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Discussion Starter #1
I just used the Volt tire inflator to increase pressure on each tire of my recently-bought 2015, per the video on https://gm-volt.com/forum/showthread.php?18943-Chevy-Volt-Flat-Tire-Tire-Inflator-Guide.

The dial initially showed pressure similar to the TPMS; I added air up to about 40 psi, according to the inflator gauge. However, TPMS shows no change.

Have folks seen this, or does this mean my inflator or its gauge is off??

I'm still in the selection process for a digital gauge so don't yet have another reliable source of info...
 

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The sensors in the wheels shut off when the wheel isn't rotating, otherwise the batteries in them would not last long. Air up your tires, then drive the car and you should see the change

Don
 

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Why would GM turn the sensors off in the Volt but not other cars with TPMS? I haven't tried my Volt but my Cruze's TPMS didn't shut off when the car wasn't moving - I could use the TPMS as an indicator when to shut off the air compressor.
 

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Why would GM turn the sensors off in the Volt but not other cars with TPMS? I haven't tried my Volt but my Cruze's TPMS didn't shut off when the car wasn't moving - I could use the TPMS as an indicator when to shut off the air compressor.
It is a different generation TPMS. The sensor will go into suspense mode if the car is parked for a time to conserve the lithium button battery. The only certain method of waking up the TPMS is to drive 1 - 2 miles at normal speed.
 

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Well, it appears not all of them do shut off - Some still transmit when the vehicle is parked, but they transmit far less often than when the vehicle is in motion

From Wikipedia: "When used in low-profile wheels, TPMS sensors wear out sooner, as well as when they are used in poor road conditions. With a battery change then meaning that the whole sensor will have to be replaced and the exchange being possible only with the tires dismounted, the lifetime of the battery becomes a crucial parameter. To save energy and prolong battery life, many dTPMS sensors do not transmit information when not rotating (which eliminates spare tire monitoring) or apply a complex, expensive two-way communication which enables wake-up of the sensor."

I *think* even the ones which do shut completely off when the car is parked, it may be an hour or two after the wheels stop moving

Don

Edit: the 'd' in dTPMS stands for our direct measuring system, which can relay the exact tire pressure to the dash. Many newer cars are now using an indirect system which counts the tire rotation using the ABS wheel sensors - An underinflated tire has a slightly smaller circumference which causes the wheel to rotate faster than the other three and that triggers the alarm . . . . but it can't tell you the actual tire pressure
 

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Discussion Starter #6
Hi folks,

Thanks for the responses. FYI, I did run errands after this, and didn't see any change in the TPMS.
 

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Hi folks,

Thanks for the responses. FYI, I did run errands after this, and didn't see any change in the TPMS.
Do you have an accurate tire pressure gauge? I like this one from INTERCOMP.

If you just need to add few pounds of air pressure to a tire I like the Air Hawk tire inflator. Also, Ryobi has a decent inflator that works with the same 18V lithium battery pack as the other Ryobi One+ battery powered tools.
 

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Regardless of the air source, I fill my tires using a pressure gauge. I top off, then release a bit of air until all 4 at at the same psi. When I drive the car, it generally agrees with the pressure I set using my gauge. Sometimes a slight difference of maybe a 1/4 psi on my gauge can end up with the dash showing 1 psi difference for that tire. I don't sweat that.
 

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My tire pressures sometimes drop over time. I’ve never had a problem for the past 6+ years using the tire pressure display on the DIC as a real time indicator gauge when increasing the tire pressures in my 2012 Volt. Before I start driving (so the tires are cold), I turn on the car, plug a store-bought air pump into the cigarette lighter outlet and clip the hose to the tire valve, turn on the pump, and pump air into each tire as needed as I watch the display to see when the pressure reaches the desired number. I’m satisfied with the display numbers, don’t use a separate hand held gauge to confirm the pressure (the few times I’ve used a hand held gauge to check, the display is on the mark or within 1 psi).

Most times I back out of the garage and park on the driveway (more room to maneuver) before pumping up the tires (is that sufficient to turn on the sensors?), but at least once when only the driver’s side rear tire needed air, and once when a slow leak had depleted the passenger side rear tire, the pumping was done without moving the car from where it had been parked overnight.

I suspect most Gen 1 Volts would behave the same way. I don’t know why the OP’s 2015 Volt display didn’t reflect any changes in the tire pressure when using the GM equipment to do so. The display works fine for me using my own air pump. Perhaps the OP’s Volt air pump wasn’t firmly connected, so no air was going into the tire. I suggest he could look at the display for the current reading, then let enough air out of a tire to see the display number drop 1 psi or so, and then use the pump to inflate it back up again. If there’s no change in the display when lots of air is let out of the tire, then that could help locate the source of the problem (would sensor batteries for all four tires go out at the same time?), and the Volt air pump could be used to reinflate the tire.
 

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With the car running I always see a change when adding 12 -20 sec of air which moves the PSI about 3 psi.

the tire sensor will trigger

1. pressure change
2. moving
3. via a electronic signal like from a tire trigger tool ( not a magnetic)

always good to double check air is actually going INTO the tire :)
 

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The pressure shown on the air compressor guage will typically show higher than the tire pressure while it is running because it has to output higher pressure in order to increase the pressure in the tire.
Just pick up a cheap tire guage from any auto store and use that. You don't need anything too fancy.
 

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Also, while occasional use is fine, I would not use that emergency inflator regularly. The replacement will be expensive when it burns out. If you want something small and portal, you can get one for under $30 (+10%-25% tax tariff?) like the one below from Harbor Freight. Bonus, no need to remove and replace the one in your cargo area.

Bolt EV air compressor Harbor Freight Item 61788.jpg
 

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Also, while occasional use is fine, I would not use that emergency inflator regularly. The replacement will be expensive when it burns out. If you want something small and portal, you can get one for under $30 (+10%-25% tax tariff?) like the one below from Harbor Freight. Bonus, no need to remove and replace the one in your cargo area.

View attachment 156571
Heh. That one is about $65. For about $75-80, you can get a 3 gallon pancake compressor, coupler set, and 50 feet of air hose that'll fill your tires in about half the time.
 

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Discussion Starter #14
Thanks, all - you've given me some good ideas for trouble-shooting and for alternative approaches. Much appreciated!
 

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yes to above

I hate having to get the air-filler out of the back hatch ( unwind-rewind ) so I keep a low cost extra one under the front seet.
same idea with the other item next to it :)
 

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My tire pressures sometimes drop over time. I’ve never had a problem for the past 6+ years using the tire pressure display on the DIC as a real time indicator gauge when increasing the tire pressures in my 2012 Volt. Before I start driving (so the tires are cold), I turn on the car, plug a store-bought air pump into the cigarette lighter outlet and clip the hose to the tire valve, turn on the pump, and pump air into each tire as needed as I watch the display to see when the pressure reaches the desired number. I’m satisfied with the display numbers, don’t use a separate hand held gauge to confirm the pressure (the few times I’ve used a hand held gauge to check, the display is on the mark or within 1 psi).

Most times I back out of the garage and park on the driveway (more room to maneuver) before pumping up the tires (is that sufficient to turn on the sensors?), but at least once when only the driver’s side rear tire needed air, and once when a slow leak had depleted the passenger side rear tire, the pumping was done without moving the car from where it had been parked overnight.

I suspect most Gen 1 Volts would behave the same way. I don’t know why the OP’s 2015 Volt display didn’t reflect any changes in the tire pressure when using the GM equipment to do so. The display works fine for me using my own air pump. Perhaps the OP’s Volt air pump wasn’t firmly connected, so no air was going into the tire. I suggest he could look at the display for the current reading, then let enough air out of a tire to see the display number drop 1 psi or so, and then use the pump to inflate it back up again. If there’s no change in the display when lots of air is let out of the tire, then that could help locate the source of the problem (would sensor batteries for all four tires go out at the same time?), and the Volt air pump could be used to reinflate the tire.
It could be but the Owner's Manual states that you need to drive the Volt for up to 2 miles before the TPMS will provide accurate/updated tire pressure readings. Sometimes just adding or removing air from the tire will wake up the TPMS.
 

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It could be but the Owner's Manual states that you need to drive the Volt for up to 2 miles before the TPMS will provide accurate/updated tire pressure readings. Sometimes just adding or removing air from the tire will wake up the TPMS.
I don’t know where in the Owner’s Manual such information is located. My 2012 Volt Owner’s Manual material regarding the TPMS in the Vehicle Care section doesn’t mention anything about "waking up" the sensors or needing to drive any distance to update the tire pressure readings on the DIC. What I note in the TPMS sections of both the 2012 and the 2018 manuals is only that "using the DIC, tire pressure levels can be viewed," and the information regarding the DIC information displays says the display "shows the approximate pressures of all four tires."
 

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I have a 60 gallon 240V air compressor that I use for sand blasting, air tools etc but don't use it for tire filling unless I've used it for one of the others and the tank still has air. I have a portable direct drive compressor that I used to blow out computers that I use for filling tires. On the road every gas station has air you can just pull up to and fill up although I haven't done that in years. No need to carry an extra compressor around even for flats when you have one in the trunk. On thing I've noticed I rarely have to pump up tire on the other cars that I keep at 32 psi (although 24 to 28 is called for) whereas the 41 psi on the Volt leaks out at a regular rate (more so than I would have expected).
 

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I prefer to use a multi tire inflator. If you have stupidly deep pockets you can buy some fancy system. I just went to harbor freight, sacrificed several plastic air lines and used a 1 to 4 air line manifold block. I put an inline pressure gauge in the incoming line and screw on tips just like the inflator uses. Cost me less than $100, not counting the compressor.

This way, I can hook it up and it will equalize the pressure in all four tires, up or down.
 
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