What are universal sensors and original sensors? And how do direct and indirect TPMS differ?
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A distinction is made between direct and indirect tire pressure monitoring systems.
Direct TPMS systems measure and record air pressure data with extreme precision using sensors that are built into the valves in the tires. The data is transmitted wirelessly to the vehicle’s on-board electronics system almost in real time and also appears on the driver’s display.
Indirect TPMS systems use the so-called ABS system. This determines air pressure loss using the rolling circumference of the wheel. However, these ABS systems have very tight legal tolerances and, unlike direct systems, are not suitable for all vehicles.
TPM systems should be considered in the following areas/situations:
- Diagnostics when the warning light appears on the display
- Maintenance, repair or replacement of the sensors
- Tire changes
- Assembly of complete wheels
- Tire repairs
- Tire fittings
- Service checks (e. g. general checks for TÜV)
Special expert tools make it easier to install and remove sensors. They also ensure that the nut and valve for the sensor holder are fixed with the correct torque.
For mounting, you can choose either an aluminium or snap-in valve (rubber valve). Separate sensor versions are available for both types of valves (to ensure that the valve and sensor are compatible).
A snap-in valve is generally cheaper and easier to install than an aluminium valve. However, it should be considered that, because of the centrifugal force, a snap-in valve can not be used at maximum speeds above 210 km/h. Aluminium valves are suitable for speeds > 210 km/h.
Please note: the valve should be inspected every time you change the tire. This involves replacing the valve insert, valve cap, nut, washer and seal. Special service kits containing the necessary spare parts are available for this maintenance procedure.
- Whenever you change the tires: install sensors in the wheels of vehicles with direct TPMS.
- To prevent the valve and sensor from corroding, replace the wear parts – valve insert, nut, seal and cap – using special service kits.
- Use diagnostics/programming tools to check the battery charge.
- Replace low or dead batteries: sensors have a finite battery life (varies between 4-10 years).
- Analyse and resolve the problem that has caused the warning light in the display to turn on.
- In general, in accordance with § 29 of the German Road Traffic Licensing Regulations (StVZO), a non-functioning TPMS is classified as a minor fault and must be rectified immediately by the vehicle owner. A workshop needs to be able to correct this fault at any point.
The obligation to have TPMS presents workshops with completely new challenges. In particular, new questions arise regarding the technology for direct TPMS. Experience shows that the market development and spread of TPMS are progressing at great speed. It is, therefore, both reasonable and necessary for workshops to prepare ahead for servicing tires with TPMS.
What does a workshop need to bear in mind to prepare in the best possible way for working with direct TPMS on a daily basis in the future?
- The most essential thing: prepare well for the customer handover. That means establishing the vehicle details, determining whether it has direct or indirect TPMS and obtaining information about the TPMS, as well as being transparent when explaining and justifying the additional costs involved.
- Just as important: train employees to use the new technology.
- Money is also important: investment is needed in suitable sensors and the correct diagnostics and programming tools.
- Stay ahead of the competition: workshops should gain an early competitive advantage by informing their customers about their TPMS service.
- It’s not just about outward appearances: it is also important to optimise and adapt internal tire service processes.
- To guarantee customer satisfaction, communicate the duration and prices for tire servicing needed for adjusting vehicles with direct TPMS.
- Record everything on paper or in the system: document the condition of the TPMS both before and after any work is done.
- Check the warning light and the indicator on the vehicle’s display – if the light is on, diagnostics are needed to determine whether there is a system error or loss of air pressure (see vehicle logbook).
- Check the valve Is the seal damaged? Is there any corrosion?
- Scan the sensors using a diagnostics/programming tool.
- Document the scan results (initial status of the vehicle’s TPMS).
- Execute the customer order, e.g. change the wheels, replace the tires or sensors, service the valve. When necessary, reconfigure the (new) sensors to the vehicle and check the TPMS.
- Document the status of the vehicle’s TPMS at the end (the TPMS status must not be worse than the initial status) and inform the customer.
Please note: As a functioning TPMS is part of the operating licence, the workshop must ensure functionality after every repair. Corresponding documentation of the status of the TPMS before and after carrying out maintenance and diagnostics and completing the customer order, therefore, acts as a safeguard within the scope of liability and warranty.
There are over 150 different sensors on the market.
- The sensors must be pre-programmed for the vehicle.
- The vehicle and sensor must be compatible, i.e. not every sensor can be fitted in every vehicle.
- For winter tires/spare tires or where a sensor is replaced, it is possible to use either original sensors or unprogrammed universal sensors.
Universal sensors are not pre-programmed and can, therefore, be used in most vehicles without a problem. The benefit is that the workshop does not need to stock a large variety of original sensors in order to meet the needs of all customers. A good basic stock of universal sensors is more than adequate.
A special programming tool is also needed for universal sensors to program the sensors for specific vehicles. This programming tool is used initially to retrieve the vehicle’s technical data in order to then determine the position of the tire in which the sensor to be programmed is located. After that, the original sensor is recognised by the programming device can retrieve data used to program the new sensor. This, in a way, imitates the original sensor. Assuming there is no old original sensor available, the programming tool can also be used to generate a new sensor ID.
Original sensors are already pre-programmed with details of a specific vehicle. Original sensors can, therefore, only be used in the few vehicles that they are specially designed for. Due to the large number of different sensors available, and because a minimum of four of each of the most important original sensors would need to be kept in stock in order to satisfy customer demand, the inventory required and the workshop's fixed capital would increase.
You will find the relevant coverage list in our download section or in the sens.it® application software. This list is updated regularly, as soon as new vehicles are available.
When this problem occurs, please try to find the vehicle by selecting the ‘Manufacturer & Model’ option instead.
When no diagnostics tool is available, it is also possible to read the ID directly off the case of (most) sensors. The website www.reifendrucksensor.info, supported by ALLIGATOR, provides important advice on where to find the ID on the particular sensor.
ALLIGATOR does not currently offer its own diagnostic tools , but does work closely with relevant device suppliers.
The ALLIGATOR sens.it® programming tool was developed to communicate with sens.it® sensors. It is therefore not possible to use this device to read sensor data of any kind.
sens.it® is a complete product system. It is, therefore, not possible to program sensors made by other manufacturers.
A duplicate of this component can be produced using the serial number (ID) of the OE sensor that is currently installed in the vehicle and which needs to be replaced. This procedure eliminates the need to reconfigure the sensor with the vehicle – a clear advantage in terms of saving time and improving customer service.
There are two options for determining the ID number:
1. Getting an electronic read-out of the sensor ID number using a diagnostic device, or
2. Reading the ID straight off the sensor case after removing the tire.
For programming, this ID number is entered into the 'OE sensor ID ' data field. Detailed instructions for the whole programming procedure can be found in the installation instructions provided under 'information material' in our downloads section.
Important: Always make a note of which sensor was fitted to which wheel!
When a new sensor ID is created, the sensors must be reconfigured with the vehicle.
The relearning methods for vehicles vary considerably. Fundamentally, there are three different versions: automatic relearning, via the OBDII interface in the vehicle or manual relearning via the on-board computer. To determine which method should be used, check the vehicle handbook or contact the manufacturer.
When a set of tires is being prepared before the vehicle arrives, then the sens.it® sensor can be programmed in advance. To do this, select the correct vehicle and generate a serial number (ID) for the sensors of concern (AutoGenerateID button). In this case, a relearning procedure must be carried out after fitting the set of wheels.
A sensor that has been accidentally programmed for the 'wrong' vehicle can be reprogrammed multiple times.
Any number of OE sensors per vehicle can be replaced with sens.it® sensors.
A sensor battery typically lasts 5 to 7 years.
When the diagnostics for the sensor indicate an empty battery, the whole unit has to be replaced.
From a technical perspective, all valves are constructed in the same way. The difference in colour only serves to customise the look of the valve for a particular wheel or vehicle.
According to current EU regulations, the 315 MHz frequency can not be used in Europe for tire pressure monitoring.
As soon as the pressure in one of the tires drops below the threshold value set in the vehicle, the system will warn the driver. The settings are usually to be found directly on the vehicle, whether inside the fuel tank cover or on the inside part of the driver’s door.
Vehicles with indirect tire pressure monitoring use ABD/ESP systems and determine the tire pressure based on algorithmic data. No direct measurement by TPM sensors is needed for this.
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