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Don't Understand Initializing Tire Pressure Warning System

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I screwed up today! o_O I set all my tires to 33 PSI and went into the car to see what pressures were displayed. They hadn't changed from what they were set at before I adjusted everything to 33 PSI. I stupidly fooled around and must have selected the wrong button (meter switch to the setting icon; then to vehicle setting; then to "TPWS"; then I selected "Setting Pressure" and that's where I must have selected something wrong!). :oops: Now all I get for each tire is "--" The sensors won't show the current PSI. I read pages 469 to 473 on Initializing The Tire Pressure Warning System as I think selecting the "Setting Pressure" button caused my problem but the directions are totally confusing to me. :unsure: Can anybody give my the "Initializing The Tire Pressure Warning System for Dummies" directions so I can get the readings to reappear again on the car readout as well as the Toyota app on my iPhone. All I get for each tire is "--". I'm letting the car sit for several hours right now and will reset the pressures again to 33 PSI. I just need to know how to get the car to readout the pressures in each tire. :(

I have tried reading the numerous posts/threads on this and haven't been able to really understand what I did wrong and how to correct it.

Thank you in advance for helping me. 馃檹
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Your display will update once you start driving the vehicle. The jury is still out was to when this happens but the manual hints at 10 to 30 minutes of drive time. This is odd though since tire pressure should be measured with cold tires.
 

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Discussion Starter · #3 ·
My wife drove the car over 2 hours right after this happened and I still get the "--" displayed for each tire. I thought they would reset with time too but no dice.
 

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Have you followed all the instructions in the manual? In particular, there seems to be something significant about parking for 20 minutes or more with the car off. It says that if initialization is not completed after an hour, park for 20 minutes or more and then drive it again.

The drive must be done without shutting the car off or using reverse. Either of these actions causes the initialization procedure to start again.
 

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Discussion Starter · #5 · (Edited)
EDIT: A-r-r-g-g-h! I went back just now to check it and "--" is back on!! I don't know why that happened but I'll try it again after letting the car sit out for 20 minutes and checking the tire pressures.

EUREKA!! I followed the directions as written to a "T" and lo and behold, the tire pressure indicators all came back. I think I didn't start the car in hybrid mode and my wife backed out yesterday so it didn't reset itself because of that. Today, I set all pressures to exactly 33 PSI (spare to 60 PSI) followed the directions on initializing the car EXACTLY (went to "Set Pressure" and held OK until there were three flashes of tire warning icon and message saying it was ready for initialization) and then drove in straight directions mostly at or over 25 MPH for about 30 minutes. When I came back, the tire pressure settings were all back on. Thank you and Happy Thanksgiving! 馃崡馃崡馃嵎馃嵎馃懆鈥嶐煃仇煣欌嶁檪锔
 

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When the vehicle starts, the TPWS will always show -- until you drive it for a hundred feet or so.
This is different from the prolonged -- after you hit initialize TPWS. I "think" that has some voodoo in registering the pressure sensors present to the system.
 

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Discussion Starter · #7 ·
OK, I'll look after I travel a few hundred feet. It is sending the Toyota app pressures so it seems to have them in memory somewhere.
 

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BTW I just read through the section on Initializing TPWS in the manual Page 474.

It is main functions seem to be 1) Establish "golden" pressure, so a loss of 25% from that would trip the warning light. 2) Establish the positions of the four wheels so it knows which wheel is running low on pressure.

It is supposed to be done after every tire rotation. I highly doubt this was ever done at the dealer after a service stop, as I have never gotten car back with -- on TPWS screen (only time it happened was after initial delivery), yet, my wheel positions seem just fine and never confused.
 

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The TPMS always shows -- when the car is first started. The sensors need to wake up by driving a little before they start reporting. The TPMS shows the live reports from the sensors. It does not show remembered pressures.
 

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The Toyota app does remember the pressures. It seems to save the last reported pressure. After parking the car, it still shows the slightly elevated pressures from the warm tires. This is probably the last report from when the car was shut off.
 

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I don't know how on-topic this is, however I aired down my tires to 36 psi. Backed it out of the garage and parked it in front of my house in the street. It sat there for several hours. Later in the evening I started the car and backed it up about 25 feet, maybe 2 car lengths. I found the air pressure page on the MID (never go there so forget which subscreen it lives in). It was already giving me an alert, either from backing from the garage to the street which could have been 50' if you count forward and reverse. Of course there was no speed involved either.

The alert shows the 2 front tires in orange stating low tire pressure of 35. Tire pressure was equal for all 4 tires, all reporting 35, however only the front tires were orange. I drove the vehicle twice last night for a long time and on highway (not to clear the tire warning).
So my question is: What is the setpoint for the tire pressure? The door sticker suggests 33psi for the tires. My car came with 40+, it had settled to 38 when I started checking yesterday (this is over 3 months of ownership). I figured 38 would be good for handling but didn't realize it was already at 38 and figured I'd try 36. Okay, so 1psi difference between Toyota and my pressure gauge. No big deal.

I don't know what the setpoint is, but with many TPMS scenarios, one tire can be out low/high by a percent and trip an error or any tire can be below the setpoint and trip an error.
I will air up later to 38 on my gauge which may end up being 37 on the Toyota screen. Curious though what the setpoint is.
With that, after making a pressure change my display is updated unlike OP's showing a communication error of sorts.

OP, have you yet aired up to a higher pressure above 33 to see if you have the sensor triggered.
I had one or 2 tires aired down to around 34 based on my gauge so I could 'add' air to reach my desired PSI.
 

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The "benchmark" pressures, are whatever pressures in the tires, when the initialization procedure was launched.
Based on what you said, the initialization was done incorrectly at delivery: front tires had high pressures > 47 PSI (35 / .75 = 46.7), and rear tires probably had lower pressure close to 35.
To fix all this, set all four tires to 35 PSI, and execute procedure on Page 474 of the manual. In the future, the system will alert when you have lost 25% of benchmark pressure (26 PSI)
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Discussion Starter · #13 ·
I don't know how on-topic this is, however I aired down my tires to 36 psi. Backed it out of the garage and parked it in front of my house in the street. It sat there for several hours. Later in the evening I started the car and backed it up about 25 feet, maybe 2 car lengths. I found the air pressure page on the MID (never go there so forget which subscreen it lives in). It was already giving me an alert, either from backing from the garage to the street which could have been 50' if you count forward and reverse. Of course there was no speed involved either.

The alert shows the 2 front tires in orange stating low tire pressure of 35. Tire pressure was equal for all 4 tires, all reporting 35, however only the front tires were orange. I drove the vehicle twice last night for a long time and on highway (not to clear the tire warning).
So my question is: What is the setpoint for the tire pressure? The door sticker suggests 33psi for the tires. My car came with 40+, it had settled to 38 when I started checking yesterday (this is over 3 months of ownership). I figured 38 would be good for handling but didn't realize it was already at 38 and figured I'd try 36. Okay, so 1psi difference between Toyota and my pressure gauge. No big deal.

I don't know what the setpoint is, but with many TPMS scenarios, one tire can be out low/high by a percent and trip an error or any tire can be below the setpoint and trip an error.
I will air up later to 38 on my gauge which may end up being 37 on the Toyota screen. Curious though what the setpoint is.
With that, after making a pressure change my display is updated unlike OP's showing a communication error of sorts.

OP, have you yet aired up to a higher pressure above 33 to see if you have the sensor triggered.
I had one or 2 tires aired down to around 34 based on my gauge so I could 'add' air to reach my desired PSI.
OP here. No, I followed the directions in the OM and set them all to 33 PSI which the manual said was important to calibrate the tire pressure sensors correctly. Now that I have been told you have to drive forward 100鈥 before they appear on the screen everything is fine and they (the sensors) are reporting the correct tire pressure (double checked with my digital tire pressure gauge). The Toyota APP on my iPhone is showing the correct pressures once more too. The entire procedure was (and is) confusing to me but that is the way they designed it apparently so who am I to question it. Thank you everybody for your help in solving this issue. One thing I did get out of this mess was purchasing a Li-Ion battery powered Craftsman air inflator so there is no more fooling with extension cords or plugging into the 12 volt outlet in the car. I just carry the inflator from tire to tire and that鈥檚 it. No more freezing my butt off trying to adjust pressures as the inflator stops when it reaches my set pressure (33 PSI for the 4 tires and 60 PSI for the spare).
 

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The "benchmark" pressures, are whatever pressures in the tires, when the initialization procedure was launched.
Based on what you said, the initialization was done incorrectly at delivery: front tires had high pressures > 47 PSI (35 / .75 = 46.7), and rear tires probably had lower pressure close to 35.
To fix all this, set all four tires to 35 PSI, and execute procedure on Page 474 of the manual. In the future, the system will alert when you have lost 25% of benchmark pressure (26 PSI)
Interesting, thanks for the info.
I didn't go to the manual as I didn't expect it would list the setpoint (benchmark) value. Nor did I think I'd have to set a benchmark.
I wonder if my values will be cleared when I get in next since I drove it quite a bit last night. I may have driven 30 minutes, it's pretty close if it wasn't.

I guess without knowing what pressure was used during initialization I can't say how far off it is now. I'll check the dash to see if it has self corrected. If not I will air back to 38 and see if it adjusts. It should clear the warning after driving if I return pressure to a value within the 25% tolerance.
Pretty odd that it is just 3 psi lower than what the pressure was before I made adjustments, it may have been right at the teetering point of tripping a warning anyway.
I guess this is good to know now vs having it trip a light on a cold morning at 35 psi. I'd probably assume the system broke if I have 35 psi and threw a light. Dealership may warranty out a sensor and have to break down the tire then I'd have a vibration, blah blah blah. Yeah, slightly exaggerated of course.
 

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OP here. No, I followed the directions in the OM and set them all to 33 PSI which the manual said was important to calibrate the tire pressure sensors correctly. Now that I have been told you have to drive forward 100鈥 before they appear on the screen everything is fine and they (the sensors) are reporting the correct tire pressure (double checked with my digital tire pressure gauge). The Toyota APP on my iPhone is showing the correct pressures once more too. The entire procedure was (and is) confusing to me but that is the way they designed it apparently so who am I to question it. Thank you everybody for your help in solving this issue. One thing I did get out of this mess was purchasing a Li-Ion battery powered Craftsman air inflator so there is no more fooling with extension cords or plugging into the 12 volt outlet in the car. I just carry the inflator from tire to tire and that鈥檚 it. No more freezing my butt off trying to adjust pressures as the inflator stops when it reaches my set pressure (33 PSI for the 4 tires and 60 PSI for the spare).
The only thing I can think of it is allows Toyota to implement one technology to all vehicles allowing the user to set the benchmark vs having a system designed for higher or lower rated vehicles.
I suppose in a truck performing towing duties the operator could set a benchmark before a towing trip at the higher tire pressures they may use. Tripping a warning at 40 psi perhaps if a tire dips lower vs a car tire that never sees high pressures like a tow vehicle.

So I found 2 positive points out of this mess. haha
 

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The only thing I can think of it is allows Toyota to implement one technology to all vehicles allowing the user to set the benchmark vs having a system designed for higher or lower rated vehicles.
I suppose in a truck performing towing duties the operator could set a benchmark before a towing trip at the higher tire pressures they may use. Tripping a warning at 40 psi perhaps if a tire dips lower vs a car tire that never sees high pressures like a tow vehicle.

So I found 2 positive points out of this mess. haha
Another reason for no hard setpoint is that the recommended tire pressure for the SE 18 inch tires is different from the XSE 19 inch tires (33 vs 35). This also allows people to swap to different tires that require different pressures. (i.e. SE owner puts XSE wheels on their car).
 

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Interesting, thanks for the info.
I didn't go to the manual as I didn't expect it would list the setpoint (benchmark) value. Nor did I think I'd have to set a benchmark.
I wonder if my values will be cleared when I get in next since I drove it quite a bit last night. I may have driven 30 minutes, it's pretty close if it wasn't.

I guess without knowing what pressure was used during initialization I can't say how far off it is now. I'll check the dash to see if it has self corrected. If not I will air back to 38 and see if it adjusts. It should clear the warning after driving if I return pressure to a value within the 25% tolerance.
Pretty odd that it is just 3 psi lower than what the pressure was before I made adjustments, it may have been right at the teetering point of tripping a warning anyway.
I guess this is good to know now vs having it trip a light on a cold morning at 35 psi. I'd probably assume the system broke if I have 35 psi and threw a light. Dealership may warranty out a sensor and have to break down the tire then I'd have a vibration, blah blah blah. Yeah, slightly exaggerated of course.
The benchmark pressure will NOT clear, unless you do initialization again.
 

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Right, I get that.
Setting my tire pressure back to 38 (which it was before I lowered it) should clear the warning code as it will be within spec based on the original benchmark. Correct?
Correct but it will not give you much tolerance to keep from tripping the idiot light. It might resurface on a cold day as tires change 1 PSI for every 10 degrees F in ambient temp.

I would just do it right and execute the procedure, which the dealer should have for pre-delivery service but they didn't.
 
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