Tire Pressure Warning Light - Dead Sensor..

It's not the first TPWS sensor failure on a 3rd Gen I've seen. No worries as you do from time to time get a hold of bad parts and its covered under 3yr/36k warranty.

 

This has been happening to me for the last couple weeks. It blinks, stays on, turns off randomly. I have yet to take it in though. They say its from overfilling huh? interesting. Mine are overfilled by a couple lbs. but nothing drastic.

 

It is not from overfilling. If it was then half the Pri on this site would be having the problem.

 

I have my tires at 42/40 with no problem. Just be sure to reset the TPMS with the button under the steering wheel when you adjust tire pressures. This resets the system to the current pressure in the tires. Then, if the pressure in a single tire drops something like 8 psi or 25%, then the TPMS warning comes on.

 

A blinking tire PSI light indicates a loss of communication or improper communication between a sensor and the TPWS ecu. Do NOT let a dealer tell you your 42/40psi or whatever higher psi you run is the cause of your blinking light. I have, on occasion, seen a fully functional sensor fall "asleep". It can be woken up by decreasing tire psi 6psi in 30 seconds. I think you should try this. So if your goal psi is 42/40, inflate them all to 50psi and deflate back to 42/40. If that doesn't cure your problem then a trip to a more compentent/knowledgable dealer will fix it.

 

I would let the dealer service advisor know that you visit PriusChat and that the people on this site advise you that this problem is with the sensor and not tire pressures. Many people on this site run their tire pressures at 40+ psi with no problems. I would also make the point that the Owner's Manual states that when the light flashes and then goes solid that this indicates a faulty sensor.

If after this discussion, they still want to hang their hat on tire pressures, then it would be time to look for another dealer.

 

I know this is a minority view, but this illustrates just why I hate the whole TPMS idea....period.

I would make sure that the tires are set where you want them, and then ignore the stupid light, at least until you're ready to seriously tackle trouble-shooting the system. It just makes no sense to keep making dealer visits to solve a "problem" that is only an issue if you're dumb enough not to know how to use a tire gauge.

I just used the wheels from a previous-gen Prius [an '05] to mount new Michelin Harmony tires on our '10, at the 3500 mile point. No TPMS sensors, since I took the 2010 OEM wheels/tires and stored them intact to remount on the car at resale time. So the silly light comes on, and I ignore it.....after driving for 48 years, I find I can successfully manage tire pressures without this complex, failure-prone, thoroughly unnecessary complication known as TPMS.

I'm 65, not 18, but you're getting an early education in the way dealer service departments tend to operate - if they can diagnose a problem quickly, with known tools and technology, then you're fine. If nothing convenient exists to track down the problem, good luck. TPMS, in my experience, falls into the latter category. Only you can decide how much trouble it's worth to get the stupid light to turn off.

(Yes, clearly one or more of the sensors is either failing or already failed - the challenge comes in finding which one, without tearing down all of the tire/wheel assemblies. It can be done, but you have to have the right tools for measuring signal strength, and the time and desire to pursue it. This dealer apparently doesn't / won't....}

 

If it were my car, I'd have a tire shop use their electronic tool to read the tire sensor ids and battery condition. It's probably a low battery (in a new car ), for which the solution is to install a replacement sensor. Sensors are about $100 from a dealer, or $25 on eBay. Then the new sensor has to be registered with the car, which requires either the Toyota Techstream scantool or a fairly expensive aftermarket tool that a tire shop may or may not have.

It could be some other fault, such as a bad TPMS receiver or a bad connection to it. But a weak/dead sensor is the first thing to check. Tire shops usually have the equipment to diagnose the sensors, while you'll have to use a dealer for the rest of the system.

Since one dealer just blew you off on your first attempt, take it as a lesson in how much business you should send his way. Try another dealer who wants your business.

 

Good news is always plus. Hope this takes care of your problem. Thanks for following up on this and letting us know the outcome.

 

Did they replace the rear sensor that they indicated was "weak"?

Take it back until they fix the problem. I know taking it back is a pain but they need to fix their problem.

 

The prosecution rests....

TPMS, guilty as charged. (Good grief, this is such an unnecessary complication to automotive life....)