System description - tyre pressure monitoring system

The tyre pressure monitoring system is part of the software in the ABS control unit - J104-. The system is used to detect slow tyre pressure loss from a wheel. Event memory entries for the Tyre Pressure Loss Indicator are stored in the ABS control unit - J104-. The Tyre Pressure Loss Indicator compares the speed and the rolling circumference of the individual wheels via the ABS sensors.

After the following work or modifications, the tyre pressure monitor display button - E492- must be pressed and held until a confirmation is sounded.

• Change in tyre pressures
• Changing one or more wheels
• Interchanging wheels, e.g. from front to rear
• Removing and fitting one or more wheels

A change in a wheel's rolling circumference will be indicated by the tyre pressure monitor warning lamp - K220- lighting up in the dash panel insert. A tyre's rolling circumference may change as a result of:

• Insufficient tyre pressure
• Structural tyre damage
• Uneven load distribution in the vehicle
• Increased load on one axle, e.g. due to towing a trailer
• Use of snow chains.
• Temporary spare wheel installed
• Wheel renewal

System fault in the ABS system

If a fault in the ABS is displayed by the ESP and TCS warning lamp - K155- or the traction control system warning lamp - K86-, then the tyre pressure loss indicator warning lamp - K220- -arrow- will also light up. However, no fault will be stored in the Tyre Pressure Loss Indicator system.

The warning lamp cannot be extinguished by pressing the TPM button - E492-. In this case, please carry out the following steps:

• Connect ⇒ Vehicle diagnostic tester, and select “Guided Fault Finding” ⇒ Vehicle diagnostic tester.

Follow instructions on screen to perform basic setting.

Perform basic settings

Running gear

Brake system

01 - Self-diagnosis compatible system

Anti-lock brake system ABS Bosch 8.2 or Anti-lock brake system ABS/EDS/ASR/ESP Bosch 8.2i (depending on

version)

Functions

Tyre pressure monitor display / Tyre pressure warning

Follow instructions on screen to perform basic setting.

Perform basic settings

Following each wheel change, the SET button must be actuated whilst the ignition is switched on and the vehicle is stationary until an audible signal is sounded. An audible signal confirms that basic setting has been performed.