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2000 Suburban "Service 4WD" warning lite

This light comes on frequently, and I have been to three garages to check system. All three say the system is fine (which I already knew since I use 4WD often) and can’t explain why the light comes on. I live in a remote mountain area of West Texas 200 miles from the closest Chevy dealer. I would be reluctant to take it to a dealer anyway since I’ve had two Chevy dealer experiences where the “Check Engine” light came on and I was charged over $600 only to have the light come back on in a few days.



What’s up with “Service 4WD,” does anyone know? This is very important because, as I say, I use 4WD often on remote roads where I can’t have drivetrain problems. BTW, this vehicle has 115,000 miles on it.



Many, many thanks in advance. Pete

Wonder if it is not a light to remind you to change oil in 4wh drive system?

Perhaps so, but I change the oil in transfer case every 30k miles or so. Maybe the sensor doesn’t realize I’ve changed it. Thanks so much for the reply, amigo. It’s worth looking into.