Toyota Prius is equipped with Tire Pressure Monitoring System (TPMS) for the purpose of warning the driver when one or more of the tires are significantly under-inflated, creating a potentially unsafe driving condition. In this article we discuss the reasons for the amber colored TPMS warning light in Prius, and how you can reset it.
The TPMS warning light illuminates in Toyota Prius when air pressure is low in one or more of the tires, battery has depleted in a pressure sensor, TPMS receiver module has malfunctioned, or a pressure sensor has been damaged.
Low tire pressure
When the amber colored TPMS warning light turns on in your Prius, stop your vehicle when it is safe to do so and check tire pressure on all the wheels, including the spare wheel (if your vehicle has one). Driving on a significantly under-inflated tire causes the tire to overheat and can lead to tire failure.
Reinflate the tires
Reinflate all the tires of your Prius to the manufacturer specified air pressure, which is mentioned on the vehicle placard or tire inflation pressure label usually located on the B-pillar or the edge of the driver door. If you can’t find the label, check the size of your tire which is mentioned on the sidewall of the tire, and match it to the tire pressure information shown below. These are official cold tire pressure values for Prius from Toyota.
- 195/65R15 91S: Front: 36 psi, Rear: 35 psi
- 195/65R15 91S (ZVW51L-AHXBBA model only): Front: 39 psi, Rear: 36 psi
- P215/45R17 87V: Front: 33 psi, Rear: 32 psi
- T125/70D17 98M (spare): 60 psi
- 195/65R15 91H: 32 psi all tires
Resetting the TPMS warning light
After you have inflated all the tires to the correct air pressure, the TPMS warning light should turn off automatically after driving for a few miles. Toyota Prius uses the direct method for monitoring tire pressure, which means a pressure sensor actively records the internal pressure of the tire on each wheel. If the warning light doesn’t turn off you should perform a reset procedure.
The tire pressure warning system must be initialized when the tire inflation pressure is changed such as when changing travelling speed or load weight.
When the tire pressure warning system is initialized, the current tire inflation pressure is set as the benchmark pressure.
TPMS reset procedure for Toyota Prius
- Park the vehicle in a safe place and turn the power switch off.
Note: Initialization cannot be performed while the vehicle is moving.
- Adjust the tire inflation pressure to the specified cold tire inflation pressure level.
Note: Make sure to adjust the tire pressure to the specified cold tire inflation pressure level. The tire pressure warning system will operate based on this pressure level.
- Turn the power switch to ON mode.
- Navigate to the settings tab in the multi-information display using the steering wheel controls.
- Select the vehicle settings icon , and then press confirmation button.
- Select “Maintenance System”.
- Select “TPMS”, then press and hold the confirmation button on the steering wheel.
- When initialization completes, a message is displayed on the multi-information display and the tire pressure warning light illuminates.
WARNING: Do not initialize the tire pressure warning system without first adjusting the tire inflation pressure to the specified level. Otherwise, the tire pressure warning light may not come on even if the tire inflation pressure is low, or it may come on when the tire inflation pressure is actually normal.
If the low tire pressure light does not turn off automatically after reinflating the tires in your Prius, increase the tire pressure by 5 psi on top of the factory recommended value, and drive your vehicle for at least 10 miles (16 km). After the TPMS warning light turns off, and the vehicle has been parked for a few hours, reduce the tire pressure to the factory recommended value.
To ensure the tire pressure warning system operates properly, do not install tires with different specifications or makers, as the tire pressure warning system may not operate properly
Chilly weather can turn on low tire pressure light in Prius
Cold weather is one of the most common cause for low tire pressure warning light in Toyota Prius. When analyzing WheelsJoint’s statistical data, it has been observed that there is sharp rise in the number of searches for TPMS warning light causes at the start of every winter season, about three times higher as compared to mid summer season.
The air, like most other substances, expands when heated and contracts when cooled. So when the weather gets colder, the tire pressure decreases, which could trigger TPMS warning light in Prius. The tire pressure will vary with temperature by about 1 psi (7 kPa) for every 12°F (6.5°C).
Inflate tires when cold
Tire pressure in Prius should always be set based on cold inflation tire pressure. This is defined as the tire pressure after the vehicle has not been driven for at least three hours, or driven less than 1 mile (1.6 km) after a three-hour period.
Do not adjust tire pressure when hot
The tires on your Prius can get around 50 degrees hotter than the outside temperature when you’re driving, which increases the tire pressure by about 4 psi – this is normal and there should be no adjustment for this increased pressure.
Does altitude affect tire pressure?
Yes, altitude can change tire pressure values, but it is negligible and not a cause for concern. If you drive your Prius from sea level to Mount Evans Scenic Byway in Colorado which is the highest paved road in North America at the altitude of 14,130 feet (4,307 m), the tire pressure should theoretically increase by approximately 6 psi. But, the decrease in ambient temperature at higher elevation contracts the air in tires and compensates for any altitude pressure changes.
Is it safe to drive Prius with low tire pressure?
The driving characteristics of Prius change even if the air pressure is 5 psi less than manufacturer’s recommended value: the braking distance can be longer, cornering worse, and at particularly high speeds there is even a risk that the tire will burst. Low tire pressure also increases tire wear, and the higher rolling resistance of the tire means higher fuel consumption. So it is recommended to reinflate the tires to the correct pressure as soon as possible.
Dead battery in a tire pressure sensor
Each tire pressure sensor in Prius is powered by a built-in lithium-ion battery. When the battery is depleted, the sensor stops transmitting tire pressure information to the receiver module. When this happens, the TPMS warning light will flash every time the engine is started, and will remain illuminated until you turn off the vehicle.
How long do the pressure sensor batteries last?
The tire pressure sensor batteries usually last anywhere from 5 to 10 years in Prius. When the battery is depleted, you must replace the sensor itself, as the battery is sealed into the sensor unit and is non-replaceable.
Identifying a faulty pressure sensor
The most reliable method for detecting a faulty tire pressure sensor or a sensor with dead battery is by testing each sensor with a scan tool. For example, MaxiTPMS TS408 is commonly used for diagnosing and programming tire pressure sensors. A sensor that is not detectable by the scanner is most likely defective and should be replaced with a new one.
If you don’t want to spend over a hundred bucks on a scanner, then head over to any reputable tire shop and perform a TPMS diagnostic scan of your Prius. Some shops like Discount Tire and Pep Boys offer free of charge TPMS diagnostic services.
Installed new tires?
If a pressure sensor stopped responding after you installed new tires on your Prius, it is possible the sensor got damaged during tire installation. These sensors are quite sensitive, and can be easily damaged if utmost care is not taken while changing tires.
Toyota Prius TPMS user guide
Your vehicle is equipped with a tire pressure warning system that uses tire pressure warning valves and transmitters to detect low tire inflation pressure before serious problems arise.
If the tire pressure drops below a predetermined level, the driver is warned by a warning light.
The compact spare tire is not equipped with a tire pressure warning valve and transmitter.
Installing tire pressure warning valves and transmitters
When replacing tires or wheels, tire pressure warning valves and transmitters must also be installed. When new tire pressure warning valves and transmitters are installed, new ID codes must be registered in the tire pressure warning computer and the tire pressure warning system must be initialized. Have tire pressure warning valve and transmitter ID codes registered by your Toyota dealer.
Registering ID codes
The tire pressure warning valve and transmitter is equipped with a unique ID code. When replacing a tire pressure warning valve and transmitter, it is necessary to register the ID code. Have the ID code registered by your Toyota dealer.
Replacing tires and wheels
If the ID code of the tire pressure warning valve and transmitter is not registered, the tire pressure warning system will not work properly. After driving for about 20 minutes, the tire pressure warning light blinks for 1 minute and stays on to indicate a system malfunction.
Situations in which the tire pressure warning system may not operate properly
In the following cases, the tire pressure warning system may not operate properly.
- If non-genuine Toyota wheels are used.
- When a replacement tire is used, the system may not operate correctly due to the structure of the replacement tire.
- A tire has been replaced with a tire that is not of the specified size.
- Tire chains etc. are equipped.
- An auxiliary-supported run-flat tire is equipped.
- If a window tint that affects the radio wave signals is installed.
- If there is a lot of snow or ice on the vehicle, particularly around the wheels or wheel housings.
- If the tire inflation pressure is extremely higher than the specified level.
- If wheel without the tire pressure warning valve and transmitter is used.
- If the ID code on the tire pressure warning valves and transmitters is not registered in the tire pressure warning computer.
Performance may be affected in the following situations.
- Near a TV tower, electric power plant, gas station, radio station, large display, airport or other facility that generates strong radio waves or electrical noise.
- When carrying a portable radio, cellular phone, cordless phone or other wireless communication device.
When the vehicle is parked, the time taken for the warning to start or go off could be extended.
When tire inflation pressure declines rapidly for example when a tire has burst, the warning may not function.
TPMS reset guidelines
- Make sure to carry out initialization after adjusting the tire inflation pressure. Also, make sure the tires are cold before carrying out initialization or tire inflation pressure adjustment.
- If you have accidentally turned the power switch off during initialization, it is not necessary to press the reset switch again as initialization will restart automatically when the power switch has been turned to ON mode for the next time.
- If you accidentally press the reset switch when initialization is not necessary, adjust the tire inflation pressure to the specified level when the tires are cold, and conduct initialization again.
When initialization of the tire pressure warning system has failed
Initialization can be completed in a few minutes. However, in the following cases, the settings have not been recorded and the system will not operate properly. If repeated attempts to record tire inflation pressure settings are unsuccessful, have the vehicle inspected by your Toyota dealer.
- When operating the initialization of the system, the tire pressure warning light does not flash 3 times and the setting message does not appear on the multi-information display.
- After driving for a certain period of time since the initialization has been completed, the warning light comes on after blinking for 1 minute.
Repairing or replacing tires, wheels, tire pressure warning valves, transmitters and tire valve caps
- When removing or fitting the wheels, tires or the tire pressure warning valves and transmitters, contact your Toyota dealer as the tire pressure warning valves and transmitters may be damaged if not handled correctly.
- Make sure to install the tire valve caps. If the tire valve caps are not installed, water could enter the tire pressure warning valves and the tire pressure warning valves could be bound.
- When replacing tire valve caps, do not use tire valve caps other than those specified. The cap may become stuck.
To avoid damage to the tire pressure warning valves and transmitters
When a tire is repaired with liquid sealants, the tire pressure warning valve and transmitter may not operate properly. If a liquid sealant is used, contact your Toyota dealer or other qualified service shop as soon as possible. After use of liquid sealant, make sure to replace the tire pressure warning valve and transmitter when repairing or replacing the tire.
Replacing tire pressure warning valves and transmitters
Because tire repair or replacement may affect the tire pressure warning valves and transmitters, make sure to have tires serviced by your Toyota dealer or other qualified service shop. In addition, make sure to purchase your tire pressure warning valves and transmitters at your Toyota dealer. Ensure that only genuine Toyota wheels are used on your vehicle. Tire pressure warning valves and transmitters may not work properly with non-genuine wheels.
Tire pressure keeps getting low
If the TPMS warning light turns on frequently in your Prius, and the tire pressure is also decreasing after you have reinflated the tires, there may be an air leak. One or more of the tires may have been punctured by an external object, or the air may be leaking from a defective value stem.
Can I disable the TPMS system in Prius?
No, the TPMS system is federally mandated, and cannot be disabled in Toyota Prius. All vehicles must have a working tire pressure monitoring system to be legally compliant.
Use OBD2 scanner for diagnosis
Since Toyota Prius is equipped with on-board diagnostics (OBD), a fault diagnosis can provide initial indications of where the malfunction is located. But when it comes to TPMS, a basic code reader will not suffice. You will need an advanced scanner to monitor TPMS data or read TPMS codes.
BlueDriver is a commonly used scanner by DIYers that can read TPMS codes for most vehicles and isn’t too expensive – costs about a hundred bucks. You can also clear the TPMS fault codes with this device which will turn off the warning light, but the light may come back on if the on-board diagnostic system detects a fault again.