Hyundai Accent: Description and Operation

1. System Description

The TPMS monitors the pressure and temperature of a vehicles tire to alert on pressure variations that may impact the driving conditions. Messages deduced from processed data are displayed at the Instrument Cluster (IC) via 2 warning lamps. In parallel, the ECU executes error evaluation on input and output signals. Pressure monitoring during parking is provided.

The ECU processes data from the WE sensor, determines the state of the tires and communicates the required warning message via the hard wire line to the driver.

2. Functional Description

Warning Thresholds

Hard Warning

One non temperature compensated hard warning threshold applies to front and rear axle of vehicle. If the pressure reported by the WE sensor is below the tire-specific minimum pressure then the low pressure warning telltale is illuminated. A warning is reset when tire pressure is reported to be at 207kPa (30psi).

Fast Pressure Loss

Fast pressure loss function is deactivated during parking and only active while driving. So it abovids that a warning is set when the driver manually deflates the tire to a level above hard warning threshold.

Upon a rapid pressure decrease the WE emits a delta-p telegram which triggers the fast pressure loss function to start. Including the first dp-telegram the function waits for a 2nd telegram of the same wheel electronic and calculates the pressure loss rate. If the pressure drops by more than 20kPa/min, a "fast pressure loss" warning is generated and displayed with a maximum of 60s delay while driving.

Initialization

The initialization function determines which WE sensor identifier belongs to the vehicle.

The corresponding set of identifiers is stored in the ECU memory and used to determine if a received RF telegram comes from a wheel unit, which belongs to the vehicle.

Only telegrams containing known (initialized) identifiers are being supervised in the warning algorithm.

The initialization function is implemented in two independent parts: as an auto learning function.

Initialization-auto Learning

AL starts every time, the vehicle was parked long enough to change or permute wheels (19min), and is traveling again at a speed that ensures that the WE sensors are transmitting.

AL is automatically considering all WE identifiers received and extracts, based on statistical evaluation, IDs belonging to the WEs mounted on the vehicle. If new (unknown) IDs are detected, their recurrence will be tracked by AL.

AI compares the acceleration reported by the wheel unit to the vehicle speed to rule out transmissions received from neighboring vehicles traveling with different speeds.

A WE sensor identifier is assigned to the vehicle when 8 RF telegrams have been received while driving above 25km/h.

Sensor Registraion

Vin And Vehicle Name Writing

Schematic Diagrams

Schematic Diagram Connector pin number Pin No. Discription Remark 1 - 2 - ...

TPMS Sensor. Repair procedures

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