Maybe you didn't know this...
04-17-2015, 07:24 PM
#1
Instructor
Thread Starter
Maybe you didn't know this...
A few things people may not know about the C7. I’ve been studying the service manuals.
If you, like me, jacked up the car while it was locked, not opening a door, you learned about the tilt sensors. These two sensors are above the windshield on either side. Data from their accelerometers are saved, learning the car’s attitude (tilt) when the engine is shut off, so once locked the alarm is triggered if anyone tilts the car as with a jack. Doing it this way, it works fine even if you park on a hill.
The other function of these sensors is to sense any motion in the cockpit when it is locked. To see this, put your fob away from the car with its windows open or top off/lowered. Reach into the car and the alarm will sound. (Then you’ll run to the fob to turn it off.) Both these functions can be shut off temporarily using the switch beside the trunk release left of the steering wheel.
My 2006 seat memory gave me problems with not setting the fore/aft position. The motor/potentiometer was replaced under warranty. After that, about twice a year I’d remove the seat, disassemble the position potentiometer, and retension the wiper, which would keep it working several more months. A real pain and surely it's not just me. In the C7, the position is determined by a rotating magnet and a Hall effect sensor counting turns. This should be very reliable, but I hope the memory that holds the count is nonvolatile, that is, that it doesn’t forget the count if the battery is disconnected.
The C7 uses several Hall effect sensors, including crank and cam position sensing. For those not electronics geeks like me (we’re electric fans), a Hall effect sensor measures static magnetic fields unlike the old days of coils, which sense fields only when there is movement.
Chevy has made a LOT of unseen improvements.
Dave
If you, like me, jacked up the car while it was locked, not opening a door, you learned about the tilt sensors. These two sensors are above the windshield on either side. Data from their accelerometers are saved, learning the car’s attitude (tilt) when the engine is shut off, so once locked the alarm is triggered if anyone tilts the car as with a jack. Doing it this way, it works fine even if you park on a hill.
The other function of these sensors is to sense any motion in the cockpit when it is locked. To see this, put your fob away from the car with its windows open or top off/lowered. Reach into the car and the alarm will sound. (Then you’ll run to the fob to turn it off.) Both these functions can be shut off temporarily using the switch beside the trunk release left of the steering wheel.
My 2006 seat memory gave me problems with not setting the fore/aft position. The motor/potentiometer was replaced under warranty. After that, about twice a year I’d remove the seat, disassemble the position potentiometer, and retension the wiper, which would keep it working several more months. A real pain and surely it's not just me. In the C7, the position is determined by a rotating magnet and a Hall effect sensor counting turns. This should be very reliable, but I hope the memory that holds the count is nonvolatile, that is, that it doesn’t forget the count if the battery is disconnected.
The C7 uses several Hall effect sensors, including crank and cam position sensing. For those not electronics geeks like me (we’re electric fans), a Hall effect sensor measures static magnetic fields unlike the old days of coils, which sense fields only when there is movement.
Chevy has made a LOT of unseen improvements.
Dave
04-17-2015, 07:41 PM
#2
Moderator
The interior motion sensor is inactivated if the roof is off. There is a switch in the drivers side front roof pin hole that turns it off when the roof is removed. At least in the 2014's.
Seat memory is nonvolatile.
Seat memory is nonvolatile.
04-17-2015, 10:13 PM
#4
04-17-2015, 10:18 PM
#5
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Good information, thanks.
04-17-2015, 11:30 PM
#6
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St. Jude Donor '16
Very good info - thanks for sharing! I had an experience with the motion sensor at a dealership. I was admiring a coupe which had its top removed. It was parked on the wide, covered sidewalk outside the showroom. I reached in to feel the sueded microfiber seat inserts and...yep! I bet the sales guys had a lot of fun that day betting on which customers would set it off.
BJ
BJ
