I've heard different stories so I'm hoping someone can clear this up for me. When a 2001-2004 Vette is parked, after a certain amount of time passes, the sensors go into "sleep" mode. I've heard that even in "sleep" mode, they still transmit tire pressures continuously once every 60 minutes, but I've also heard that they don't do this. So which is it? And if they do in fact keep transmitting while in "sleep" mode, what is the purpose for this? It's not like the tires are being driven on, so I don't get why this needs to happen if this is the case. Can someone verify what the situation is with passage from a service manual? Thanks in advance for an answer.

 

Don't know for sure, but I seriously doubt they "transmit" every hour - they don't have "timers" built into them!

Now, it is very possible that the BCM "pings" them every hour with the car turned off, (perhaps to verify an above 24-lb pressure condition within an hour of any restart), but I would be surprised... well, not "that" surprised!

 

That would be my "guess". It would also explain why it takes a while to see new pressure readings as the sensors maybe "wake" up after they are in motion?

One way to test it would be to park the car in the garage and note the DIC pressure readings then let the air out of one of the tires. Come back in a couple hours, start the car and let it idle for a while without moving it. My guess is it would not indicate a flat tire. If it did, then something is communicating even with the tires not in motion.

Just curious... why are you concerned?

 

So, I guess these things are just chirping away in the parts bins every 60 seconds until they find a home?

 

Didn't realize the sensors transmit when in sleep mode. Good info.

 

I have never had the OEM '01-'04 sensors, but I got the Schrader aftermarket sensors a couple of years ago.

I have read the factory information that matches to 8Vette7's description.

My aftermarket Schrader's don't appear to transmit at all in sleep mode. When I have been driving the car the pressure is about 2 or 3 psi higher than when cold. For example when I park the car they might read 33 psi. Several days later when I start driving the car they will still read 33 psi until I have gone several miles (frequently about 6 or 7 miles at highway speed). Then they will report the colder temperature of about 30 psi.

I understand that the older '97-'00 sensors go dormant and do not transmit until moving. Both the early and late OEM sensors were made by Schrader. I wonder if my later style aftermarket Schrader's use the early style dormant strategy that may be different from the OEM?