Mercedes A Class — 12 - 18
Tyre-pressure monitoring system reset and calibration guidance.
Reset or calibrate the tyre monitor
Restart the tyre pressure loss warning system if you have:
1. Changed the tyre pressure.
2. Changed the wheels or tyres.
3. Fitted new wheels or tyres.
Before restarting, make sure that the tyre pressures are set properly on all four tyres for the respective operating conditions. The recommended tyre pressures can be found on the tyre pressure table on the fuel filler flap.
The tyre pressure loss warning system can give reliable warnings only if you have set the correct tyre pressure. If an incorrect tyre pressure is set, this incorrect value will be monitored.
Make sure that the key is in position 2 in the ignition or ignition on.
(1) Press ◄ or ► on the steering wheel to select the Serv. menu.
(2) Press the ▲ or ▼ button to select Tyre pressure.
(3) Press the OK button.
The Run Flat Indicator active Restart with OK message appears on the multifunction display.
If you wish to confirm the restart:
(4) Press the OK button.
The Tyre press. now OK? message appears on the multifunction display.
(5) Press the ▲ or ▼ button to select Yes.
(6) Press the OK button.
The Run Flat Indicator restarted message appears on the multifunction display.
After a teach-in period, the tyre pressure loss warning system will monitor the set tyre pressures of all four tyres.
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If you wish to cancel the restart:
Press the OK button.
or
If the Tyre press. now OK? message appears, press the ▲ or ▼ button to select Cancel.
Press the OK button.
The tyre pressure values stored at the last restart will continue to be monitored.
Before resetting the system
Set all tyres on the Mercedes A Class to the correct cold pressures first. Resetting the monitor with an incorrectly inflated tyre can store an unsafe reference value.
How tyre-pressure monitoring systems work
Direct TPMS uses a pressure sensor inside each wheel. It can usually identify a pressure loss before the vehicle moves and may show individual tyre pressures on the dashboard. Sensor replacement or relearning can sometimes require specialist equipment.
Indirect TPMS uses the ABS wheel-speed sensors to identify a tyre whose rolling circumference has changed. This system normally needs recalibrating after tyre pressures are adjusted, tyres are replaced or wheels are moved.
Dashboard wording and reset steps vary between trim levels and software versions. Follow the vehicle’s on-screen instructions and owner’s manual where they differ from the guidance above.