My hand held tire gauge shows 30 psi in all 4 tires, but dash shows 27,29,28,30. Is there a way to reset the monitors?

 

The tire pressure sensors can not be reset. Honestly, I'd put my money on the pressure showing on the sensors over that of the handheld gauge.

When are you checking the DIC as compared to the gauge? The Tire sensors will not update when the car is stationary but once per hour. I would consider getting the pressure set so that all the TPMS readings are at 30 psi cold and then check them with your gauge and you can the see what the handheld reads to compare.

 

Well....I tried to get a little more info from your profile, but there's nothing there.

Did you just get the car? Is it new, or did you get it used? Does it have some wheels other than the OE ones on it? Did you put new sensors in it recently?

The only reason the sensors would not be registered with the TPMS computer in your car is if different wheels with a different set of sensors was put on.

If your car has been sitting still for more than 15 minutes, the sensors only transmit once per hour. When you start driving faster than 20 mph the sensors start transmitting once every 60 seconds.

So, if your car has been sitting for a while when you check the pressures with a gauge, you need to drive it faster than 20 mph for a few minutes for the sensors to send the current pressures to the TPMS and get displayed on the DIC.

The DIC is a good reference for a general idea of what your pressures are (actually the sensors are very accurate, but the DIC only displays to the nearest +/- 1 psi, and driving at high elevations makes the display about 2 or 3 psi low). So, check and set your pressures with good gauge.

If you move your sensors (i.e., if you get new tires and they move the one that was on the LF to the RR), if you get new sensors, or if you have a couple sets of wheels/tires/sensors, you need to register the sensors with a tool as in the video below.

Bob

 

most difference I have ever seen between DIC and my dedicated Vette air gauge is 1-2 psi. I have found my tires will lose about that level of pressure due to temperature drop overnight in my shop. try watching the changes in the DIC readiings ( vs. your gauge) to see if your tires stay consistently at a given pressure overnight then check 'em with your gauge and use that difference in all future readings - with the DIC being the one you want to read 30 psi cold.

 

It may be the gage and not the TPMS. Anyway you can reset (index) the TPS but you can not calibrate them.