Low tire pressure warning.

**gaC5** · 07-26-11, 03:43 PM

I'm getting a low LR tire pressure warning on my display. I checked the tire pressure with a gauge and it shows 30#. What I put in all my tires. It is showing 21# on the display. Is this a bad tire pressure sensor?

**Toms01** · 07-26-11, 04:02 PM

Could very well be a TPS unit going/gone bad. Have you tried to reprogram them?

**gaC5** · 07-27-11, 01:13 PM

Originally Posted by Toms01

Could very well be a TPS unit going/gone bad. Have you tried to reprogram them?

It was the right rear tire. It was showing 21# pressure. I always thought the left side was on the drivers side.

**Tuna** · 07-27-11, 02:18 PM

Originally Posted by gaC5

It was the right rear tire. It was showing 21# pressure. I always thought the left side was on the drivers side.

Time to reprogram the system so that it really knows which tire/wheel it is reporting.
Time to check for a nail, screw or something else.

When I get a low pressure warning and the tire it's flagging is okay, I always check the rest just to make sure.

**gaC5** · 07-28-11, 12:54 PM

Guess I do need to reprogram it. If the tire gets low again I'll check for a nail or something. Thanks

**navy2kcoupe** · 07-28-11, 02:30 PM

Sounds like you might have gotten new tires and the rims were installed on the
opposite sides from where they started. When the programming is done, the
sensors address is equated to a tire position. If it's assigned to the left rear, it's
just for reporting purposes only. You can move that wheel all around on your
vehicle, and unless you reprogram it, it will ALWAYS report as the left rear.
Ditto for the other three. You might want to also drop the left front pressure
to 21 pounds and see if you get a correct callout on that one as well. I'll bet that
if you reduce the left rear to 21 pounds that it shows up as the right side on the
display. Play around with it, it can't hurt and you'll find out exactly which sensors
need to be reprogrammed.
Andy

**timfitz63** · 08-06-11, 03:52 PM

My '04 recently displayed "XXX" in the right-rear tire pressure indication; I got a quick re-programming at a local tire change place and it corrected the issue. But I suspect my sensors may be nearing the end of their lifespan.

In any case, a '98 I was driving recently coincidentally gave the same "SERVICE TIRE MON SYS" message as well, but all pressure displays were blank (no values, no "X's"). Did the presentation for missing tire pressure(s) change (blank to "XXX") sometime between the '98 and '04 model years? Just trying to debug the problem on the '98; I suspect it's merely the sensors getting old as well in that case, but want to eliminate broader problems with the system as a whole, if I can.

**mrm1149** · 08-07-11, 05:41 AM

I've found that original sensors are usually good for around 30,000 miles or so.................

**timfitz63** · 08-08-11, 08:49 AM

Originally Posted by mrm1149

I've found that original sensors are usually good for around 30,000 miles or so.................

Perhaps. But they also have a finite battery life (I've heard estimates of around 5-6 years, on average). I was mainly curious about the difference in presentation on the DIC (blank on a '98 vs. "XXX" on an '04), though.

Assuming the tire pressure sensor batteries are still strong, it may just require a simple reprogramming to correct, so the vehicle recognizes the sensors; the rims are not the originals, and they may not be the original (i.e., programmed) sensors either...? Otherwise, the implications are a deeper problem with the TPMS...

Trying to start simple (and inexpensive), though...

**mrm1149** · 08-08-11, 09:05 AM

If you're getting a blank display try driving the '98 for several miles. The sensors don't function when the car is not in motion for awhile...................

**timfitz63** · 08-08-11, 09:29 AM

Originally Posted by mrm1149

If you're getting a blank display try driving the '98 for several miles. The sensors don't function when the car is not in motion for awhile...................

Yeah, I remember reading that too. Unfortunately, the DIC gave the "SERVICE TIRE MON SYS" after it was driven for several miles; still blank where the pressure values would appear...

I suspect the sensors are just tango uniform; like I said, just trying, if possible, to isolate (or better yet, eliminate) broader TPMS problems.

**mrm1149** · 08-08-11, 09:59 AM

Originally Posted by timfitz63

Yeah, I remember reading that too. Unfortunately, the DIC gave the "SERVICE TIRE MON SYS" after it was driven for several miles; still blank where the pressure values would appear...

I suspect the sensors are just tango uniform; like I said, just trying, if possible, to isolate (or better yet, eliminate) broader TPMS problems.

Hmmm....Could be that the sensors were never programmed to the car, incorrect generation of sensor, just a few things that pop into my Irish mind. Or ultimately they may simply be dead.

**timfitz63** · 08-08-11, 10:13 AM

Originally Posted by mrm1149

Hmmm....Could be that the sensors were never programmed to the car, incorrect generation of sensor, just a few things that pop into my Irish mind. Or ultimately they may simply be dead.

Yeah, that's definitely the first thing to try (reprogramming); most tire change shops will attempt to do that for you, gratis.

That failing, I'll probably just live with resetting the "SERVICE TIRE MON SYS" message every time I start the car (under the presumption that the sensors are old and 'expired') until replacing the rims and tires.

Still wouldn't mind hearing from anyone whether the blank value vs. "XXX" is an expected difference between the model years (1998 vs. 2004)...

**Red Vette** · 08-08-11, 04:47 PM

Originally Posted by mrm1149

I've found that original sensors are usually good for around 30,000 miles or so.................

From the research I've done, and it is not an absolute, it appears that the life of the sensors depends on use and time. GM says that the battery life will last 5 years or so for normal driving. So if you put 15K on each year, then 5 years would be about 75K. If you only have 30K on the clock, they you've gone about 2 years, even though the actual time may be more than 5 years. The batteries disappate their charge even when the Corvette is not being driven, but no where near as much as if the Corvette is driven many miles. My 02 coupe is still on the first OEM sensors, but I only have 32K miles on it. That is 9 years going on 10. I expect to be replacing them in the near future.
Barrett

**timfitz63** · 08-08-11, 05:00 PM

Originally Posted by Red Vette

From the research I've done, and it is not an absolute, it appears that the life of the sensors depends on use and time. GM says that the battery life will last 5 years or so for normal driving. So if you put 15K on each year, then 5 years would be about 75K. If you only have 30K on the clock, they you've gone about 2 years, even though the actual time may be more than 5 years. The batteries disappate their charge even when the Corvette is not being driven, but no where near as much as if the Corvette is driven many miles. My 02 coupe is still on the first OEM sensors, but I only have 32K miles on it. That is 9 years going on 10. I expect to be replacing them in the near future.
Barrett

OK. So the tire sensors must go into a 'sleep' mode, of sorts, when the car is not moving, in order to conserve battery power. That's good to know. My '04 only has around 17k on it, so mine may be doing better than I had thought a week or so ago...

Odds are this '98 (which has less than 10k on it) just needs a full sensor reset; just gotta find a tire change place nearby to do it!