fuel and tire pressure gauges stopped functioning

[kyleroden]

A couple of weeks ago I took my 2007 prius to the dealership for its first oil change (7 months, 5k miles). Soon after, my tire pressure warning light came on.. I checked all 4 tires... the lowest was 29 PSI on one of the rear tires(could use some air but not really alarming). I use the button under the steering wheel to reset, but I can not get the light to go off. Today I realized that my gas guage has read full for 120 miles now (First time i've put a <10% ethanol blend in it, miracle corn gas? doubtful). What could be wrong? Kind of seems like something happened to it at the dealership. Reluctant to take it back because I have put an EV button in and a speed switch(to enable stereo functions while driving) in, back when i first bought the car. I'm sure they'd try to blame it on that somehow

Any ideas would be appreciated.

[blzlovr]

Add some air to the tire and see if the light turns off. According to the manual if the tires are low the reset button will not turn off the light. My 2007 usually goes 100 to 150 miles before the full pip disappears.

[richard schumacher]

Put air in the tires. 29 PSI can noticeably reduce fuel economy. Check tire pressures at least monthly.

[bac]

Originally Posted by blzlovr

Add some air to the tire and see if the light turns off. According to the manual if the tires are low the reset button will not turn off the light. My 2007 usually goes 100 to 150 miles before the full pip disappears.

Have to agree. Pump you tires all to the desired level - then hold in the reset button again. I think you'll be golden. Please let the group know if that's not the case.

... Brad

[Danny Hamilton]

Originally Posted by kyleroden

Any ideas would be appreciated.

The fuel gauge is just like that. I've had it drop the first pip after 45 miles, and I've had it wait over 200 miles before it dropped the first pip. I wouldn't worry about it yet.

If it still hasn't dropped the first pip when you get around 250 miles, you'll probably want to take it to the dealer. I doubt they are going to care about your switch or EV mod for a fuel gauge issue.

As for the low tire pressure alert, keep in mind that it isn't enough to just press and release the [SET] button. You need to hold it in for a bit. I can't remember how long, but I think it describes it in the owners manual. I also can't recall if the vehicle needs to be on when setting the alert, but I think it does. Additionally, make sure you set the alert when the vehicle hasn't been driven for a few hours. If you are driving the vehicle, or have just finished driving it, when you set the alert the tires will be warm and the pressure in the tires will be higher. Then as they cool off and the pressure drops, you'll end up closer to the alert threshold than you intended.

Finally, as a few have mentioned, 29 PSI is low enough that you might want to consider checking all your tires and getting them at least up to spec. before setting the alert.

If that doesn't help, you may have a faulty sensor in one of the tires. You'll probably want to have it checked out. Again I don't think the dealer is going to try and say that your switch or EV mod damaged the sensor in the tire.