Tire pressure monitor (TPM), activation - GF40.15-P-0001-02TRU
In the event of air pressure changes by the driver, if a wheel is/wheels are changed, the adjusted air pressure values must be stored as specified monitoring values in the TPM [RDK] control unit (N88).
The driver can determine the filling pressure to be monitored manually by "Reactivation" of the tire pressure monitor via the operating menu in the instrument cluster (A1). The temperature-compensated pressure thresholds for the warnings are determined by means of pressure values at the instant of reactivation. Manual reactivation is only planned as a stopgap solution for critical application cases if the automatic filling detection fails.
Reaction of TPM [RDK] control unit after manual reactivation
If the pressure values of the tires are plausible individually as well as in relation to each other for the TPM [RDK] control unit and are above the minimum pressure specific to the model series, reactivation is carried out. The immediate operation feedback "Tire pressure monitor reactivated" takes place.
Adopt conditions current pressure values as new specified values:
- Pressure values filtered for three minutes
- Awaiting individual wheel detections
- Plausibility check of pressure values carried out
- Determination of specified pressure values after a positive plausibility check
Conditions for reinitializing filling detection
- Ignition restart after an idle time of more than three minutes
- TPM wheel sensor reports a pressure change when vehicle is stationary
- New individual wheel/new individual wheels found after the start of a journey
Conditions for filling detection:
- Filling detection started
- No pressure change (temperature-compensated) by more than 0.1 bar in the observation period (compare max/min value)
- Tire pressures are above the minimum pressure specific to the model series
Operation description:
The TPM system is permanently operational and is not operated actively by the driver. Each time CAN B (Controller Area Network bus Class B (interior)) is awoken by the starting procedure or ignition "ON", the TPM [RDK] control unit carries out a reinitialization and starts to transmit messages to the instrument cluster.
A reactivation of the TPM system can be triggered via the left multifunction steering wheel button group (S110) and right multifunction steering wheel button group (S111) in the multifunction steering wheel and the instrument illumination rheostat and reset button (A1r1) on the instrument cluster.
The TPM system can be reactivated in the following cases:
- after a tire pressure change (e.g. by refilling)
- after wheel/wheels change
Filling detection is also restarted when the TPM system is reactivated manually.
System message (request for system activation)
Reactivate tire pressure monitor:
- Adjust tire pressure correctly in each wheel
- Switch on ignition (circuit 15 "ON")
- Select the standard display with the system selection button (S110s3)
- Select the TPM system with the scroll forward/back button
Reactivate tire pressure monitor:
Press the instrument illumination rheostat and reset button.
The display changes to the selection screen with preselection "No". Press the button + and -, setting of specific functions and volume control on the multifunction steering wheel. The selection screen appears for approx. two seconds with selection "Yes" and then changes immediately to the confirmation screen.
Reactivation of tire pressure monitor carried out
As of this instant the TPM system monitors the (new) adjusted air pressure values in all rotating wheels. The TPM system has stored the current tire pressure as a new reference value.
All other buttons cause the activation sequence to be aborted.