Tire pressure - 2004 Yamaha YZ 250

The TPS sensor may be dirty or defective...be sure all tires are above 33 psi...

To reset the tire pressure system, do the following:

(NOTE!....Do not reset the check tire pressure system without first
correcting the cause of the problem and checking
and adjusting the pressure in all four tires. If you reset
the system when the tire pressures are incorrect,
the check tire pressure system will not work properly
and may not alert you when a tire is low or high.)

1. With the engine off, turn the ignition to ON.
2. Press the MODE button until the DIC reads LOW
TIRE PRESSURE HOLD SET TO RESET.
3. Press and hold the SET button until you hear a
chime, and TIRE PRESSURE RESET is displayed.

You will hear three chimes, then the LOW TIRE
PRESSURE message will go off and the DIC will return
to TIRE PRESSURE NORMAL. If the LOW TIRE
PRESSURE message comes back on, the check tire
pressure system has not reset. Repeat the procedure.
The system completes the calibration process during
driving. The system learns the pressure at each tire
throughout the operating speed range of your vehicle.
The system normally takes between 30 and 60 minutes of
driving to learn the tire pressures. The system normally
takes 10 to 20 minutes of driving in each speed range to
learn tire pressures. The speed ranges are 20 to 40 mph
(32 to 64 km/h), 40 to 60 mph (64 to 96 km/h), and above
60 mph (96 km/h). This time may be longer depending on
your individual driving habits. The learning process does
not need to be completed during a single trip. Once
learned, the system will remember the tire pressure until
the system is reset.

I found this on another site, it may help to understand what is happening, I also saw that there is a problem with the valve stems cracking since they're made out of aluminum and causing that problem. Here's the explanation provided on another site:

RodneyJ Answered 6 years ago
If a customer with a 2005 or later DaimlerChrysler vehicle equipped with Tire Pressure Monitoring (TPM) is concerned that the TPM lamp is on continuously, please be sure to inform the customer that the system is in place to warn of a low tire pressure situation, and a system diagnosis may not be required. The customer should be aware of the following: The Tire Pressure Monitoring (TPM) System will warn the driver of a low tire pressure based on the vehicle recommended cold placard pressure (the placard is located on the drivers side B-pillar).
The tire pressure will vary with temperature by about 6.9 kPa (1 psi) for every 6.5 Degrees C (12 Degrees F). This means that when the outside temperature decreases, the tire pressure will decrease - the customer should adjust his tire pressure for this decrease in pressure - please refer the customer to his vehicle owner's manual for information on how to properly inflate his vehicle's tires. The tire pressure will also increase as the vehicle is driven - this is normal and there should be no adjustment for this increased pressure.
The TPM System will warn the driver of a low tire pressure if the tire pressure falls below the low pressure warning threshold for any reason, including low temperature effects.
The TPM System will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off until the tire pressure is at or above recommended cold placard pressure. Once the low tire pressure warning has been illuminated, the tire pressure must be increased to the recommended cold placard pressure in order for the TPM warning lamp to be turned off. The system will automatically update and the TPM warning lamp will extinguish once the updated tire pressures have been received. The vehicle may need to be driven for up to 10 minutes above 25 kph (15 mph) to receive this information.


FOR EXAMPLE:

A 2006 300 has a recommended cold (parked for more than 3 hours) placard of 207 kPa (30 psi).

If the ambient temperature is 18 Degrees C (65 Degrees F) and the measured tire pressure is 186 kPa (27 psi) the TPM lamp will be OFF.

IF NOTHING IS DONE TO THE AIR PRESSURE IN THE TIRES and the ambient temperature drops to 20 Degrees F (-7 Degrees C) while the vehicle is parked, the approximate tire pressure will be 157 kPa (23 psi) and the TPM lamp will be ON.

IF THE VEHICLE IS DRIVEN TO REACH NORMAL OPERATING TEMPERATURE

WITHOUT ADJUSTING THE AIR PRESSURE and the ambient temperature stays at -7 Degrees C (20 Degrees F), the approximate tire pressure will rise to 186 kPa (27 psi) and the 1PM lamp will be ON.

To turn the TPM lamp OFF the tires must be inflated to the vehicle recommended cold placard pressure.

In order to properly maintain vehicle tire pressure, please refer to the owner's manual for additional information regarding tire inflation.

NOTE :Tire pressure should always be set based on cold inflation tire pressure (defined as the tire pressure after a vehicle has not been driven for more than 3 hours - and in outside ambient temperature).

Seasonal temperature changes will affect tire pressure, and the TPM system will monitor the actual tire pressure in the tire.
If a diagnosis of the system is required (for example, the lamp did not extinguish, or the lamp is flashing), please refer to service information available in TechCONNECT for additional information for TPM diagnosis. Please be aware that if the Wireless Control Module (WCM) is replaced, the TPM placard values may need to be reprogrammed. The TPM placard values do NOT need to be updated if the WCM has NOT been replaced, the TPM placard values are properly set at the factory.

That signal is from your tire monitoring sensors, telling you that there is air pressure difference between tires. The tire pressure should be same in all tires.

This (!) symbol is your TIRE PRESSURE MONITORING SYSTEM (TPMS) warning light.
The manual has this to say about it:
This system monitors tire pressure. if the low tire pressure warning light illuminates, check the tire pressure in all four tires. Adjust the low tire pressure to the recommended cold tire pressure shown on the Tire and Loading information label located in the driver's door opening. After tire pressures are adjusted, the vehicle will need to be driven at speeds above 16 MPH (25 km/h) to activate the TPMS and turn off the low tire pressure warning light.

TIRE PRESSURE MONITOR SYSTEM
The Tire Pressure Monitor System (TPMS) uses radio and sensor technology to check tire pressure levels. If your vehicle has this feature, sensors are mounted on each tire and wheel assembly, except the spare tire. The TPMS sensors monitor the air pressure in your vehicle's tires and transmit tire pressure readings to a receiver located in the vehicle.

The TPMS is designed to alert the driver, if a low tire pressure condition exists. This system also allows the driver to check tire pressure levels using the Driver Information Center (DIC).

When a low tire pressure condition is detected, the TPMS displays the "CHECK TIRE PRESSURE" warning message on the DIC, and at the same time illuminates the low tire pressure warning symbol.

You may notice, during cooler weather conditions, that the tire pressure monitor light, located on the instrument panel cluster, and the "CHECK TIRE PRESSURE" message will appear when the vehicle is first started and then turn off as you start to drive the vehicle. This could be an early indicator that the tire pressures are getting low and need to be inflated to the proper pressure.

Each tire, including the spare (if provided), should be checked monthly when cold and inflated to the inflation pressure recommended by the vehicle manufacturer on the vehicle placard or tire inflation pressure label. (If your vehicle has tires of a different size than the size indicated on the vehicle placard or tire inflation pressure label, you should determine the proper inflation pressure for those tires.)

As an added safety feature, your vehicle has been equipped with a tire pressure monitoring system (TPMS) that illuminates a low tire pressure telltale when one or more of your tires is significantly under-inflated.

Accordingly, when the low tire pressure telltale illuminates, you should stop and check your tires as soon as possible, and inflate them to the proper pressure. Driving on a significantly under-inflated tire causes the tire to overheat and can lead to tire failure. Under-inflation also reduces fuel efficiency and tire tread life, and may affect the vehicle's handling and stopping ability.

Please note that the TPMS is not a substitute for proper tire maintenance, and it is the driver's responsibility to maintain correct tire pressure, even if under-inflation has not reached the level to trigger illumination of the TPMS low tire pressure telltale.

The "CHECK TIRE PRESSURE" warning message and low tire pressure light (telltale) will appear at each ignition cycle until the tires are inflated to the correct inflation pressure.

The Tire and Loading Information label (tire information placard) shows the size of your vehicle's original tires and the correct inflation pressure for your vehicle's tires when they are cold.

Your vehicle's TPMS can alert you about a low tire pressure condition but it does not replace normal tire maintenance.

NOTICE: Do not use a tire sealant if your vehicle has Tire Pressure Monitors. The liquid sealant can damage the tire pressure monitor sensors.

RESETTING THE TPMS IDENTIFICATION CODES
Each TPMS sensor has a unique identification code. Any time you rotate your vehicle's tires or replace one or more of the TPMS sensors, the identification codes will need to be matched to the new tire/wheel position. Each tire/wheel position is matched to a sensor, by increasing or decreasing the tire's air pressure. The sensors are matched to the tire/wheel positions in the following order: LF TIRE (left front tire on the driver's side of the vehicle), RF TIRE (right front tire on the passengers side of the vehicle), RR TIRE (right rear tire on the passengers side of the vehicle), and LR TIRE (left rear tire on the driver's side of the vehicle).

You will have one minute to match the first tire/wheel position, and five minutes overall to match all four tire/wheel positions. If it takes longer than one minute, to match the first tire and wheel, or more than five minutes to match all four tire and wheel positions the matching process stops and you will need to start over.

The TPMS sensor matching process is outlined below:

1. Set the parking brake.
2. Turn the ignition switch to "RUN" with the engine off.
3. Turn the headlamp switch from "OFF" to the parking lamps setting four times within three seconds. A double horn chirp will sound and the TPMS low tire warning light will begin to flash. The double horn chirp and flashing TPMS warning light indicate that the TPMS matching process has started. The TPMS warning light should continue flashing throughout the matching procedure. The "SERVICE TIRE MONITOR" message will be displayed on the Driver Information Center (DIC).
4. Start with the driver's side front tire.
5. Remove the valve cap from the valve cap stem. Activate the TPMS sensor by increasing or decreasing the tire's air pressure for 10 seconds, then stop and listen for a single horn chirp. The single horn chirp should sound within 15 seconds, confirming that the sensor identification code has been matched to this tire and wheel position. If you do not hear the confirming single horn chirp, you will need to start over with Step 1. To let air-pressure out of a tire you can use the pointed end of the valve cap, a pencil-style air pressure gage or a key.
6. Proceed to the passenger's side front tire, and repeat the procedure in Step 5.
7. Proceed to the passenger's side rear tire, and repeat the procedure in Step 5.
8. Proceed to the driver's side rear tire, and repeat the procedure in Step 5.
9. After hearing the confirming horn chirp for the left rear tire, check to see if the TPMS warning light is still flashing. If it is, turn the ignition switch to LOCK to exit the sensor matching process. If the TPMS warning light is not flashing, the five minute time limit has passed and you will need to start the process over beginning with Step 1.
10. Set all four tires to the recommended air pressure level as indicated on the Tire and Loading Information label.
11. Put the valve caps back on the valve stems. The spare tire does not have a TPMS sensor. If you replace one of the road tires with the spare, the "CHECK TIRE PRESSURE" message will be displayed on the DIC screen. This message should go off once you re-install the road tire containing the TPMS sensor. The "SERVICE TIRE MONITOR" message is displayed when the TPMS is malfunctioning. One or more missing or inoperable TPMS sensors will cause the service tire monitor message to be displayed.

It either has Tire Pressure Monitor (TPM), or Flat Tire Monitor (FTM)

TPM:Checks the tire inflation pressure in the four mounted tires. The system indicates if the tire inflation pressure has dropped considerably in one or several tires.

FTM:Keeps track of the inflation pressures in the four mounted tires as you drive. The system triggers an alert whenever the inflation pressure drops significantly in relation to the pressure in another tire.

Seance the car manufactures most likely did not produce the tires that are on the vehicle they will only give there recommendations as to the correct tire pressure. Always look around the perimeter of the tire and it will tell you the proper pressure for that tire. hope this helps. Good luck.

You'll get a lot of opinions on what tire pressure to run but the correct tire pressure for you is not a matter of polling other rider's opinion. Here are the basics you'll need to decide for yourself. Start with the BIKE (not the tire *see below) manufacturer's recommendation in the owners manual or under-seat sticker. This is the number they consider to be the best balance between handling grip and tire wear. Further if you're running alloy wheels on poor pavement, consider adding 2 psi to the recommended tire pressure just to reduce the likelihood of pothole damage. Just as you would for a car, increase the pressure 2 psi or so for sustained high speed operation (or 2-up riding) to reduce rolling friction and casing flexing. Check your tire pressure regularly, as they say. In order to get optimum handling a tire has to get to its optimum temperature which is different for each brand of tire. Unless you own a tire pyrometer that will measure tire temperature directly, you’ll need to measure it indirectly by checking tire pressure since tire pressure increases with tire temperature. Tire temperature is important to know because too much flexing of the casing of an under-inflated tire for a given riding style and road will result in overheating resulting in less than optimum grip. Over-pressurizing a tire will reduce casing flexing and prevent the tire from getting up to the optimum operating temperature and performance again suffers. Sliding and spinning the tires also increase tire temperatures from friction heating. A technique for those wanting to get the most out of their tires on the street is to use the 10/20% rule. First check the tire pressure when the tire is cold. Then take a ride on your favorite twisty piece of road. Then, measure the tire pressure immediately after stopping. If the pressure has risen less than 10% on the front or 20% on the rear, the rider should remove air from the tire. So for example, starting at a front tire pressure of 32.5 psi should bring you up to 36 psi hot. Once you obtain this pressure increase for a given rider, bike, tire, road and road temperature combination, check the tire pressure again while cold and record it for future reference. Each manufacturer is different. Each tire model is different. A tire design that runs cooler needs to run a lower pressure (2-3 psi front) to get up to optimum temperature. The rear tire runs hotter than the front tire, road and track. So the rear tire cold-to-hot increase is greater. Dropping air pressure has the additional side effect of scrubbing more rubber area. When I used the tire pressures recommended by Ducati (32.5F/36R) for my 916 on my favorite road, I got exactly 10/20% on a set of Bridgestone BT-012SS. So I guess I'm an average rider and the BT-012SS runs at an average operating temperature compared to other brands. For the track you'll have to drop the cold tire pressures an additional 10/20%. Track operation will get tires hotter (increasing the cold-to-hot pressure range) so starting at say 32/30 psi now should bring you up to the same temperature (and pressure) that 35/39 psi gave you for the street. Don't even think about running these low track cold pressures on the street. Finally, dropping tire pressures on street tires for track use has its limitations, so street compound tires on the track often get too hot and go beyond sticky to greasy. That's why you have race tires. Race tire compounds are designed for severe operation at these higher temperatures for a limited number of thermal cycles. On the other hand, a race tire on the street usually won't get up to the appropriate temperature for good performance. At street speeds, the race compound often won't perform as well as a street tire. Finally, a tire that is inflated to a lower pressure than recommended will have a tire profile that will sag slightly in the middle. This sagging profile results in increased rolling friction and causes the tires to run hotter. This will reduce tire life but it will also increase tire traction or grip. Depending upon racing conditions and the overall setup of the bike the increased grip may be necessary to be competitive even at the cost of tire life. * Tire Manufacturer's Recommendations Japanese sportbikes seem to have an extra 4-6 psi specified for their tires, compared to the equivalent Ducati. Why? A tire manufacturer will recommend a pressure that is a balance between tire life and grip. When a bike manufacturer is developing a new model their test riders will determine what pressures in their opinion, best suit the new model. The recommended pressures are the best for general street (not track) riding, so you can increase grip somewhat by reducing pressures. But to answer the question about higher recommended tire pressures for Japanese in-line fours versus Ducati twins - in-line fours heat up their tires more than a twin so a higher starting pressure is needed to prevent overheating the tires, particularly the rear tire. Years ago, superbike racers discovered that it was easier to modulate the power to prevent wheelspin on the Ducati V-twins than it was to do the same on the Japanese inline-fours. This is because there is a longer interval (in terms of both time and crankshaft rotation) between cylinders firing, which gives the rear tire a break - time to recover traction and match its speed to that of the motorcycle. More recently, more sophisticated traction control systems have been tried to reduce tire temperatures, improve tire life and lap times,,,

You'll get a lot of opinions on what tire pressure to run but the correct tire pressure for you is not a matter of polling other rider's opinion. Here are the basics you'll need to decide for yourself. Start with the BIKE (not the tire *see below) manufacturer's recommendation in the owners manual or under-seat sticker. This is the number they consider to be the best balance between handling grip and tire wear. Further if you're running alloy wheels on poor pavement, consider adding 2 psi to the recommended tire pressure just to reduce the likelihood of pothole damage. Just as you would for a car, increase the pressure 2 psi or so for sustained high speed operation (or 2-up riding) to reduce rolling friction and casing flexing. Check your tire pressure regularly, as they say. In order to get optimum handling a tire has to get to its optimum temperature which is different for each brand of tire. Unless you own a tire pyrometer that will measure tire temperature directly, you’ll need to measure it indirectly by checking tire pressure since tire pressure increases with tire temperature. Tire temperature is important to know because too much flexing of the casing of an under-inflated tire for a given riding style and road will result in overheating resulting in less than optimum grip. Over-pressurizing a tire will reduce casing flexing and prevent the tire from getting up to the optimum operating temperature and performance again suffers. Sliding and spinning the tires also increase tire temperatures from friction heating. A technique for those wanting to get the most out of their tires on the street is to use the 10/20% rule. First check the tire pressure when the tire is cold. Then take a ride on your favorite twisty piece of road. Then, measure the tire pressure immediately after stopping. If the pressure has risen less than 10% on the front or 20% on the rear, the rider should remove air from the tire. So for example, starting at a front tire pressure of 32.5 psi should bring you up to 36 psi hot. Once you obtain this pressure increase for a given rider, bike, tire, road and road temperature combination, check the tire pressure again while cold and record it for future reference. Each manufacturer is different. Each tire model is different. A tire design that runs cooler needs to run a lower pressure (2-3 psi front) to get up to optimum temperature. The rear tire runs hotter than the front tire, road and track. So the rear tire cold-to-hot increase is greater. Dropping air pressure has the additional side effect of scrubbing more rubber area. When I used the tire pressures recommended by Ducati (32.5F/36R) for my 916 on my favorite road, I got exactly 10/20% on a set of Bridgestone BT-012SS. So I guess I'm an average rider and the BT-012SS runs at an average operating temperature compared to other brands. For the track you'll have to drop the cold tire pressures an additional 10/20%. Track operation will get tires hotter (increasing the cold-to-hot pressure range) so starting at say 32/30 psi now should bring you up to the same temperature (and pressure) that 35/39 psi gave you for the street. Don't even think about running these low track cold pressures on the street. Finally, dropping tire pressures on street tires for track use has its limitations, so street compound tires on the track often get too hot and go beyond sticky to greasy. That's why you have race tires. Race tire compounds are designed for severe operation at these higher temperatures for a limited number of thermal cycles. On the other hand, a race tire on the street usually won't get up to the appropriate temperature for good performance. At street speeds, the race compound often won't perform as well as a street tire. Finally, a tire that is inflated to a lower pressure than recommended will have a tire profile that will sag slightly in the middle. This sagging profile results in increased rolling friction and causes the tires to run hotter. This will reduce tire life but it will also increase tire traction or grip. Depending upon racing conditions and the overall setup of the bike the increased grip may be necessary to be competitive even at the cost of tire life. * Tire Manufacturer's Recommendations Japanese sportbikes seem to have an extra 4-6 psi specified for their tires, compared to the equivalent Ducati. Why? A tire manufacturer will recommend a pressure that is a balance between tire life and grip. When a bike manufacturer is developing a new model their test riders will determine what pressures in their opinion, best suit the new model. The recommended pressures are the best for general street (not track) riding, so you can increase grip somewhat by reducing pressures. But to answer the question about higher recommended tire pressures for Japanese in-line fours versus Ducati twins - in-line fours heat up their tires more than a twin so a higher starting pressure is needed to prevent overheating the tires, particularly the rear tire. Years ago, superbike racers discovered that it was easier to modulate the power to prevent wheelspin on the Ducati V-twins than it was to do the same on the Japanese inline-fours. This is because there is a longer interval (in terms of both time and crankshaft rotation) between cylinders firing, which gives the rear tire a break - time to recover traction and match its speed to that of the motorcycle. More recently, more sophisticated traction control systems have been tried to reduce tire temperatures, improve tire life and lap times,,,