Toyota tire pressure monitoring system how it works (TPMS)

A tire pressure monitoring system is designed to alert the driver of low tire pressure. If, while driving, a pressure drop in one of the wheels is detected, the corresponding indicator lights up on the instrument cluster, indicating the need for immediate pressure adjustment.

Toyota tire pressure monitoring system how it works (TPMS)

tire pressure monitoring system (TPMS) how it works?

The tire pressure monitoring system (TPMS – Tire Pressure Monitoring System), used on Toyotas, belongs to the “indirect” action schemes and functions as part of ABS, which is able to perceive a constant difference in wheel speed (a flat tire has a smaller rolling radius and so it rotates a little faster).

But such a TPMS cannot simply compare the speed of one individual wheel with the rest, since the car does not move in an absolutely straight line very often, in any corner, the outer wheels will always travel more than the inner ones, and the front wheels more than the rear ones. Therefore, a conventional control system adds the speeds of each two diagonal wheels, calculates the difference between these sums, and divides it by the average speed of all four wheels. If the obtained ratio differs from the set one, then the system diagnoses the change in pressure, but it cannot identify a specific tire.

The disadvantages of this scheme are:

  • impossibility to determine a sharp drop in pressure;
  • the inability to determine simultaneously the pressure drop even in two wheels located on the same side or the same axle, not to mention all four wheels;
  • the dependence of the system performance on the degree of wheel slip, the condition of the rubber, and the vehicle load;
  • actuation in case of pressure drop not less than 25-30%;
  • the need for long-term calibration (pre-setting).

In this regard, Toyota used in parallel a second method of pressure control using ABS. The fact is that the tire and the rim actually represent an oscillatory circuit, the characteristics of which directly depend on the elasticity of the tire, and hence the pressure in it (meaning the circular vibrations of the tire in the direction of rotation). It turned out to be possible to isolate the frequency of these oscillations from the signal of the wheel speed sensor, and to judge the pressure drop by its change.

Nevertheless, TPMS is notable for its noticeable inertia – in order to detect a flat tire, you need to drive a considerable distance (sometimes up to 20-30 km), you will have to go a long way after normalizing the pressure so that the indicator goes out.

Here is a guide on Tire Weight By Size.

tire pressure monitoring system Development

The introduction of this system by Toyota began in the second half of the 90s. As you can see, it was used mainly on models of the Corolla family and large rear-wheel drive cars, ranging from class E and above.
But it seems that the Japanese cooled off quite quickly to this scheme, so today they have abandoned its use on most models, including the Corolla 120 of the later years of production.

ModelSeriesRelease Year
CorollaAE100, AE104, CE10104.1998-08.2000
Corolla/SprinterAE110, AE114, CE11#, EE11104.1998-08.2000
Sprinter CaribAE11#04.1998-07.2002
Corolla Levin/Sprinter TruenoAE11#04.1998-08.2000
Corolla SpacioAE11#04.1998-05.2001
Corolla / Corolla FielderCE121, NZE12#, ZZE122, ZZZE12408.2000-
Corolla Runx/Corolla AllexNZE12#, ZZE122, ZZE12401.2001-
Corolla SpacioNZE121,ZZE12#05.2001-
Mark IIJZX10109.1996-08.1998
Mark IIJZX100, JZX10108.1998-10.2000
Mark II / Mark II BlitJZX11010.2000-
Chaser / CrestaJZX10109.1996-08.1998
Chaser / CrestaJZX100, JZX10108.1998-06.2001
Crown / Crown MajestaJKS175, JZS171, JZS175, JZS177, UZS171, UZS17509.1999-2005

Tire Pressure Monitoring System Indicators

Tire Pressure Monitoring System Indicators

There are at least two options for indicators on the instrument cluster – ISO K11 and K10. The most famous of them, of course, is the first one – the “horseshoe with arrows”. By the way, in the Western world with these indicators there is a similar problem – “what kind of light bulb is this?” – according to surveys, most of the drivers there do not understand their meaning.

A working indicator should light up when the ignition is turned on and go out after 3 seconds. If the system has detected a drop in tire pressure, then in order for the indicator to go out, after normalizing the pressure, it is necessary to drive a certain distance at a speed of at least 30 km / h. The indicator is powered directly from the output of the ABS control unit.

The principles laid down in the system allow for the possibility of its incorrect operation (the indicator does not light up at low tire pressure or, conversely, it lights up at normal pressure) under the following conditions:

  • tires of non-recommended size are used,
  • tires of different sizes or models are installed on different wheels,
  • wheels have a different grip on the road,
  • a spare wheel
  • is used, – wheels with snow chains are used,
  • the tire pressure is significantly higher than the nominal one,
  • the tire pressure has sharply decreased due to a puncture,
  • the system has not been pre-adjusted,
  • the vehicle is moving on rough or icy roads
  • the vehicle is moving at a speed below 30 km/h,
  • for short trips (up to 5 minutes).

If the indicator stays on at normal pressure and in the absence of these conditions, this may indicate a malfunction of the TPMS itself.

tire pressure monitoring system TPMS settings

The adjustment must be made after any work related to the replacement of wheels and tires (disks), otherwise, the system will not be able to function normally. The adjustment procedure is shown below (preliminary pressure in all four wheels must be correctly adjusted).

Type 1  – models without setting button and with DLC1 connector (early version)

  • 1) Turn on the ignition.
  • 2) Connect the terminals “TS” and “E1” of the diagnostic connector DLC1 under the hood.
  • 3) After 30 seconds, depress and hold the brake pedal until the system indicator flashes 3 times at 2-second intervals.

Type 2  – models with installation button and with DLC1 connector (transitional version)

Note. The installation buttons have several design options – with a pictogram, with an inscription or nothing at all, but differ in their characteristic shape and location – at the bottom of the instrument panel on the driver’s side.

  • 1) Turn on the ignition (the car must be stationary).
  • 2) Connect the terminals “TS” and “E1” of the diagnostic connector DLC1 under the hood.
  • 3) Press and hold the setting button until the system indicator blinks 3 times.
  • 4) After that, in order for the system to save the correct settings, it is necessary to drive a certain distance.

Type 3  – models with setting button and without DLC1 connector (late version)

  • 1) Turn on the ignition (the car must be stationary).
  • 2) Press and hold the setting button until the system indicator blinks 3 times.
  • 3) After that, in order for the system to save the correct settings, it is necessary to drive a certain distance.

tire pressure monitoring system reset

The pressure control system, although it operates as part of the ABS, also provides its own small self-diagnosis. Codes on those models where the DLC1 connector was still used are read in the standard Toyota way by the number of indicator flashes when the ignition is on and the “TC” and “E1” terminals are closed. Deleting codes is done in the same way as deleting ABS codes.

  • 21  – Intake air temperature sensor (open/short)
  • 31  – Speed ​​sensor (fault)
  • 42  – Stop light switch (fault)
  • 49  – Stop light switch (open or short)

It would seem, where does the temperature sensor and brake lights? In fact, the ABS control unit uses ambient temperature data to calculate its effect on tire pressure, and as for brake lights, when the brake is pressed, the system stops monitoring pressure.

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