胎压监测(Tire pressure Monitoring) en

Passenger Car - Chassis

Tyre Pressure Monitor (TPM)

Introduction training

As of 01/04

Titel

Without words (1)

System Components (2)

System Functions (8)

The most important in the end (17)Expensive and dangerous Wrong t y re pressure,

Loss money?

1 % higher fuel consumption 10 % shorter life

2 %

30 % shorter life

4 % higher fuel consumption

45 % shorter life

higher fuel consumption

1243

System components:

1. Wheel antennas X4 (A2/44 - 47)

2. TPM control module (N88)

3. Wheel sensors X4 (A69/1 - 4)

4. Metal valves

The tyre pressure monitor (TPM) is a system for

permanently monitoring tyre inflation pressure. For

this the tyre inflation pressure and tyre temperature

are measured in the tyre at certain intervals and

transmitted telemetrically to the TPM/[RDK] control

module (N88) via an high frequence (HF)

transmission link.

The tyre pressure monitor system supports the driver

when checking the correct tyre inflation pressure and

thus serves active safety.

Via the multifunction display (MFD/A1p13) in the

instrument cluster (A1) the driver is informed about

the current tyre inflation pressure or about the

necessary corrections to the tyre inflation pressure

and flat tyres.

General information:

1 countering nut

2 spacer ring (2x45°)

3 filling valve

4 pin Ø 2 mm

5 clamping screw a manufacture date b identification code A69/1 wheel sensor TPM left front A69/2 wheel sensor TPM right front A69/3 wheel sensor TPM left rear A69/4 wheel sensor TPM right rear A69/5 wheel sensor TPM spare wheel Advantages - Life and Economics - Tyre wear and fuel consumption are reduced by having the correct tyre pressure.

The wheel sensors (A69/1-4) is mounted on the metal valve (not visible from outside) and measures the air pressure and temperature inside the tyre. The data transmitted by the wheel sensors are received by wheel specific antennas (A2/44-47). The TPM/[RDK] control module (N88) evaluates this data and determines the position of the transmitter from the field strengths measured at the wheel antennas. This ensures that the data can be correctly matched to the relevant wheel.

The tyre pressure of each wheel adjusted and activated by the driver is stored in the TPM/[RDK] control module (N88) as a specified pressure to be monitored. The data evaluated by the TPM/[RDK] control module is shown in the multifunction display (MFD) of the instrument cluster (A1) in the form of messages relevant to the operation and function (N88). - Regular checking of tyre inflation pressure is simplified.

- The tyre pressure monitor does not relieve the operator from a regular manual check of tyre inflation pressure (at least every 14 days). In the process the correct tyre inflation pressure must be adjusted by means of the table in the fuel filler flap. The tyre pressure monitor does not warn of a tyre inflation pressure which is incorrectly adjusted.Advantages - Safety

- It takes place an early warning with fast pressure loss.

- Tyre burst by excessive drumming work, caused by driving too fast with insufficient air pressure, are avoided.

- The driver is requested to check the tyre inflation pressure.

- There is a warning in good time in the event of a rapid pressure drop (pressure drop >0.2 bar).

General function

Advantages - Comfort

The t y re pressure control consists of the following components:The battery-operated wheel sensor is mounted within the tyres and measures the tyre pressure and temperature of wheel sensor electronics. Each wheel sensors possesses an identification (ID),with one transfers. The sensors work in 433MHz or 315 MHz

(USA/ROW)

.1 clamping screw 2 filling valve 3 spacer ring 4 countering nut

5 cap A69/1 wheel sensor TPM left front A69/2 wheel sensor TPM right front A69/3 wheel sensor TPM left rear A69/4 wheel sensor TPM right rear

The following are located in the housings:

- Pressure sensor

- Temperature sensor - Transmission stage - Lithium battery for internal voltage supply. Note:

The TPM/RDK wheel sensors cannot be dismantled into its individual parts.

Together with the filling valves (2) the left front tire pressure monitor wheel sensor (A69/1), right front tire pressure monitor wheel sensor (A69/2), left rear tire pressure monitor wheel sensor (A69/3) and right rear tire pressure monitor wheel sensor (A69/4) form a compact unit and are fitted in the rims like a screw-on valve. Modifications to the rims are not required. * four aluminum of valves * four wheel sensors

* TPM control unit (N88)

* system activation button

Structure:

1clamping screw 2filling valve

3spacer ring

4countering nut 5cap A69/1 wheel sensor TPM left front A69/2 wheel sensor TPM right front A69/3 wheel sensor TPM left rear A69/4 wheel sensor TPM right rear

In the context of energy management the TPM left front wheel sensor

(A69/1), the right front wheel sensor (A69/2), left rear wheel sensor

(A69/3) and right rear wheel sensor (A69/4) change over automatically between the following operating modes:

- Powersave mode while the component is in storage prior to installation.

- As long as no pressure change dependent on specified value is

detected, data telegrams are sent at intervals of 55 seconds to

monitor the system and to detect very slow changes in pressure.

- The measuring rate and transmission rate is increased (0.8 seconds), if

a rapid change in pressure change has been detected at one wheel.

The TPM control module (N88) is thus provided with a number of

measured values within a short period of time, allowing reliable

evaluation of the pressure change.

- Switching OFF the measuring/transmission electronics at

temperatures > 120° C, as reliable recording of data and data transfer

is not guaranteed in this operating condition.

- The measuring/transmission electronics is switched ON again

automatically when the system cools down to < 100° C.

Function:

Energy management

Because of the wheel sensor battery size and therefore the battery

capacity is also limited by the restricted space available. An intelligent

energy management system provides an estimated service life of approx.

7 years with a single battery. When wheel sensor battery defect, it is only to exchange the complete wheel sensor.

* four aluminum of valves

* four wheel sensors

* four wheel antennas

* TPM control unit (N88)

* system activation button

Function:

The tyre pressure values of the individual wheels are received

telemetrically and passed on to the TPM/[RDK] control module

(N88). The wheel position is detected by measuring the field

strengths.

The determined tyre pressure values of the individual wheels are

received telemeterically from the respective wheel antenna and

transmissed to the tyre prseeure monitor control module (N88).

By the measurement of the field strengths at the wheel antennas the

wheel position is recognized.

A2/44 Left front TPM wheel antenna

A2/45 Right front TPM wheel antenna

A2/46 Left rear TPM wheel antenna

A2/47 Right rear TPM wheel antenna

* four aluminum of valves

* four wheel sensors * four wheel antennas

* TPM control module (N88) * system activation button

The TPM control module (N88) consists of a radio frequency

receiver module, a control module circuit board with

microprocessor control and an interface for the CAN data bus.

When comparing the actual tyre pressure with the stored

nominal pressure, the temperature of the tyre is taken into

account. The TPM control module (N88) calculates valid limits for the actual tyre temperature.

If the tyre pressure falls below these limits, the TPM control

module (N88) passes an appropriate CAN signal to the

instrument cluster (A1) according to the pressure deviation.

This CAN signal is processed in the instrument cluster (A1) and

the relevant information is displayed to the driver via the

multifunction display (MFD).

Task - Tyre Pressure Monitor control module (N88):

The TPM system activation button is located on the right-hand

side of the multifunction steering wheel. It is the "+" button on

the + and - button (setting specific functions and volume

control) (S111s1).

When the system is activated, the air pressures for the wheels

set by the driver are stored in the TPM control module (N88) as

the desired monitoring data.

Task - System Activation Button (show in W211):After changing the tyre pressure by the dirver, after a wheel exchange or exchange of wheel sensor or the TPM control module (N88). The adjusted tyre pressure values in the TPM control module (N88) must again be stored as target monitoring being.Repair Note:

difference control module:

1. Instrument cluster (A1)

- INITIALIZING

2. Driver-side SAM control module with fuse and

relay module (N10/1)

- Outside air temperatures

- Terminal 61 ON (for detecting "engine

running")

3. for EIS control module (N73)

- Wheel speeds

- Circuit 15 ON

4. Central gateway control module (N93)

- Country code

- Engine / body variant

- Diagnosis active

The following information is issued via the engine compartment bus:

1. Instrument cluster (A1)

•T y re pressures

•Messages relevant to operation •Messages relevant to function

2. Central gateway control module (N93)•Diagnosis

Input signals:

•Left front TPM wheel antenna (A2/44)•Right front TPM wheel antenna (A2/45)•Left rear TPM wheel antenna (A2/46)•Right rear TPM wheel antenna (A2/47)•Power supply, terminal 30

Via the engine CAN bus, there are connections to the:

•Instrument cluster (A1)

•Driver-side SAM control module N10/1)•EIS [EZS] control module (N73)•Central gateway control module (N93)T y re pressure monitor (TPM), displaying massage:

The t y re pressure monitor system allows the driver to call up a display of the

instantaneous actual pressures in the individual t y res in the multifunction

display (MFD/A1p13) when the vehicle is moving or while it is stationary with the

ignition ON. The values displayed are the actual measured values without

temperature compensation. Changes in the pressure displays while driving are

due to changing temperatures of the air inside the tires.

Different messages:

1.Messages relevant to OPERATION:

A1r1 reset button for IC (R button)•Rapid pressure drop (>0.2 bar/min.)

•Dropping below a warning limit (the adjusted specified pressure is

checking of the tire inflation pressures.

•Functional failure of tire pressure monitor system.

Displaying t y re inflation pressure:

•Starting from the standard display, press the button three times or the button twice on the multifunction steering wheel.

•The instantaneous actual pressures in the individual t y res appear in the multifunction display (A1p13).

Pressure display without numerical values

Occasionally, a pressure display without numerical values may be displayed for

a short time instead of the pressure values. This is the case when an activation sequence has been triggered, or when wheel sensors have recently been replaced or different wheels have been fitted. In these cases the t y re pressure monitor system checks whether the locations of the wheels have changed. The pressure values are only displayed when the system has been able to match the signals to the wheels.

By measuring the field strengths at the left front tire pressure monitor antenna (A2/44), the right front tire pressure monitor antenna (A2/45), the left rear tire pressure monitor antenna (A2/46) and the right rear tire pressure monitor antenna (A2/47), the system’s logic circuits automatically detect the wheels with wheel electronics installed on the vehicle, and can identify their locations. If the wheel assignment changes (e.g. when changing a wheel), a learning process commences which can identify the state after approx. 10-15 minutes driving. This process is only active while driving in order to prevent incorrect assignment due to signals from other vehicles.Function-relevant messages in the MFD (A1p13) indicate a system condition, where neither actual tire pressures nor other TPC system messages will be displayed. Possible system messages via the instrument cluster is/are (YELLOW messages)Function-relevant messages are divided into:

1.

system FAULT (error) messages

•System faults are memorized in the control unit TPC (N88) with a fault code.

2.

•System events are memorized in the control unit TPC with an event code.

•System events describe system operating conditions, so in the case of memorized event codes, there is no need to change any system components !

This message appears, if ...

•Message indicates CAN-data bus malfunctions or defect system components or at least one wheel without wheel sensor.

•If this message appears, a fault code is stored in the TPM control unit (N88).This message appears, if ...

•Message indicates missing CAN bus message

from TPM control unit to, or malfunction in

instument cluster.

•Message also appears on cable interruption or

disconnected TPM control unit.

•If the TPC control unit is disconnected while

"ignition ON" this message only appears after

ignition ON/OFF.

This message appears, if ...

•one or more wheel sensor/s has/have been

replaced and the system is still in the learning-in

process.

•external transmitters disturb data exchange

•the temperature of at least one wheel sensor has

reached 120C

•additional active wheel sensor/s have been

detected by the antennas (e.g. winter tyres in

boot).

Tyre Pressure Control

currently not active

Tyre Pressure Control Visit Workshop!Tyre Pressure Control Display Defective

These messages appear after activating the system.• Activation is necessary after change of tyre pressure, change of wheel position or wheel sensor/wheel replacement.

• The activation process can be started while "ignition ON " or engine running.

This message appears if ...

• Following system activation the pressure values will only be displayed after the individual wheel sensor positions have been acknowledged by TPM control unit.

• This requires approx. 10-15 minutes of driving time. Until that only the messages shown on the right will be displayed.

This message appears if ...

• tyre pressure is >0.3 bar above the memorized reference value

• the control unit TPM has been replaced

• after a red warning message has been displayed • the control unit TPM has been set to "not active "(message appears for 30 seconds after each engine start)

Tyre Pressure Control re-activate system!

Tyre Pressure Control

Activated!

As of 01.09.2002

Pressure display after few mins driving!

Tyre Pressure Control

Activated!up to 31.08.2002Pressure display after few minutes of driving

Re-activated with

R button

As of 01.09.2002

Tyre Pressure [bar]

up to 31.08.2002

¾These messages appear in YELLOW (information) or RED (warning) colour.¾Operation-relevant messages are memorized in the event memory of the control unit TPC.

¾They represent a normal operating function of the TPC system and are no reason to change system parts.¾If a red warning message appears, it will not be displayed anymore after ignition ON/OFF. Instead the message shown on the right will be displayed.¾Warning messages appear without position indication as long as the activation process has not been sucessfully performed.

¾Every red warning information is followed by a request to reactivate the system.

This message appears, if ...

•This message appears if tyre pressure in one or more wheels drops between 0.2-0.4 bar below

the set value of the control unit TPC (memorized during the last activation mode). The tyre

position will not be indicated. The message

appears only after ignition off/on to remind the driver to check the tyre pressure and re-activate the system afterwards.

•If re-activation is not performed, the message will be displayed for 30 seconds after each

engine start.This warning information will be displayed, if...

•Tyre pressure drops >0,4 bar below the set value of the control unit TPC (memorized during the last activation mode.

•This warning message will also be displayed if the TPC control unit refuses the sucessful activation due to following reasons:

1.TPC control unit detects tyre pressure below the specifications for the vehicle.

2.TPC control unit detects tyre pressure differs > 0.4 bar between left and right tyre of one axle.•New vehicles with TPC leave the factory with activated TPC control units with increased set pressure of approx.

3.5 bar.

•Correcting the tyre pressure to vehicle specification during PDI-inspection leads to a warning message displayed in the MFD due to the factory TPC system activation with 3.5 bar. This is no system fault!

Note:

The driver should immediately stop the vehicle and check the tyres, if necessary mount the spare wheel.

Tyre Pressure Control

Check tyres!Tyre Pressure

Check tyre!This warning information will be displayed, if...•System records a pressure loss of > 0.2bar/min.•If pressure drop occurs at only one wheel, this warning message will only be displayed if the

activation process has not yet been sucessfully performed.

•After correcting the tyre pressures system has to be re-activated !This warning information will be displayed, if...

•the TPC system registers a pressure loss of >0.2 bar/min. in the front left tyre.

•The driver should immediately stop the vehicle and check the front left tyre, if necessary mount the spare wheel.

•After correcting the tyre pressures system has to be re-activated !

Fault code and Event code:

The TPC control unit memorizes all messages either in the event memory or in the fault memory. Depending on operating condition they can be shown as "current and stored" or just "s tored".

A present event or fault code will be marked …current and stored“ only until ignition ON/OFF, after that it will only be shown as "s tored

Tyre Pressure

Attention tyre defect!

Hard and Soft warning function:

1.

Driving safety is not guaranteed if rapid pressure loss occurs. The responsibility to decide wether to continue driving at low speed to the nearest repair shop or instead mount the spare wheel for further driving.

• Should the temperature-compensated tyre pressure be > 0.4 bar below the set value, a "hard warning " message in red colour will be displayed in the MFD instantly.

• A "Hard warning " message is displayed in red colour if the TPC

control unit detects rapid pressure loss (> 0.2 bar/min). This warning message is displayed instantly via the MFD.

• After ignition ON/OFF, the "Hard warning " message will be replaced by a "Soft warning " message 2. If pressure loss is detected but driving safety still guaranteed, the TPC control unit displays a so called "soft warning " message in yellow colour via the MFD. The driver is urged to correct the tyre pressure at the next possible chance. (seeping presuress loss)• Such a "soft warning " message is issued for example if the temperature-compensated tyre pressure is > 0.2 bar and < 0.4bar lower then the set value in the TPC control unit.

• A "Soft warning " will be repeated after every engine start or igniton ON/OFF for 30 seconds until the system has been re-activated.

• After correcting the pressure the system must be re-activated.

Tyre Pressure Control

Check tyres!

Tyre Pressure Check tyre!

01/04 Passenger Cars - Chassis - Tyre Pressure Monitor (TPM)

The most important in the end 17

The most important in the end 01/2004

The actual tyre pressure value in the multi-function display indicated as soon as all

identify's of the wheel sensors once from the TPM control module to receive became,

even if no normal activation were present! Notes:

buttons.After repair work on the vehicle, the TPM system can be activated also by using the Star diagnosis.

- Only the series W211 the event memory in the Star diagnosis can be deleted!

- If a tire temperature of >120° C is detected, the wheel sensor will stop measuring and transmit the data to

TPM. Until the tyre temperature cools down to <100° C, the system will automatically switch ON again.

- Every 10° C ambient temperature rises the tyre pressure will increase by 0.1 bar!

Initial startup with manual settings input for new control module:

1. Initial startup requirements for TPM control module

- installed a NEW TPM control module

- correct tyre pressure on all wheels before starting this function

2. Tips

- at the end of this function, the fault code and event code memory are erased

- after the wheel sensors identification numbers and the specified tyre pressure values

have been written, TPM control module (N88) will activated automatically.

- read out the tyre specified pressure from the filler cap/cover.