Visitor, 2004 Chevrolet Suburban 1500
I replaced the 4wd transfer switch in 2007 and
now again it is not working, this would be the
second switch I would replace, all GM parts
Visitor, 2004 Chevrolet Suburban 1500, 4WD, 118,000 mi
sometimes when driving my truck will shift into 4wd and when i push the button to put it back into 2wd the light just flashes. i have to restart my truck several times before it will switch back.
At approx 30000, SER 4WD message, dealer said it was a bad transfer case motor, replaced motor.
At 65000 same problem same solution.
At 105000 same problem, now wondering if outside moisture is causing problem. Dried transfer case motor
out and problem seems to be gone. Recall last times problem occured was raining and damp for prolong time. Another Suburban owner stated he cured problem by sealing around transfer case motor with HD sealer. Might be worth a try.
Visitor, 2004 Chevrolet Suburban 1500, 4WD, 55,000 mi
Had the 4wd service come on at 55,000. Boss had an 2003 Tahoe that did the same thing. Both vehicles had sensor replaced. Now it is back on with 88,000 miles. Will try cleaning grounds.
I had to take to dealer who replaced sensor and charged me 1800.00 to fix 2 years later the kight is coming on again but it isnt locked in 4wd this time like last time