TPMS and DDS

[pecky]

Two different tyre pressure monitoring systems are used on the Astra-H.

DDS

The DDS is a function of the ABS MK60 ESP and calculates the pressure loss in the tyres via the wheel speed sensors of the ABS. When the vehicle is being driven, the speed of each wheel is monitored continually. Loss of pressure in the tyre reduces the tyre's diameter and thereby the rotational speed of the wheel. If the system detects a difference in rotational speed such as this, the control indicator (red) will light up. The DDS is an indirect measurement system as it only gives a warning about loss of air but does not say which tyre/wheel is affected.

The control indicator lights up when there is a pressure deviation of approx. 30% compared with the other tyres. If there is a fault in the system, the (yellow) control indicator lights up.

TPMS

The tyre pressure monitoring system (TPMS) is a direct measuring system which works together with the DDS. Four pressure and heat sensors located in the tyres continually monitor the inflation pressure whilst the vehicle is being driven. The air/inflation pressure is transmitted by radio wave directly to the TPMS control unit (which is also a receiver). In contrast to the Vectra-C, the TPMS on the Astra-H only works with one receiver (TPMS control unit). All signals received (pressure, heat) are first evaluated by the TPMS control unit and transmitted on the CAN bus via the ABS control unit to the instrument cluster.

The current tyre inflation pressures can be read from the Info Display.

If the system detects that there is a pressure difference in one or more tyres, an indicator appears in the Info Display showing the position of the faulty tyre. Pressure differences down to 0.1 bar can be displayed.

For the system to work, all wheels have to be fitted with pressure sensors, all tyres have to be inflated to the specified air pressure and the system has to be initialised.

The tyre pressure monitoring system is ready to operate once the ignition is on and continually checks the tyre pressure once the vehicle has reached a speed of 30 km/h.

The DDS operates together with the TPMS and serves as a back-up system should one or all of the tyre pressure sensors fail. The DDS system indicates a deviation in air pressure or a system fault by means of a control indicator in the instrument panel:

• Yellow display, system fault
• Red display, deviation in tyre pressure

Note: The spare wheel is not fitted with a tyre pressure sensor.
Should there be a deviation in tyre pressure, the TPMS displays the following messages in the Info Display along with the current measurements for the individual tyres:

• Slight pressure deviation: Display reads "Check rear left tyre pressure"
• Large pressure deviation: Display reads "Warning! Pressure loss in left rear tyre"

If there is a fault with one or all of the tyre pressure sensors, the TPMS operation automatically switches to the DDS system of the ABS. It calculates the pressures automatically from a speed of approx. 30 km/h by means of the wheel speed sensors.

Vehicles with tyre pressure monitoring systems can be recognised by the fact that the tyre valve stems are made of metal and have aluminium caps, instead of the usual rubber stems and plastic caps.

In the event of a puncture, do not use liquid tyre repair systems as they will damage the tyre pressure sensors.

[pecky]

Tyre pressure sensor

The tyre pressure sensor contains a metal tyre valve. A non-changeable battery supplies the tyre pressure sensors with voltage.
DDS

Service:

After the tyre pressures have been corrected, or if a tyre or wheel has been changed or the wheels swapped over (e.g. a front wheel to the rear), the system must be reprogrammed/initialised:

• Press the DDS button for 4 seconds (with the ignition on or engine running), the control indicator will flash 3 times
• The system is operational once a certain distance has been covered, i.e. different speed ranges are programmed in by means of different driving profiles. It can take up to a maximum of one hour to program all the speed ranges.

TPMS/DDS
• Service:

After the tyre or wheel has been changed, the tyre pressure sensor replaced or the wheels swapped over (e.g. a front wheel to the rear), the system must be reprogrammed/initialised:

• Press the DDS button for 4 seconds (with the ignition on or engine running), the control indicator will flash 3 times
• The TPMS system will display the measured pressure in the Info Display after approx. 2 min (min. speed 30 km/h).
• The DDS requires a certain distance to be covered for programming purposes (see above).
• The DDS is used to allocate/position the pressure sensors / wheels.

Note: The system at first only distinguishes between the front and rear axles (after 10 min. driving time at a min. of 30 km/h). Only when there is a loss of pressure does it distinguish between left and right as well.

Service:

If a customer is trying out the TPMS (e.g. by inflating the right tyre to a higher pressure), the display may indicate the wrong side of the vehicle (i.e. it may show that the left tyre has a higher pressure).

Not until the vehicle is driving along will the previously programmed DDS then allocate the wheel or sensor correctly, after which the display in the Info Display will be correct.

Should the customer have concerns, assign the tyre pressure sensors unambiguously to the TPMS control unit by using the following programming procedure:

Version 1:

• Reduce the tyre pressure to approx. 1 bar and re-inflate as described below.
• Proceed with each tyre in turn.

• Front left: 3.0 bar
• Front right: 2.7 bar
• Rear right: 2.4 bar
• Rear left: 2.1 bar

• Tyre pressure sensors are now active.

Or

Version 2:

• Drive the vehicle for a short while at a speed above 30 km/h to close the roll switches, i.e. activate the pressure sensors.
• Inflate the tyres:

• Front left: 3.0 bar
• Front right: 2.7 bar
• Rear right: 2.4 bar
• Rear left: 2.1 bar

Then proceed as follows for both methods:

• Press DDS button for 4 seconds (with ignition on or engine running).
• Control indicator lights up yellow to confirm that the correct pressure setting has been detected (each pressure value must have been received once, total duration approx. 2 minutes).
• Perform re-set again: Press DDS button for 4 seconds (with ignition on or vehicle running), control indicator will flash 3 times

The system has now assigned the pressure sensors unambiguously and is operational.

Note: Both procedures should be carried out within 15 minutes.

The pressure can be read off from the Info Display (if the pressure should drop quickly, the transmission will occur while stationary).

On both versions, a faulty wheel sensor can be detected by the loss of the associated pressure value in the display.

Example: 2.7 bar is not displayed - front right wheel sensor is faulty.

Re-inflate the tyres to the correct pressure.

Note: If a pressure sensor should fail during a journey, no pressures will be shown in the display.

Note: To check the tyre pressures on vehicles with TPMS, attach the adapter, which is located on the tank filler flap, to the tyre valve before attaching the tyre pressure checker.

Service:

The seal rings of the valve stems and valve inserts must be replaced every time the tyre is changed.

When tightening the nut on the tyre pressure sensor, it is essential to observe the specified tightening torque to prevent the sensor getting damaged. Information on fitting tyres can be found in the Astra-H

Service Instruction, group "E".

TPMS control unit

The electronic control unit is the interface to the vehicle electrical and electronic systems. Wheel data is transmitted via RF (radio frequency) signals to the control unit where it is processed. The driver is informed of the current status via the Info Display. The control unit is connected to terminal 15 and terminal 31 as well as the low-speed CAN bus in order to communicate with other control units and for system diagnosis.

In contrast to the Vectra-C, only one version is used for radio transmission:

• TPMS, 433 MHz connection between ECU and sensors

Warning and alarm

The system uses the standard tyre pressure as a reference, therefore the front and rear wheels may show different values.

If the tyre pressures have been increased by at least 0.1 bar, the control unit assumes the new values as the default values the next time the ignition is switched on.

A warning message is output:

• Detected tyre pressures is -0.3 bar

An alarm message is output if:

• Detected tyre pressure is -0.6 bar
• Detected tyre pressure drops by more than 0.3 bar/min