Tire pressure monitor (TPM), messages relevant to operation - GF40.15-P-0001-05TB

Messages relevant to operation in the multifunction display (A1p13) of the instrument cluster (A1) inform the driver that the air pressure in at least one wheel is changing or has changed. The messages ensue in "yellow" (information messages) or in "red" (warning messages).

When "red" warning messages appear, the tire pressure monitor warning lamp (A1e66) in the instrument cluster (A1) is activated. Messages relevant to operation are stored in the TPM [RDK] control unit (N88) with an event code.

The messages relevant to operation describe a regular operating condition.

In the event of complaint there is no reason to exchange system components.

The following messages relevant to operation can occur:

Information message

If the air pressure in one or more tires drops > 0.2 bar but not > 0.4 bar below the pressure set by the driver and stored in the TPM [RDK] control unit (N88), this is displayed on the multifunction display (A1p13) without specifying the tire location.

The information message appears for the first time in the next ignition sequence. The driver is therefore requested to check the tire inflation pressures and correct them if necessary and then reactivate the tire pressure monitor (TPM) system.

If the system is not reactivated, this information message appears repeated for approx. 30 seconds each time the engine is started and then goes out again.

Fig 1: Screen Display - Correct Tyre Pressure

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Warning message

If the tire pressure monitoring system (TPM) detects rapid pressure loss (> 0.2 bar/min) in several wheels simultaneously or in an unassigned wheel, this warning message is shown in the multifunction display (A1p13).

The tire pressure monitor warning lamp (A1e66) in the instrument cluster (A1) is activated at the same time.

The driver is requested to stop the vehicle immediately and check all the tires for any foreign bodies which have entered. To make the vehicle safe to drive the spare wheel is to be fitted if necessary or TIREFIT tire repair kit used

After using TIREFIT the corresponding left front TPM [RDK] wheel sensor (A69/1), right front TPM [RDK] wheel sensor (A69/2), left rear TPM [RDK] wheel sensor (A69/3), or right rear TPM [RDK] wheel sensor (A69/4) should be replaced.

Fig 2: Screen Display - Caution Tire Defect

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Warning message (shown, as an example, for a pressure loss in the left front tire)

If the tire pressure monitoring system (TPM) detects rapid pressure loss (> 0.2 bar/min) in a wheel that is assigned to a wheel location, the warning message shown opposite is displayed in the multifunction display (A1p13).

The tire pressure monitor warning lamp (A1e66) in the instrument cluster (A1) is activated at the same time.

The driver is urged to stop the vehicle immediately and to check the relevant tires for any foreign bodies which may have entered. To make the vehicle safe to drive the spare wheel is to be fitted if necessary or TIREFIT tire repair kit used

Fig 3: Screen Display - Caution Tire Defect (FL)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Warning message

If the air pressure in one or more tires drops > 0.4 bar below the specified pressure set by the driver and stored in the TPM [RDK] control unit (N88), this is displayed on the right multifunction display (A1p13).

If the pressure loss is in only one wheel, this warning message is displayed as long as this is not yet assigned.

The tire pressure monitor warning lamp (A1e66) in the instrument cluster (A1) is activated at the same time.

Fig 4: Screen Display - Check Tires

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

This warning message is also displayed, if the TPM control unit (N88) refuses to perform an order to activate on the grounds of implausible pressure values.

Implausible pressure values:

The tire inflation pressure adjusted by the driver is under the minimum pressure stored in the TPM [RDK] control unit (N88), a tire inflation pressure specific to a model series which must not be dropped below.
The pressure difference of the tire inflation pressures on an axle is > 0.4 bar.

Remedy:

Correct the tire inflation pressures and reactivate the tire pressure monitor (TPM) system.

On new vehicles the tire pressure monitor (TPM) is activated by the plant with an increased tire inflation pressure (approx. 3.5 bar). The TPM [RDK] control unit (N88) has stored these tire inflation pressures as specified pressures to be monitored. By correcting the tire inflation pressure in the workshop this warning message is displayed in this ignition sequence. The system must be reactivated.

Warning message (shown, as an example, for a pressure loss in the left front tire)

If the air pressure in a wheel that is assigned to a wheel location drops > 0.4 bar below the pressure set by the driver and stored in the TPM [RDK] control unit (N88), this is displayed on the multifunction display (A1) in the instrument cluster (A1p13).

The tire pressure monitor warning lamp (A1e66) in the instrument cluster (A1) is activated at the same time.

Fig 5: Screen Display - Check Tires (FL)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

System message after a previous warning message

If in the previous ignition sequence a red warning message has been issued, the yellow system message opposite is displayed from the current ignition sequence and the following sequences, as long as the system has not been reactivated.

The tire pressure monitor warning lamp (A1e66) in the instrument cluster (A1) is activated at the same time.

Fig 6: Screen Display - Reactive Tyre Pressure Monitor After Corr. Press

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.