Tire pressure monitor control unit, task - GF40.15-P-3000-03R

Model 230

Fig 1: Identifying Tire Pressure Monitor Control Unit Function And Components

Courtesy of MERCEDES-BENZ USA

Task

When comparing the actual tire pressure with the stored nominal pressure, the temperature of the tire is taken into account. The TPM control unit (N88) calculates valid limits for the actual tire temperature.

If the tire pressure falls below these limits, the TPM control unit (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 appropriate information conveyed to the driver via the left multifunction display (A1p13) and right multifunction display (A1p15).

Input signals:

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

Via the CAN-engine compartment there is a connection to:

Driver-side SAM control unit (N10/10)
Passenger-side SAM control unit (N10/11)
Instrument cluster (A1)
EIS [EZS] control unit (N73)

The following information is processed:

Instrument cluster (A1)

Initializing

Driver-side SAM control unit (N10/10)

Outside air temperature

Passenger-side SAM control unit (N10/11)

Terminal 61 ON (to detect "engine running")

EIS control unit (N73)

Diagnosis active
Wheel speeds
Circuit 15 ON
Country code
Engine / body variant

The following information is issued via the CAN-engine compartment:

Instrument cluster (A1)

Tire pressures
Messages relevant to function
Messages relevant to operation

EIS control unit (N73)

Diagnosis