Tire pressure monitor function - GF40.15-P-0001T

MODEL 211 up to 31.5.05 with CODE (475) Tire pressure monitor except CODE (494) USA version except CODE (498) Japan version

MODEL 211 up to 30.6.05 with CODE (475) Tire pressure monitor with CODE (494) USA version with CODE (498) Japan version

Fig 1: Tire Pressure Monitor Function Diagram

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

General

The tire pressure monitor is a system for permanent monitoring of the tire inflation pressure. For this purpose, tire inflation pressure and tire temperature are measured in the tire at certain intervals and transmitted by telemetrics to the TPM [RDK] control unit (N88) via an HF transmission path.

The tire pressure monitor system assists the driver when checking the correct tire inflation pressure and thus serves active safety. Via the multifunction display (A1p13) in the instrument cluster (A1) the driver is informed about the current tire inflation pressure or about the necessary corrections to the tire inflation pressure and about flat tires.

Advantages

Safety:

"Tire bursts" due to excessive flexing energy, triggered by driving quickly with too low air pressure.
The driver is requested to check the tire inflation pressure.
A timely warning ensues in the event of a rapid (pressure drop > 0.2 bar/minute).
A timely warning ensues in the event of a rapid (pressure drop > 0.2 bar/minute).
The nature of the system is such that a sudden depressurization cannot be detected.

Comfort:

Regular checking of tire inflation pressure is simplified.
The tire pressure monitor system does not relieve the driver of his obligation to check the tire inflation pressure manually on a regular basis (at least every 14 days). In the process the correct tire inflation pressure must be adjusted by means of the table in the fuel filler flap. The tire pressure monitor system does not warn about an incorrectly adjusted tire inflation pressure.

Service life and economy:

Tire wear and fuel consumption are reduced by having the correct tire pressure.

System components

The tire pressure monitor system consists of the following components:

Left front tire pressure monitor antenna (A2/44)
Right front TPM [RDK] wheel antenna (A2/45)
Left rear tire pressure monitor antenna (A2/46)
Right rear TPM [RDK] wheel antenna (A2/47)
Left front tire pressure monitor sensor (A69/1)
Right front tire pressure monitor sensor (A69/2)
Left rear tire pressure monitor sensor (A69/3)
Rear right tire pressure control wheel sensor (A69/4)
TPM [RDK] control unit (N88)
System activation button in the multifunction steering wheel

Function

The wheel sensor is mounted on the metal valve (not visible from outside) and measures the air pressure and temperature inside the tire.

The data transmitted by the wheel sensors are received by wheel-specific antennas. The TPM [RDK] control unit (N88) evaluates this data and determines the position of the transmitter from the field strengths measured at the wheel antennae. This ensures that the data can be correctly matched to the relevant wheel.

In the TPM [RDK] control unit (N88) the air pressure activated and adjusted by the driver of each wheel is stored as the specified pressure to be monitored.

In the multifunction display (A1p13) of the instrument cluster (A1) the data evaluated by the TPM [RDK] control unit (N88) is displayed in the form of messages relevant to operation and function.

Messages relevant to operation

Rapid pressure loss (> 0.2 bar/min).
Dropping below a warning limit (the set target pressure is dropped below by more than 0.2 bar).
Request for reactivation of system.
Rejection of system activation because of implausible pressure values.

Messages relevant to the function:

Influence of an external interference source preventing tire inflation pressure from being checked.
Function failure of tire pressure monitor system.

Displaying tire pressure monitor (TPM) of tire inflation pressure	Up to 31.08.02	GF40.15-P-0001-03T
	As of 01.09.02 up to 31.5.04	GF40.15-P-0001-03TA
	As of 01.06.04 up to 31.5.05 with CODE (475) tire pressure monitor except CODE (494) USA version except CODE (498) Japan version Up to 30.6.05 with CODE (475) tire pressure monitor with CODE (494) USA version with CODE (498) Japan version	GF40.15-P-0001-03TB
Tire pressure monitor (TPM), activation	Up to 31.08.02	GF40.15-P-0001-02T
	As of 01.09.02 up to 31.5.04	GF40.15-P-0001-02TA
	As of 01.06.04 up to 31.5.05 with CODE (475) tire pressure monitor except CODE (494) USA version except CODE (498) Japan version Up to 30.6.05 with CODE (475) tire pressure monitor with CODE (494) USA version with CODE (498) Japan version	GF40.15-P-0001-02TB
Tire pressure monitor (TPM), messages relevant to the function	Up to 31.08.02	GF40.15-P-0001-04T
	As of 01.09.02 up to 31.5.04	GF40.15-P-0001-04TA
	As of 01.06.04 up to 31.5.05 with CODE (475) tire pressure monitor except CODE (494) USA version except CODE (498) Japan version Up to 30.6.05 with CODE (475) tire pressure monitor with CODE (494) USA version with CODE (498) Japan version	GF40.15-P-0001-04TB
Tire pressure monitor (TPM), messages relevant to operation	Up to 31.5.04	GF40.15-P-0001-05T
Tire pressure monitor (TPM), messages relevant to operation	As of 01.06.04 up to 31.5.05 with CODE (475) tire pressure monitor except CODE (494) USA version except CODE (498) Japan version Up to 30.6.05 with CODE (475) tire pressure monitor with CODE (494) USA version with CODE (498) Japan version	GF40.15-P-0001-05TB
Detect seeping pressure loss, function		GF40.15-P-2001T
Detecting rapid pressure loss, function		GF40.15-P-2004T